Rainfed agriculture is associated with crop production without supplemental irrigation, and a relatively lesser quantity of annual rainfall is being used for crop cultivation. From a historical perspective, rainfed croplands meet about 60% of the food and nutritional needs of the World’s population and are the mainstay of marginal and subsistence farmers, including India. By 2050, the world will need to produce 70% more food to nourish its ever-growing population of 9.7 billion. It is necessary to fabricate a sufficient quantity of quality and nutritious food by using the scarce natural resources in the climate change era. Of India’s 329 million hectares of geographical area, nearly 140 million hectares are net sown area and out of it 70 million hectares is rainfed. The future of India’s food and livelihood security will depend on the progress in improving the productivity of the rainfed areas. The book “Rainfed Agriculture and Watershed Management” has been written to fulfill the requirement of undergraduate and post-graduate students of agriculture and allied sciences considering the syllabus of ICAR. This book attempt to present the recent up-to-date information on dryland/rainfed agriculture and watershed management with appropriate illustrations. This book contains chapters like, an introduction to rainfed agriculture, farming and climate classification, history and development of rainfed agriculture, climate of rainfed agro-ecosystems, soils prevalent in rainfed agro-ecoregions, abiotic stresses affecting crop production in rainfed regions, crop adaptation mechanisms to abiotic stresses, untapped yield potential of crops in rainfed regions, constraints for crop production in rainfed regions, prospects to improving agriculture in rainfed regions, water harvesting and soil moisture conservation, rainfall analysis and rainfed crop planning, choice of crops and cropping systems, tillage and cropping techniques, soil fertility management, weed management, integrated pest and disease management, contingent crop planning, integrated farming system for rainfed regions, alternate land use systems, rehabilitation of degraded rainfed lands, agricultural land use planning for rainfed agroecosystem management, watershed management, secondary agriculture in rainfed regions and farm mechanization. These information help to enhance the productivity of rainfed regions in a sustainable manner. This book’s another goal is to provide up-to-date information’s for aspirants of various competitive exams. I hope this book will be very useful for the students, competitive exam aspirants, teachers, agronomists, soil scientists, crop scientists, extension specialists and others interested in rainfed agriculture.
R. Rex Immanuel, M.Sc. (Ag)., Ph.D. Assistant Professor Department of Agronomy, Faculty of Agriculture Annamalai University, Annamalainagar-608 002 Tamil Nadu, India.
1 Introduction............................................................................................................. 1
2 Farming and Climate Classification...................................................................... 9
Rainfed Farming ....................................................................................................... 9
Irrigated Farming .................................................................................................... 10
Dry Farming.............................................................................................................11
Dryland Farming..................................................................................................... 12
Humid Farming....................................................................................................... 12
Classification of Climate......................................................................................... 14
Classification of Rainfed Ecosystems based on Aridity Index ............................... 18
Global Rainfed Land Scenario................................................................................ 25
India: Rainfed/Dryland Scenario ............................................................................ 33
Rainfed/Dryland Agro-climatic/Agroecological regions/sub-regions in
India ........................................................................................................................ 34
3 History and Development of Rainfed Agriculture in India............................... 45
4 Climate of Rainfed Agro-Ecosystems.................................................................. 51
Solar Radiation ....................................................................................................... 51
Temperature ............................................................................................................ 52
Rainfall.................................................................................................................... 54
Indian Monsoon ..................................................................................................... 54
Onset of the Southwest Monsoon ........................................................................... 54
Monsoon Withdrawal.............................................................................................. 66
Characteristics of Seasonal Rainfall in Rainfed Regions ....................................... 71
Effective Rainfall .................................................................................................... 73
Length of Growing Period ...................................................................................... 78
Dew Fall.................................................................................................................. 82
Wind........................................................................................................................ 83
5 Soils Prevalent in Rainfed Agro-Ecoregions....................................................... 85
Black Soils.............................................................................................................. 85
Red Soils................................................................................................................. 88
Alluvial Soils.......................................................................................................... 90
6 Abiotic Stresses Affecting Crop Production in Rainfed Regions.....................
Light Induced Stress............................................................................................... 91
High Temperature Stress......................................................................................... 95
Visible Plant Injuries due to Extreme Temperature .............................................. 100
Drought................................................................................................................. 104
Classification of Drought...................................................................................... 105
Geographical Spread of Drought in India..............................................................111
Oceanic-atmospheric Phenomena and Monsoon Failure/Drought ......................117
Effect of Water Deficit on Physio-Morphological Characteristics of
the Plants.......................................................................................................... 121
Unseasonal precipitation-Hailstorm ..................................................................... 126
Physical Damage to Plants by Wind..................................................................... 128
Humidity ............................................................................................................... 128
7 Crop Adaptation Mechanisms to Abiotic Stresses........................................... 131
Escaping Drought ................................................................................................. 131
Stress Avoidance ................................................................................................... 132
Water Conservation Strategies in Plants............................................................... 133
Plant Mechanisms to Accelerating Water Uptake................................................. 137
Drought Tolerance ................................................................................................ 138
8 Untapped Yield Potential of Crops in Rainfed Regions.................................. 141
Alfisols/Oxisols..................................................................................................... 141
Vertisols ................................................................................................................ 142
Inceptisols............................................................................................................. 143
Entisols/Aridisols.................................................................................................. 144
9 Constraints for Crop Production in Rainfed Regions .................................... 147
Climatic Constraints ............................................................................................. 147
Edaphic Constraints.............................................................................................. 148
Technological Challenges..................................................................................... 153
Socio-economic and Cultural Challenges............................................................. 156
10 Prospects to Improving Agriculture in Rainfed Regions ................................ 161
11 Water Harvesting and Soil Moisture Conservation......................................... 173
Principles of Water Harvesting and Soil Moisture Conservation ......................... 177
Agronomical Measures......................................................................................... 178
Mechanical Measures ........................................................................................... 187
Biological Measures ............................................................................................. 196
Ex-situ Water Harvesting ...................................................................................... 201
12 Rainfall Analysis and Rainfed Crop Planning ................................................. 213
Scientific Organisations Supporting Weather data’s Sources
and Forecasts.................................................................................................... 213
Selection of Suitable Crops using Aridity Index .................................................. 217
Percentage Departure of Rainfall.......................................................................... 222
Standard Deviation and Co-efficient of Variation................................................. 231
Moisture Availability Index (MAI)....................................................................... 233
Rainfall Criteria Suitability for Rainfed Crops..................................................... 234
Determination of Length of Growing Period........................................................ 242
Probability Analysis of Rainfall for Rainfed Crop Planning ................................ 246
Scheduling of Supplemental Irrigation During Dry Spells................................... 249
13 Choice of Crops and Cropping Systems ........................................................... 253
Rainfed Rice-based Production Systems.............................................................. 254
Cropping Systems................................................................................................. 257
Common Cropping Systems in Rainfed Regions................................................. 264
Crop Substitution in Rainfed Regions.................................................................. 268
14 Tillage and Cropping Techniques...................................................................... 271
Preparatory Cultivation......................................................................................... 271
Optimum Time of Sowing .................................................................................... 277
Pre-monsoon Sowing............................................................................................ 278
Methods of Sowing............................................................................................... 278
Seeding Depth....................................................................................................... 280
Crop Density......................................................................................................... 281
Reducing Water Losses Due to Evaporation - Mulching...................................... 283
Reducing Water Losses Due to Transpiration....................................................... 286
Antitransparents.................................................................................................... 287
Windbreaks and Shelterbelts................................................................................. 288
15 Soil Fertility Management.................................................................................. 293
Plant Nutrients in the Soil..................................................................................... 295
Diagnosis of Plant Nutrient Disorders.................................................................. 300
Inorganic Fertilization........................................................................................... 304
Fertilizer use by Crops in World........................................................................... 305
Balanced Fertilization............................................................................................311
Concepts of Fertilizer Recommendation .............................................................. 319
Organic Sources of Crop Nutrients....................................................................... 328
Green Manures...................................................................................................... 334
Legume Effect....................................................................................................... 336
Introduction of Legumes in Crop Rotations......................................................... 338
Biofertilizers......................................................................................................... 341
Integrated Nutrient Management / Integrated Plant Nutrient Supply................... 349
16 Weed Management ............................................................................................ 353
Critical Period of Weed Competition.................................................................... 354
Integrated Weed Management .............................................................................. 355
17 Integrated Pest and Disease Management........................................................ 369
Preventive Methods.............................................................................................. 369
Mechanical Control............................................................................................... 373
Biological Control................................................................................................. 374
Promoting Natural Enemies.................................................................................. 375
18 Contingent Crop Planning ................................................................................. 379
Delayed Onset of Monsoon .................................................................................. 380
Intermediary Dry Spells........................................................................................ 383
Mid-term Correction............................................................................................. 383
Early Withdrawal (or) Cessation of Monsoon ...................................................... 386
19 Integrated Farming System for Rainfed Regions............................................ 389
Principles of Integrated Farming System.............................................................. 390
Components of Integrated Farming System ......................................................... 390
Conceptual Framework of Location Specific IFS- models................................... 399
IFS Profitability and Employment........................................................................ 404
Significance of Integrated Farming System.......................................................... 408
20 Alternate Land Use Systems.............................................................................. 409
Land Capability Classification.............................................................................. 409
Agroforestry.......................................................................................................... 415
Silvipastural System ............................................................................................. 423
Alley Cropping ..................................................................................................... 425
Ley Farming.......................................................................................................... 428
21 Rehabilitation of Degraded Rainfed Lands...................................................... 429
Wastelands/degraded Lands of India .................................................................... 429
Management of Degraded Lands.......................................................................... 432
Tree Planting Techniques in Wastelands............................................................... 439
22 Agricultural Land Use Planning for Rainfed Agroecosystem
Management........................................................................................................ 445
Objectives of Agricultural Land Use Planning..................................................... 446
Concept and Strategies of Agricultural Land Use Planning ................................ 446
23 Watershed Management..................................................................................... 453
Factors that Govern the Geomorphologic Characteristics of a Watershed ........... 453
Principles of Watershed Management .................................................................. 455
Objectives of Watershed Management ................................................................. 456
Classification of Watershed................................................................................... 458
Delineation of Watersheds.................................................................................... 461
Watershed Development Programmes in India..................................................... 465
Factors Affecting Watershed Management ........................................................... 469
Constraints in Watershed Management ................................................................ 473
Integrated Watershed Management....................................................................... 474
Organizational Requirement of Watershed........................................................... 481
Approaches in Watershed Management................................................................ 485
Watershed Treatment / Development Plan............................................................ 491
Action Plan for Watershed Development Programmes........................................ 492
Application of Geographical Information System (GIS) and
Remote Sensing in Watershed Management................................................... 493
India - WRIS......................................................................................................... 495
Bhuvan IWMP-SRISHTI...................................................................................... 501
24 Secondary Agriculture in Rainfed Regions...................................................... 503
25 Farm Mechanization........................................................................................... 509
Annexures ............................................................................................................ 537
Annexure I: Agroclimatic/Ecological Regions of India ....................................... 537
Annexure II: Popular Cultivars/Hybrids suitable for Rainfed Farming
Regions.......................................................................................................... 540
Annexure III: Weeds............................................................................................. 547
Annexure IV: Ready-Reckoner Integrated Pest and Disease Management
(IPDM) Practices for Major Rainfed Crops.................................................. 554
Annexure V: Composition of Common Chemical Fertilizer Sources (%) ........... 567
Annexure VI: Multipurpose Trees Suitable for Rainfed Regions......................... 568
Annexure VII: Research Institutes and Research Projects related to
Rainfed Farming............................................................................................ 573
Annexure VIII: Days related with Significant Events.......................................... 574
Annexure IX: International Years......................................................................... 576
Annexure X: International Decades...................................................................... 577
Glossary ................................................................................................................ 579
References............................................................................................................. 587
