Energy analysis of weed management practices

in Aerobic rice

Dr B.Sreedevi, P.C.Latha, A.Sandhyarani, D. Sreenivas and R.MahenderkumarIndian Institute of Rice Research,

Hyderabad, India

INTRODUCTION

Energy is one of the most important indicators of crop performance AND has been used to provide an accurate overall evaluation of the energy consumption linked to agriculture.

Improvement of energy gain and energy efficiency through optimizing energy input and increasing energy output, contributes significantly to sustainable development in agriculture.

Energy analysis Is needed to investigate how to improve the management practices for energy efficient crop production

Energy use in Agriculture

Direct sources : Directly releases the energy to the system Renewable direct sources :- can be subsequently replenished e.g.

energies of human beings , animals, solar and wind energy, fuel wood, agricultural wastes etc.

Non-renewable direct sources :- which cannot be replenished (at least in near future) e.g:-coal and fossil fuels.

Indirect sources:- do not release energy directly but release it by conversion process. Some energy is invested in producing indirect sources of energy e.g. seed, manure.

Renewable indirect sources :- Can be replenished in due course of time. Non-renewable indirect sources:- pesticides,fertilizers and machinery

manufacturing

• In developed countries, increase in the crop yield was mainly due to increase in the commercial energy inputs in addition to improved crop varieties and mechanization.

• In developing countries mechanization still needed.

• As level of fertility increased, yield and economical parameters increased linearly, while reverse trend is observed with energy productivity and energy intensiveness.

• Indian agriculture: Consumption of energy has been increasing at a steady rate for improving the productivity but the energy use efficiency is declining consistently.

• In the changing climatic scenario, sustainability of any cropping system lie on energy use pattern /consumption in the system.

Rice is Life ?• Rice is grown in more than 89 countries. Farmers from irrigated,

upland, lowland, and the flood-prone areas across Asia are the major producers of rice.

• The leading consumers of rice include China, India, Indonesia Bangladesh, Vietnam, Myanmar,

• Japan, Thailand, Brazil and the Philippines• Rice farming is a major source of employment, especially for the

poor.• About 4/5 of the world’s rice production is grown by small scale

farmers in low income, developing countries.• A wide range of rainfall distribution pattern (drought, submergence,

deepwater) and distinct differences in soils (coastal and inland salinity, alkalinity, acidity), agro-climatic situations (high humidity) and seasons has resulted in the cultivation of thousands of varieties and One can see a standing rice crop at some part of the country or the other in any time of the year.

Rice Production Scenario in India

Single largest food source to 70% of Indians

Contributes - 43% food production 20-25% of AGDP; Exports > 12,000 Crores

Worlds largest area - 43 M ha; IR 58%, RSLL 23%; RUL 12%; SDW 4% and DW / FP 3%; Production ~106 Mt (2011-12); Y-2.31 t/ha @ 225 g rice/d

Widely grown in diverse conditions 15 soil groups; 16/20 AEZ, Temp. 10-450 C, RF- 400-3500mm, Altitude - < MSL to 2000m;

Max. use of resources and inputs: 24% of GCA, > 50% IW; ~35% fertilizers; 17-18% pesticides

> 120 million rice farm holdings

Rice is life and source of livelihood for millions

Aerobic riceAerobic rice is a viable option where the shortage of water does not allow the growing of lowland rice.grow rice like an upland crop, such as wheat, on non-flooded aerobic soils without stress, thereby eliminating continuous seepage and percolation and greatly reducing evaporation.

Traits Aerobic Rice Upland RiceWater Source Irrigated Rainfed

Drought Prone No Yes

Response to Inputs Yes (=Irrigated) Low/No

Tolerance to flooding Yes No

Stress level Low High

Yield level ~Irrigated lowlands 2.5 to 3.0 t/ha

Rooting Shallow to mod Deep Deep rooted

Weed management in Aerobic rice• In aerobic system, weeds are a major constraint •Aerobic soil conditions and dry tillage practices, besides alternate wetting and drying conditions, are conducive for germination and growth of highly competitive weeds, and uncontrolled weeds cause grain yield losses of 50-97%.• Information on energy use of different weed management practices is limited.

Objectives: To compare different weed management practices and analyze energy utilization patterns and energy efficiencies in aerobic rice and To investigate how to improve the management practices for energy efficient aerobic rice production system.

Agronomic Package Followed Land preparation: As like that of maize, sorghum or any garden crops (Fine tilth soil with 4-5 repeated ploughings, application of FYM 10 tons/ha)Seed rate of 25kg ha-1 at depth of 3-5 cm with row spacing of 20 x10cm in 1st fortnight of June. Thinning and gap filling was done at 3 weeks after sowing.

Irrigation: Need based irrigation (5-7 days interval) upon noticing visible symptoms of hairline cracks on soil surface. Fertilization: Based on soil testing 120:50:50 NPK. Blanket application of Full dose of P and ¾ K ; Nitrogen was applied as splits 1/3 at 10-12 DARE, 1/3 at Maximum tillering stage and 1/3 at Panicle Initiation stage . ¼ K at Panicle Initiation stage. Iron deficiency occurred in seedling stage and spraying of FeSo4 @ 1% for 3 times at weekly intervals was done.

Prophylactic spray of one dose of cartop-hydrochloride insecticide was taken up in tillering stage. No nematode incidence or disease incidence occured.

T.No. Treatments1 Pendimethalin (30EC)@1.00 kg a.i./ha(3-4 DAS) fb Bispyribac- sodium (10%SC)@35

g.a.i./ha (25-30 DAS)

2 Pendimethalin (30EC)@1.00 kg a.i./ha(3-4DAS) fb 2,4 D,Na salt (80WP) @0.06 kg.a.i /ha (25–30 DAS)

3 Pendimethalin (30EC) @ 1.00 kg a.i./ha (3-4 DAS) fb Ethoxysulfuron (15WSG) @ 15 g.a.i./ha (25-30 DAS)

4 Pendimethelin (30EC) @ 1.00 kg a.i./ha (3-4 DAS) fb (Chorimuron + Metsulfuronmethyl) 20WP @ 40 g.a.i./ha (25-30 DAS)

5 Butachlor (50EC)@1.5 kg/a.i./ha (3-4DAS) fb Bispyribac-sodium (10%SC)@35 g.a.i./ha (25-30DAS)

6 Butachlor (50EC)@1.5 kg/a.i./ha (3-4DAS) fb 2,4-D,Na salt (80WP) @ 0.06 kg.a.i /ha (25–30 DAS)

7 Butachlor (30EC) @ 1.00 kg a.i./ha (3-4 DAS) fb Ethoxysulfuron (15WSG) @ 15 g.a.i./ha (25-30 DAS)

8 Butachlor (30EC) @ 1.00 kg a.i./ha (3-4 DAS) fb (Chorimuron + Metsulfuronmethyl) 20WP @ 40 g.a.i./ha (25-30 DAS)

9 Mechanical weeding/weeder at 20& 45 DAS10 Need based hand weeding 3 times at 20,40 and 60 DAS11 Un weeded

Major weeds of RiceGrasses

Echinochloa colona (Jungle grass) Echinochlo crusgalli (Barnyard Grass)

Eleusine indica (Goose grass)

Panicum repens (Ginger Grass)

Paspalum dilatatum (Scruot grass)

Paspalum distichum

Paspalum hydrophilum (Water Paspalum)

Leersia oryzoides(Rice Cutgrass)

Digitaria sanguinalis (Common crab grass)

Dactylactenium aegyptium(Crow foot grass)

Dinebra retroflexa (Viper grass) Leptochloa uninerva

Sedgees

Cyperus difformis (Umbrella sedge)

Cyperus rotundus (Nut Grass, Nutsedge)

Cyperus iria (Sedge weed)

Fimbristylis dichotoma Scirpus maritius Kyllinga nemoralis (White kyllinga)

Broad leaf weeds

Alternanthera echinata Marsilea quadrifolia (The Water Fern)

Ammania baccifera (Blistering Ammania)

Eclipta alba (False daisy) Commelina benghalensis- (Asiatic dayflower)

Convolvulus arvensis(Field bindweed)

A Complete inventory of all crop in puts was prepared

Energy value of each treatment was determined based on energy inputs and energy production for the individual treatment.

Inputs and outputs were converted from physical to energy measure through published conversion coefficients (Mittal&Dhawan1988 et.al. , Devsenapathy2009 et.al).

Energy out put from the product was calculated by multiplying the amount of production and its corresponding energy equivalent

Net energy return:- difference between gross output energy produced and input energy.

Energy ratio:- Output energy/Input energy. Energy profitability:- net energy return (MJ/ha)/input energy

(MJ/ha) Specific energy:- energy input (MJ/ha)/ economic yield (t/ha) Energy productivity:- crop economic yield (t/ha)/energy input

(MJ/ha)

TreatmentsGrain Yield (t/ha)

Panicle/m2 (No.)

Panicle

Weight (g)

Weed dry weight (g/m2)

Pendimethalin fb Bispyribac- sodium 3.88 265 2.19 29.73

Pendimethalin fb 2,4 D,Na salt 3.51 244 2.20 37.89Pendimethalin fb Ethoxysulfuron 3.41 256 2.24 38.50Pendimethelin fb (Chorimuron + Metsulfuronmethyl) 3.38 240 2.17 32.86

Butachlor fb Bispyribac-sodium 3.76 266 2.14 32.19Butachlor fb 2,4-D,Na salt 3.35 240 2.19 47.93Butachlor fb Ethoxysulfuron 3.33 247 2.14 48.21Butachlor fb (Chorimuron + Metsulfuronmethyl) 3.37 237 2.09 37.43

Mechanical weeding/weeder 3.48 259 2.28 27.12Need based hand weeding 4.03 287 2.05 20.53Un weeded 1.92 162 1.63 109.3C.D. (0.05) 0.28 20 0.51 4.89C.V (%) 11.35 8.54 7.59 10.64

Indices Weed Population

TreatmentsWeed control

efficiency Weed index Grasses Sedges BLW

Pendimethalin fb Bispyribac- sodium 72.80 3.72 5.30 (2.41) 8.17 (2.94) 2.73 (1.80)Pendimethalin fb 2,4 D,Na salt 65.33 12.90 6.43 (2.63) 6.73 (2.69) 2.20 (1.64)Pendimethalin fb Ethoxysulfuron 64.78 15.38 6.73 (2.69) 8.93 (3.07) 2.97 (1.86)Pendimethelin fb (Chorimuron + Metsulfuronmethyl) 69.94 16.13 5.77 (2.50) 9.67 (3.19) 3.23 (1.93)

Butachlor fb Bispyribac-sodium 70.55 6.70 5.20 (2.39) 6.70 (2.68) 2.23 (1.65)Butachlor fb 2,4-D,Na salt 56.15 16.87 7.20 (2.77) 7.03 (2.74) 2.33 (1.68)Butachlor fb Ethoxysulfuron 55.89 17.37 6.40 (2.63) 7.83 (2.89) 2.57 (1.75)Butachlor fb (Chorimuron + Metsulfuronmethyl) 65.75 16.38 7.10 (2.76) 9.30 (3.13) 3.07 (1.89)

Mechanical weeding/weeder 75.19 13.65 8.20 (2.95) 8.93 (3.07) 12.80

(3.65)Need based hand weeding 81.22 0 1.80 (1.52) 4.20 (2.17) 5.30 (2.41)Un weeded

0 52.36 49.30 (7.06) 23.30 (4.88) 46.20 (6.83)

C.D. (0.05) NA NA 0.1 0.11 0.09

C.V (%) 2.09 2.03 2.03

TreatmentsEnergy input

(MJ/ha))

Energy output (MJ/ha)

Net Energy Return(MJ/ha)

Specific energy

(MJ/T)

Energyratio

Energy Productivity

Energy Profit

Pendimethalin fb Bispyribac- sodium 20714.4 57036 36,321.6 5.34 2.75 0.00019 1.75

Pendimethalin fb 2,4 D,Na salt 20786.1 51597 30,810.9 5.92 2.48 0.00017 1.48

Pendimethalin fb Ethoxysulfuron 20845.6 50127 29,281.4 6.11 2.40 0.00016 1.40

Pendimethelin fb (Chorimuron + Metsulfuronmethyl) 20647.3

649686

29,038.64

6.11 2.41 0.00016 1.41

Butachlor fb Bispyribac-sodium 20714.4 55270 34,555.6 5.51 2.67 0.00018 1.67

Butachlor fb 2,4-D,Na salt 20786.1 49245 28,458.9 6.20 2.37 0.00016 1.37

Butachlor fb Ethoxysulfuron 20845.6 48951 28,105.4 6.26 2.35 0.00016 1.35

Butachlor fb (Chorimuron + Metsulfuronmethyl) 20647.3

649539

28,891.64

6.13 2.40 0.00016 1.40

Mechanical weeding/weeder 19943.78

5115631,212.2

25.73 2.57 0.00017 1.57

Need based hand weeding 20866.22

5924138,374.7

85.18 2.84 0.00019 1.84

Un weeded 19770.18

28224 8,453.82 10.30 1.43 0.0001 0.43

Table- Energy Analysis in Aerobic rice

Energy input • Energy inputs expressed in absolute terms for seed, fertilizers, insecticides,

irrigation etc were the same for all treatments except weed management treatments

• Fuel (Diesel, Electricity) is the largest component of total energy input.• Next largest component is fertilizer .• Herbicides represent a small portion of total energy input. The energy input

levels for weed control represent only 3-4% of total energy input.• Direct measures of weed control are likely to be affected slightly by the

changing energy situation.

• Highest energy input was recorded by need based hand weeding because it required a higher number of labour i.e human energy and lowest by unweeded control.

• Mechanical weeding required lower input than chemical weed control and manual weeding

• Among chemical treatments, pendimethalin fb (clorimuron + metsulfuron methyl) and pretilachlor fb (clorimuron+ metsulfuron methyl) used lower energy input.

Energy Output• Highest gross and net energy output was from need

based hand weeding as well as pendimethalin fb bispyribacsodium and butachlor fb bispyribacsodium application due to better weed management, resulted in higher yields.

• Energy ratio, Specific energy, energy productivity and energy profit can define the efficiency and performance of the test treatments. High energy ratio, high energy productivity, high energy profit and low specific energy were recorded by need based hand weeding as well as pendimethalin fb bispyribacsodium

ConclusionsThe net energy returns of different weed

management practices can be quantified and stratified for proper planning of sustainable aerobic rice production system.

In the present investigation, among different weed management treatments, need based hand weeding as well as Sequential application of Pendimethaline followed by Bispyribacsodium gave higher energy profit, energy ratio and energy productivity.

Unweeded treatment without weed management cannot be practical.

THANK YOU….