fertilizer use by crop in the sudan · 2006. 3. 9. · fertilizer use by crop in the sudan the...

Fertilizer use by cropin the Sudan

The Sudan has almost 17 million ha of cultivated land, and the potentially cultivable area is much larger. It is the largest area of cultivable land in the Arab world. The agricultural and

livestock sectors make an important contribution to the national economy. The climate is hot and rainfall uncertain but the

Blue and White Nile Rivers have enabled the development of large irrigation schemes. However, the rainfed sector, which provides a livelihood for the majority of the population, has been neglected. The productivity of the irrigation schemes

has declined in recent years. Food production has increased because of expansion in the cropped area, while yields have

tended to fall. Outside the irrigation schemes, farmers use little fertilizer. Even in the scheme areas, fertilizers are underused.

Overall, fertilizer use is at a very low level.

TC/D/A0416E/1/2.06/300


FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS

Rome, 2006

Land and Plant Nutrition Management Service

Land and Water Development Division

The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

© FAO 2006

All rights reserved. Reproduction and dissemination of material in this information product for educational or other non-commercial purposes are authorized without any prior written permission from the copyright holders provided the source is fully acknowledged. Reproduction of material in this information product for resale or other commercial purposes is prohibited without written permission of the cop y right holders. Applications for such permission should be addressed to the Chief, Publishing Management Service, Information Division, FAO, Viale delle Terme di Caracalla, 00100 Rome, Italy or by e-mail to [email protected]

Fertilizer use by crop in the SudanFirst version, published by FAO, Rome, 2006

Food and Agriculture Organization of the United NationsViale delle Terme di Caracalla00100 Rome, ItalyTel.: (+39) 06 57051Fax: (+39) 06 57053360E-mail: [email protected] site: www.fao.org

iii

Contents

Preface viiAcknowledgements viiiAbstract ixList of acronyms xi

1. Introduction 1The economy 2

Geography 3

Climate 5

Soils 7Mineral fertility status of soil series on some irrigated schemes in the Sudan 10

Hydrology and water resources 11

Vegetative cover 12

Agro-ecological zones 13

2. Agriculture and farming systems 17The agriculture sector 17

Land tenure 17

Land use 19

Farming systems 19Traditional farming systems 21Semi-mechanized farming systems 22Irrigated farming systems 23The Gezira scheme 27

Agricultural research 28

Technology transfer and extension 29

Agricultural credit 30

Agricultural markets: inputs and outputs 32

iv

3. Fertilizer use in the Sudan 33Consumption of mineral fertilizers 33

Prices of imported fertilizers 33

Recommended rates of fertilizer application 35

Fertilizer research 35Cooperative programmes 35Cotton in irrigated schemes 38Sugar cane 38Sorghum in irrigated schemes 38Wheat 39Groundnut in irrigated schemes 39Sunflower 39Vegetables in irrigated clay soils 40

Economic evaluation of fertilizers 41

4. The 25-year plan 43

References 45

v

List of tables

1. Main geomorphologic units in the Sudan 8

2. Water withdrawal in the Sudan 12

3. Agro-ecological zones in the Sudan 13

4. GDP shares of the agriculture subsectors, 1992–2004 17

5. Government irrigation schemes in the Sudan 20

6. Irrigated areas in the Sudan 23

7. Irrigated crops 26

8. Average yields of irrigated crops 26

9. Potential and actual crop yields in the Rahad irrigation scheme 27

10. Ratio of agricultural credit to GDP in selected countries 31

11. Annual disbursements by the ABS by farming system 31

12. Mean fertilizer nutrient consumption in the irrigated sector, 2000–02 3313. Approximate proportions of fertilizers applied by crop 33

14. Fertilizer import prices, 1995–2005 34

15. Recommendations for N (as ASN) application 34

16. Recommended rates of fertilizer application 35

vi

List of figures

1. Administrative boundaries of the Republic of the Sudan 1

2. Climate zones of the Sudan 6

3. Precipitation index 1921–1994 8

4. Dominant soil map of the Sudan 9

5. Creeping desertification in the Sudan 14

6. Trends in yields of rainfed sorghum in semi-mechanized and traditional areas 21

7. Trends in harvested area of rainfed sorghum in semi- mechanized and traditional areas 22

8. Trends in harvested areas of irrigated wheat and cotton 24

9. Trends in yields of irrigated wheat and cotton 25

vii

Preface

This study, commissioned by the Food and Agriculture Organization of the United Nations (FAO), is one of a series of publications on fertilizer use on crops in different countries.

The aim of the series is to examine the factors underlying present fertilizer usage. These factors include the agro-ecological conditions, the structure of farming, cropping patterns, the availability and use of mineral and organic plant nutrients, the economics of fertilizers, and research and advisory requirements. The reports examine those factors that will or should determine the future development of plant nutrition on a country-by-country basis.

In the past two decades, there has been an increasing focus on the adverse environmental impact of both the underuse and the overuse of plant nutrients. The efficient use of plant nutrients, whether from mineral fertilizers or from other sources, involves the shared responsibility of many segments of society including international organizations, governments, the fertilizer industry, agricultural research and advisory bodies, traders and farmers. The publications in the series are addressed to all these parties.

Fertilizer use is not an end in itself. Rather, it is a means of achieving increased food and fibre production. Increased agricultural production and food availability can, in turn, be seen as an objective for the agriculture sector in the context of contributing to the broader macroeconomic objectives of society. The FAO/IFA 1999 publication Fertilizer strategies provides a review of the options available to policy-makers.

The contents of the series of studies differ considerably from country to country in view of their different structures, histories and food situation. However, in each case the aim is to arrive at a better understanding of crop nutrition in the country concerned.

viii

Acknowledgements

This study is based on the work of Elamien Hassan Elamien, National Programme Coordinator of the Special Programme on Food Security and Director of the Food Security Department, Planning and Agriculture Economics Administration, Ministry of Agriculture and Forests, Khartoum.

The study benefited from the inputs of K. Isherwood (consultant FAO), J. Poulisse and T. van den Bergen (FAO).

The background cover photograph is from the FAO Media base: FAO/F. Bots; the other photographs are from EcoPort: Arnoldo Mondadori Editore S.p.A. (eggplant), H.V. Dutuhurburu and Pankaj Oudhia (mango).

ix

Abstract

The Republic of the Sudan is the largest African country in terms of area. The climate is generally hot, tropical in the south, arid in the north. Rainfed agriculture depends largely on the arrival of rain-bearing southwesterly winds in the main agricultural belt. When these fail, as happened especially in the 1970s and 1980s, drought and famine follow. The country has substantial surface water resources, especially in the Blue Nile River and White Nile River (which meet at Khartoum) and has extensive plains of cultivable soils. The cultivated area is 16.7 million ha but the potentially cultivable area is much larger. The frequency of low-rainfall years is tending to increase and creeping desertification is a problem in the north.

Despite increasing oil exports, the agricultural and livestock sectors continue to make a major contribution to gross domestic product. Cotton is the main export commodity, followed by oilseeds and livestock. The agriculture sector provides a livelihood for three-quarters of the population.

Large-scale, Nile-based irrigation schemes have dominated agricultural development in the Sudan. The largest and best known of these is the Gezira scheme, covering some 870 000 ha. However, a large proportion of the population depends on rainfed agriculture. Food production per capita has kept pace with population growth but is relatively low. The yields of the staple crops, such as sorghum, have not increased, and higher production has been obtained by extending the cultivated area, with a negative impact on the environment.

Almost 1.9 million ha (about 11 percent of the cultivated area) are equipped for irrigation, 96 percent of which is fed from surface waters. Wheat, cotton and sorghum are the most important crops in irrigated areas, followed by groundnuts. In the 1990s, irrigation schemes were privatized without adequate preparation. Cotton production is now half that of the early 1990s. Yields of all crops are well below their potential.

x

The Agricultural Bank of Sudan and commercial banks provide agricultural credit but farmers in rainfed areas have difficulty in obtaining formal credit. The Ministry of Finance subsidizes the irrigation sector.

Despite a moderate to poor mineral fertility of most soils, fertilizer consumption is very low, averaging about 4 kg of total nutrients per cultivated hectare. Farmers in the rainfed sector apply very little fertilizer. The price of fertilizers has risen steadily in the past decade.

Until 1992, the Government controlled the marketing of agricultural inputs and outputs. However, as part of the economic reforms in the 1990s, it removed most of the controls on private traders. However, parastatal organizations still dominate the fertilizer supply system.

The Sudan has a long-established agricultural research structure. In recent years, agricultural research has lacked adequate funding but it is still substantial. There have been a number of cooperative programmes concerning the use of fertilizers, notably the FAO Fertilizer Programme, a fertilizer programme funded by the European Economic Community, Sasakawa Global 2000, and assistance from various bodies, e.g. the German development agency and the Arab Authority for Agricultural Investment and Development. Recent programmes concerning the use of non-traditional fertilizers have yielded promising results in terms of response and the economics of application.

In the context of a 25-year plan, the Government is taking a number of measures to promote the development of agriculture and to improve rural services.

xi

List of acronyms

AAAID Arab Authority for Agricultural Investment and Development

ABS Agriculture Bank of Sudan

AEZ Agro-ecological zone

ARC Agricultural Research Corporation

ARRC Animal Resources Research Corporation

B Boron

CEC Cation exchange capacity

Cu Copper

EEC European Economic Community

Fe Iron

GDP Gross domestic product

GTZ Gesellschaft für Technische Zusammenarbeit (German development agency)

IAEA International Atomic Energy Agency

ICARDA International Center for Agricultural Research in the Dry Areas

ILO International Labour Organization

IMF International Monetary Fund

LDC Least-developed country

Mn Manganese

MOAF Ministry of Agriculture and Forestry

MOFNE Ministry of Finance and National Economy

NVRP Nile Valley Regional Programme

OPEC Organization of the Petroleum Exporting Countries

S Sulphur

xii

* Phosphate and potash may be expressed as their elemental forms P and K or as their oxide forms P2O5 and K2O. Nitrogen is expressed as N. In this study, phosphate and potash are expressed in their oxide forms.

SASC Sudanese Arab Seed Company

SCC Sudan Cotton Corporation

TTE Technology Transfer and Extension Administration

UNDP United Nations Development Organization

WUA Water users association

Zn Zinc

Fertilizers

AS Ammonium sulphate

ASN Ammonium sulphate nitrate

NPK Complex fertilizer containing N, P and K

TSP Triple superphosphate

N: Nitrogen

P2O5 or P: Phosphate*

K2O or K: Potash*

Currency equivalents (August 2005): US$1 = SD240

Weights and measures

1 ha = 2.4 feddans

1 feddan = 0.42 ha

1 kantar = 143 kg

1

Chapter 1

Introduction

The Republic of the Sudan is located in the northeast corner of Africa (15.00 °N, 30.00 °E). The country comprises 26 states (Figure 1) and has three levels of government: federal, state and local. Khartoum is the capital. The Sudan is the largest African country in terms of area (2.5 million km2), accounting for 8.3 percent of the total area of Africa. The topography is that of a gently sloping plain, generally flat and featureless with the

RedSea

EqyptLibyanArab

Jamahiriya

Chad

CentralAfrican

Republic

Dem. Rep.of the Congo

Eritrea

Ethiopia

KenyaUganda

NORTHERN

NORTHERNDARFUR

NORTHERNKURDUFAN

WESTERNKURDUFAN

SOUTHERNKURDUFAN

WHITENILE

SOUTHERNDARFUR

ALWAHDANORTHERN

BAHR ALGAZAL

WESTERNDARFUR

WESTERNBAHR AL

GAZAL

WARAB

AL BUHAURAT

WESTERNEQUATORIA

BAHR ALJABAL

EASTERNEQUATORIA

JUNQOLEY

SENNAR

BLUENILE

SENNAR

AJJAZIRA

QADARIF

KASALAKHARTOUM

REDSEA

RIVERNILE

Geographic Projection

FIGURE 1Administrative boundaries of the Sudan

Fertilizer use by crop in the Sudan 2

exception of Jabal Marrah, the Red Sea Hills, the Nuba Mountains and the Imatong Hills.

According to FAOSTAT, the area of “arable land and permanent crops” in the Sudan is 16.65 million ha, of which 0.42 million ha are under permanent crops. However, estimates of the total area of potentially cultivatable land range from 36 million to 84 million ha (see Chapter 2). Some 117 million ha of permanent pasture support a livestock population of almost 120 million head.

The estimated population (2005) of the Sudan is 35.3 million, compared with 23 million in 1993, with an average growth rate of 2.6 percent/year. More than two-thirds of the population in the Sudan work in agriculture and animal husbandry. The absolute population density is 7 persons/km2. Vast areas, such as the western desert, are almost unpopulated. The population density is higher in areas with water and fertile soils, such as areas adjacent to the Nile River and its tributaries. For example, the Al-Gezira area (between the White Nile River and the Blue Nile River) has a population density of 20 persons/km2.

In spite of the large area of agricultural land in the Sudan, the continuing rapid growth of the population results in pressure on land resources in certain favoured areas of the country.

THE ECONOMYNegative growth rates and internal and external imbalances characterized the national economy in the 1970s and 1980s. The Government launched a liberalization programme in 1992. This reform programme succeeded in reversing the decline in economic growth. However, the accompanying monetary expansion resulted in triple-digit inflation by 1996. A macroeconomic reform package prepared by the International Monetary Fund (IMF) and launched in mid-1996 led to the restoration of macrostability and a reduction in inflation. In 1999, the Sudan began to export crude oil. Together with the monetary policy, this stabilized the exchange rate and led to economic growth. However, despite the oil exports, agricultural production remains the country’s most important sector. As regards average per-capita food supplies, statistics place the Sudan just above the least-developed countries (LDCs).

Chapter 1 – Introduction 3

GEOGRAPHYThe region known as Northern Sudan lies between the Egyptian border and Khartoum. It consists of two distinct areas: the desert and the Nile Valley. The Nubian Desert lies to the east of the Nile River, and the Libyan Desert lies to the west of the river. Both deserts are stony with sand dunes. The Nile River flows through the desert and provides an alluvial strip of habitable land some 2 km wide, whose productivity depends on the annual flood.

Western Sudan is a generic term describing the regions known as Darfur and Kordofan, amounting to 850 000 km2. Its dominant feature is the absence of perennial streams, and people and animals must remain within reach of permanent wells. Consequently, the population is sparse and unevenly distributed. Western Darfur is an undulating plain dominated by the volcanic massif of Jabal Marrah with an elevation of 900 m above the Sudanese Plain. Drainage from Jabal Marrah supports a settled population. Unlike western Darfur, northern and eastern Darfur are semi-deserts with little water either from the intermittent streams (known as wadis) or from wells that normally run dry in the winter months. Northwest of Darfur and continuing into Chad lies the region called the jizzu, where sporadic winter rains from the Mediterranean Sea frequently provide excellent grazing into January or even February. The southern region of Western Sudan is known as the qoz, a land of sand dunes. In the rainy season, there is extensive grassland. The sources of water are more reliable than in the north, with boreholes and hafir (constructed ponds). A unique feature of Western Sudan is the Nuba mountain range of southeast Kordofan, a conglomerate of isolated dome-shaped, sugarloaf hills that ascend steeply and abruptly from the great Sudanese Plain. Many hills are isolated and extend for only a few square kilometres, but there are several large hill masses with internal valleys that cut into the mountains high above the plain.

The Central Clay Plains of the Sudan stretch eastward from the Nuba Mountains to the Ethiopian frontier, broken only by the Ingessana Hills, from Khartoum in the north to the far reaches of southern Sudan. Between the Dindar and the Rahad Rivers, a low ridge slopes down from the Ethiopian highlands with occasional hills. The Central Clay Plains


are productive and provide the main support of the national economy. Settlements cluster around available water supplies. The Gezira is located on the Central Clay Plains, between the Blue Nile and the White Nile Rivers. The Gezira produces cotton for export.

Eastern Sudan is located northeast of the Central Clay Plains. The region is divided between desert and semi-desert and includes Al Butanah, the Qash Delta, the Red Sea Hills and the Coastal Plain. Al Butanah is an undulating territory located between Khartoum and Kassala. It provides good grazing for cattle, sheep and goats. East of Al Butanah is a peculiar geological formation known as the Qash Delta. Originally a depression, it has filled with sand and silt brought down by the flash floods of the Qash River, creating a delta above the surrounding plain. Extending 100 km north of Kassala, the whole area watered by the Qash River is rich grassland and arable land that is productive long after the water of the river has reached its delta. Trees and bushes provide grazing for camels from the north, and the rich moist soil provides an abundance of food crops and cotton.

The Red Sea Hills are located north of the Qash River. Dry, bleak and cooler than the surrounding land, particularly in summer, they stretch northward into Egypt, a mass of hills where life is hard and unpredictable for the inhabitants. Below the hills is the Coastal Plain of the Red Sea, varying in width from about 56 km in the south near Tawkar to about 24 km near the Egyptian border. The coastal plain is rocky, dry and barren.

The Southern Clay Plains, which can be regarded as an extension of the Northern Clay Plains, extend from northern Sudan to the mountains on the Sudan–Uganda border. In the west, they extend from the border with the Central African Republic eastward to the Ethiopian Highlands. Several features divide this great Nilotic plain. First, the White Nile River bisects the plain and provides large permanent areas of water, such as Lakes Fajarial, No and Shambe. Second, As Sudd, the world’s largest swamp, constitutes an expanse of lakes, lagoons and aquatic plants whose area at the time of the high floodwaters exceeds 30 000 km2. As Sudd has a high rate of evaporation and consumes on average more than half the waters that come down the White Nile River from the equatorial lakes. These waters also create a floodplain known as the toic that provides grazing


when the floodwaters are lost in the permanent swamp and sluggish river, the Bahr al Jabal, as the White Nile River is called in the Sudan.

The land rising to the south and west of the Southern Clay Plains is referred to as the Ironstone Plateau (Jabal Hadid), a name derived from its lateritic soils and increasing elevation. The plateau rises from the west bank of the Nile River, sloping gradually upward to the Congo–Nile watershed. The land is well watered, providing rich arable land, but the streams and rivers that descend from the watershed divide and erode the land before flowing onto the Nilotic plain into As Sudd. Along the streams of the watershed are the gallery forests, the beginnings of the tropical rain forests that extend far into the Democratic Republic of the Congo. To the east of the Jabal Hadid and the Bahr al Jabal are the foothills of the mountain ranges along the Sudan–Uganda border – the Imatong, Didinga and Dongotona – which rise to more than 3 000 m, contrasting with the great plains in the north.

CLIMATEThe Sudan lies within the African tropical region belt. Its climate ranges from equatorial in the south to savannah in the centre and continental in the north, and from arid in the north to tropical, with wet and dry seasons in the far southwest. Temperatures do not vary greatly with the season at any location; the most significant climate variables are rainfall and the length of the dry season. Variations in the latter depend on which of two airflows predominate: dry northeasterly winds from the Arabian Peninsula, or moist southwesterly winds from the Congo River basin. The average annual rainfall varies greatly between the south (1 200–1 500 mm) and the north (less than 75 mm).

From January to March, the country is under the influence of the dry northeasterly winds. There is practically no rainfall in the country during this period except in a small area in the northwest where the winds from the Mediterranean Sea bring occasional light rains.

By early April, the moist southwesterly winds reach southern Sudan, bringing heavy rains and thunderstorms. By July, the moist air reaches Khartoum. In August, it extends to its usual northern limits around Abu Hamad (although in some years, the humid air may even reach


the Egyptian border). The flow becomes weaker as it spreads north. In September, the dry northeasterlies begin to strengthen and to push south; by the end of December, they cover the entire country. In general, the rainy season extends from April to November.

In some years, the arrival of the southwesterly winds and their rain in central Sudan can be delayed, or they may not come at all. When that happens, drought and famine follow. In the 1970s and 1980s, the southwesterly winds failed frequently, with disastrous results for the Sudanese people and the economy.

RedSea

EqyptLibyanArab

Jamahiriya

Chad

CentralAfrican

Republic

Dem. Rep.of the Congo

Eritrea

Ethiopia

KenyaUganda

_̂KhartoumN

ile Riv

er

BlueN

ileR

iver

Wh it

eN

ile

Riv

er

B a hrel

Ar ab River

Ba

hre

l JebelR

iver

Geographic Projection

Legend

_̂

Hyperarid

Arid

Dry Semi-Arid

Dry Subhumid

Moist Subhumid

Humid

Rivers

Capital

FIGURE 2Climate zones of the Sudan


Temperatures are highest at the end of the dry season. However, the far south, with only a short dry season, has uniformly high temperatures throughout the year. In Khartoum, the warmest months are May and June, when the average temperature is 41 °C and can reach 48 °C. Northern Sudan, with its short rainy season, has hot daytime temperatures all year round, except for winter months in the northwest where there is precipitation from the Mediterranean Sea in January and February. Conditions in highland areas are generally cooler, and the hot daytime temperatures during the dry season throughout central and northern Sudan fall rapidly after sunset. In general, May is considered to be the hottest month in most areas of Sudan whereas December and January are the coldest. Low temperatures in Khartoum average 15 °C in January and have dropped as low as 6 °C after the passing of a cool front.

The haboob, a violent duststorm, can occur in central Sudan when the moist southwesterly flow first arrives (May–July).

Most of the Sudan is exposed to a northeasterly cold dry front that carries some rain that falls on the Red Sea coast. The rain may fall also in the inland parts of the country that remain dry in winter. In summer the front moves northward accompanied by rain clouds from the south. Therefore, the rainfall occurs in autumn and the length of the rainy period is linked with the length of the continental front in the north of the country.

Studies indicate that areas receiving lower average rainfall are tending to increase. Figure 3 shows the precipitation index for 1921–1994.

SOILSThe soils of the Sudan are broadly divided into six main categories with respect to their location and manner of formation:ÿdesert,ÿsemi-desert,ÿsand,ÿalkaline catena,ÿalluvial,ÿironstone plateau.There are many local variations within these soil categories. The main

groups are: alluvial clay deposits in the central and eastern parts of the


country; stabilized sand dunes in the west and north; and red ironstone soils in the south.

The soil types in the Sudan include: Alfisols, Aridisols, Entisols, Inceptisols, Ultisols and Vertisols (Figure 4).

Table 1 shows the main soils in the Sudan according to the American Soil Classi-fication System.

On a geographical basis, the country’s soils consist of three categories: the Arenosols and Regosols of the north and west central areas; the Vertisols of the

-2

-1.5

-1

-0.5

0

0.5

1

1921 1931 1941 1951 1961 1971 1981 1991

May– Sep. standardized departures from 1921–1994 mean rainfall for stations 20 W and 8-18 Noo

FIGURE 3Precipitation index 1921–1994

Note: The index is based on the probability of precipitation; > 2 indicates very wet, and < -2 indicates extremely dry.Source: Climate Analysis Center.

TABLE 1Main geomorphologic units in the Sudan

%

Desert 26.7

Semi-desert 15.5

Semi-desert Red Sea area 2.7

Qoz 9.6

Central Clay Plains 8.5

Alluvial plains and channels 4.2

Eroded Darfur plains 3.7

Southern Clay Plains 9.9

Marshes 1.6

New Jahar areas 9.5

Plateaus and east and southeast plains 4.2Source: Sudanese Technical Committee, 2004.


central region; and the Ferralsols of the south. Less extensive and widely separated, but of major economic importance, is a fourth group consisting of Fluvisols found along the lower reaches of the White Nile and Blue Nile Rivers, along the main Nile River to Lake Nubia, in the delta of the Qash River in the Kassala area, and in the Baraka Delta in the area of Tawkar near the Red Sea in Ash Sharqi State.

For agriculture, the most important soils are the Vertisols in central Sudan that extend from west of Kassala through Al Awsat and southern Kordofan. They are known as cracking soils because of the practice of allowing them to dry out and crack during the dry months in order to

Bo – Chromic CambisolsBd – Dystric CambisolsBe – Eutric CambisolsBh – Humic CambisolsFo – Orthic FerralsolsFp – Plinthic FerrasolsGd – Dystric GleysolsGe – Eutric FleysolsGh – Humic GleysolsGm – Mollic GleysolsI – LithosolsJc – Calcaric FluvisolsJe – Eutric fluvisolsLc – Chromic LuvisolsLf – Ferric LuvisolsLg – Gleyic LuvisolsNe – Eutric NitosolsQc – Cambic ArenosolsQI – Luvic ArenosolsRd – Dystric RegosolsRe – Eutric RegosolsVc – Chromic VertisolsVp – Pellic VertisolsX – XerosolsXh – Haplic XerosolsXI – Luvic XerosolsY – YermosolsYh – Haplic YermasolsWater bodies (WR)Rock debris (RK)Dunes/Shifting sand (DS)

18

12

6

FIGURE 4Dominant soil map of the Sudan

Sourec: DSMW-FAO-UNESCOOriginal scale: 1:5 million


restore their permeability. They are used in the areas of Al Jazirah and Khashm al Qirbah for irrigated cultivation. East of the Blue Nile River, large areas are used for mechanized rainfed farming. West of the White Nile River, traditional farmers use these soils to grow sorghum, sesame, groundnuts and, in the area around the Nuba Mountains, cotton. The southern part of the clay soil zone lies in the broad floodplain of the upper reaches of the White Nile River and its tributaries, covering most of Aali an Nil and upper Bahr al Ghazal States. Subject to heavy rainfall during the rainy season, the floodplain is inundated for four to six months. As Sudd is permanently flooded and adjacent areas are flooded for one or two months. In general, this area is poorly suited to crop production, but farmers use the grass it supports in dry periods for grazing.

The Arenosols and Regosols in the semi-arid areas south of the desert in northern Kordofan and northern Darfur States support vegetation used for grazing. In the southern part of these states and the western part of southern Darfur are the so-called qoz sands. Livestock raising is the major activity in this area but a significant amount of crop cultivation, mainly of millet, also occurs. Farmers grow groundnuts and sesame as cash crops. Gum arabic is produced mainly on the qoz sands by tapping Acacia senegal (known locally as hashab). Farmers occasionally plant hashab trees when land is returned to fallow.

The Ferralsols of the south cover most of western Al Istiwai and Bahr al Ghazal States. They underlie the extensive moist woodlands found in these states. Crop production is scattered and the soils, where cultivated, lose fertility relatively quickly. Even the richer soils are usually returned to bush fallow within five years.

Mineral fertility status of soil series on some irrigated schemes in the SudanThe soil series of the Gezira, Rahad, New Halfa, Es Suki, Guneid, Sennar and Kenana irrigated schemes have different parent materials. They have moderate to poor mineral fertility. The main causes are the low content of nitrogen (N), available phosphorus (P) and sometimes potassium (K). There have also been reports of deficiencies of sulphur (S), iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn). Nevertheless, the relatively high cation exchange capacity (CEC) and percentage base saturation


values of these soils indicate their greater ability to retain added nutrients and a reduced tendency to lose them through leaching.

HYDROLOGY AND WATER RESOURCESExcept for a small area in northeast Sudan, the entire country is drained by the Nile River and its two main tributaries, the Blue Nile River (Al Bahr al Azraq) and the White Nile River (Al Bahr al Abyad). The longest river in the world, the Nile River flows for 6 737 km from its farthest headwaters in central Africa to the Mediterranean Sea. The importance of the Nile River has been recognized since ancient times; for centuries the river has been a lifeline for Sudan.

The Blue Nile River flows out of the Ethiopian Highlands to meet the White Nile River at Khartoum. The Blue Nile River is the smaller of the two; its flow usually accounts for only one-sixth of the total. However, in August, the rains in the Ethiopian Highlands swell the Blue Nile River until it accounts for 90 percent of the total flow of the Nile River. Several dams regulate the river flow.

The White Nile River flows north from central Africa, draining Lake Victoria and the highland regions of Uganda, Rwanda, and Burundi. At Bor, the great swamp of the Nile River, As Sudd, begins. Much water is lost through evaporation. In order to provide for water transportation through this region and to speed the river flow so that less water would evaporate, the Sudan began building the Jonglei Canal from Bor to a point just upstream from Malakal. However, security problems caused by the civil war in the south of the country led to construction work being suspended in 1984.

South of Khartoum, the Jabal al Auliya Dam stores the water of the White Nile River and then releases it in the autumn when the flow from the Blue Nile River slackens. Much water from the reservoir is diverted for irrigation projects in central Sudan.

The White Nile River has several substantial tributaries that drain southern Sudan. For example, in the southwest, the Bahr al Ghazal drains a basin larger in area than France.

Above Khartoum, the Nile River flows through the desert in a large S-shaped pattern to empty into Lake Nasser behind the Aswan High Dam in Egypt. The Atbara River, flowing out of Ethiopia, is the only


tributary north of Khartoum, and its waters reach the Nile River for only the six months between July and December.

The estimated total net flow from the secondary basins is more than 150 million m3 (equivalent to

14 percent of the calculated general flow). The general constant discharge of the White Nile River is 16 000 million m3 and that of the Blue Nile River is 34 000 million m3. The estimated seasonal discharge of the Atbara River is 3 000 million m3.

The Nubian stone sand represents 25 percent of the available formations in Kordofan, Darfur, Khartoum and the northern states and is considered the best source of good quality groundwater in Sudan. The water of these sediments supports the drinking-water and irrigation water network in Kassala and Darfur. The groundwater level is near the land surface but it experiences seasonal and annual changes depending on the rates of pumping and recharge. The formation of Om Rawaba accounts for about 20 percent of the area of the Sudan.

The estimated total natural renewable water resources of the Sudan are 149 km3/year, of which 30 km3/year are produced internally. In a dry year, the internal water resources fall to about 22 km3/year. Of the internal water resources, 28 km3/year are surface waters and 7 km3/year are groundwater, while the overlap between surface water and groundwater is an estimated 5 km3/year. By virtue of to the Nile Waters Agreement with Egypt, the total actual renewable water resources of the country are 64.5 km3/year.

Table 2 shows the breakdown of water withdrawals in the Sudan.Water consumption amounts to 1 187 m3/inhabitant/year, representing

58 percent of total actual renewable water resources.

VEGETATIVE COVEREstimates of the area of “forest” vary from less than 60 million ha (Forestry Administration) to about 91 million ha (Ministry of Agriculture and Natural Resources and FAO) depending on how it is defined. In fact,

TABLE 2Water withdrawal in the SudanWater use km3 %

Irrigation and livestock 36.10 96.7

Domestic 0.99 2.6

Industry 0.26 0.7

Total 37.35 100Source: FAO AQUASTAT.


dense stands of trees cover only 20–24 million ha of the total forestland. Forests and woodlands are typically tall shrubs in areas of low rainfall in the north and tropical high forests in the south. “Forests” in the Sudan account for 70 percent of household energy, wood and animal feed.

Nomadic herders who follow traditional methods graze the rangelands in Sudan. The animal density is 0.99 head/ha. The area of natural rangelands amounts to about 56.4 million ha (25 percent of the total area). This pastureland meets 83 percent of the feed needs of livestock.

AGRO-ECOLOGICAL ZONESThe agro-ecological zones (AEZs) in the Sudan vary from north to south (Table 3). The zones are determined by agroclimatic factors (the amount of rainwater and its distribution) and the soils. Temperature, moisture and vegetative cover are secondary factors. It is not possible to reverse or change the course of the ecological degradation in most of the areas.

The Sudan is divided into different agro-ecological areas, each characterized by a different vegetative cover resulting from the environmental factors (climate, land and topography). In addition to the role of people and animals, rainfall plays an important role in the composition of the plant groups from north to south.

The desert area is the largest. It extends across the country from east to west and from the northern borders to latitude 15 °N. The average rainfall ranges from 0 to 75 mm and the rainy period lasts for two months. The area is not populated and not suited to any form of irrigated agriculture.

TABLE 3Agro-ecological zones in the SudanAgro-ecological zone Average

rainfall (mm)

Percentage of total

area

Desertification

Desert 0–75 26.9 Completely desertified

Semi-desert 75–300 18.4 Greatly affected by desertification

Low-rainfall savannah (sandy) 300–400 9.7 Affected to a medium extent

Low-rainfall savannah (clayey) 400–900 17.4 Slightly affected

High-rainfall savannah 800–1 300 10.6 Very slightly affected

Flood area 800– 1 000 11.6 Not affected

Mountainous Different 5.4 Not affectedSource: Sudanese Technical Committee, 2004.


The semi-desert area extends between 13 and 15 °N in the western direction from the Nile River, where the sandy soil is dominant, and 16 and 15 °N in the eastern direction of the Nile River. There is no irrigated agriculture, with the exception of some surface irrigation or irrigation with pumps or flood irrigation in the area located between the two Blue Nile and White Nile Rivers and to the east. Nomadic and semi-nomadic people use this area for grazing camels and sheep.

In the last three decades, most of the northern borders of this area have experienced degradation and become desert. The desert has also encroached on the low-rainfall savannah area on the southern borders (Figure 5). The average rainfall ranges between 75 and 250 mm and the

Chad

Egypt Red Sea

Blue Nile

Wh

ite

Nile

CentralAfricanRepublic

Democratic Republic of the Congo Kenya

Ethiopia

LibyanArab

Jamahiriya

Abouhamad

1958

1975

1985

Salina

Khartoum

Uganda

= Vegetation

FIGURE 5Creeping desertification in the Sudan

Source: Sudanese Technical Committee, 2004.


rainy period lasts for two to three months. Limited agriculture is practised in these areas on the edges of the wadis.

Irrigated agriculture starts in the savannah area. The area located west of the Nile River is known as the low-rainfall and sandy soil savannah area, while the eastern area is known as the clayey soil savannah area. Both areas have distinctive vegetative cover and land-use patterns.

The average rainfall in the low-rainfall savannah area ranges between 250 and 500 mm in a period of three to four months. The area is devoted to traditional rainfed farming, which includes millet, sorghum, groundnut, sesame, watermelon and gum arabic. In the rainy season, it provides grazing for cattle, sheep, camels and goats. Farmers grow early-maturing sorghum on the eastern part of the area, and sheep and camels graze the area during the rainy season. The farming systems lack even simple forms of technology, but the area contributes significantly to national production and exports.

The high-rainfall savannah area is the largest ecological area and the area with the greatest agricultural potential. It consists of: (i) the Central Clay Plains; and (ii) the Southern Clay Plains.

The area of the Central Clay Plains is considered to be the most productive. It is flat, with a deep, black soil covered by large trees and long, dense grass. This area is suitable for mechanized rainfed agriculture. It produces sorghum, millet, cotton and sesame. Research has demonstrated the possibility of growing other cash crops such as sunflower and soybean on a large scale. This area, except for the banks of the Nile River, is less densely populated compared with the western high-rainfall savannah area. Cattle and sheep graze the area in summer and it has good potential for livestock production. The rainfall in this area averages 500–800 mm/year in a rainy period of four to five months.

The Southern Clay Plains have a medium population density. They are home to Nile tribes whose livelihood depends mostly on livestock. The soils of the wadis consist of relatively recent Nile clayey deposits. Almost no economic or social development has taken place in this isolated part of the country, which is dominated by subsistence agriculture. Millet, sorghum and rice are grown, and these crops, together with dairy products, represent the main staples of the local population. The number of livestock has increased because only a limited number of the animals


is slaughtered, and overgrazing has increased for this reason. The average rainfall ranges between 800 and 1 000 mm and the rainy period lasts for five to seven months. Floodplains of the White Nile River are located in the centre of the area.

The tropical rainfall zone lies in the extreme south of the country. The soil is red. The rainfall ranges between 1 000 and 1 500 mm and the rainy period lasts for seven to eight months. A subsistence economy is dominant, except in areas surrounding the cities. Millet, sorghum, banana, root crops and legumes are grown in this area. The population lives mostly from hunting and fishing. The development of the agriculture sector has been very slow despite the possibility of growing cotton, tea, tobacco, coffee and pineapple on a commercial or semi-commercial basis. The area is infested with tsetse fly and contains only a limited number of livestock.

17

Chapter 2

Agriculture and farming systems

THE AGRICULTURE SECTORThe Sudanese economy is predominantly agricultural (including crop and livestock production, forestry, wildlife and fisheries) with an overall average contribution of about 45 percent to the country’s gross domestic product (GDP) (Table 4).

In 2003, the agricultural share of the GDP increased by 5.2 percent compared with the previous year, in 2004 by 4.5 percent, marked by a recovery in the rainfed mechanized sector in these two years. The agriculture sector provides for some three-quarters of the population, accounts for about two-thirds of the employment and supplies about 60 percent of the raw materials needed by the manufacturing sector. Agriculture provides more than 90 percent of the non-oil export earnings. Cotton is the main export commodity, followed by oilseeds and livestock. The Sudan is the world’s largest producer of gum arabic, whose exports range between 20 000 and 40 000 tonnes and earn some US$50–80 million.

LAND TENUREThe Permanent Constitution of 1973 established the rights to own, bequeath and inherit property. However, these rights were suspended in 1985.

The Sudan has long had a system of land registration through which an individual, an enterprise or the government could establish title to a

Subsector Average 1992–94

Average 2002–04

(%)

Agriculture 40.3 45.4

Irrigated crops 10.9 12.3

Rainfed semi-mechanized crops

3.2 2.1

Rainfed traditional crops 4.9 7.5

Forestry & others 2.9 3.0

Livestock 18.4 20.5

TABLE 4GDP shares of the agriculture subsectors, 1992–2004

Source: Bank of Sudan, annual reports.


piece of land. Such registration was used extensively in northern Sudan, especially in Al Khartoum, Al Awsat and Ash Shamali provinces. Before 1970, all other land (unregistered) belonged to the State, which held ownership in trust for the people who had customary rights to it. In 1970, the Unregistered Land Act declared that all wasteland, forest and unregistered lands were government land. Before the passage of this act, the Government had avoided interfering with individual customary rights to unregistered land, and in the late 1980s it again adhered to this policy.

The Government owned most of the land used by the modern agriculture sector and leased it to tenants (e.g. in the Gezira scheme) or to private entrepreneurs, such as most operators of large-scale mechanized rainfed farming. However, in the late 1980s, the large area of land used for pasture and for subsistence cultivation was communally owned under customary land laws that followed a broadly similar pattern. In agricultural communities, the right to cultivate an area of unused land became vested in the individual who cleared it for use. The rights to such land could be passed on to heirs but normally the land could not be sold or otherwise disposed of. The right also applied to land left fallow although there were communities in Bahr al Ghazal, Aali an Nil and Al Istiwai where another individual could claim such land by clearing it.

Among the northern communities practising transhumance, the rights to cultivated land were much the same, but the dominant position of livestock in community activities had introduced certain other communal rights, e.g. common rights to grazing land, and right-of-way to water and grazing land.

In the western savannahs, private ownership of stands of hashab trees could be registered, an exception to the usual government ownership of the forests. However, dead wood for domestic fuel and the underlying grass were common property. Water, a matter of greatest importance to stock raisers, was open to all if free standing, but wells that had been dug and the associated drinking troughs were private property and were retained by the person who dug them season after season.

In northern Sudan, especially in the western savannah where increasing population and animal numbers have put pressure on the land, violations of customary laws and conflicts between ethnic groups over land rights

Chapter 2 – Agriculture and farming systems 19

have been increasing. Local government agencies have attempted to resolve these problems, but only on a case-by-case basis.

LAND USEAs at 1991, only partial surveys of the land resources of the Sudan had been made, and estimates of the areas included in different land-use categories varied considerably. Figures for potentially arable land ranged from an estimate of 35.9 million ha made in the mid-1960s to one of 84 million ha published by the Ministry of Agriculture and Natural Resources in 1974. Estimates of the amount of land actually under cultivation ranged from 7.5 million ha, including about 10–11 percent in fallow, to 12.6 million ha.

Substantial variations also exist in land classified as actually used or potentially usable for livestock grazing. The Ministry of Agriculture and Natural Resources and FAO have classified about 24 million ha as pastureland. The 1965 estimate of land use classified 101.4 million ha as grazing land. In 1975, an interagency mission of the International Labour Organization (ILO) and the United Nations Development Programme (UNDP) to the Sudan estimated the total potential grazing land at between 120 million and 150 million ha.

However, in the late 1980s, the consensus was that the Sudan still had a substantial amount of land suitable for future cropping. The 1975 ILO–UNDP mission believed that two-thirds of the potential area for livestock grazing was already in use.

In addition to land suitable for cultivation and livestock grazing, the Sudan also has about 76–86 million ha of desert. In addition, swamps and inland waters cover an area of about 2.9 million ha, and urban settlements and other features created by human activity cover about 0.3 million ha.

FARMING SYSTEMSFarming systems in the Sudan are functions of the AEZs and socio-economic conditions. There are three main farming systems for crop production: irrigated, semi-mechanized and traditional. Other farming systems are: livestock, fishery and forestry.

Historically, large-scale Nile-based irrigation schemes have been a pillar of the Sudan’s strategy for agricultural development. There are 1.7–2.1 million ha of irrigated land within the Nile River basin in


Northern, Khartoum, Gezira, Sennar, Blue Nile and White Nile States. The Government owns and manages the Gezira scheme (0.9 million ha) and the Rahad, Suki and New Halfa schemes (0.4 million ha) (Table 5).

A rainfed, commercial semi-mechanized farming system has been developed on generally alkaline clay soils and loams. It extends to about 5.9 million ha in the states of El Gadaref, Blue Nile, Upper Nile, White Nile, Sennar and Southern Kordofan.

The rainfed, traditional farming systems are the main

subsistence systems prevalent almost everywhere in the Sudan, accounting for an area of 9.2 million ha, mostly in Kordofan, Darfur, White Nile and Blue Nile States.

Cattle, goats, sheep and camels (about 130 million head in total) constitute the bulk of the livestock sector. Livestock in the Sudan may be classified as extensive, semi-intensive and intensive systems depending on the types of animals reared and whether for subsistence, traction or market. The extensive system is entirely dependent on natural pasture and is physically, socially and economically fragile. The system concerns the vast majority of herders in the drylands of the country. Unlike the extensive system, the intensive system requires considerable skills, efficient management and a great deal of animal feed. It is common in the irrigated and urban areas. The semi-intensive system lies between these two systems. Seventy percent of the rural population are agropastoralists.

Despite the fact that the ratio of cultivable land per person is high (about 3 ha/person), the Sudan faces food deficit problems and a lack of other basic needs, especially in rural areas.

TABLE 5Government irrigation schemes in the Sudan

Scheme Equipped irrigation area

(‘000 ha)

Gezira and Managil 871

White Nile pump schemes 192

New Halfa 152

Rahad 122

Blue Nile pump schemes 113

Gash Delta (spate irrigation) 101

Northern pump scheme 42

Suki 35

Tokar Delta (spate irrigation) 31

Guneid Sugar 16

Assalaya Sugar 14

Sennar Sugar 13

Khashm El Girba 18

Other areas 143

Total 1 863Source: FAO AQUASTAT.


Traditional farming systemsThe contribution of crops and livestock to GDP fluctuates considerably. The available evidence suggests that GDP growth in agriculture has stemmed mainly from increases in the cultivated area in rainfed farming regions. This increase has come at a cost to the environment, while yields have declined on a long-term basis (Figure 6). In essence, there has been an unsustainable increase in the area harvested (Figure 7) and a decline in productivity for more than two decades.

Comparing the average productivity (yields) of the main cultivated crops (sorghum, millet, sesame and groundnut) in the traditional rainfed sector for the period 1992/93–2002/03 with the period 1970/71–1980/81 and assuming constant prices, farmers would have had to increase their cultivated area by 75 percent in order to maintain the same level of 1970/71 income.

If the trend of expansion in the area of sorghum continues, it is likely to have serious consequences on the sustainability of crop yields in the traditional farming systems and for farm incomes. It is particularly alarming for the poor because even in years of high output from crops and

ton

ne

s/h

a

Traditional Semi-mechanized

1970/71

1973/74

1976/77

1979/80

1982/83

1985/86

1988/89

1991/92

1994/95

1997/98

2000/01

1.6

1.4

1.2

1

0.8

0.6

0.4

0.2

0

FIGURE 6Trends in yields of rainfed sorghum in semi-mechanized and traditional areas


livestock the traditional farming areas produce a proportion of rural GDP that is lower than the proportion of the rural population that lives there.

Families living in the traditional farming areas find employment as casual labour for short periods outside the region. However, these opportunities have declined in the last 10–15 years. The traditional rainfed sector obtained only 1–5 percent of all formal agricultural credit in 2001 and received few other support services, such as research and extension. Public investment in the basic infrastructure for rural and agricultural development is also negligible. It is not surprising that yields are low and declining or stagnating for most crops. The pastoralists and small farmers in the traditional sector are those most vulnerable to poverty. Therefore, improved productivity in the traditional farming areas is of crucial importance if the large number of people who are to some extent dependent on this farming system are to improve their incomes.

Semi-mechanized farming systemsThe GDP from semi-mechanized farming has been declining, although a partial recovery occurred in 2003 and 2004. In the 1980s,

Traditional Semi-mechanized

1970/71

1972/73

1974/75

1976/77

1978/79

1980/81

1982/83

1984/85

1986/87

1988/89

1990/91

1992/93

1994/95

1996/97

1998/99

2000/01

4 500

4 000

3 500

3 000

2 500

2 000

1 500

1 000

500

0

'000 h

aFIGURE 7

Trends in harvested area of rainfed sorghum in semi-mechanized and traditional areas


1–2 million labourers moved to the semi-mechanized farming areas where they could find three to four months work at weeding and harvest time. This number has fallen by at least half as a result of the decline in the semi-mechanized farming areas, together with the substantial reduction in the irrigated cotton areas. This has serious negative implications for many families in the traditional rainfed farming areas that depended on the employment in the semi-mechanized subsector.

The situation could worsen if the current trend toward a decline in the domestic and international demand for sorghum continues and there is no diversification into other crops. The absence of appropriate land tenure policies and environmental considerations are among the main constraints on this subsector.

Irrigated farming systemsThe proportion of the irrigation sourced from surface waters, as opposed to groundwater (wells), was 96 percent in 1995. In 2000, 11 percent of the cultivated area was equipped for irrigation (Table 6). Between 1995 and 2000, the area with full or partial control fell at a rate of 0.9 percent/year.

Wheat, cotton, sorghum and groundnut are the most important crops in irrigated areas. While having a positive impact in some subsectors (e.g. livestock), liberalization had a negative impact on the irrigated subsector. The irrigated schemes were privatized without passing through a transitional stage, which could have paved the way for active private-sector involvement. When the schemes were privatized, the situation became one of a run-down irrigation infrastructure, withdrawal of basic agricultural services, and a lack of alternative source of credit. The poor performance of the irrigation schemes in the 1990s had a serious impact on the employment and welfare of farmers and of the many landless labourers living in the irrigation schemes.

Reductions in the areas of the traditional crops led to opportunities for other crops such as vegetables and a substantial increase in livestock production. This diversification was important Source: FAO AQUASTAT.

TABLE 6Irrigated areas in the Sudan

Irrigation Year ‘000 ha

Full or partial control 2000 1 731

Spate 2000 132

Area equipped for irrigation 2000 1 863

Area salinized 1999 199


but did not reduce the need for substantial reforms in the management of the large schemes such as the Gezira scheme.

Water users associations (WUAs) will in the future be responsible for water management of the irrigation system and collection of water fees will be established. Water fees, cost of inputs and services provided by the Government will be charged on the basis of full cost recovery.

Figure 8 shows that the area of irrigated wheat also fluctuated substantially between the mid-1980s and the end of the 1990s, and that the area planted to cotton declined steadily. This is partly a reflection of the poor management of cotton production in government-run irrigation schemes. As the area of irrigated cotton declined, it was offset by an increase in the area of irrigated sorghum until the early 1990s, but then this area fell again to about the same level as in the late 1980s. The main reasons were considerable pressure on the government-owned and government-run schemes to increase grain production. The Government requested that the irrigation schemes increase wheat and sorghum production as a contribution to its food security initiative, which it had

Wheat Cotton

1970/71

1973/74

1976/77

1979/80

1982/83

1985/86

1988/89

1991/92

1994/95

1997/98

2000/01

500

450

400

350

300

250

200

150

100

50

0

'00

0 h

a

FIGURE 8Trends in harvested areas of irrigated wheat and cotton


introduced because of concerns about the impact of drought on rainfed sorghum production.

Farmers were strongly encouraged and assisted through credit programmes to produce wheat. With these inducements, the area under wheat increased sharply in 1990/91. The Government stimulated production using two main policies: (i) declaring an attractive price before planting at which the Government would purchase the production; and (ii) providing inputs for wheat production. Wheat production declined steadily after 1991/92 when the Government abandoned its efforts to stimulate an increase in grain production as part of its food security strategy. In subsequent years, reduced credit for wheat production has led to reductions in the area planted.

Figure 9 shows that wheat yields fluctuated considerably throughout the 1980s and 1990s and that production followed a similar trend, increasing on average at about 7 percent/year.

Table 7 shows the irrigated crops in full or partial irrigation schemes.

Wheat Cotton

1970/71

1973/74

1976/77

1979/80

1982/83

1985/86

1988/89

1991/92

1994/95

1997/98

2000/01

3

2.5

2

1.5

1

0.5

0

ton

nes/h

aFIGURE 9

Trends in yields of irrigated wheat and cotton


In terms of overall pro-duction, irrigated farming accounts for 99 percent of cotton, 100 percent of wheat, 52 percent of groundnut, 100 percent of sugar cane, 25 percent of sorghum, and 80 percent of fruits and vegetables.

Average yields in the irrigated areas are far higher than in the rainfed areas but are still below their potential, especially compared with yields obtained at research stations and by productive farmers. This is attributable to a variety of constraints and limitations.

Table 8 compares average crop yields with the potential yield with improved cereal varieties in the irrigated sector.

The cotton yield under irrigated systems is generally low, at about 5.5 kantar per feddan (1 kantar equals 143 kg of seed cotton, which gives about 45 kg of lint). Heat stress, pests and diseases are major causal factors. A few improved varieties have been released for the irrigated sector, and research is in progress to produce high-yielding and disease-free varieties.

The yields of oil crops (groundnut and sunflower) in the irrigated sector are very low: 2 000 kg/ha for groundnut and 793 kg/ha for sunflower. Improved varieties of groundnut (kriz, medani and sudan) have been released.

Table 9 provides a comparison of actual with potential yields in the Rahad irrigation scheme.

TABLE 7Irrigated crops

Source: FAO AQUASTAT.

Crop Year ‘000 ha

Cotton 2000 167

Fodder 2000 142

Groundnuts 1989 91

Maize 2000 68

Other roots and tubers 2000 16

Potatoes 2000 16

Rice 2000 4

Sorghum 1989 355

Sugar cane 2000 70

Sunflower 2000 21

Vegetables 2000 97

Wheat 2000 103

Source: Agricultural Statistic Department, MOAF.

TABLE 8Average yields of irrigated crops

Crop Average yield Potential yield

(tonnes/ha)

Millet 0.6 3.6

Sorghum 1.5 3.8–5.7

Wheat 1.6 3.3–4.1


Large-scale irrigation schemes have not been financially sustainable. Therefore, they have needed subsidies from the federal budget as well as government guarantees for obtaining credit from commercial banks. Efforts to control production practices, including the choice of crop by the farmer, have resulted in farmers producing crops that are less susceptible to control by these measures. Performance problems in irrigation schemes include: inefficient water management; non-collection of water charges and land-use fees; low productivity; and large debt burdens. Government support to these large-scale subsidized schemes has deprived other agriculture subsectors of funds needed for the development of basic infrastructure and support services.

The Gezira schemeThe primary objective of the Gezira scheme was to produce cotton. The land is farmed by 114 000 tenants on an average holding of 20 feddan (about 8 ha). The scheme consists of 18 large units called “groups”, which range in size from 60 000 to 190 000 feddans. Each group consists of smaller units called “blocks”. These blocks consist of “numbers”, each of 90 feddans. Each tenant has to plant according to the approved rotation so that, for example, all the cotton grows at the same time. Initially, the tenants practised a six-course rotation. However, because of many failures, this was changed in the early 1980s to an eight-course rotation (cotton, fallow, fallow, cotton, fallow, sorghum, cowpea and fallow), with a nominal cropping intensity of 50 percent. This kept the demand for water within the capacity of the irrigation system. Since then, there has been further diversification and intensification.

TABLE 9Potential and actual crop yields in the Rahad irrigation scheme

Source: FAO AQUASTAT.

Crop Potential yield Minimum actual yield Maximum actual yield

(kg/ha) (kg/ha) (% of potential) (kg/ha) (% of potential)

Groundnut 760 160 21 340 45

Sorghum 400 120 30 284 71

Wheat 600 100 17 380 63

(kantar/ha) (kantar/ha) (% of potential) (kantar/ha) (% of potential)

Cotton 3.6 1.2 32 2.9 80


Until recently, the main Gezira scheme had a nominal cropping intensity of 75 percent in a five-course rotation of cotton, wheat, groundnuts and sorghum with one fallow, while the Managil scheme had a 100-percent cropping intensity with no fallow. However, fallow has now also been introduced in the Managil scheme in order to give a target cropping intensity of 75 percent throughout, although various problems have kept the actual intensity below that figure in recent years.

AGRICULTURAL RESEARCHUntil 2001, several research institutes under different ministries administered various aspects of the national agricultural research programme. Under administrative reforms approved in 2001, the Government put all the research institutes, except the Animal Resources Research Corporation (ARRC), under the responsibility of the newly established Ministry of Higher Education and Scientific Research. The ARRC deals with livestock, while the Agricultural Research Corporation (ARC) is responsible for crops, forestry and pastures. A number of public universities (also under government control) contribute to agricultural research. The National Research Centre for Genetic Engineering is responsible for applied genetic research. The Industrial Research Centre is responsible for food science and medicinal plants; and the Atomic Energy Research Centre is responsible for mutation breeding, food preservation and sanitation.

Agricultural research has long been underfunded. Currently, the annual budget allocated to the ARC, ARRC and universities is only about 0.03 percent of GDP. The limited budget has resulted in a decline in staff numbers, reduced resources for funding research activities in the field, and a deterioration in the research facilities because of a lack of maintenance. Despite these difficulties, the ARC still has a staff of 250 researchers and in the last year it has generated some 60 innovations. However, few of the technologies developed have undergone testing in the field. An important challenge is to make them available in regions where they are relevant. There has been virtually no economic evaluation of technologies.

Another challenge facing agricultural research is the need to focus on small-scale farmers. Most agricultural research programmes tend not


to be based on integrated land-use management or farmers’ needs. The focus is often on high-input technologies for industrial crops, which may benefit large-scale farmers or those in irrigation schemes. Innovative, low-input technologies and farming systems, which could benefit small-scale farmers in rainfed areas, have often been neglected.

Research has developed packages for the sustained production of most crops grown under irrigation. These packages are available to the extension service, production schemes and private sector. Types, quantities, rates and/or times of application of inputs are usually specified for each crop. These packages have been developed and approved by the ARC after a long period of research. The variables include:ÿhigh-yielding varieties of better quality that are tolerant to water or

heat stress;ÿland preparation;ÿnutrient requirements;ÿadequate water requirements;ÿeconomic pest control;ÿweed control;ÿharvesting.

TECHNOLOGY TRANSFER AND EXTENSIONExtension is the responsibility of the individual states. The new national strategy for agriculture, launched in 2001, and the recognition that extension is a critical factor in improving agricultural production and food security, led to the Extension Department becoming the Technology Transfer and Extension Administration (TTE). The TTE plans to establish a network with administrations in the state ministries responsible for agriculture and working with the states, the ARC and universities. Plans are in place to have ten technology transfer and farmer training centres by 2006 and to have 2 000 demonstration farms. There is also a plan to merge the extension services for rainfed and irrigated crops.

The TTE has four main thematic programmes: improving crop productivity: promotion of improved seeds; integrated mechanization; and development for rural women. Only about 10 percent of farmers use certified seeds. Until recently, central government handled seed production


and certification through the Seed Unit of the Extension Department in the Ministry of Agriculture and Forestry (MOAF). However, the seeds were not of good quality and they were also expensive. National seed production was limited to field crops, while seeds for horticultural crops were usually imported. The Seed Multiplication Department in the MOAF was semi-privatized in 2000 and entrusted to a new joint ownership company (public–private). The Government donated physical assets to the newly formed Arab Sudanese Seed Company, taking a 42 percent share of the company’s capital. The Arab Authority for Agricultural Investment and Development (AAAID), Al Aktan Company and the Farmers’ Bank provided the remaining financing. The TTE retained responsibility for seed certification and control.

AGRICULTURAL CREDITIn total, formal lending to agriculture in 2001 was about SD44 000 million (US$183 million). About 58 percent of this credit was extended to irrigated agriculture, mainly for cotton production. Semi-mechanized rainfed agriculture and some large livestock enterprises received about 40 percent, while traditional small-scale farmers received only 1–2 percent.

The main sources of finance for irrigated agriculture are the Ministry of Finance and National Economy (MOFNE), the government-owned Agriculture Bank of Sudan (ABS) and commercial banks. A consortium of commercial banks has agreed to contribute to the financing of the agriculture sector. The MOFNE has considerable contingency liabilities through its guarantee of loans extended by commercial banks via the consortium. Other sources include the Sudan Cotton Company (SCC), and the Sudan Gezira Board provides fertilizer on credit to farmers.

In spite of the high contribution of the agriculture sector to GDP, the ratio of formal agricultural credit to the GDP in Sudan is very low compared with certain other Arab and Asian countries (Table 10).

Informal credit is an important source of finance for agriculture, but information on its extent is not available.

Lending to the agriculture sector commenced with the formation of the ABS in 1957. The ABS now has 91 branches and its loans provide about 20 percent of farmers’ total credit requirements. On average, two-


thirds of the credit disbursed by the ABS in the period 2000–02 was for the irrigated sector compared with only 9 percent for the traditional rainfed sector (Table 11).

The prospects for improving the availability of credit to small-scale farmers are poor without government guarantees or collateral provided for loans. The ABS has attempted group lending but this has proved unsuccessful and costly.

Traditional farmers are a poor credit risk because of their uncertain environment, low yields (even in good years), remote location and inadequate infrastructure for marketing and support services.

The important policy changes needed for the irrigated sector are mainly structural. The most important are changes in the Land Act to allow conversion of tenants’ current rights into tradable long-term leases. This arrangement coupled with the introduction of a sustainable savings and crop insurance system in the major irrigation schemes, through the creation of farmer-owned savings associations, will facilitate access to credit. Crop insurance will also provide more security to lending institutions.

TABLE 11Annual disbursements by the ABS by farming system

Source: ABS.

Farming system 2000 2001 2002 Average Percent of total

(SD thousand million) (%)

Traditional rainfed 0.54 0.33 0.55 0.47 8.9

Semi-mechanized rainfed 0.82 1.61 1.37 1.27 36.4

Irrigated 1.72 3.27 5.47 3.49 66.7

Total 2.28 5.21 7.39 5.23 100

Source: MOAF, Committee Report, Decree No. 3/2003.

TABLE 10Ratio of agricultural credit to GDP in selected countriesCountry Credit as % of GDP

Bangladesh 14.1

Egypt 4.7

India 8.4

Jordan 2.5

Morocco 4.7

Oman 0.3

Pakistan 4.3

Philippines 17

Republic of Korea 24

Sudan 0.3

Syrian Arab Republic 8

Thailand 15

Tunisia 2.5


AGRICULTURAL MARKETS: INPUTS AND OUTPUTSUntil 1992, the Government largely controlled the marketing of agricultural inputs and outputs. However, as part of the economic reforms in the 1990s, it removed most of the controls in favour of private traders. Private bodies now undertake the marketing of most agricultural commodities, including livestock. The remaining government interventions relate to cotton and sugar, and the pricing systems for both commodities are tied to international prices. The SCC sets farmgate prices for seed cotton, and the MOAF continues to announce a minimum price for gum arabic.

Since 1990, private traders have been playing an increasing role in input procurement and distribution systems. Private-sector specialist organizations are becoming increasingly important suppliers of seeds for the main field crops and vegetables. The ginneries select and distribute cotton seed. There is a proposal to privatize cotton-ginning activities. The National Seed Propagation Administration has been privatized and is now the Sudanese Arab Seed Company (SASC). Private companies, specialized banks and public schemes import crop protection chemicals and farm machinery.

While there are no longer restrictions on the importation of fertilizers, the fertilizer supply system still reflects the previous emphasis on cotton, and the SCC still largely coordinates their procurement and distribution. However, traders are increasingly contracting with farmers at the beginning of the season and they sometimes provide production inputs or land preparation services. The remaining state intervention hinders private traders from playing a more active role in the procurement and distribution of crop production inputs.

33

Chapter 3

Fertilizer use in the Sudan

CONSUMPTION OF MINERAL FERTILIZERSRainfed farming, whether mechanized or traditional, rarely uses any fertilizer, although responses of durum wheat and cotton to N and P are reported in high-rainfall areas. Fertilizer is used in the irrigated sector to varying degrees (Table 12).

Some NPK fertilizers are imported, mainly for use on vegetables. On the basis of a cultivated area of 16.6 million ha, this amounts to only 4 kg of plant nutrients per hectare. Table 13 lists estimates of the proportions of fertilizers used on the major crops.

PRICES OF IMPORTED FERTILIZERSTable 14 evidences the rising prices of imported urea and triple phosphate (TSP) since 1995.

Source: FAOSTAT.

TABLE 12Mean fertilizer nutrient consumption in the irrigated sector, 2000–02Fertilizer N P2O5 K2O

(‘000 tonnes nutrient)

Urea 54.3

Triple superphosphate 11.1

Potassium chloride 3.8

TABLE 13Approximate proportions of fertilizers applied by crop

Note: 1N = basic dose of N × 1, 2N = basic dose of N × 2, 1P = basic dose of P × 1, etc. The basic doses are: 1N = 40 kg N fertilizer/feddan, 1P = 40 kg P fertilizer/feddan, and 1K = 40 kg K fertilizer/feddan.Source: Approximations from figures of MOAF, Arab Organization for Agricultural Development and FAOSTAT.

Crop Urea TSP NPK

(%)Cotton (2N–3N) about 35 0 0Wheat (2N–1P) 20–30 60 0Sorghum (1N) 15–20 0 0Sugar cane (4N–5N) 20 20 0Vegetables (2N) NPK 10 5 90Other crops 0 15 10


TABLE 14Fertilizer import prices, 1995–2005

Source: MOAF; Agricultural Statistics Department, August 2005.

Year Urea TSP

(SD/tonne) (US$/tonne) (SD/tonne) (US$/tonne)

1995 19 142 73.63 1 445 54.02

1996 25 075 96.45 38 056 146.37

1997 40 896 157.29 44 380 170.69

1998 29 048 111.72 41 536 159.86

1999 30 346 116.72 46 634 179.36

2000 38 653 150.99 44 390 173.40

2001 22 769 87.58 45 397 174.61

2002 36 263 139.47 42 144 162.09

2003 39 658 152.53 44 422 170.86

2004 56 040 215.54 59 609 229.27

2005 54 519 209.69 67 684 260.32

* In N, not ASN.

TABLE 15Recommendations for N (as ASN) application

Crop Application rate

(kg ASN/ha)

Banana 285–475 kg N*/ha/year, split in 6 applications (every 2–months), including 285 kg ASN/ha, the rest coming from other N sources

Citrus 190–380 kg/ha, basal at the beginning of vegetation phase, 95–190 kg/ha after harvest

Cotton 140–240 kg/ha basal and 95–190 kg/ha between square formation and peak lowering

Cucumber 240 kg/ha as basal dressing, 1–2 additional dressings with the same quantity

Date-palm 0.2–0.4 kg per tree and application (3 per year)

Eggplant 285 kg/ha basal 1–2 top-dressings with 140 kg/ha

Groundnut/alfalfa 50–70 kg/ha as starter application owing to later N fixation by symbiosis

Maize 190–285 kg/ha basal and 95–190 kg/ha at 4 leaf-stage

Mango 190–380 kg/ha basal at beginning of vegetation phase, 95–190 kg/ha after harvest

Melons 285 kg/ha basal 1–2 top-dressings with 140 kg/ha

Onions 190 kg/ha basal and 2 top-dressings with 140 kg/ha each

Sesame 140–190 kg/ha in one basal application

Sorghum 140 kg/ha basal and 95 kg/ha at 2–4 leaf-stage

Sugar cane 190–240 kg/ha basal and 190–240 kg/ha three months later

Tomato 140–285 kg/ha at sowing/transplanting, second application with 95–240 kg/ha 3–4 weeks later

Wheat/durum 190 kg/ha basal and 95–140 kg/ha at shooting

Chapter 3 – Fertilizer use in the Sudan 35

RECOMMENDED RATES OF FERTILIZER APPLICATIONTable 15 shows the recom-mended application rates for ammonium sulphate nitrate, while Table 16 lists those for urea and TSP.

FERTILIZER RESEARCHThe Sudan has a tradition of research on the use of mineral fertilizers, probably associated with the development of irrigated agriculture.

Early investigations (Burhan, 1969, 1971; Burhan and Jackson, 1973; Burhan and Taha, 1974) examined crop response to single-nutrient fertilizers in long-term trials on cotton, over 18 seasons, in a 3–4 course rotation. The soils were typical Vertisols, low in organic matter, poor in organic N, low in available P but with a good reserve of K, characterized by a high pH (7.5–8.5). The results were as follows:ÿ The response to 190 kg/ha of urea was consistent and significant in

all 18 seasons.ÿ There was a positive response to P as TSP in about 30 percent of the

seasons.ÿResponses to K were rarely reported.The response to P was attributed to variations in soil moisture before

the planting season. In wet seasons, there was generally a positive response. This may also be related to the yield of cotton. Responses to the rate of urea application over four seasons revealed a curvilinear relationship for all four seasons.

In the 1960s and 1970s, a number of researchers examined the fertilization of sorghum and wheat. In this period, tissue analysis as an indicator of the fertilizer status of cotton was investigated.

Cooperative programmesSome programmes have been carried out in cooperation with other agencies:ÿ FAO Fertilizer Programme 1977–1991;

TABLE 16Recommended rates of fertilizer application

Source: MOAF; Agricultural Statistics Department, 2005.

Crop Urea TSP

(kg/ha)

Cotton 190 -

Sorghum 190 -

Sugar cane 475 95

Wheat 190 95


ÿ European Economic Community (EEC) Fertilizer Programme 1977–1987;ÿ ARC / International Center for Agricultural Research in the Dry

Areas (ICARDA) / Organization of the Petroleum Exporting Countries (OPEC)/ Nile Valley Regional Programme (NVRP);ÿ Sasakawa Global 2000 (1980s);ÿ Gesellschaft für Technische Zusammenarbeit (GTZ – German

development agency);ÿ International Atomic Energy Agency (IAEA);ÿ AAAID.

FAO Fertilizer ProgrammeThe initial donor was Denmark, followed by the EEC, Belgium, the United Kingdom, the Netherlands, the International Fertilizer Industry Association and, later, Kuwait, Saudi Arabia, Morocco and the Arab Fertilizer Association. On-farm trials were carried out on cotton and wheat in Gezira. Demonstrations using N and P complemented the research findings. The programme also covered Khartoum, the Nile River and Gezira outside the scheme. Later, it included the White Nile River, the Blue Nile River, Kassala, Kordofan and Jabal Marrah. Trials were carried out on smallholder vegetable farms producing onions, tomatoes and potatoes. The programme procured fertilizers and other inputs and established rural stores. A good distribution system for inputs was established involving the ABS and implemented by the Extension Department of the MOAF. The programme involved about 1 000 demonstrations and trials, and 9 000 field days with 200 000 farmers participating.

ARC/ICARDA/NVRP The programme ran from 1978 to 1994 and focused on cool-season legumes and wheat. Leguminous crops respond to small starter doses of N and P. The project addressed the needs for fertilizers on various soils (Gezira Vertisols, Gerf, upland terraces, and Karu soils). The programme involved both on-station and on-farm research. It established N and P recommendations for wheat in Gezira and the northern region, for


different varieties on different soils (Ageeb and Abdalla, 1988; Gorashi, 1988; Ibrahim et al., 1991). The project was extended to New Halfa, where the response to phosphate was not significant. Foliar fertilization gave positive results, indicating a response to micronutrients and trace elements.

Global 2000This programme started in the 1980s in association with Sasakawa Global 2000. Its aim was to promote wheat production and technology transfer to farmers. It covered most of the Gezira scheme and developed technological packages involving land preparation, food needs and balanced fertilization in both demonstrations and on-farm fields. The results achieved on wheat with the cooperation of the ARC and Gezira extension staff were very positive.

IAEAThis work involved trials with N15 and P32 and, in cooperation with GTZ, research on micronutrients.

AAAIDThe AAAID was established in 1977 with the following objectives:ÿ development of agricultural resources and food production;ÿ exchange of agricultural products;ÿ promotion, financing and implementation of agricultural projects;ÿ research and studies;ÿ cooperation with relevant organizations.The AAAID has carried out work on zero tillage in the context of a

full technological package for all agricultural operations supported by an efficient management system. It has also conducted fertilizer trials on the effect of:ÿ Zn and boron (B) on grain filling of sunflower (5 ha);ÿ Zn and P on grain filling of sunflower (5 ha);ÿ P on the growth and yield of cotton (10 ha);ÿ P on the growth and yield of sorghum (5 ha);


ÿ different sources of N (urea, ammonium nitrate) on the growth and yield of sorghum, cotton and sunflower (5 ha per crop).

The main findings were:ÿ The superiority of zero tillage was confirmed on the pilot farm.ÿ The local variety wads ahmed out-yielded local and imported

sorghum varieties.ÿ The sunflower variety hysun 33 out-yielded damazin 1/3, panar

7353 and panar 7393.ÿ Application of B to sunflower resulted in an increase in grain

filling.ÿ Application of P resulted in an increase in the yield of sunflower.

Cotton in irrigated schemesA poor response of cotton to urea fertilization as well as N losses from urea have been reported, with a negative impact on yield. Comparisons showed that yields with NPK complex fertilizer, ASN and ammonium sulphate (AS) were higher than with urea. Possible explanations are that the N is present in a more readily available form for crop uptake and, therefore, losses are lower compared with urea. Moreover, the fertilizers tested contain more than one plant nutrient.

Sugar caneAn NPK fertilizer, ASN and AS were compared with urea on sugar cane on the Gunied and Kenana sugar estates. The rates were the equivalent of two, four and six times the basic dose of N compared with four times the basic dose of urea. NPK and ASN at the first two rates produced better yields and, in one trial, an equal yield compared with standard practice. These results need confirming on on-farm plots.

Sorghum in irrigated schemesIn recent years, sorghum yields in irrigated schemes have been falling. An NPK complex fertilizer, ASN and AS were compared with urea. A considerable yield increase was observed compared with standard fertilization practice using urea, possibly for the reasons mentioned for cotton.


WheatOn-station and on-farm trials on wheat took place in 1999/00 and 2000/01 at Gezira, Rahad and New Halfa in order to test the effect of different sources and rates of N on the growth and yield of bread wheat. Both types of trials used different levels of NPK complex fertilizer, ASN and AS. Compared with the control (zero N), the application of the fertilizers resulted in a significant increase in grain yield at the three locations: 51–160 percent at Rahad, 39–162 percent at Wad Medani, and 13–45 percent at New Halfa. The N-use efficiency for all three sources was at its lowest level with the highest dose of N at all three locations. At Rahad, a single dose of ASN was more efficient under a low yield environment, as were two doses of N as NPK under a high yield environment. In Gezira, one dose of N as NPK or one dose of N as ASN seemed to be more efficient for the low-yield environment and two doses of N as NPK for the high-yield environment. At New Halfa, the response to the fertilizers and N-use efficiency for all three sources was relatively low; this warrants further research.

Groundnut in irrigated schemesOn-station and on-farm trials tested the response of groundnut to three sources of N fertilizer (NPK, ASN and AS) at two doses (0.5 N and 1 N) on the large irrigated schemes in the 2000/01 season. At New Halfa, Gezira and Sennar Research Station, the treatments gave a higher average yield than did the unfertilized control. At Rahad Research Station, a treatment of 1 N as AS and a treatment of 1 N as NPK gave the highest average yield compared with the control. At New Halfa, 1 N as NPK, 1 N as ASN and 0.5 N as NPK gave a higher yield than the control. The results for immature pods also followed this trend, apart from the treatment 0.5 N as NPK (which gave a lower number of pods than did the control). The result of the average number of pods per plant at Rahad Research Station shows that all the treatments gave lower numbers than did the control apart from a treatment of 1 N as AS and a treatment of 0.5 N as AS. However, the differences in all trials were not significant.

SunflowerOn-station trials and on-farm trials at Rahad and New Halfa for the seasons 1999/00 and 2000/01 evaluated the response of sunflower to


different types of fertilizers. The fertilizers tested were NPK complex, ASN, AS and urea at varying application rates. Significantly higher yields were obtained in response to the application of fertilizers. The yield increases in the on-station trials were in the range of 43–81 percent and those in the on-farm trials were in the range of 27–100 percent.

Vegetables in irrigated clay soilsField experiments carried out in the winter seasons of 1999/2000 and 2000/01 evaluated the effect of different sources of N on the yield performance of certain vegetables. The experiments were carried out at the Gezira and Rahad research farms using three levels of N (1 N, 2 N and 3 N). However, in the 2000/01 season, the 3-N treatment was discontinued at Wad Medani and a treatment of 1.5 N was added at the Rahad experiments. These treatments were compared with the standard treatments for tomato and onion (2 N as urea + 1 P) and control (zero N) in randomized complete block designs.

On tomato at the Gezira research farm in 1999/2000, 3 N as NPK and 2 N and 3 N as ASN produced the highest tomato yield and significantly out-yielded the standard treatment (2 N as urea). There were no significant differences in tomato yields between the standard treatment and 1 N in the case of all three fertilizers. At the Gezira research farm in 2000/01, treatments of 1 N and 2 N as NPK complex produced the highest yield of tomatoes. Significant yield differences between the sources and rates of N were obtained in both seasons. The highest tomato yield was obtained by applying NPK at the rate of 3 N, followed by NPK at the rate of 2 N.

In the case of onions, in the experiments at Gezira research farm in the 1999/2000 season, the overall average bulb yield was low but the treatment effects were significant. The treatment of 3 N as NPK produced the highest bulb yield, but differences in the case of the 1-N treatment, for each of the N fertilizers, were not evident. At Rahad, applying 2 N either as AS or as NPK resulted in significant variations in the onion yield. No significant yield differences were detected between the various N sources for broad bean, snake cucumber and pumpkin.


ECONOMIC EVALUATION OF FERTILIZERSThe economic evaluation of fertilizer applications was performed for the on-farm trials in the Gezira, Rahad, New Halfa, Guneid and Kenana schemes. This involved constructing partial budgets for each crop tested at each location and comparing and evaluating net benefits of the different fertilizer treatments.

For cotton, the treatments of 2N as ASN and 2N as NPK yielded higher net returns in the Gezira scheme. In the case of Rahad, the most promising treatments were: 1 N as ASN + 1 N as ASN, and 1 N as NPK; while in New Halfa the treatments of 1 N as ASN and as NPK were the most profitable.

For wheat, the treatment of 1 N as AS in Gezira and 1 N as NPK in New Halfa were the best options.

For sorghum, the treatment of 2 N as ASN yielded the highest net benefits in the Gezira Scheme, while treatment 1 N as AS proved best in the New Halfa scheme. In the case of Rahad, treatments of 1 N NPK and (1 N NPK + 1 N NPK) produced the highest net benefits.

For groundnut, the application of 1 N as NPK yielded the highest net return was achieved from, but with the marginal rate of return was low.

For sugar cane, the treatment of 2 N as ASN gave the highest net returns in Guneid, while a treatment of 4 N as ASN was the most profitable in Kenana.

43

Chapter 4

The 25-year plan

The Government has prepared a 25-year plan to promote rural development. Its objectives are: “to stir up and trigger rural development so as to give rise to rural communities in which all services are provided: fresh water, technical education, health care, electricity, fossil fuel and renewable sources of energy and other development projects with fair and just distribution between all regions, cultures and ethnic groups.”

The plan addresses six constraints facing the sector in the medium term:ÿ low and declining yields,ÿ recurrent drought,ÿ inadequate infrastructure,ÿ trade constraints,ÿ weak institutional capacity,ÿ low private investment.The plan proposes that the main policy for resolving these constraints

should be through a broad framework for growth in the agriculture sector based on the following actions:ÿ a new land law that provides for, among other measures, long-term

leases with land-use conditions, tradability of leases and a reduction in the number and size of very large farms in the semi-mechanized areas;ÿ more relevant and effective agricultural research and extension;ÿ improved financial services in rural areas;ÿ programmes to improve the marketing of agricultural and livestock

products, such as wheat, oilseeds and milk;ÿ maintenance of a strategic reserve to enhance national food

security;ÿ investments to improve domestic water supplies in rural areas;ÿ programmes to improve the welfare of families in the traditional

rainfed farming areas;


ÿ efficient use of water for irrigation;ÿ combating desertification by rehabilitating vegetation cover through

upgrading of pastures, rehabilitation of forests, reforestation and the promotion of agroforestry.

45

References

Ageeb, O.A.A. & Abdalla, H.H. 1988. Researcher-managed trial, the response, yield in Gezira. Paper presented at the Third Wheat Coordination Meeting, 4–6 September. Wad Medani, Sudan, Agric. Res. Corp.

Burhan, H.O. 1969. Rotation responses of cotton in the Gezira. In M.A. Siddeg & L. Hughes, eds. Cotton growth in Gezira environment, pp. 51–57.

Burhan, H.O. 1971. Responses of cotton to levels of fertilizer nitrogen in the Sudan. Cott. Grow. Rev., pp. 116–127.

Burhan, H.O. & Jackson, J.E. 1973. Effect of sowing date plant, plant population date, nitrogenous fertilizer and insect control on cotton yield and its year to year variation in the Sud an Gezira. J. Agric. Sci. Camb., pp. 481–389.

Burhan, H.O. & Taha, M.A. 1974. Effect on New cotton varieties of sowing date, plant population and time of fertilizer application. Cott. Grow. Rev., pp. 177–186.

Gorashi, A.M. 1988. The response of wheat to different levels of N and P at New Halfa. Paper presented at the Third Wheat Coordination Meeting, 4–6 September. Wad Medani, Sudan, Agric. Res. Corp.

Ibrahim, H.S., Babiker, E.A., Omer, M.M., Gorashi, A.M., Salih, A.A., Sati, E. & Mohamed, M.I. 1991. Response of wheat to different rates of N P combinations and the method of P application in the Sudan. Paper presented at the Nile Valley Annual Coordination Meeting 16–23 September. Cairo.


The Sudan has almost 17 million ha of cultivated land, and the potentially cultivable area is much larger. It is the largest area of cultivable land in the Arab world. The agricultural and

livestock sectors make an important contribution to the national economy. The climate is hot and rainfall uncertain but the

Blue and White Nile Rivers have enabled the development of large irrigation schemes. However, the rainfed sector, which provides a livelihood for the majority of the population, has been neglected. The productivity of the irrigation schemes

has declined in recent years. Food production has increased because of expansion in the cropped area, while yields have

tended to fall. Outside the irrigation schemes, farmers use little fertilizer. Even in the scheme areas, fertilizers are underused.

Overall, fertilizer use is at a very low level.

TC/D/A0416E/1/2.06/300

fertilizer use by crop in the sudan · 2006. 3. 9. · fertilizer use by crop in the sudan the...

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