Manual on integrated soil management and conservation practices

Manual on integrated soil management and conservation practices iii Foreword The processes of land erosion in various regions of Latin America and Africa have their origin in social, economic and cultural factors that translate into the over-exploitation of the natural resources and the application of inadequate practices for the management of soils and water The consequences of this are damage to much of the agricultural land, with detrimental effects on food production for the growing population in these continents Over the last few decades, many efforts have been made to stop the degradation of agricultural land but the process of adoption of new conservationist technologies by the farmers is still slow Furthermore, the availability of technical personnel trained for this change is limited The technological strategies that have been developed for the management and conservation of soil and water sometimes are not adapted for the beneficiaries, because they could not participate in the processes of the diagnosis, planning and execution of the actions In addition, the promotion of conservation tillage systems and practices that were not adapted to specific regional requirements has created credibility problems with the farmers probably since they had been developed in other places and introduced without a correct diagnosis of the local situation The development of technologies that guarantee the maintenance of agricultural land productivity in Latin America and Africa is a challenge that both technicians and farmers must face through collaborative research and field work in the farmers’ own environments and conditions This includes identification of the problems of management and conservation of soils and water and a greater emphasis on the evaluation of the potential for systems of conservation tillage adapted to the specific conditions of each region This Manual has been put together with the objective of assisting actions by the diverse groups of human beings who intervene in the conservation of the natural resources, particularly soil and water resources and in the context of each continent, country, region or zone The Manual brings together a collection of concepts, experiences and practical suggestions that can be of immediate use for identifying problems and for formulating, executing and evaluating actions so as to benefit and to improve the productivity and conservation of soil and water resources This Manual is based on the Training Course for Soil Management and Conservation, focused particularly on efficient tillage methods for soil conservation, held at the International Institute of Tropical Agriculture (IITA) in Ibadan, Nigeria from 21 April to May 1997 It was jointly organized by IITA and FAO with the participation of specialists from both national and international organizations The publication serves as a guide that will allow technicians and farmers to jointly discover ways to solve the problems and the limitations posed by land degradation in Latin America and Africa Participatory action by technicians and farmers will be the basis for success in benefiting these regions It is hoped that the Manual will help to attain the ultimate objective, which is to improve the productivity of the soils and water in a rapid and efficient manner iv Acknowledgements The present Manual is based on the Training Course on Soil Management and Conservation with Special Emphasis on Conservation Effective Tillage Methods jointly organized by José Benites, Land and Plant Nutrition Management Service (AGLL) and Theodor Friedrich, Agricultural Engineering Branch (AGSE), FAO and the International Institute of Tropical Agriculture (IITA) in Ibadan, Nigeria The training course would not have been possible without the active support of the Director General of IITA, Lucas Brader, as well as his staff, in particular R Booth, J Gulley, R Zachmann, R Carsky, Y Osinubi, B Akisinde, G Kirchof and G Tian and we would like to express our gratitude for this support We would further like to thank the authors of the different papers for their collaboration in this publication, particularly Elvio Giasson, Leandro Prado Wildner, José Barbosa dos Anjos, Valdemar Hercilio de Freitas and Richard Barber, as well as Cadmo Rosell, John Ashburner, Robert Brinkman and R Dudal for assisting with the editing of the different language versions Special thanks are due to Lynette Chalk for her efficient preparation of the text and formatting of this document and Riccardo Libori for his elaboration of the graphics Manual on integrated soil management and conservation practices v Table of contents Page FOREWORD iii A CKNOWLEDGEMENTS iv INTRODUCTION Objectives Structure and content KEY ENVIRONMENTAL AND SOIL FACTORS INFLUENCING PRODUCTIVITY AND MANAGEMENT Topography Rainfall Soil limitations Soil conditions Productivity 2 5 12 GENERAL PRINCIPLES FOR THE DEVELOPMENT OF SOIL MANAGEMENT STRATEGIES Objectives of soil management for agriculture Principles for the development of soil management practices 13 13 14 CONCEPTS AND OBJECTIVES OF TILLAGE IN CONSERVATION FARMING Why conserve the soil? The concept of integrated management – conservation farming Technical tillage parameters 27 27 28 32 TILLAGE IMPLEMENTS Moldboard plough Disc implements Chisels Spike-toothed tines – levellers and harrows Rotary cultivators (rotavators) Rollers Direct drilling - zero tillage 37 37 38 40 42 42 42 43 IMPLEMENTS AND METHODS FOR THE PREPARATION OF AGRICULTURAL SOIL Objectives of soil preparation Implements for soil preparation 45 46 47 EFFECT OF TILLAGE ON SOIL PHYSICAL PROPERTIES Causes of physical soil degradation Stages in the physical degradation of soil Principal physical characteristics affected by tillage 51 51 52 52 PRINCIPAL TILLAGE METHODS Terminology, definitions and classification of tillage systems Principal types of tillage system 55 55 57 vi Page Strip tillage or zonal tillage Ridge tillage Combined tillage and seeding systems Subsoiling LAND USE ACCORDING TO ITS CAPABILITY Land evaluation 69 70 75 76 81 81 10 SOIL COVER 87 11 CONTOUR FARMING 91 12 GREEN MANURE Concept Functions of green manure Characteristics to consider when selecting types of green manure Characteristics of green manure Management of green manure Effects of green manure on the soil properties 93 93 93 94 95 99 102 13 PHYSICAL BARRIERS FOR THE CONTROL OF RUNOFF Terracing Safe waterways 113 113 120 14 GULLY CONTROL Concept Gully dimensions Measures for control and stabilization 125 125 125 126 15 RAINWATER CAPTURE AND IRRIGATION Principal factors affecting the establishment of systems for rainwater capture Methods for in situ rainfall capture Irrigation aspects 131 131 132 137 16 SELECTION OF ALTERNATIVE TECHNOLOGIES Information sources concerning alternative technologies Technology selection on the basis of farmers’ circumstances Technology selection on the basis of environmental considerations Technology selection on the basis of “Problem – Solution” relationships Reflections concerning the selection of soil management technologies 143 143 143 145 146 166 17 PARTICIPATORY PLANNING IN THE EXECUTION OF SOIL MANAGEMENT PROGRAMMES Micro-catchment areas as planning units Implementation of programmes and projects Objectives of a programme and project Enthusiasm as the driving force for development Success – the source of enthusiasm Participation - the road to follow Destructive participation How to improve constructive participation How to increase participation Some criteria for selecting an appropriate technology 169 170 171 171 172 172 173 173 174 174 178 Manual on integrated soil management and conservation practices vii Page Participating with the rural families in planning the soil management practices Community planning Making thematic maps Establishing priorities for the actions to be undertaken in the microcatchment basin Formulation of projects Conservation farm planning Community mapping Implementation of soil management plans 179 180 181 182 182 183 183 184 BIBLIOGRAPHY 187 A NNEXES Comparison of field work rates with tillage implements Purchase and maintenance costs for tillage implements Notebook for participatory planning in our community 197 197 199 201 viii List of tables Page Training course on “Methods of soil management and conservation: efficient tillage methods for soil conservation” Mulch cover and soil loss from two simulated rainfalls 15 Average effect of the nature and orientation of crop residues on the erosion of a sandy loam soil by wind at a uniform velocity 15 Effects of mulch cover and the type of tillage on the amount of moisture (mm) stored in 120 cm soil depth Faizabad, India 17 Types of tillage and their effect on the moisture, temperature and rate of emergence for cowpea and soybean 17 Application of mulch and the quantity of earthworm casts 18 Effects of cover crops on infiltration rates with and without earthworm activity 19 Straw production and the relationships of C/N and of the grain/straw weight for annual crops, Santa Cruz, Bolivia 21 Effects of deep tillage on some physical properties and on root development in a compacted soil 24 10 Work rates per unit area needed to carry out a selection of agricultural tasks on the farm 46 11 Effect of tillage systems on the soil density and porosity 53 12 Quantity of residues remaining on the soil after different tillage treatments 56 13 Tillage systems classified according to the degree of disturbance to the soil and the surface cover of residues 57 Moisture content, residue cover and maize yield for four tillage systems in Oxford, North Carolina, USA 62 15 Working characteristics of the chisel plough for stubble 63 16 Effect of tied ridges on the yields of different crops in Tanzania 71 17 Effects of tillage on runoff and soil loss for soils cultivated with maize in Nigeria 72 18 Guide-table for definition of the classes and sub-classes of land use capability for group soils of the Lageado Atafona catchment basin, Santo Ângelo, Brazil 86 14 Manual on integrated soil management and conservation practices ix Page 19 Evaluation of the effect of increasing the quantity of maize residues in the soil cover on the runoff flow, the runoff velocity and the total soil losses 88 Effect of the annual crop type on soil losses by erosion Average rainfall of 300 mm and a slope between 8.5 and 12.8 percent 89 Effect of the type of perennial crop or vegetation on erosion losses of soil Weighted averages for three soil types in the State of São Paulo, Brazil 89 Losses of soil and water during the growth cycles of soybean, wheat, maize and cotton in a red dystrophic latosol soil and a slope of percent 89 Total soil losses in plots with a 7.5 percent slope for a Red-yellow podsolic soil under simulated rainfall of 64 mm/h and with different quantities of crop residues 90 24 Chemical composition of some residues used as a dead vegetative cover 90 25 Percentage of soil cover as a function of the management of residues from different crops 90 26 Effect of management and conservation practices on erosion losses under annual crops 91 27 List of the main species used as green manure and soil cover 96 28 Production of biomass and analysis of the nutrients in the vegetative cover of winter green manure species evaluated at the CPPP 106 Nutrient content of the components (stems and leaves) of summer cycle annual species with a potential for use as a green manure, soil cover and for soil recovery 106 Nutrient content of the stems and leaves of winter cycle, semi-perennial and perennial species with a potential for use as a green manure, soil cover and for soil recovery 107 Effect of different species of green manure for controlling nematodes in a dark-red latosol soil (LE) from Cerrado 108 Allopathic effect of crops and species used for green manure (Bidens alba), on the germination of seeds from a selection of weeds 109 33 Length, slope and drop in level for graded terraces 119 34 Recommended spacing for bench terraces 122 35 Construction recommendations for the spacing of staked structures in gullies 127 36 Monthly rainfall recorded at Petrolina, PE, Brazil for the period 1985 – 1994 132 37 Values of the Tank Coefficient for a Class A tank (Kp) for estimated values of the reference rate of evapo-transpriration 141 Limitations, causes and elements of possible soil management solutions 147 20 21 22 23 29 30 31 32 38 200 Annex – Purchase and maintenance costs for tillage implements Implements with vertical tines a b c Stubble mulch chisel plough Change all points every years 450 Vertical tined Vibro-cultivator (imported) Change all 34 points every years 700 Rotary mower Change the knives twice per year Change the belts twice per year Change the oil three times per year Total Note: 400 400 200 150 These costs are calculated over a ten-year period for a farm of 100 The labour charges are not included for changing the discs, bearings and knives, or for lubrication It is considered that each implement will complete a total of passes per year and that the discs and points will be changed after 000 of tillage SUMMARY OF THE PURCHASE AND TOTAL 10-YEAR MAINTENANCE COSTS FOR THE MAIN TYPES OF TINED AND CONVENTIONAL TILLAGE IMPLEMENTS (IN US DOLLARS ) Conventional tillage implements “Rome plough” Light-weight disc harrow Total 600 225 14 825 Implements with vertical tines Stubble mulch chisel plough Vertical tined Vibro-cultivator Rotary mower Total * Prices shown in brackets refer to implements fabricated at Santa Cruz 950 (2 950)* 800 (2 400) 000 (3 000) -10 750 (8 350) Manual on integrated soil management and conservation practices 201 Annex Notebook for participatory planning in our community Part Who we are Living in our community are: (F)1,A Families (P)1,B Persons (M)1,C Women (H)1,D Men (+65)1,E More than 65 years old (+14)1,F More than 14 years old (+7)1,G More than years old but under 14 (-7)1,H Under years old V Hercilio de Freitas Brazilian Enterprise for Agricultural Research and Rural Extension Santa Catarina, Brazil (EPAGRI) 202 Annex – Notebook for participatory planning in our community Part Where we are Our community is situated in: 2.1 Continent 2.2 Country 2.3 State 2.4 County 2.5 Main catchment basin 2.6 Sub-catchment basin 2.7 Micro-catchment basin 2.8 Community Manual on integrated practices of soil management and conservation 203 Part What we have Organization of our community (A)3.1 Our community has of land (AF)3.2 Each family has an average of of land (D)3.3 The distance of our community from town is km (E)3.4 Our community has schools (I)3.5 Our community has churches (O)3.6 Our community has _community associations and organizations (L)3.7 The principal community leaders are: _ _ (AE)3.8 Our community has piped water supplies ( ) Yes ( ) No (RE)3.9 Our community is connected to the electrical grid system ( ) Yes ( ) No (T)3.10 Our community has a collective transport system (TE)3.11 Our community has a telephone ( ) Yes ( ) No ( ) Yes ( ) No 204 Annex – Notebook for participatory planning in our community Part What our environmental problems consist of The problems of environmental pollution in our community can be considered Evaluation grade Adequate (1) Aspects considered (L) Domestic refuse (ES) Industrial waste (AG) Use of agro-chemicals (ER) Water erosion (D) Sewage Other problems Tolerable (2) Evaluation Worrying (3) Why? Serious (4) Very serious (5) Manual on integrated practices of soil management and conservation 205 Part What our socio-economic problems consist of Our socio-economic problems may be considered Evaluation grade Adequate (1) Aspects considered (S) Health (AN) Literacy (AP) Potable water (L) Electricity (AL) Food (M) Housing (ES) Roads (T) Transport (RE) Income Others Tolerable (2) Evaluation Worrying (3) Why? Serious (4) Very serious (5) 206 Annex – Notebook for participatory planning in our community Part What our relations are with nature What is the importance to our community of the natural resources of soil and water? Evaluation grade Adequate (1) 6.1 Soil (L) Tillage (P) Livestock (F) Forests Others 6.2 Water (CH) Drinking water (I) Industrial (IR) Irrigation (L) Domestic (CA) For animal consumption (O) Others Tolerable (2) Worrying (3) Evaluation Why? Serious (4) Very serious (5) Manual on integrated practices of soil management and conservation 207 Part Which are the soil management problems in our community? The soil management problems in our community can be considered: Evaluation grade Adequate (1) Tolerable (2) Soil (F) Fertility (C) Compaction (M) Excessive equipment traffic (FC) Lack of vegetative cover (Q) Burning of crop residues (I) Incorporation of crop residues (E) Soil erosion (V) Gullies (NM) Levels of organic matter (AM) Water storage (U) Use of the soil beyond its true capability Others Worrying (3) Evaluation Serious (4) Why? Very serious (5) 208 Annex – Notebook for participatory planning in our community Participatory action in the plan of execution LISTING THE ORDER OF PRIORITIES FOR THE ACTIONS How can we solve the problems of environmental contamination in our community? How can we solve the socio-economic problems in our community? How can we solve the soil management problems of our community? Manual on integrated practices of soil management and conservation What can assist solving our environmental contamination problems? When can we solve the problems of environmental contamination? When can we solve the socio-economic problems of the community? 209 210 Annex – Notebook for participatory planning in our community When can we solve our soil management problems? WORK PLAN / OPERATIONAL PLAN / CALENDAR OF ACTIONS Community projects Objectives (What we are going to do) Methodology (How we are going to it) Responsibilities (Who is going to it) Timing (When we are going to it) Comments Manual on integrated practices of soil management and conservation 211 WORK PLAN / OPERATIONAL PLAN / CALENDAR OF ACTIONS Group projects Objectives (What we are going to do) Methodology (How we are going to it) Responsibilities (Who is going to it) Timing (When we are going to it) Comments 212 Annex – Notebook for participatory planning in our community Thematic maps of the diagnosis THEMATIC MAP OF THE ENVIRONMENTAL DIAGNOSIS This map is prepared on the basis of the information placed in the participatory notebook (Part 4), as these refer to environmental problems in the micro-catchment basin INDICATOR SYMBOL LEGEND ENVIRONMENT ER Domestic waste (L) Industrial waste (ES) Use of agro-chemicals (AG) Water erosion (ER) Animal waste (D) Other problems (O) AG L O ES D O SYNTHESIS OF THE ENVIRONMENTAL DIAGNOSIS Micro-catchment basin Community 01 02 03 04 05 Total (L) (ES) (AG) (ER) (D) (O) Manual on integrated practices of soil management and conservation 213 THEMATIC MAP OF THE SOCIO-ECONOMIC DIAGNOSIS This map is prepared on the basis of the information placed in the participatory notebook (Part 5), as these refer to socio-economic problems SYMBOL INDICATOR LEGEND SOCIOECONOMY Health (S) Education (E) Income (R) Potable water (AP) Electricity (LU) Food (AL) Housing (MO) Roads (ES) S E R ES MO AP AL LU SYNTHESIS OF THE SOCIO-ECONOMIC DIAGNOSIS Micro-catchment basin Community 01 02 03 04 05 Total (S) (E) (R) (AP) (LU) (AL) (MO) (ES) 214 Annex – Notebook for participatory planning in our community THEMATIC MAP OF SOIL MANAGEMENT PROBLEMS This map is prepared on the basis of the information placed in the participatory notebook (Part 7), as these refer to soil management problems in the micro-catchment basin INDICATOR SYMBOL Fertility (F) Compaction (C) LEGEND SOIL MANAGEMENT Excessive equipment traffic (M) F Lack of vegetative cover (FC) Burning of crop residues (Q) Incorporation of crop residues (I) Rill erosion (E) Gullies (V) Organic matter content (NM) C M O U FC Q AM Water storage (AM) Soil use beyond its capability (U) Others (O) NM V I E Synthesis of the soil management diagnosis Micro-catchment basin Community 01 02 03 04 05 Total (F) (C) (M) (FC) (Q) (I) (E) (V) (NM) (AM) (U) (O) ... for soil conservation • General principles for the development of soil management strategies Manual on integrated soil management and conservation practices Soil tillage • • • • Concept and. .. 164 42 Guide to the selection of soil conservation practices for different crops and slopes in El Salvador 165 40 Manual on integrated soil management and conservation practices xi List of figures... development of soil management practices 13 13 14 CONCEPTS AND OBJECTIVES OF TILLAGE IN CONSERVATION FARMING Why conserve the soil? The concept of integrated management – conservation farming Technical