East Africa's grasses and fodders

Tasks for vegetation science 29

Series Editors

HELMUT LIETH

University ofOsnabrock, Germany

HAROLD A. MOONEY

Stanford University, Stanford, Calif., US.A.

East Africa's grasses and fodders:Their ecology and husbandry

Joseph G. BOONMANIndependent Consultant

Formerly of Kitale (Kenya)

•

Springer-Science+Business Media, B.V.

Library of Congress Cataloging-in-Publication Data

Boonman. J. G.East Africa's grasses and fodders : ecology and husbandry I J.G.

Boonman .p. cm. -- (Tasks for vegetarIan scIence; 29)

Includes bIblIographical references (p. ) and Index.ISBN 978-90-481-4176-0 ISBN 978-94-015-8224-7 (eBook)DOI 10.1007/978-94-015-8224-7I. Forage plants--Afrlca. East. 2 . Grasses--Afrlca. East.

3. Pastures--Afrlca. East. 4. Grassland ecology--Afrlca. East.I. TItle . II. Series.SBI93.3.A353B66 1992633.2'02'0967--dc20 92 -23961

Printed on acid-free paper

This book was partly financed by the Netherlands Minister for Development Cooperation. Responsibility for thecontents and for the opinions expressed rests solely with the author; publication does not constitute an endorsement bythe Netherlands Minister for Development Cooperation.

All Rights Reserved© Springer Science+Business Media Dordrecht 1993Originally published by Kluwer Academic Publishers in 1993.Softcover reprint of the hardcover Ist edition 1993

No part of the material protected by this copyright notice may be reproduced or utilized in anyform or by any means, electronic or mechanical, including photocopying recording

or by any information storage and retrieval system, without written permissionfrom the copyright owners.

To EUy, my wife and home-editor whohelped this book develop with more patienceand encouragement than I had any right toexpect

TABLE OF CONTENTS

Series editor's preface

PART I: GENERAL1. INTRODUCTION

1.1 Grasses for livestock, soils and environment1.2 Schools of thought1.3 Towards more intensive strategies1.4 This book's approach

2. HISTORY OF GRASSLAND DEVELOPMENT (1900-1970)2.1 Uganda

2.1.1 Green-manure crops2.1.2 Grass rests in the crop rotation

2.2 Kenya2.2.1 Veterinary control2.2.2 Farmers' introductions

2.3 East Africa as a "gene centre"2.4 The start of grassland research in East Africa

2.4.1 Early locations of grassland research2.4.2 Mineral deficiencies (1920s)2.4.3 Ecological approach (1930s)2.4.4 Soil conservation

2.5 New varieties and commercial seed multiplication2.6 Summary

3. THE GRASSLAND ENVIRONMENT3.1 Climate of eastern Africa (l5°N-15°S)

3.1.1 Rainfall3.1.2 Temperature

3.1.2.1 Temperature zones3.2 Soils3.3 The natural grassland environment

3.3.1 Grassland mapping3.3.1.1 Ecological classification3.3.1.2 Vegetation types3.3.1.3 Ecological and physiognomic classification

3.3.2 Semantics3.3.3 Primary and secondary grasses

3.4 Proposed zonation for grassland improvement3.4.1 Zone I (Afro-alpine)

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3.4.2 Zone II (Humid to subhumid)3.4.2.1 Zone I1K1 (Kikuyugrass zone, 1750-3000 m)3.4.2.2 Zone lIsT (Stargrass zone, 1250-1750 m)3.4.2.3 Zone I1EL (Elephantgrass zone, < 1250-1500m)3.4.2.4 Zone II (Coastal areas)

3.4.3 Zone III-high (> 1000m)3.4.3.1 Zones II +III -low (Coastal areas)

3.4.4 Zone IV3.4.5 Zones V and VI

3.5 Summary

4. HUSBANDARY OF NATURAL GRASSLAND4.1 Legumes in natural grassland4.2 Secondary grasses and their communities

4.2.1 Kikuyugrass4.2.1.1 Ecology of Kikuyugrass4.2.1.2 Kikuyu grassland improvement

4.2.2 Stargrass4.2.2.1 Ecology of Stargrass and general aspects4.2.2.2 Star grassland improvement

4.2.3 Elephantgrass4.2.4 Other natural grassland communities of Zone II

4.3 Primary grasslands of Zones III and IV4.3.1 Grazing and botanical composition

4.3.1.1 Rotational grazing4.3.2 Weed- and bush control

4.3.2.1 Acacia control in Ankole, western Uganda4.3.2.2 Reseeding in West Pokot, Kenya

4.3.3 Burning4.3.4 Mowing for conservation4.3.5 Oversowing

4.3.5.1 Seed establishment4.3.6 Fertilizers

4.4 Grassland at the coast4.5 Fallow (post-cultivation) grass communities

4.5.1 African Couchgrass (Digitaria abyssinica)4.5.2 Ecology and zonation of cultivated and weed grasses

4.6 Summary

5. FROM SHIFTING CULTIVATION TO CROP-GRASS ROTATIONS5.1 Steps in crop intensification

5.1.1 Conventional bush fallow (shifting cultivation)5.1.2 From bush- to weed fallow5.1.3 Continuous cropping

5.2 The control of soil fertility5.2.1 Green manures (leguminous)5.2.2 Kraal manure

5.2.2.1 Composition and effects of manure5.2.2.2 Manure logistics5.2.2.3 Night paddocks

5.3 The role of grass in the crop rotation

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5.3.1 Organic matter under grasses5.3.2 Soil-chemical effects of grasses5.3.3 Soil-physical effects of grasses

5.3.3.1 Differences between organic manures and grasses5.3.4 Grass roots and soil structure5.3.5 Soil erosion

5.4 Ley farming in Europe5.5 Crop-grass rotation experiments in East Africa5.6 Mixed-farming today

5.6.1 How to project cultivated grasses?5.7 Summary

6. SPECIES OF CULTIVATED GRASSES6.1 Potential species

6.1.1 Geographical and environmental restrictions6.1.1.1 Environmental interactions6.1.1.2 Zonation of cultivated grasses

6.1.2 Practical restrictions to numbers of species6.2 Inputs alternative to genotype6.3 Grass species performance criteria

6.3.1 Herbage yield6.3.2 Drought tolerance6.3.3 Persistence6.3.4 Nutritive value6.3.5 Ease of management

6.4 Ecological significance of gene centre6.4.1 Gene centre of southern Africa

6.5 Major cultivated pasture and fodder species6.6 Rhodesgrass (Chloris gayana)

6.6.1 Adaptation6.6.2 Husbandry6.6.3 Ecotypes6.6.4 Commercial varieties in East Africa

6.7 Setaria (Setaria sphacelata)6.7.1 Adaptation6.7.2 Husbandry6.7.3 Animal production and nutritive value

6.8 Common Guineagrass (Panicum maximum)6.9 Buffelgrass (Cenchrus ciliaris)6.10 Molassesgrass (Melinis minutifiora)6.11 Signalgrass (Brachiaria spp.)6.12 Coloured Guinea (Panicum coloratum)6.13 Hyparrhenia rufa6.14 Stargrass (Cynodon spp.); Kikuyugrass (Pennisetum clandestinum)6.15 Temperate grasses6.16 Miscellaneous cultivated grasses6.17 Summary

7. THE ESTABLISHMENT AND HUSBANDRY OF SOWN GRASSES7.1 The first year: grass establishment

7.1.1 Direct sowing of grass seed

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7.1.2 Date of sowing7.1.3 Harrowing, rolling and sowing7.1.4 Depth of sowing7.1.5 Broadcast sowing7.1.6 Sowing in rows7.1.7 Grass seed rate7.1.8 P-fertilizer in the seedbed7.1.9 N-fertilizer in the seedbed7.1.10 Weed control

7.1.10.1 Weed species7.1.10.2 Chemical control

7.1.11 Early pasture husbandry after direct sowing7.1.12 Undersowing

7.1.12.1 Undersowing to maize7.1.12.2 Undersowing to wheat

7.2 The following years: pasture husbandry7.2.1 Mixed-farming and rotational grazing7.2.2 Seasonality in pasture production

7.2.2.1 Dry season7.2.2.2 Seasonality within the rainy season

7.2.3 Manipulation of grass availability7.2.3.1 The variation in age of the sown pasture

7.2.4 Fertilizers on sown and grazed pastures7.2.4.1 N-topdressing7.2.4.2 Strategic N-application7.2.4.3 P-topdressing

7.2.5 Mowing as a husbandry tool7.2.5.1 Mowing for conservation7.2.5.2 Mowing as "topping"

7.2.6 Last-year pasture as holding ground7.2.7 Other practical management aspects7.2.8 Recommendations7.3 Summary

8. GRASS SEED PRODUCTION IN KENYA8.1 The Kenya grass seed sector8.2 Systems of contract seed production8.3 Home-grown seed8.4 Husbandry of grass seed production

8.4.1 The first year's seed crop8.4.2 Seed harvesting

8.5 Post-establishment crops8.5.1 Rate and time of N-application8.5.2 The effect of season

8.6 Causes of low seed yields in tropical grasses8.6.1 Low seed yield in vegetatively propagated grasses

8.7 Field studies on seed formation processes8.7.1 Tillering and heading8.7.2 Spikelet development

8.7.2.1 Spikelet weight (lOoo-seed weight)8.7.2.2 The Purity and Germination Capacity (PGS)

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8.7.2.3 PGS and harvest date8.7.2.4 Seed shedding8.7.2.5 Spikelet diseases and pests

8.7.3 Seed recovery8.8 Conclusion8.9 Summary

9. GRASS BREEDING AT KITALE9.1 Variety maintenance9.2 Source material for breeding9.3 Breeding methods9.4 Heading date (maturity class)

9.4.1 Heading date and plant vigour9.4.1.1 Vigour and plant type

9.5 Gross and net variation in dependent characters9.5.1 Heading date and seeding characters9.5.2 Heading date and herbage characters9.5.3 Genetic correlations in Nandi Setaria

9.6 Variety trials9.7 Breeding Elephantgrass9.8 Apomixis9.9 Conclusion9.10 Summary

10. LEGUMES IN SOWN AND GRAZED PASTURES10.1 The clover model10.2 Nitrogen fixation

10.2.1 Amounts of nitrogen fixation and transfer10.2.2 The nutritive value of legumes

10.3 Husbandry of Desmodium-based pastures10.3.1 Disappearance under rational grazing

10.4 Approaches to the problem of legume persistence10.5 Other causes of legume disappearance10.6 Legumes in early research in East Africa10.7 How to maintain Desmodium in grazed pastures10.8 Legumes in experimental grazing practice

10.8.1 Desmodium uncinatum (Silverleaf);10.8.2 Desmodium intortum (Greenleaf);10.8.3 Glycine (Neonotonia wightii)10.8.4 Siratro (Macroptilium atropurpureum)10.8.5 Centro (Centrosema pubescens)10.8.6 Townsville Stylo (Stylosanthes humilis)10.8.7 Stylo (Stylosanthes guianensis)10.8.8 Stylosanthes fruticosa10.8.9 Other species of Stylosanthes10.8.10 Lotononis bainesii10.8.11 Calopo (Calopogonium mucunoides)10.8.12 Other tropical legumes

10.9 High-altitude pasture legumes10.9.1 Kenya white clover (Trifolium semipilosum)10.9.2 White clover (Trifolium repens)

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10.9.3 Subclover (Trifolium subterraneum)10.9.4 Miscellaneous annual clovers

10.10 Conclusion10.11 Summary

PART II: FODDERS

11. ELEPHANTGRASS AS FODDER CROP11.1 General introduction11.2 Name and natural distribution11.3 Importance as a cultivated plant

11.3.1 Soil regeneration11.3.2 Dry-season grazing11.3.3 Mulching11.3.4 Stall-feeding and zero-grazing

11.4 A re-appraisal of Elephantgrass11.5 Growth habit11.6 Tillering and leaf characteristics11.7 Elephantgrass varieties

11.7.1 Varieties and varietal identification11.7.2 French Cameroons11.7.3 Gold Coast (alias Bana)11.7.4 Clone 13

11.8 Diseases and pests11.8.1 White mould (Beniowskia sphaeroidea)11.8.2 Stunting disease11.8.3 Pests11.8.4 Disease and quality control

11.9 Herbage yields of Elephantgrass11.9.1 Yield in relation to Eco-climatic Zone

11.10 Drought tolerance11.11 Summary

12. ELEPHANTGRASS HUSBANDRY12.1 Establishment

12.1.1 Vegetative propagation12.1.2 Costs of planting12.1.3 Cost and labour efficiency of operations

12.2 Weed control12.2.1 Interrow cultivation12.2.2 Herbicides

12.3 Eradication by ploughing12.4 Plant density12.5 Harvest interval12.6 Stubble height12.7 Manure and fertilizer

12.7.1 Animal manure on and off zero-grazed Elephantgrass12.7.2 N-fertilizer

12.7.2.1 Rate and time of N-application12.7.2.2 Interaction of N-rate and harvest interval12.7.2.3 N-fertilizer and herbage nutritive value

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12.7.2.4 N-fertilizer requirements under zero-grazing12.7.2.5 N-fertilizer requirements under direct grazing

12.7.3 P-fertilizer12.7.3.1 The soil-P status under zero-grazing12.7.3.2 Animal requirements of phosphate

12.7.4 K-fertilizer12.7.5 Other minerals12.7.6 Zero-grazing and subsequent cropping.

12.8 Association with legumes12.8.1 A review of research work in East Africa12.8.2 The legume-grass balance12.8.3 Animal performance and nutritive value12.8.4 General considerations on Desmodium mixtures

12.9 Summary

13. ELEPHANTGRASS UTILIZATION13.1 Nutritive value

13.1.1 Dry matter (%)13.1.2 Sward heterogeneity

13.2 Leaf stripping in the dry season13.2.1 Spelling during the rainy season

13.3 Cutting versus grazing13.3.1 Soil mineral composition after cutting or grazing13.3.2 Yield and quality under cutting versus grazing13.3.3 Economics of zero-grazing13.3.4 Wastage13.3.5 Grazing Elephantgrass

13.4 Alternative crops or grasses for zero-grazing13.4.1 Green maize13.4.2 Maize stover compared with Elephantgrass13.4.3 Other grasses and fodders

13.5 General conclusion13~5.1 Elephantgrass13.5.2 Stall-feeding13.5.3 Zero-grazing13.5.4 A husbandry package for Elephantgrass

13.6 Summary

14. ALTERNATIVE FODDER GRASSES14.1 Giant Setaria14.2 Giant Guinea14.3 Guatemalagrass14.4 Summary

15. GRASS SORGHUM15.1 Origin and classification15.2 Sorghum types

15.2.1 Fodder Sorghum15.2.2 Sudangrass15.2.3 Columbusgrass15.2.4 Other natural hybrids

15.2.4.1 Perennial Kavirondo Sorghum

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15.2.5 Artificial hybrids15.3 Adaptation and use15.4 Husbandry

15.4.1 Establishment15.4.2 Utilization and choice of type of Sorghum15.4.3 Fertilizers

15.5 Nutritive value15.5.1 Toxicity

15.5.1.1 Sulphur (S)15.6 Diseases and pests

15.6.1 Leaf blight15.6.2 Pests15.6.3 Witchweed (Striga)

15.7 Seed production15.8 Silage15.9 Pearl millet15.10 Conclusion15.11 Summary

16. FODDER OATS16.1 Versatility of oats for fodder or grain16.2 Varieties16.3 Establishment and husbandry16.4 Nutritive value16.5 Summary

17. LUCERNE17.1 Varieties17.2 Establishment17.3 Soils and fertilizers17.4 Weed control17.5 Husbandry and utilization17.6 Nutritive value17.7 Diseases and pests17.8 Summary

18. OTHER (NON-GRAMINACEOUS) FODDER CROPS18.1 Fodder rape18.2 Kale18.3 Fodder beets and mangolds18.4 Sweet potato18.5 Leguminous fodder crops

18.5.1 Lablab or Njahi beans18.5.2 Velvet beans18.5.3 Lupins18.5.4 Vetches18.5.5 Hubam clover18.5.6 Leucaena leucocephala and other leguminous shrubs18.5.7 Additional legumes in East African literature

18.6 Miscellaneous fodder crops18.6.1 Chichory18.6.2 Russian Comfrey

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18.6.3 Canna18.6.4 Amaranthus spp.

18.7 Summary

19. HAY AND SILAGE19.1 Hay and silage of grasses

19.1.1 Haymaking19.1.2 Grass silage

19.2 Maize silage19.3 Summary19.4 General conclusion on fodders

Glossary (main species)Abbreviations and unitsReferencesIndex

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Series editor's preface

The series Tasks for Vegetation Science is devoted to a variety of research aspects in vegetation science,pure as well as applied . Of the applied problems one of the most pressing is to achieve better knowledge andimprovement of the pasture vegetation in tropical and subtropical regions.

As series editor I was impressed by the sheer volume of useful scientific information concerning pastureplants from East Africa collected during many years by Dr. Boonman and compiled in one manuscript.

Dr. Boonman first came to East Africa in 1963 on an overland journey along the river Nile which tookhim from Alexandria in Egypt to Lake Victoria in Uganda and Kenya and back again. After a brief spell asa cotton agronomist in the Sudan Gezira he joined the grassland research team at Kitale, Kenya in 1966.Improvement of seed yield of tropical grasses was his principal interest which finally led him into the field ofbreeding grasses. Well-known varieties from his work include Boma & Elmba Rhodesgrass as well as Clone13 Elephantgrass. In 1979 he was recalled to The Netherlands to head a cooperative seed company involvedin the breeding of grasses and cereals.

The author has focused this study on one region, Eastern Africa. Global application of theories runs intoconflicts too easily with local types of farming, if not with bare economics. Very few books can be foundthat describe existing practices and seek local answers by digging deep in the stacks of old, local reports .There is a wealth of knowledge available that is not being used. The author intends, in this volume, to openways to this wealth of literature.

A great deal of success in farming has been achieved with the well-known species of Elephantgrass andRhodesgrass. It is, therefore, time that empirical evidence and research information are brought together.Much counter-productive debate is avoided if the correct information is available. It then emerges thatmuch was done in the past on what is now known as agro-forestry or sustainable farming. Maintaining soilfertility through a temporary productive grass cover was recognized early on as a valuable legacy ofconventional agriculture, especially when integrated closely with grazing livestock. This has formed thebasis of the successful systems of mixed farming as we know them in East Africa.

The series editor hopes that this volume contributes to the general improvement of pastures in Africa andthe other tropical regions of the world.

Osnabriick, December 1992

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Helmut Lieth