Fundamentals of Agriculture Vol-1 PDF

U s e fu l f o r u n d e rg ra d u a te a n d p o s t-g r a d u a te s tu d e n ts & C entral/State Civil S ervices, F o rest S ervices, B a n k in g S ervices, B.Sc. (Ag.yM.Sc. (A g.) Entrance Tes...

U s e fu l f o r u n d e rg ra d u a te a n d p o s t-g r a d u a te s tu d e n ts & C entral/State Civil S ervices, F o rest S ervices, B a n k in g S ervices, B.Sc. (Ag.yM.Sc. (A g.) Entrance Test and Other Competitive Exams. Fundamentals of Agriculture A gron om y S o il S cien ce R s.1 8 5 /- Extention Education A gricu ltu re E con om ics F arm M an agem en t By : Arun Katyayan V o l-1 (Fully R e v is e d & E n la rge d E dition ) KUSHAL PUBLICATIONS AND DISTRIBUTORS VARANASI / Publisher : K u sh a l P u b lic a tio n ’s a n d D istrib u to r’s (Higher Educational Publisher) Gyanmandal Plaza Ilnd Floor, Shop No. 28 Maidagin, Varanasi-221001 U.P. (India) P h.:05 42 -3 29 1 88 7 M o b.: 09839040484 e-mail : [email protected] © Author I.S.B.N. : 81-86099-70-0 Price : T 240.00 First Edition : 2001 Sixth Edition : 2011 Selling Agents : Jain Brothers Rawat Book Depot 16/873, East Park Road Shopping Complex Karol Bagh, New Delhi Pant N agar (U.S. Nagar) L ?maiionai Book Distributing Co. Sasta Pustak Bhandar Khusnuma Complex, Basement, Opp. Rawatpur Rly. St. / Meerabai Marg, Lucknow Rawatpur, Kanpur P rim ed at : M o d e rn D eepak Press; Nadesar, Varanasi. Phone : 2502048, 2500894 J I 1 FO R EW O R D Agriculture is the backbone o f our economy. Students of Agricultural science play the important-role in the development o f agriculture, T o fulfil their needs the book Fundamentals o f Agriculture by M r. Arun Katyayan is a welcome effort. T o understand the fundamentals clearly and easily the author presented the book in a scientific and systematic manner which is the beauty of this book. The author has consiiderable experiences in teaching and designing the book for competitive purposes also. I personally congratulate Mr. Arun Katyayan for his at­ tempt at designing such a valuable book, l am confident that this book will be widely accepted among the students. I extend my best wishes to Mr. Arun Katyayan for the sucdess o f his book. 9.12.2000 Deptt. o f Agriculture Cooperation, Animal > Husbandry and Fisheries G o v t, o f J h a rk h a n d , R an ch i  PREFACE TO THE FIRST EDITION There are few books in Agriculture which satisfies the re­ quirements o f students particularly for those who are preparing for competitive examinations. This book is designed to satisfy them and is presented in a systematic manner to understand fundamental aspects clearly and easily. This book cover all the im portant chapters o f A g ro n o m y , Soil Science and Ext. Education. A set o f objective questions with answer is also in­ cluded which shows the pattern o f questions to be asked in vari­ ous competitive exams. Before the compilation o f this book, author has consulted various textbook, periodicals and journals from which matters have been heavily drawn in this book and author heartly ac­ knowledges his indebtedness for the same. In some cases, a few tables and figures have1been reproduced- acknowledgement is duly credited beneath each reproduction. In very few cases, where it has not been possible to contact and obtain permission for such reproduction, the author and publisher offer their sincere appologies. , My special and sincere regards are due to my parents, family members and wife who share each and every achieve­ ment made by me and to whom I am very much indebted. Dhamma Vijayadashmi, 2k. (Arun Katyayan)  PREFACE TO THE FIFTH EDITION Since its first edition in the year 2 0 0 1 , the book Fundamentals o f Agriculture is gone through various inclu­ sions and enlargements especially on the request of the readers and the students. It is reported to me that the readers have wel­ comed the book zealously due to the systematic presentations of the fundamentals and its very simple as well as easy to under­ stand language. Suggestions given by the readers and the earnest request made by the instrumental publisher Mr. Madan Mehrotra compelled me to manage the time to revise the book word to word. In the revision I feel that this volume requires some new additions in almost each and every chapter and the same have been incorporated. Up-to date informations and findings and the required changes are made sinceraly although your suggestions for the improvement of the book will be acknowledged. Buddha Pumima, 2008 (Arun Katyayan)  CONTENTS 1. History o f Agriculture : 1 -1 0 History of Agriculture and Agronomy, IARI, ICAR, IRRI CIM M YT, Agricultural Universities Agl. Research Institutes: 2. Cropping System and Pattern : 1 1 -2 2 Shifting cultivation, Crop rotation, Sustainable agriculture, Cropping system, Cropping pattern, Farming system, Mixed farming, Sole cropping, Cropping scheme, Monoculture, Cropping Intensity, Types o f cropping system, Multiple cropp in g, In tercroppin g, M ixed cropp in g, sequential cropping, Multistorey cropping, Terra-forming, Aeroponies. 3. Annidation and Allelopathy : 23 - 27 Annidation-Spatial arid temporal annidation, Allelopathy- True and functional allelopathy, Allelochemicals, Legume effect^ sorghum effect, Cotton effect. ' 4. Crop Ecology : 2 8 -4 2 Meaning, Microclimate, harvest Index, Sink-source ratio, Ideotypes, Ideotypes for some crops, Agro-climatic Regional Planning, Agro-climatic zones, Agro-ecological zones. 5. Dryland Agriculture : 4 3 -5 4 Dry farming, Dryland farming, Rainfed farming, Problems and Prospects of dry land agriculture, Drought and agricul­ tural drought, ICR1SAT, ICARD A, MAI, AI, MDI, TMI, Crop adaptation for dry growing conditions, Watershed manage­ ment, Water harvesting and its types, Jalshakti, Evapotrans- piration, Antitranspirants and its types, Windbreaks and shelterbelts. 6. Erosion and soil Conservation : 55 - 66 Runoff and factors affecting it, Soil loss equation, Soil conservation M easu res- Land capability classification, Mulching, S trip-cropping and its types, Conservation measures fo r H illy s lo p e s- Contour trenching, Bench terracing, Stone terracing. 7. Classification o f C rops : 6 7 -7 0 Taxonomic classification, Special classification : Arable crops, Alley crops, Augmenting crops, Border crops, Brake crops, Catch crops, Cole crops, Cover crops, Complimentary crops, Supplementary crops, Exhaustive crops, Ley crops, Paira or Utera crops, Paired row cropping, Skip cropping, Silage crops, Smother crops, Trap crops, etc. 8. Crop Production : 7 1 -1 0 8 Kharif and Rabi crops, Crops and its botanical names, Origin o f crops, Protein contents, A rea and Production, Other important facts of different crops viz. Rice, Wheat, Maize, Jowar, Bajra, Pulses, Oilseeds, Sunflower, Cotton, Jute, Sugarcane, Tobacco. 9. Seed Technology : 1 0 9 -1 1 9 Meaning, Factors affecting germination and growth, Seed Index, Real value o f seed, Purity percentage, Dockage, Isola­ tion distance, Types o f pure seeds- Nucleus seeds, Founda­ tion seed, Registered seed, Certified seed, Improved seed, V iability test, S eed dorm ancy and its breaking, Seed treatment, Seed plot technique o f potato. National seed corporation, State seed corporation. 10. W eed Problem s : 120 -1 3 6 Meaning, Criteria o f weed, Classification o f weed, Crop weed competition, Characteristics of weed, Multiplication and Dis­ semination, W eed control, Preventive method, Curative method, Biological method, Chemical control, Classification  o f Herbicides, Herbicides and its other, names,.Selective , herbicide, Contact herbicide, Active ingredient, Acid equiva­ lent, Orobanche & Striga. Herbicides for weed control in different crops. 11. Assessm ent o f Agronom ic Interactions : 1 3 7 -1 4 4 (a) Assessment o f com petition & yield advantage-LER, Relative crowding coefficient, Aggresivity, Competition index, Competition ratio, Competition coefficient. (b) Assessment o f Land use and Productivity in Multiple cropping- Multiple cropping index, Cropping intensity index, Intensity o f cropping, Specific crop intensity index, Relative cropping intensity index, Cultivated land utilization index, Diversity index, Rotational Intensity. 12. Agro-forestry and Social Forestry : 145 -1 5 2 Agro-forestry and its meaning, Objectives o f agro-forestry, Components of agro-forestry- Agri-silviculture, Sylvopastoral systems, Social forestry-meaning o f its principles, Objectives and components o f social forestry- Farm & Rural forestry, Urban forestry, Need for more forests. 13. W ater M anagem ent: 153 - 174 Irrigation, Matric potential, Capillary potential, Gravitational potential, pFvalue, Cumec, Moisture equivalent, Permanent wilting point, wilting coefficient, Soil moisture tension, Poiseuille’s law, Darcy’s law, Measurement o f soil moisture content, Tensiometer, Potential Evapo-transpiration, Lysim- eter, Evaporimeter, Consumptive use o f water, Water use efficiency, Irrigation efficiency, Irrigation period, Intensity o f irrigation, Crop ratio, Duty o f water, Delta, Weirs, Parshall Flume, Methods o f irrigation, Surface and sub-surface irriga­ tion, Sprinkler and Drip irrigation, Mjcro irrigation; Drain­ a g e- Surface and sub-surface drainage. R o c k s a n d its W e a th e rin g : 17 5 182 Igneous rocks, Sedimentary rocks, Metamorphic rocks, Rock minerals, Quartz, Feldspars, Mica,.Olivine, Tourmaline, Sources of Plant nutrients, Primary and secondary minerals, Weathering o f rocks— Physical, Chemical and Biological weathering, Development of mineral profile. Soil Form ation: 183 188 Factors o f soil formation, Parent materials, Topography, Climate, Organism, Time, Soil forming processes- Eluviation, illuviation, Gypsification, Podzolisation, Laterisation, Gleization, Solonization, Pedoturbation. Soil and its Physical Properties : 189 206 Soil and its concept, Pedology and Edaphology, Regolith, R egosol, Organic & mineral soil, Soil profile, Physical properties o f soil- Soil texture; Sand, Silt and Clay, Textural classes, Soil structure and its types, Factors affecting soil structure, Particle and Bulk density, Pore space/solid space, Soil consistence, Soil colour and soil air, Soil temp, Soil w ater- Hygroscopic water, Capillary water, Gravitational water, Available water, Field capacity, Permanent wilting percentage, Hygroscopic coefficient, Moisture equivalent, Different layers of soil water. Soil colloids and silicate clay minerals : 207 218 Meaning, Clay minerals, Composition of clay, Micelles, Acid nature o f clay, Sesquioxide clays, Silica sesquioxide ratio, Silicate clay minerals and its classification-1:1 type, 2:1 type and 2:2 type, Sources o f negative charge on silicate clays, Isomorphic substitution and exposed crystal edges. Soil Taxonom y and Soils o f India : 219 221 M odem classification, Cat clays, Catena, Caliche, Soils of India- Alluvial soils, Black soils, Red soils, Laterite soils, Desert soils. ( iv) 19. Soil Organic Matter : 222 - 230 Nature o f soil organic matter, Humic and non-humic substances, Humus and its characteristics, Factors affecting decomposition, C : N ratio and its significance, Muck and Peat soils, R ole o f organic matter, Mineralisation and im m obilisation, M ineralisation o f orga n ic n itro g e n - Aminization, Ammonification, Nitrification, Nitrogen loss : Volatilisation, Microbial denitrification. 20. M anures, Fertilizers and Biofertilizers : 2 3 1 - 254 Manures-meaning and its advantages, FYM , Compost, Night soil, Sewage and sludge, Sheep and goat manure, Poultry manure, Green manure, Green leaf manuring, Oilcakes, Fertilizers-Meaning and its classification, Fertilizer grade and ratio, Materials used in fertilizer, Precautions in mixing fertilizers, Acidity and basicity of fertilizer- Equivalent acidity and basicity, Nitrogenous fertilizers and its characteristics, Phosphatic fertilizers and Potassic fertilizers, Micronutrient fertilizers, Nitrification inhibitors and slow release fertizers. Biofertilizers and its classification, Biological nitrogen, fixation, Symbiotic and non-symbiotic N-fixation, 21. Soil fertility and Productivity : 2 5 5 -2 5 9 Available nutrient analysis o f soil and its process, Crop logging, Soil fertility and productivity, Some important-points. 22. M ineral Nutrition : 260 - 274 Meaning, Criteria o f essentiality, Form of elements absorbed by plants, Elements and its; major role, Mobility o f nutrients, Classification o f essential nutrients- major and micronutrients, Ultra micronutrients, Beneficial nutrients, Hidden Hunger, R ole o f essential plant nutrient's, Deficiency symptoms, Toxicity symptoms. ( v) 23. Saline, Alkali and Acid Soils : 275 288 Saline soils and its characteristics, ESP, Reclamation o f saline soils, Sodic soils and its characteristics, Formation and recla­ mation of sodic soils, Saline-alkali soils and its characteristics, Difference between saline and alkaline soils, Reclamation of usar soils, Acid soils and its genesis, Reclamation o f usar soils, Acids soils and its genesis, Characteristics and management o f acid soils. SAR. 24. Extension Education 289 315 Introduction, A gl. Extension Education- Objectives and principles, Basic philosophy o f extension, Learning and Principles, Basic philosophy o f extension and communica­ tion- Teaching steps, Adoption Process, Communication, Classification of Extension teaching methods, Demonstration- Method demonstration, Result demonstration and National demonstration, Training & Visit System, Lab to Land Programme, Krishi Vigyan Kendra, Technology transfer, Etawah Pilot Project, Community Development Programme, N a tio n al E xtension S ervice, P an ch ayati Raj, IR D P , Operation Flood, TRYSEM , Young Farmer’s Association, Swama Jayanthi Grama Swarozgar Yojana (SGSY), NREGA, Extension activities, Rural w elfare activities and other Programmes in India. 25. Agricultural Economics : 316 337.Introduction, Micro and Macro-Economics, Cooperatives in India, RBI & SBI, Cooperative Banking Structure, Land Development Bank (LDB), Crop Loan Scheme, Regional Rural Banks (RRBs), Marketing Services, Market Agencies or Func­ tionaries, Chracteristics o f Indian Agriculture, Problems in Indian Agriculture, Economic Holding, Marginal and Small Farmers, Agriculture Price, Price Elasticity Cost, Opportunity (vi)  Cost, Cost Elements, Cost Curves, Assets, Liabilites, E fficie n t - Measures, M onotonic and Non-monotonic relationships, AG M AR K. 26. Farm M anagem ent: 338 -3 8 1 Meaning, Objects of farm management, Production Decisions, Production Functions, Cobb-Douglas Production Function, Types of Production functions, Forms o f Factor- Factor rela­ tionship, T h e Law o f Returns or Variable proportions, Elasticity o f Production, Cost Principle, Law. of Equi-marginal return or Principle o f opportunity cost, Factor-Factor rela­ tionship, Product- Product relationship, Principle o f compara­ tive advantage, Dicision under risk & Uncertainty, National Agricu ltu re Insurance S ch em e, T yp e s & System s o f Farming, Farm Planning and Budgeting. 27. Objective M odel Questions & Answers : 382 - 475 (vii)  It is supposed that man was evolved on earth about 15 lakh years ago. This man was the evolved form o f monkey who started to m ove by stand­ ing erect on his feet. Such man has been called H o m o e re c tu s or Java man (Hom o —» continuous, erectus —> erect). Later on Java man was transformed into cro-magnan and cromaghkn into modern man. The mod­ ern man is zoologically known as H o m o sa p ien s ( sapiens means learn­ ing habit) due to his corfhnuous learning ha|it. And according to trinominial nomenclature modem man got Ihe name H o m o sa pien s sapiens. Such m odem man was evolved first in Africa about 35000 years ago what gen­ erally accepted today. In the beginning sifth man had been spending his life wildly but during the period o f 8700 -7700 B.C., they started to pet sheep and goat, although the first pet animal was D og which was used in ; The cultivation o f crop started during 7500 B.G. and thus agricultural science came into existence. T o produce the crop^human beings tilled the soil. Tilling o f soil or in another word cultivation o f soil is called Agriculture. Agriculture consists o f two Latin words i.e., , Aoric/Aqer Cultma ^.. Agriculture Soil Cultivation Thus agriculture is an art and science both in which we study all the human activities related to use of soil. Discovery and use o f Iron revolutionised the Agriculture to fulfill the needs o f rising population and earnest desires. Later on it was realized that due to lack of field m anagem ent, the productivity o f soil was started to be History o f Agriculture / 1 diminished. Therefore, Agriculturists had to study the management o f field as well as principles and practices of-crop production. Thus the term ‘ agronomy’ came into existence Agronom y consist of two Greek words viz. Agronom y = Agros + nomos = Greek words i I Field to manage Agronom y is that branch of agricultural sciences which deals with the management o f field to provide favourable environment to the crop for higher productivity in terms of quantity and quality both. Peter Decresenzi (1230 -1307 A.D.) collected many literatures related to Agronom y in his book ‘Opus Ruralium Kamo Daram’ for the first time. That is why he is called the Father o f Agronom y. Jethrotull (1674-1741 A.D.) wrote a book ‘Horse Hoeing Husbandry’ on which basis ‘seed drill’ and ‘ Horse Drawn cultivator’ were developed. The words ‘w eed’ and ‘zero tillage’were also used firstly by him. In India, scientific cultivation has been started with the commercialisation of sugarcane,cotton and tobacco. On 27 th April 1871, a joint department o f agriculture,revenue and commerce was established by Lord M ayo on the request of A.O. Hume. Due to direction issued by Famine commission 1880 , a separate central department o f agriculture was established in 1881. IARI : Imperial Agricultural Research Institute was established in 1905 at Pusa ( at that time Bengal but presently in Bihar ) under the viceroyalty of Lord curzon. In 1934, its buildings were damaged due to earthquake. Therfore in 1936. IARI was transfered to Pusa Road , N ew Delhi. After the Independence the word ‘Imperial’ wasrsubstituted by ‘In­ dian’ and now it is called Indian Agricultural Research Institute. In 1958, IARI was given the status o f deemed University by university Grant Commission. ICAR : The Royal Commission on Agriculture was constituted in 1926 under the viceroyalty o f Lord Linlithgow; On the recommendations of the Royal Commission Report of 1928, The Imperial Council o f Agri­ cultural Research 'was established on 16th July 1929. It was registered as History o f Agriculture / 2 a society under the Societies Registration act - 1860. Its first president was Md. Habibullah and secretary was S. A. Hydari. In March, 1946, it was decided to change the ‘imperial’ 'into ‘Indian1under the presidentship of Jogendra Singh and since then it is called Indian Council o f Agricultural Research. In 1966, IC A R was reconstituted into full autonomous body and its first D irector General { Chief executive) was Dr. B.P. Pal, The man­ date of ICAR is a ) T o plan undertake, aid promote, and co-ordinate education, re­ search and its application in agriculture, agro forestry, animal hus­ bandry, fisheries, home science and allied sciences. b ) T o act as a clearing-house o f research and general information relating to agriculture, animal husbandry, home science and allied sciences, and fisheries matters through its publications and infor­ mation system, and instituting and promoting transfer of technol­ ogy programmes. c) T o provide:, undertake and promote consultancy services in the fields o f education, research, training and disssemination o f infor­ mation in agriculture, agroforestry, animal husbandry, fisheries, home sciences and allied sciences. d) T o look into the problems relating to broader areas o f rural devel­ opment concerning agriculture, including post-harvest technology by developing cooperative programmes with other organizations such as the Indiap Council o f Social Scienqe Research, Council of Scientific & Industrial Research ( Barrackpore, Distt 24 Paraganas (West Bengal) 700120 14. CRRI : Central Rice Research Institute, Cuttack (Orissa) 753 006 15. CSSRI : Central Soil Salinity Research Institute, Zarifa Farm, Kachwa Road, Kamal (Haryana) 132 001 16. C SW C R TI : Central Soil and Water Conservation Research and Training Institute, 218 Kaulagarh Road, Dehra Dun (Uttarakhand) 248 195 17. C TRI : Central Tobacco Research Institute, Rajahmundry (Andhra Pradesh) 533 105 18. C TC R I : C en tra l T u b er C ro p s R es ea rc h Institute, Sreekariyam, Thiruvananthapuram (Kerala) 695 017 19. IASRI : Indian Agricultural Statistics Research Institute, Li­ brary Avenue, Pusa Campus, N ew Delhi 110 012 20. IGFRI : Indian Grassland and Fodder Research Institute, Pahuj Dam Gwalior -Jhansi Road Jhansi (Uttar Pradesh) 284 003 21. IIHR Indian Institute o f Horticultural Research, P.O. Hassaraghatta Lake>Bangalore (Karnataka) 560 089 22. npR Indian Institute/of Pulses Research, Kanpur (Uttar Pradesh) 208 024 23. nss : Indian Institute o f Soil Science, Nabi Bagh, Bhopal. (Madhya Pradesh) 462 038 24. nSR : Indian Institute o f Spices Research, P O Marikunnu e Kozhikode (Kerala) 673 012 25. nSR Indian Institute o f Sugarcane Research, P O Dilkusha, Lucknow (Uttar Pradesh) 226 002 26. ILRI Indian Lac Research Institute; Namkum, Ranchi (Jharkhand) 834 010 - 2?. llV R f Indiah lhstitute o f Vegetable Research, Varanasi (Uttar Pradesh) 221 005 History o f Agriculture / 8 28. NIR JAFT : National Institute o f Research on Jute and Allied Fibre Technology, 12 Reagent Park,Calcutta(West Bengal) 700 040 29. SBI Sugarcane Breeding Institute, Coimbatore (Tamil Nadu) 6410Q 7 30. V P K A S : Vivekanand Parvatiya Krishi Anusandhan Sansthan, Almora (Uttara khand) 263 601 Anim al Sciences and Fisheries 1. CART : Central Avian Research Institute, Izatnagar (Uttar- Pradesh) 243 122 ~ 2. CIFRI : C en tral Inland Fish eries R esea rch Institute, Barrackpore (West Bengal) 700 120 3. CIBA : Central Institute of Brackishwater Aquaculture, 75 Santhome High Road R A Puram, Chennai (Tamil Nadu) 600 028 4. C IFT : Central Institute o f Fisheries Technology, Willingdon Island, PO. Matsyapuri Cochin (Kerala) 682 029 5. C IFA : Central Institute o f Freshw ater Aquaculture, Kausalyaganga Bhubaneshwar (Orissa) 751 002 6. CIRB : Central Institute for Research on Buffaloes, Sirsa Road, Hisar (Haryana) 125 001 7. CIRG : Central Institute for Research on Goats, Makhdoom, Mathura (Uttar Pradesh) 281 122 8. CMFRl ; C en tra l M arine Fisheries R esearch Institute, Tatapuram, Kochi (Kferala) 682 014 9. CSW RI : C en tral S h eep and W o o l R esearch Institute, Avikanagar, District Tonk Via Jaipur (Rajasthan) 304 501 10. N A N P : National Institute o f Animal Nutrition and Physiol­ ogy, Adugodi, Bangalore (Karnataka) 560 030 History o f Agriculture / 9 O th er 1. NAARM National Academ y o f Agricultural Research and Management Rajendranagar, Hyderabad (Andhra Pradesh) 500 030 2. FRI Forest Research Institute, Dehradoon (Uttarakhand) 3. IC A R D A International Centre for Agricultural Research in Dry land areas, Aleppo, (Syria) 4. IC R ISAT International Crop Research, Institute for Semi Arid Tropics, Patancheru, Hyderabad. (Andhra Pradesh Aug. 1972) 5. NCERT National Council o f Educational Research & Train­ ing. N ew Delhi. 6. PBCS Potato Breeding & Certification Station. Kufri (Shimla) Himachal Pradesh. N A T IO N A L B U R E A U Agricultural Sciences 1. NBPGR : National Bureau of Plant Genetic Resources, FCI Building, Pusa N ew Delhi 110 012 2. NBSSLUP: National Bureau o f Soil Survey and Land Use Plan-. ning. Shankar N agar Am ravati Road, Nagpur (Maharashtra) 440 010 Anim al Sciences 1. NB A G R : National Bureau o f Animal Genetic Resources, Kamal (Haryana) 132 001 2. NBFGR : National Bureau o f Fish Genetic Resources, Canal Ring Road RO.Dilkusha, Lucknow (Uttar Pradesh) 226002 3. NIBAIM : National Bureau of Agriculturally Important Micro - organisms, Kusmaur, Mau Nath Bhanjan (Uttar Pradesh) 275 101 Courtesy: Handbook o f Agriculture (ICAR) a o o History o f Agriculture / 10  Shifting Cultivation/ Land Rotation/Jhumming : X., Forest land is cleared and cultivated. Due to cultivation o f the same crop generally rice on the same cleared forest land year after year; soil productivity is lost. And the crop is shifted to other slashed and burnt land. 2. H ere same crop 1. i nu i ycvu ul i>»i yvui In this case land is rotated but crop is fixe d. Th’erefi i iL iu1t'.fV1; *. V;.;. V- Annldatton and Allelopathy ( 21  The term ‘Ecology’ is derived from ‘ Oikos’ meaning home. C rop ecology means the relationship o f a crop or crop communities with its surroundings say environm ent. A local climatic condition that differs from surrounding areas because o f differences in relief, exposure or cover is called Microclimate. From the agricultural point o f view the microclimate is studied at two levels i.e. at plant level or-at soil level. M icro - clim ate at plan t lev el:, r The ecoclimate o f the plant i.e the climate just above and beneath the plant’s canopy, is different from the climate o f the surrounding environ­ ment.;The microclimate atilMPplant Icvclj.u. the ecoclimate varies with the type o f plants, morphoraflpcal featii%^6Fpi|nt i.e. height, condensed canopy, shape and sizejJB laf and stem^^^;.soiji:tolour. Soil colour modi­ fies the microclimate hm M ectma the sunlight, temperature, humidity, C O z: 0 „ level, air velocity arid'orgnnisms^Th'feplants having large morphological features reduce the air.movcment and the penet '---- n o------------ f sun rays- to the ground surface. Even emerging** — iimate near the soil surface by reducing air movement and^by.sh.S'aing the ground. In the veg­ etation covered areas, the extreme v^^K?ttsj.riH the temperatures o f the soil surface are reduced and the eco- clfmMe wJthe plant is more humid and cooler than the surroundings which favours the spread o f insect pest and diseases. The plant canopy changes the intensity and quality o f light when the light rays pass through it. In the day time when sunrays directly fall on the leaves, the leaf temperature may be higher than the air temperature and at nightjnay be lower than air temperature. M icro — clim ate a t so il level : Soil colour is one o f the factors which affect microclimate. Due to soil colour, part o f incoming radiations are reflected. T h e percentage o f the incoming radiations that is reflected, is called Albedo. Albedo varies ac­ cording to soil type, plant cover, moisture content of soil, soil organic matters, etc. Due to differences in albedo o f the soil surfaces, different thermal regimes are set up even when incoming radiations are indentical.... For example, a mulch on the soil surface becomes very hot by absorbing most o f the incoming radiations and keeps the soil cool during day time and vice - versa during night hours. W et soil absorbs more incoming radiations than dry soil. Most o f the absorbed energy is used to evaporate the soil water due to which moist soil takes longer time to heat up or to cool down. The heat gain or heat loss by the soil is five times quicker than by the water because the specific gravity of the soil is 0.2 and the sp.gr.of the water is l.O.H igh soil temperature re­ stricts the root growth. In the arid region warm (20°c-30°c) moist soil is the favourable medium for most of the cultivated crops. H arv est In d ex : The effectiveness of photosynthesis depends on- (i) a large and efficient assimilating area. (ii) A n adequate supply o f solar energy and C O z (iii) Favourable environmental conditions. The total product o f photosynthesis throughout the lifetime of the crop growing in the given circumstances depends upon the following factors- (a) the size o f the assimilating area. (b) The efficiency o f assimilation and C O z fixation. (c) The period o f efficient assimilation and C O fixation. In the Agronom y , the efficient utilisation o f assimilation and C O z fixa­ tion i.e. photosynthesis is expressed in terms of Harvest Index.H.I. is also called ‘Coefficient o f Effectiveness.’ j_j j _ Economic yield ( e.g, grain) x 100 Biological yield ( e.g.grain + straw) = - § in k _ x l0 0 Source ‘ Crop Ecology / 2 9  Grain yield can be calculated by the formula- Y=a x b x c x d ^ !.^k.o -v Where, y —► grain yield per unit area. - a —► no. of plants per unit area, b— ► no. o f fertile tillers per plant c —► no. o f grains per ear d — ► weight of the individual grain. In wheat, barley and similar cereals, the photosynthetic activity o f the ear, which is situated at the top of the stalk, makes a considerable contribu­ tion to grain formation. Practically all the drymatter o f the grain is pro­ duced by the part o f the shoot above the flag leaf node.Of this dry matter, the ear contribute about 50% in wheat and upto 70% in barley. Sink - S ou rce Ratio : Source : Such part of the plant where photosynthesis occurs; gen­ erally leaves are the source. Sink : Where photosynthates accumulate , is called sink. Gener­ ally grain is the sink but stem ( e.g. potato},root (e.g.Sugarbeet) or leaf (e.g.Palak) may be the sink. For higher HI, development o f sink is the most concerned. But the development o f sink depends on three factors-— (a) Good Source (b) Partitioning o f Photosynthates , and (c) Translocation o f Assimilates In spite o f good source if partitioning o f photosynthates is not well developed, sink will be poorly formed and thus is the lower H.I. Therefore for higher sink-source ratio, the followings are necessary— (i) Source should be good. (ii) ' Partitioning o f source i.e. photosynthates should be well devel­ oped: (iii) Translocation o f photosynthates must be good.’ (iv) And lastly photosynthates do accumulate as sink. Formation of Partitioning of Translocation Storage of Photosynthates —► Photosynthates —b of — ► Assimilates as Source Assimilates - as Sink Crop Ecology /30  Partitioning and Translocation Source Sink Fig. 14 : Sink-Source Relationship The formation o f sink from source is a reversible process but source to sink is more pronounced. With the appearance o f inflorencence, competition for assimilates between the leaves and the inflorescence takes place. When the seed formation starts, most o f the assimilates move to the grain. This internal competition is more severe as competition between plants increases i.e. plant population pressure, which is illustrated by the figure. Ideotypes ( M odel Plants) : The production o f the every plant is affected by the plant’s type, climatic condition, soil type and management factors. According to Army and Greiver ( 1967), the production o f the plant might be increased by changing plant’s type and increasing the period o f grain - filling in a cer­ tain climatic condition where management and soil factors are not limiting. There is a direct relationship between the plant’s type and the crop pro­ duction because the orientation and number o f leaves play the important role in the C 0 2 assimilation (Photosynthesis). The concept o f ldeotype was given by Donald in 1968. H e illustrated Economic Yield Crop Ecology { 31 that there should be minimum competition between the crops and the crop must be competent one to compete with weeds. The single plant Would give the better result in a group when the crop has at least competition with the same type o f the crop. Ideotype is the model plant which may be defined as “ a biological model which is expected to perform or behave in a predictable manner within a defined environment”. On the basis of envi­ ronment Donald & Hamblin (1976) identified two forms of ideotypes i.e. isolation ideotypes and competition ideotypes. Competition ideotypes are suitable for mixed cultivation. Ideotypes fo r S o m e C ro p s : W heat : According to Donald ( 1968), the ideotype for wheat or the similar crop has following features- (i) T o avoid lodging, there should be short strong stem. (ii) Few small erect leaves to allow the sunshine into its canopy. (iii) A large erect ear. (iv) The n o , o f fertile florets per unit area should be more so that H I is more. (v) There should be awns to increase the photosynthetic area. (vi) A single culm to avoid wasteful vegetative growth. (vii) Resistant to insect pests & diseases. (viii) There must be proper partitioning and translocation of assimilates. M a iz e : The plants have erect upper leaves and the lower leaves \ gradually become horizontal to allow the sunshine into its canopy and for proper movement o f air into the field. The height o f the plant is to be 1.5 metre in which 2-3 cobs may be produced on the nodes near the tassel^ Gram : Pande and Suxena (1 9 7 3 ) proposed the ideotypes for gram having following features. (i) The vegetative growth must be stopped before the starting of re­ productive stage. (ii) The plant is to have erect branching.In the prevalent varieties of gram, the spreading and branching o f its canopy is just like um­ brella which interferes to penetrate the sunshine into its canopy Crop Ecology / 32 9  causing humid conditions favourable for insect pests & diseases, (iii) T o harness the long photoperiod and favourable temperature at the time of flowering , there should be 2-3 longer pods in the leaf axis and 2-3 seeds in each pod. A r h a r : The growth of Arhar varieties in the beginning is too less i.e. in the first two months only one or two branches are come out. Therefore Arhar is unable to harness the solar energy properly in the first two months. The flower’s drop is also a major problem.The filling o f pods according to Hydro-dynamic model sets up the competition between vegetative and re­ productive phases. Considering all the views Pande & Suxena suggested ideotypes having following features- (i) The fast growth o f plant’s canopy at least in the beginning. (ii) The reproductive phase starts after the closure of vegetative growth. (iii) Long floral axis having 2-3 flowers in each trifoliate axis. (iv) Synchronised flowering i.e. all the flowers come out at the same time. (v) Active root nodules for the long time. (vi) Resistant to insect pests & diseases. R airifed u p lan d R ice : -\ (i) Short growth duration ( 85-100 days) (ii) Effective deep root system. (iii) Dwarf (less than 100cm) plant having erect leaves and thick stem. (iv) Early strong fertile tillering. (v) Synchronised flowering. (vi) Good number o f panicles at higher density about 400panicles per square metre. (vii) Highest number o f grains per panicle. (viii) Moderate seed dormancy. (ix) Resistant to insect pests & diseases e g. resistant to Helminthosporium sp. R ain fed W h e a t : A n ideotype o f rainfed wheat was conceived and proposed by Dr. Crop Ecology / 33 Asaria- (i) Large no. o f spikelets, (ii) Large peduncle, (iii) Strong and deep root system, (iv) Flat leaves parallel to soil and - (v) A grain development period coinciding with mean max! temp, o f 25°C. Ideotypes fo r D rylan d Farm ing : (i) Short growth duration. (ii) Effective root system. (iii) Drought tolerance. (iv) High yield potentiality with altered m orphology viz. (a) Plant with few leaves just sufficient to maintain photosynthetic output and growth ( to minimise the use o f water). (b) Leaves horizontally disposed for better light interception con trary to vertically disposed most effective under irrigated condi­ tions. A gro -C lim atic R eg io n al Plan n in g A gro - climatic Regional Planning in India was initiated in 1988 by the planning commission. It means under the seventh five year plan; Re­ gional planning was come into force on the basis o f agro- climatic factors for balanced regional growth.The agroclimatic factors are Rainfall, tem­ perature, soil, topography , cropping and farming system and water re­ sources. A g ro - C lim atic Z on es : Agro- climatic zone is a land unit is terms o f majordimatessuitable for a certain range o f crops and cultivars.(FAO , 1983). On the basis o f criteria o f homogenity in agro- characteristics such as w ater surplus and w ater deficit, India was divided into 11 agro- cli­ matic zones... Later on, India was divided into 15 agro- climatic zones on the basis of w a te r surp.ulus, w a te r d eficit and c ro p p in g system. Crop E co lo g y / 34  A n ecological region is an area o f the earth’s surface characterised by distinct ecological responses to macro —climates expressed-by soils, vegeta­ tion fauna and aquatic systems. Agro- ecological region is the land unit cut out o f agro climatic region when superimposed on land form and the kind o f soils and soil conditions that act as modifiers to climate and length o f growing- period. The classification is on the basis o f :- (i) Growth period (ii) Rainfall/potential evapotranspiration (iii) Soil ' (iv) Districts. ' There are two components o f ecological zones- (i) Biotic factors viz Fauna and Flora. (ii) Abiotic factors viz water, minerals, light etc. A t present India has been divided into 21 agro ecological zones. The detailed descriptions o f 15 agro- climatic zones are as follows- 1. W estern Him alyan Region : Includes Jammu and Kashmir, Himachal Pradesh & Hilly areas of U.P. climate is cool and humid. Annual rainfall- 1650-2000 mm. Important crops are Wheat, Maize, Paddy and Potato. It is divided into 3 subregions. Cropping Intesity is lowest in J & K and highest in H.P. T h e productivity level o f all the crops is below the na­ tional average. T o develop this region- (i) Intensify the soil and water conservation planning. (ii) Land utility planning should be implemented viz. Agriculture for 30% sloppy land," Horticulture for 30-50% slope, paddy for above 50% ' slope. (iii) Good storage for transportation, marketing & processing. (iv) Irrigation management likewater harvesting technique '" (v) Livestock management etc. 2. Eastern Himalayan Region : Sikkim, Hills o f Darziling, Arunachal Pradesh ,NagaIand, Meghalaya ,Manipur, Tripura, Mizoram, Assam, Jalpaiguri area o f W.B. and some parts o f Bihar,Climate humid & sUb- humid, 1840-3528mm.annual rainfall, 5 sub-regions,main crops-Maize , Paddy, Jute, Rapeseed. Shifting cultivation on l/ 3 ri o f cultivated, area, soil erosion more. C r o p E c o lo g y / 35  For the development of this region-...... (i) Soil and water conservation for each watershed. (ii) Educate the people about the harmful effect o f land erosion at panchayat level. (ft) Facilities o f good supply of inputs, marketins transportation, processing & storage. (iv) Adoption o f Integrated Farming system because o f different Di­ etary pattern of. local people. (v) Good communication & Transport facility. 3. Low er Gangetic Plain : West Bengal; Productivity o f rice is lower than the national average 15 q/ha but this region contributes 12% o f the total rice production in India. Crops :Rice,Jute, Rapeseed and Wheat. Rape- seed , Maize & Potato are newly introduced; moist humid and dry humid climate , 4 subregions. 1302-1607 mm. annual rainfall. Followings are negative points- (i) lack of good water management;drainage problem, (ii) Use o f local variety (iii) Less use o f H Y V (iv) poor extension work (v) Inad­ equate supply of, inputs (vi) P oor marketing & processing (vii) Lack o f trans­ portation and storage (viii) Dependent on Monsoon (ix) Soil & water ero­ sion (x) Uneducated & poor Farmers (xi) P oor electric supply. 4. M iddle Gangetic Plain : Eastern parts o f U.P. and Bihar plains. 40% o f total cropped area is irrigated,cropping intensity 142% ( India’s national Cl 136% ). Low productivity o f rice, 3subregions o f earstem U.P. and 9subregions of Bihar ,moist sub humid to dry sub humid climate. 1211- 1470 mm, annual rainfall, main crops - Sugarcane, Paddy, Maize ,Wheat. 5. U pper Gangetic Plain : Remaining parts o f U P and 3 sub re­ gions, dry sub humid to sub dry climate, 721-979 mm. annual rainfall. Main Crops- Rice, Wheat, Maize and Sugarcane. Irrigation intensity is 131% and Cl 145%. Irrigation by canal and tube well. Special planning to grow vegetables & fruits scientifically. Milk production and processing units are being established. Maximum dry areas: Western dryland region. Gujarat Plains and Hills are called oilseed region. Plantations & spices are grown in western coast and ghats. Coconut cultivation is Island region. Crop Ecology / 36  6. Transgangetic Plains : Punjab, Haryana, Shiwalik region, Sriganganagar, Delhi semi -d ry areas o f plains, dry areas o f Thar ( Rajasthan), Maximum Net shown area and irrigated area. Cropping In­ tensity highest, low poverty, maximum use of ground water. Followings points for the development of this region- (i) good water m anagem ent. (ii) management and reclamation of user soil. (iii) Proper use o f ground water. Diversification of crops. (v) Introduction o f Leguminous crops in cropping system, (vi) Proper livestock & pasture management. (vii) Increasing o f area under vegetables, fruits and pastures 7. Eastern Plateau & Hills : Wainganga, Eastern Hilly areas of M.P; inland Orissa, ChHotanagpur plateau, Platean and Hilly regions of West Bengal, Chhattisgarh.5 subregions, moist sub humid to dry subhumid. 1271-1436mm annual rainfall, Main crops: Rice , Wheat,Maize , Ragi, 67% small and marginal farmers have 25% o f agricultural land only. Shal­ low and undulating land. Horticulture development planning is being in­ tensified. Irrigation through tanks & tubewells. 8. Central Plateau and Hills : about 46 districts of M.P. Chhattisgarh, U.P. and Rajasthan. Undulating soil topography, Ravines present, 14 sub regions, 400- 1550 mm annual rainfall, semi-arid to dry sub-humid climate, Main crops : Wheat, Gram, Jowar,Bajra,Paddy. 75% area is rain affected where following programmes are being run- (i) Watershed m anagem ent. (ii) Crop diversification. (iii) Reclamation o f Ravine area. (iv) Other programmes. 9. W estern Plateau & Hills : Main regions of Maharashtra , ma­ jor parts of M.P. and some parts of Rajasthan. 4 subregions,semi-arid cli­ mate, 602-1040 mm annual rainfall. It covers maximum parts of peninsu­ lar area. Major crops- Jowar,Bajra, Cotton and Wheat. Net sown area 65%, 11% forest area, irrigated area 12.4%. Irrigation mainly by canal. Crop Ecology / 37 50% Jowar of our country from this region.Best quality o f orange, grape and banana. Following suggestion for this zone- (i) Management of minor irrigation. (ii) Improvement in the conditions o f cattle and buffaloes. (iii) Cultivation o f costly crops. 10. Southern Plateau & H ills : about 35 districts o f Andhra, Karnataka, Tamil Nadu, typically semi arid zones.81% dryland farming and 111% cropping intensity. 6 subregions, 677-1000m m annual rainfall, cultivation o f low value crops. Suggestions- (i). Proper utilization of dryland technology in watershed area. (ii). Increase fertilizer use efficiency. (iii). Minor irrigation programme. 1 1. East Coast Plains : East coast of T.N. , Andhra & Orissa. Soils are mainly alluvial and coastal sands. Irrigation through canals & tanks. 6 sub regions semiarid and dry sub humid climate, 780-1287 mm annual rainfall. Main crops : Rice, Groundnut, Ragi, Jowar 8c Bajra. 20.3% of total rice production in India is from this zone & 17.5% groundnut preva­ lence of alkaline and saline soils. Development o f fisheries due to waterlog­ ging.75% area rainfed. In place of shifting cultivation, integrated Horticul­ ture Agriculture programme should be adopted by tribal people. 12. W est Coast Plains and Ghats : Westcoast o f T.N. Keral, Karnataka, Maharashtra and Goa. Main occupation is cultivation of spices and plantation crops; 4 subregions, dry sub- humid to humid , 2226-3640mm annual rainfall, main crops - Rice, Ragi, Groundnut and Tapioca, sugges­ tions - (i) Storage of rain water. (ii) Proper use of ground water, (III) Increase in area under fruits and vegetable.. ,, (iv) Fisheries management , 13. Gujarat Plains. & Hills ; 19 districts of Gujarat, 7 sub regions, arid and low rainfall, 340-1793 mm annual rainfall, 32.5% irrigated land through wells and tubewells. Main crops- Maize, Wheat,Rice, Groundnut, T ob a cco , Cotton.Jowar, Bajra,This zone is famous for oilseed crops Hence Crop Ecology / 38 called oilseed region. Cl V l l 4 %. About 60% area is drought prone. 78% rainfed; suggestions - (i) Rain water harvesting and its management. (ii) Dryland farming & management of canal & ground water. (iii) Development o f Agro-forestry and arid-Horticulture. 1 4. W e s te rn D ry R e g io n : 9 districts of Rajasthan, hot sandy desert, erratic rainfall, high evaporation, scanty vegetation, no perrenial rivers, general occurence o f drought, 95 mm annual rainfall, 1.2% forest area, 4.5% pasture area,6.3% irrigated area, Cl : 105%. Main crops- Bajra, Gram, Wheat, Rapeseed.Two main plannings- (i) Indira Gandhi Cannal and... (ii) D D P ( Drought Development programme). 15. Island Regions : Island territories o f Andaman & Nicobar and Lakshadeep. 3000m m annual rainfall spread over 8-9 months. Largely forest zone with undulating larid.CoconutcultivaUOhon 50% area o f total cropped area,humid climate, main crops- R ic e & C ocon u t. Main emphasis (i) Crop Improvement. (ii) Water Management. - (III) Fisheries. A g ro - E co lo gical Z o n es : India has been divided into 21 agro-ecological zones- 1. W estern Him alaya I.: Cold arid region with shallow sedimentary soils, covering Laddakh and Gilgit. Tem p less than8°C, Rainfall less than 150 mm which is 15% less than annual P E T , Growing period less than 90 days. Cover 15.6 million hectare ( 4.7% of total geographical area). 2. W estern Him alaya II : Warm subhumid with brown forest & podzolic soils, J & K, H.P ; northwest Hilly areas of U P. (Uttarakhand); 17>7 mha ( 5.4 % ), Rainfall 1600-2000tnm, exceeds PET, water surplus, Growing period 150-210 days i 3. W e s te rn P la in s : H ot arid region, with desert and alkaline soil. Covers west Rajasthan, Southwest Haryana, Punjab, Kutchha Peninsula, north o f Kathiawada. 29.6 mha (9% of total geographical area). Rainfall Crop Ecology ( 39 300mm, PET: 1500-1900 mm, Deficit 1200-1600mm. Growing period less than 90 days. “ , 4. Deccan P la te a u I : Hot arid region , with mixed red & black soil, part of Deccan plateau including district o f Raichur, Bellary o f Karnataka & Anantpur o f Andhra. 4.7 mha (1.4 % ) Rainfall 400-500 mm, P E T : 1800- 1900mm, Growing Period less than 90 days. 5. North Plain and Central H ighland : H ot semiarid region with alluvial derived soil. Parts o f North plain, Central High land and Gujarat plains. 32.9 mna (1 0 % o f total geog. Area.), Rainfall 400-800mm, PET : 1400T800m m , Growing period 90-150 days. 6. Central ( M alw a) Highland and Kathiawada Peninsula : Hot, semiarid region with medium deep black soil, west M.P., East Rajasthan, and Gujarat, Kathiawada, 1.84 mha ( 5.6 % ) Rainfall 600-900 mm,PET : 1600-2000mm Growing period 90-150 days. 7. Central Highland ( M alw a & Bundelkhand). : H ot subhumid region with medium & deep black soil, Central highland including distt of Raipur, Sagar, Bhopal, Sehore, Shajapur, Hoshangabad. 8.2 mha (2.5%) Rainfall 1000-1500mm,PET: 1300-1500mmprowing period 150-180 days. 8. Deccan Plateau I I : H ot semiarid with shallow & medium black soil, West Maharashtra, North Kamatka, A.P. 33.0 mha (10%), Rainfall 600-l000m m , P E T : 1600-1800mm, Growing p erio d : 90-150 days. 9. Deccan Plateau and Eastern Ghat : H ot semi-arid with red and black soil.Major part o f Andhra Pradesh, 20.8 mha (6.3 % ), Rainfall 600 -1000 mm, P E T : reduction 40%,growing period : 90-150 days. 10. Eastern Ghat ( T N upland) and Deccan Plateau : H ot semi arid region with red loamy soil, South o f Deccan plateau, T.N. upland, West Karnataka, 22.7 mha ( 6.9%) Rainfall 600T00O m m , PET: Deficit 400-700 mm, growing period 120-150 days. 11. Deccan Plateau and Centred H ighland ( Bundelkhand) : H ot and subhumid region with red and black soils. Bundelkhand part of M.P..North Vidarbha, 13.7 mha ( 4.2%)Rainfall 1000-1500mm, P E T : 1500- 1600mm. D eficit: 500-700mm, growing period : 150-180 days. 12. Eastern Plateau ( Chhatisgarh Region) : H ot subhumid with Crop Ecology /A O \ \ red and yellow soils; parts of eastern plateau covering Chhatisgash state, Palamu of Jharkhand and Kaimur of Bihar. 13.2 mha (4%).,Rainfall 1200- 1600m m ,PE T: 1400-1500mm,(Deficit 500-700mm) growing period: 150- ISO days. 13. Eastern (Chhotanagpur) Plateau & Eastern G h a t : H ot sub humid region with red loamy soil, Chhotanagpur plateau o f Jharkhand, West o f W.B., Eastern Ghat o f Orissa, Baster region o f M.P., 27.8mha (8.5%) Rainfall 1000-1600mm, P E T : 1400-l700m m , growing period 150- 180 days. 14. Northern Plains :H ot subhumid region with alluvial soil, part of Indogangetic plain including plain of west Himalaya, Area 12.2 mha (3.7%), Rainfall 1000-1200 mm, PE T : 1400-1800mm,growing period 150-180 days. 15. Eastern Plains : H ot subhumid region with alluvial soil , North east UP, North Bihar, Foothill of eastern Himalaya, ‘ 9.3 mha (2.8%), Rain­ fall 1400-1600m m ,PET: 1300-1500mm,growing p erio d : 180-210days. 16. Assam & Bengal Plains : H ot humid with alluvial soil. Plains of the Bramhaputra and Ganges rivers, parts o f Assam & W.B. , 11.7 mha ( 3.6%)Jrainfall increases from 1400/ 1600mm in the Ganges plain to 1600/ 2000mm in the Bramhaputra plain.P E T : 1000-1400 mm, growing period more than 270 days. 17. North Eastern Hills ( Purwanchal) : Warm humid region,Red & laterite soil, north east states o f Nagaland, Meghalay, Manipur, Mizoram, South Tripura, l ‘0.7mha (3.3 % ). Rainfall 1600-2600mm exceeds PE T : Dryspell 100-150mm in post - monsoon period, growing period more than 270 days. 18. Eastern Him alaya : Warm humid , brown - hill soils, Northern -part o f W.B., North Assam, Most part o f Arunachal, Sikkim,8.0 mha( 2.4%), Rainfall exceeds 2000mm occurs throughout year, PE T : less than precipi­ tation , growing period more than 270 days. 19. Eastern Coastal Plain : H ot and sub - humid alluvial derived soil, East Coast plain, The kavery delta to Gangetic delta, 8.1 mha (2.5 % ), Rainfall 1200-1600mm, PET: 400-500 m m ' deficit 20%less, growing pe­ riod: 150-210 days. Crop Ecology / 41  2 0.W estern Ghat & Coastal Plain : H o t humid red laterite, alluvial, sahyadris ,west coast o f Maharashtra, Karnataka, Kerala, 10.1 m ha(3.0% ) , Rainfall exceeds 2000mrrt, P E T : 1400- 1600mm, Deficit 300 -400 mm , dryspell in Feb- April,growing period more than 270 days. 2 1.Islands o f Andam an, N icobar & Lakshdweep :H ot humid, red loam- sandy loam, Andman Nicobar & Lakshdweep groups, 0.8 mha ( 0.3%),rainfall: 1600-3000mm, exceed PET : except 300-400mm deficit during December to March, suitable for plantation crops, growing period more than 270 days. □ o n  Dryland Agriculture means cultivation of crops entirely under rainfed condition. According to the ‘Principles of Agronom y’ written by Reddy and Reddi, Dryland Agriculture may be classified into three groups on the basis of annual rainfall. (a ). D ry Fanning: Cul'iwili'Mi o f ciupsin aieas where annual rainfall is less than 750 mm and cipp^fai]ur;^,^ | | to, j^rojpnged dry spells during crop period are most comrnpriSD^tfairriihgfiSjjracticed in arid regions with the help of moisture dfjgfservation practices. Alternate land use system is suggested in this region/.:.. (b ). Dryland Fam ij^g ^ Q jjltjy^ q n ^ o f^ o p s in areas where annual rainfall is m ore than 750j^ im.bub'fegs t h « £ p m m is called Dryland Farming. Dry spells may occur, less frequent. Higher Evapotranspiration ( ET) than the total prec£plt§ti' is the main reason for moisture deficit in these areas. The soil and e conservation rhea- sures is the key for dryland farming practice in i arid regions.Drainage facility may be requited i‘spi->uci|h/ in black sojj (c) Rainfed Farm ing : Means cultivation of crops in regions where annual rainfall is more than llSQ-mnYTmere is less chances o f crop fail­ ures due to dry spells. There is adequate rainfall and drainage becomes the important problem in rainfed farming. This farming is practiced in humid regions. United Nations Economic and Social Commission for Asia and the:.following constituents in the given table- -v' ' Drylan d.- Agriculture 7 43  Table 5.1 Dryland vs RainfeJ Farming S.N o C onstituent D ry la n d F arm in g R a in fe d F a n n in g 1. Rainfall (mm) < 8 0 0 (le s s th a n ) > 8 0 0 M o is tu r e a v a ila b ility ’ 2. S h o r ta g e E n o u g h to the CroD 3. Growing Season < 2 0 0 d a y s > 2 0 0 d a y s A r id a n d s e m ia r id a s w e ll a s H u m id & S u b b u m id 4. Growing Regions uplands of sub-humid and r e g io n s humid reaions In te r c r o p p in g o r 5. C r o p p in g sy ste m Single Crop or Intercropping d o u b le c r o p p in o 6. C o n s tra in ts W in d & W a te r e r o s io n W a te r e r o s io n Problem s & Prospects o f Dryland Agriculture : In our country, irrigated area constitutes 33% and 67% is dryland and rainfed , out o f 143.8 million hectares o f cultivated land. Total cropped area is 187.94 mha. Such dryland agriculture contributes about 44% o f national food grain production. The maximum irrigated area will be achieved 50% after the full utilization o f all sources o f irrigation. In this way 50% cultivated area will remain unirrigated: After full exploitationof dryland ,it may contribute upto 75% o f total foodgrain production. Pulses and oil­ seeds are mainly grown in such areas. Important commercial crops viz Cotton, Castor, Groundnut and all coarse grains viz Jowar, Bajra, Maize crops are rainfed. The major part o f milk , meat, wool hides, bonemeal etc are also from this area. Dry farming areas are characterised by very low and highly variable and uncertain yields. Problems o f dry land agriculture are- (a) Inadequacy and uncertainty of rainfall and its erratic distribution. Expected rainfall in a year is 650 mm but 80% o f it is received in 75-90 days o f the monsoon season. — M (b) Late onset and early cessation o f rains. , (c) Prolonged dryspells during the crop-peripd, , (d) Low moisture retention capacity. (e) Poor soil fertility condition. (f) Socio - economic Constraints particularly because of'the.predomi­ nant^ of small arid marginal’ farmers. 54% o f the holdings is less than one hectare. ; : Dryland A gricu ltu re / 44  (g) Technological and developmental constraints. (h) Limited infrastructure development and unproper and untimely availability of credits and agricultural inputs. There are three types o f agriculture possible in Dryland areas- viz. (i) Crop production (ii) Animal husbandry with pastures management and (iii) A gro forestry. Drought and Agricultural D ro u gh t: Indian Meteorological Department, Pune defined: Drought as a situation occuring in any areas in a year when annual rainfall is less than 75% of the normal. W hen deficiency of rainfall is above 50% of the nor­ mal, called severe drought, However, agricultural drought is the moisture deficit which results when amount o f water available in the soil is not sufficient to meet the demands o f potential evapotranspiration (PET). Areas where drought has occurred in 20% of the years during the period are considered Drought areas and where it has occurred in more than 40% o f the years, called chronic drought areas. IC R ISAT : International Crop Research Institute for the Semi-Arid Tropics : established on Oct 11,1972 near Hyderabad ( Patancheru). IC AR D A : International Centre for Agl.Research in Dry Areas in 1977 at Aleppo ( Syria). M oisture Availability Index (M AI) is the ratio between rainfall (weekly/ monthly) at 50% probability level to potential evapotranspiration o f the corresponding period. Rainfall at 50 %: probability M AI = PET Aridity Index (A.I.) WD Where WD — > Water Deficit la F= : PET X100 PET —^ Potential evapotranspiration M oisture Deficit Index (MDIJ Where P : Precipitation Im - P-PET X 100 Thbrnthwaite Moisture Index (TM I) Im a W here A E : Percent probability o f Actual evaporation. Dryland 'Agriculture' -/:45  :c 1.S 2 cx £ xM 4o -J 3 «£. Crop Adaptation for Dry Growing Conditions —) ^ i * -8 1 ,8 i o , bs & | l3 X ^ O S - Dryland Agriculture. /  Ima is-much superior to Im in explaining the variability in crop yields from year to year. W atershed Management : Watershed means an area of land whose runoff drains td a com ­ mon point i.e. in the river or waterpool. Watershed m a yb e defined as a natural unit of land whose runoff collects & flows out o f the area through a single common outet into a river or other waterbody. It is a drainage basin which is demarcated by ridges or gullies. Watershed, drainage area or catch­ ment area are generally interchangeably used meaning for the same. Ordi­ narily the catchment area ( water collecting a rea ) is larger but the area of watershed is comparatively smaller.Watershed area is the unit from the both angles i.e. land unit and water body unit,but there are separate units for both land and water in the catchment area.Therefore catchment area comprises of all the areas from which water flows out into a common river or waterpool. The different river’s tributaries having different water catch­ ment areas flow out into a common larger river. The larger drainage area is called river basin. The water catchment area of a tributary is called sub­ catchment area and the different catchment areas may be identified in it for its certain parts. Th e catchment area of this certain part is called watershed area: Th ere’ may be variations in the watershed area. When these varia­ tions are m ore in number it means the area is hilly, undulating or rolling and w e get smaller watershed area whereas in the plain we get larger.The watershed for the agricultural purpose may be several fields o f farmers that contribute runoff water to the flow at the lower point. The runoff move- ment depends on the land topography. Runoff from the upper fields, enters into the lower fields in a watershed causes soil and water erosion. Soil conservation measures in an isolated manner are not sufficient to check the erosion. Therefore, it is necessary that soil Conservation mea* sures should be adopted on the watershed basis instead of personal indi­ vidual field. In the dryland areas, soil and water erosion, flood etc. are the major problems.Considering these points, the Govt, o f India launched a Watershed Management Programme in the seventh five year plan to de­ velop dryland areas on the basis o f watershed.For soil and water conserva­ tion measures,watershed is demarcated into sub watersheds & micro- watersheds.Micro-watersheds are the basis for planning and execution.In the beginning,there was a plan to develop 4000 watersheds in different agro-climatic regions,The Department o f Agriculture provided the funds for this programme and the responsibility o f evaluating 47 watersheds" management programmes initiated in different states was given to ICAR.This programme was accelerated in 1983 when world bank gave the assistance in the development of four watersheds. Watershed management programme has following features— (a ) S o il & W a te r C on servation M easu res : Soil and water conservation measures on the watershed basis include all those measures which are effective in preventing or delaying the movement o f soil and rock particles.In it the emphasis is given on soil surveying,contour and graded bunding,repairing o f old bunds and dams, land reclamation,digging o f farm ponds etc. (b ) Scientific D ry Farm in g : The agricultural activities like con­ tour ploughing, pre-monsoon ploughing, deep ploughing, mulching, de­ velopm en t o f n ew ,varieties according to agrordim atic zon es,w eed control,integrated nutrient management and integrated pest management improve the production in dryland areas, (c ) F orestry an d d evelopm en t o f p astu re; an d (d) Anim al husbandry and development o f dairy : Proper animal husbandry,artificial insemination,economic assistance to the milk produc­ ing cooperative socities etc.are to be adopted. - Dryland* Agriculture. / 43 A im s an d O bjectives o f W atersh ed M an agem en t 1. T o protectsconserve& improve the land resources for efficient and sustained production; 2. T o protect and enhance water resource, moderate floods &reduce silting up o f tanks,increase irrigation and conserve rainwater for crops and thus mitigate droughts. 3. T o utilise the naturaHocal resources for improving agriculture and allied occupation or industries so as to improve socio-economic conditions o f the local residents. Thus, watershed management is the planned use o f watershed lands in accordance with pre-determined objectives, such as the control o f ero­ sion, stream flow, sedimentation, and the improvement o f vegetative cover and other related resources. Such watershed management integrate plans for soil conservation, soil improvement, irrigation drainage, flood preven­ tion and development o f water supplies for all purposes. In case o f agricul­ tural micro-watersheds, important aspects are soil conservation measures, soil improvement, storage and utilisation o f runoff water. In dry farming areas, watershed approach provides an ideal means for integrated devel­ opment. There is a need for multipronged approach to maximise crop production & also to ensure stability in rural income for integrated water­ shed management having following steps— (i) Water harvesting (ii) Location specific technology for crop production , (iii) Adoption o f intercropping and crop substitution according to soil suitability (iv) Afforestation on cultivable wastes and marginal lands (v) Practice o f dryland horticulture to minimise risk. Mango, guava, ber, pumegranate, sapota and tamarind have good potential on marginal land. (vi) M ore efficient exploitation &use o f ground water and irrigation (vii) Development of dairying and pasture management (viii) Stall fed goat and sheep farming needs to be popularized Dryland Agriculture / 49  (ix) Popularisation of sericulture and mulberry cultivation (x) Processing of farm & horticultural produce (xi) Sound extension and training programmes for the farmers W a te r H arvesting/Ru noff Concentration/Rainfall Precipitation: In humid climates, runoff usually occurs only when rain falls on a saturated soil. Under semi-arid conditions, the total annual precipitation may or may not be sufficient, but most o f the rain falls in a short period causing humid climate conditions and resulting into runoff. In both conditions, the excess rain water should be safely guided and collected in nearby ponds for recy­ cling in drier period for life saving irrigation. Water harvesting is defined as the collecting and storing water on the surface of soil for subsequent use.lt is a method to induce,collect,store and conserve local surface runoff for agriculture in arid and.semiarid regions.Water harvesting was developed to a fine art about 2000 years by the Nabateans.The term ‘water harvesting’ was first time used by Myors. Normally water harvesting is more effective in areas situated near hill side or in the areas where large portion is bare soil and cultivation is done on small portions. The technology of wafer harvesting differs according to soil types,topography,annual rainfall and the crops to be grown. In India three types of water harvesting techniques are generally practiced— (i). In ter-row w ater h arvesting : Practiced in arid areas with light soil where annual rainfall does not exceed 400-450 mm. The crop is sown in narrow strips between wide intervals that are ridged as artificial miniature watersheds. Later on these are compacted to increase runoff to the crop rows. It is more practical since no land is sacrificed for harvesting water. 3 0 cm IO O c m Fig. 5.2 Inter - row water harvesting system Dryland Agriculture / 50  Fig. 5.3 Modified inter - row water system ; ii). Inter- p lo t o r M icro p lo t W a te r H arvestin g : In this case water is harvested in the passages or furrows between, the plots when rain­ fall is comparatively more. Runoff from the sloping area supplements rain­ fall for raising crop on level land. (iii). W ater harvesting in farm ponds.& Reservoirs Surface runoff from small watersheds is stored in farm ponds & reservoirs for utili­ zation as supplemental or life saving irrigation. This harvested water can either be used as life saving irrigation to Kharif crops at the time o f drought due to irregular monsoon or as supplemental irrigation to winter crops. Since the stored water is limited, steps should be takdn to reduce losses from seepage and evaporation. Suitable lining materials for pond beds and anti-evaporants should be found out and used. Runoff can be increased by either by land alteration dr by chemical treatment. Impermeable catchments are prepared by spraying asphalt compounds. Thin plastic films or metal sheets can also be used to cover ground surface for water collection. Waterbdfne asphalt emulsions are much effective in controlling seepage loss. Bentonite has excellent sealing prop­ erties if kept continuously wet. In the case o f Broad Bed & Furrow system, excess water during rainy season is collected through the furrows and passed through grassed waterways into farm pond or reservoirs. s; The stored water should be recycled most judiciously’ so as to get maximum return out of it. Only one or two irrigations are possible with the limited water stored. Therefore supplemental irrigation can be scheduled by two approaches viz. soil moisture depletion approach and critical stage approach. Irrespective o f the crop stage, irrigation is scheduled when soil D ry la n d A g ric u ltu re J 51 moisture approaches to permanent wilting point to save the crop. This supplemental irrigation is known as life- saving irrigation. Jalshakti: a chemical which when applied (mixed) in soil, improves the aeration, infiltration and waterholding capacity of the soil. Evapo- transpiration ( ET) : Soil moisture is the most limiting factor in dryland agriculture. About 60-75% o f the rainfall is lost through evaporation. The evapo-transpira- tion is the evaporation from the soil surface and transpiration from the plant surface. Such losses can be reduced by (i) mulches (ii) antitranspirants (iii) wind breaks and (iv) weed control. A ntitranspiran ts Such materials are applied to transpiring plant surfaces to reduce water loss from the plant. Antitranspirants are o f four types- (a) Stom ata Closing Type : Such antitranspirants reduce water loss through stomatal closing. e.g. phenyl mercuric acetate ( PM A), herbi­ cides like Atrazine in low concentrations, A B A and C 0 2 (b ) Film Form ing Type : Retard moisture loss due to formation of thin film as physical barrier.e.g. Mobileaf, hexadecanol, silicone, oils, waxes. (c) Reflecting Type : Such materials reflect the radiation and thus reduce leaf temp and vapour pressure gradient from leaf to atmo­ sphere and ultimately transpiration is reduced e.g. celite (a diatomaceous earth product) and Kaolin. Application o f 5% Kaolin spray reduces tran­ spiration loss. (d) Growth retardants : Such chemicals reduce shoot growth and increase root growth and thus enable the plants to resist drought. It also induces stomatal closure e.g. cycocel (ccc). Antitranspirants generally reduce photosynthesis. Therefore, their use is limited to save the crop from death under severe moisture stress. They have some practical use in nurseries and horticultural crops. W in d b re a k s an d S h elter belts Windbreaks are such structures which break the wind - flow and reduce wind speed while shelterbelts are rows o f trees or shrubs planted for Dryland A griculture / 52 protection o f c ro p against w ind. T h ey provide a protective shelter against Fig. 5 : Planting o f trees & shurbs as shelter belt wind and suitable habitat for birds and honeybees as well as produce cattle feed and fuel wood. In the wind erosion areas, windbreaks & shelterbelts are to be planted. They prevent soil erosion, arrest the march o f desert and protect the agricultural and residential lands from dust- storms. A rows o f trees & shrubs planted across the wind - direction is the most effective. It reduces the wind speed upto 60-80% on leewide side. The height of tall tree and length o f windbreak determine the extent of protec­ tion provided to soil. Windbreak & shelterbelt provides the protective shel­ ter against dessicating winds to the extent o f 5-10 times the height o f tall tree on windward side and upto 30 times on leeward side, For example, a 10-11m tall windbreak when encountered by 45-50 km/hr. wind, it re­ duces on windward side to 20-30 km/hr and to 10 km per hour on just leeward side which is illustrated by the figure 5.4. The wind-break reduces the windspeed on the leeward side at 200m away upto 20% only and in the area as at 300m away, there is no effect at all. Therefore at a interval o f 300m, such windbreaks should be repeated. T o control weed erosion, the capacity o f shelterbelt depends upon the speed and direction o f wind. In case o f high windspeed, the protective area is reduced and in such areas, the interval between two shelterbelts is Dryland Agriculture /53 to be reduced. T o counter wind’ s direction, it is necessary to be long length of windbreak so that wind blows across the wind break. Depending upon the porosity o f shelterbelt, certain amount o f wind passes through it and some deflects & crosses over it. Thus it does not produce turbulence o f Fig. 5 : Planting of trees & shurbs as shelter belt Reduction in wind speed, reduces the evaporation losses and makes avail­ able more water to crops. According to planting pattern of trees & shrubs as shelterbelt, the grasses & shrubs are planted on the outer rows which train the wind to rise much above the ground surface. The inker rows are \ o f small trees and the outer rows are planted by tall trees which further raise the wind level. The beneficial effects o f shelterbelts are m ore clearly seen in drought areas. In such areas windbreaks o f 3-7 rows and 15-30m wide are more effective. It modifies the micro- climate favourable for crop production and shelters for birds, honey bees & pet animals. Dryland Agriculture j 54  Soil erosion is. the process o f the removal of, soil particles from the parent body and transportation o f such particles by wind and/or water. R un off: That portion o f the precipitation whichj. rbed by the soil but finds its way into the streamsafter meetings istent demands of evapo- transpiration including interci pu jij other losses. In another words, runoff is the excess water lioin p u itation. that moves out o f field and finds its way to river, lakf s etc. Runoff = Itration + Interception + Surface on] Duration and: distri- Evapo-transpi (B ) Physiographic Factors7 (i) Watershed Characteristics : Topography o f soil , Soil types, Orientation, Geology, Vegetal Covqrnjshape and size of wa­ tershed.. - ' / (ii) Channel Charaetehshc&%- s i^ , ;slOpd y-cross- section and rough ness o f channel bed. W iz f-o s to n a r i & 'S o i r C o ris e rO a flo r i V 55  (C ) Geological Factors ; - Lithological, structural and hydrological characteristics o f the aquifers, permeability, porosity, transmissivity etc. Rainfall, type of vegetation and soils are the important factors that influence erosion. High intensity rainfall o f long duration causes severe erosion. Rainfall intensity o f more than 5cm/hr is considered as severe. Due to presence o f vegetation on the soil, there is no break down o f soil aggregates. S o il L o ss E quation d u e to W a te r E ro sio n : Based on the mechanism and factors influencing soil erosion, an universal soil loss equation was developed.It is useful forpredicting soil loss due to water erosion. A = R K LS C P W here A ►Predicted soil loss ( t/acre/year) R — ► Rainfall and runoff factor K — ►Soil erodibility L — ►Slope Length S — ►Slope gradient or steepness C “ ►Soil cover and management P — ►Erosion Control Practice. Active soil erosion by water and wind is prevalent over 140 million hectares resulting in the loss o f 600 0 million tonnes o f fertile soil contain­ ing about 5.5 3 million tonnes o f N.P.K. Soil Loss Equation D u e to W ind Erosion : E = IRKFCW DB Where E — ►Soil loss by wind erosion 1 —►Soil cloddines factor R —►Surface cover factor K —♦ Surface roughness factor F —♦ S o il textural class factor C Local wind factor W t * R eid width factor D W ind Direction Factor B Wind Barrier factor E r o t f o r i &rid S6it C o n s e r v a t io n J.56  Wind erosion control measures should aim at reducing wind velocity or altering soil characteristics. Soil Conservation Measures : Soil conservation is the preservation o f soil against deterioration and loss by using it within its capabilities, and applying the conservation practices needed for its protection and improvement.More specially,soil conservation consists o f using the land within the limits of economic practi­ cability while safeguarding it against impoverishment or depletion by ero­ sion, deposition,exhaustion o f plant nutrientsfthrough leaching excessive cropping or overgrazing).accumulation o f toxic salts, burning,water log­ ging (inadequate drainage), improper cultivation or any type o f improper use or failure to protect the land from soil or impairment o f productive- ness.The fundamental principles of soil conservation are— (i) Land use based on its capability (ii) Conservation o f soil and moisture to avoid damage to the soil, and (iii) Use o f best soil crop management practices, correction of acidity, alkalinity and drainage etc. Land Capability Classification The first requisite to conservation o f land is to fit the crop to the capa­ bilities o f the soil and the water availability.Lands are mainly used for agriculture,pastures and forestry. Th e capability o f land to grow crops de­ pends on the nature and properties o f soils. On the basis of capability or limitations,the lands are grouped into two major groups viz— (A ) Lands suitable for cultivation : Such lands are used for agri­ culture or cultivation of crops.Such land has four classes.These four classes are differentiated on the basis of limitations.These limitations are (i) Erosion :may be water erosion or wind erosion denoted by ‘e ’.(ii) Climate by (c) (iii) Water characteristics by (w) due to excess water,drainage problem (iv) Soil by (s) : low water holding capacity or low plant nutrient content of soil. (B ) Lands not suitable for cultivation : Such lands has also four classes which all are not capable o f supporting cultivation o f crops.These lands are used for growing grasses,forestry and supporting wild life. Erosion and S oil Conservation / 57  Thus lands are together grouped into eight classes by U.S. soil conser­ vation service.The first four classes viz class I,II,III, and IV are used for cultivation and the classes from V to VIII are not used for cultivation.But for the regular cultivation,only first three classes viz I,II,SdII are used Class I : N o limitations hence well suited for intensive crop cultiva­ tion, have permanent irrigation system, well drained level lands with high water holding capacity. Such lands need only crop management practices to maintain their productivity like use o f fertilizers,manures, crop rotation etc. Example o f class I are alluvial soils o f Indo-Gangetic plains.. Class II : Moderate limitations which reduce choice o f crops,require moderate conservation practices. Limiting factors are : (a) gentle slope (b) moderate erosion hazard (c) inadequate soil depth (d) less than ideal soil structure and workability (e) slight to. moderate alkali or saline conditions and (f) somewhat restricted drainage, Example o f class II soils are deep red soils and black soils. Management practices are strip crop ping, contour tillage,rotation involving grasses and legumes and grassed waterways. Class I II : Severe limitations requiring special conservation measures, limitations are moderately steep slope, high erosion hazard, very slow water permeability, shallow depth and resticted root zone, low water hold­ ing capacity, low fertility, moderate alkali and salinity and/or unstable soil structure. Example : Shallow red soils,slightly saline black soils.. Conserva­ tion measures require management practices mentioned for Class fl having higher proportion o f grasses or legumes in crop rotation.Tile and other drainage may also be needed. Class IV : Very severe limitations on choice o f crops;suitable for Occa­ sional cultivation,best use for pasture/hay; extensive use o f close growing crops; such land requires very careful management e.g.shallow soils, saline sqils, alkaline soils. K C la s s V : Limitations are (ij interference from stream flow (ii) short growing season (ill) stony or rocky soils (iv) Ponded areas where drainage is not possible. Pastures can be developed on these soils, used for grazing and forestry e.g. Arid soils, rocky soils, uneven or rolling soils which are not suited for cultivation. Erosion and Soil Conservation / 58  ClassVI : Moderate limitations on use for grazing/forestry. 'H. Class. VII : Severe limitations which restrict their use for grazing, w ood land or wildlife. Class VIII : Extremely rough land, not suitable for any kind o f crop production, its use is restricted to recreation,- wildlife,.aesthetic purpose and watershed protection, e.g. sandy beaches, river wash etc,. Conservastion Measures for agl. Lands are grouped under two heads (a) C rop m anagem ent according to the capability o f land and.. moisture. (b) Agronomic and Engineering Measures. Factors influencing measures are (i) soil (ii) land slope and (iii) rain­ fall characteristics of the area. Measures : (A ) Agronom ic M easures : are adopted where slope is less than 2% and erosion problems are not severe. These measures help to - (i) intercept raindrops and reduce the splash effect. (ii) to obtain a better intake of water rate by improving the cont- ent of organic matter and soil structures. (iii) to retard and reduce the over land runoff through the use of- (a ) Contour Cultivation : Cultivation o f crops along the contours o f a slope. It has following advantages - (i) conserve soil and water (ii) conserve soil fertility (iii) increase crop yield (iv) much less power required (v) less wear and tear of implements and less time is required. Disadvantage: The establishment of contour farming on undulating land is tedious. (b) Mulching ; Mulch is any material applied on the soil sur- , face to check evaporation and improve-soil water. It is de­ fined as a natural or artificially applied layer o f plant resi­ dues or other materials on the surface of the soil. Mulches are used for various reasons but water conservation and erosion control are the most important for agriculture in dry regions, e.g. crop residues leaves manures, straw, plastic films etc. Erosion and Sati Conservation / 59 Effects o f M ulching: (i) Mulching affects soil water through (a) runoff control (b) Increased infiltration (c) Decreased evaporation (d) weed control. (ii) affects soil temp. through- fa) radiation shielding (b) H eat conduction and trapping (c) evaporative cooling. (Hi) im proves soil nutrients status through, (a) organic matter addition (b) differential nitrification fc) mineral solubility. (iv) im proves soil structure. (v) affects soil biological regime through (a) O.M. additions (b) micro­ bial and soil fauna populations (c) plant root distributions. (vi) affects soil erodibility. (vii) affects soil salinity through- fa) Leaching and (b) Evaporation control. Mulches by reducing evaporation, reduce subsequent return o f the salts to the leached zone. T ypes o f M ulches : (i) Soil mulch o r dust mulch : If the soil surface is loosened, it acts as a mulch for reducing evaporation. It is called soil mulch or dust mulch. Intercultivation creates soil mulch in growing crops. Its usefulness is doubtful in alfisols but helps in closing deep cracks in vertisols. (ii) Stubble m ulch: Crop residues like wheat straw or cotton stalks etc. are left on the soil surface as a stubble mulch. (iii) Straw mulch : Straw is used as a mulching material. (iv) Plastic mulch :Plastic materials like polyethylene, polyvinyl chlo ride are used as mulching materials. (v) Vertical mulching : Subsoiling is probably the most effective method o f breaking hardpans to improve root penetration, aera­ tion and water percolation.To prolong the beneficial effect o f subsoilin g,a m eth od called vertica l m ulching has b een developed.The object o f vertical mulching is to fill slots with O.M. and keeping them open and functional for a longer period.In Erosion and S o li Conservation / £0  black soils,to improve infiltration and storage of rain water vertical mulches are formed. It consits o f digging narrow trenches across the slope at intervals and pjacing the straw or crop residues in these trenches. This is mostly practiced in coffee gardens. The pruned plant material is placed in contour trenches formed be­ tween rows o f coffee or in trenches around the plants in con­ centric each year in one circle. (c ) ' D e n s e g ro w in g c ro p s : provide maximum cover to soil e.g. cow pea & moong. Growing of Bidi tobacco causes maximum loss o f soil and water. Therefore a cover- cum —manure crop is grown during the early monsoon before tobacco transplanting. Intercropping o f Maize + Arhar/ Urd, does not reduce water and soil lo s s. (d ) Strip Cropping : In strip cropping , two or more than two crops are grown simultaneously in strips wide enough to permit independent cultivation but narrow enough for the crops to in­ teract agronomically. Strip cropping is essentially another form o f rotation. It may be defined as the process of growing the series o f alternate strips of various types of crops laid out so that all tillage and management practices are performed across the slope or on the contour. It controls the runoff erosion and main­ tains the soil fertility. It is o f four types-. (i) Contour Strip Cropping : Growing o f soil- exposing and erosion - permitting crops in strips of suitable widths across the slopes on contour, alternating with strip of soil - protect­ ing and erosion - resisting crops. Such cropping shortens the length o f slope, checks the runoff, helps to desilt it and in creases water absorption. H ere care o f contour is o f utmost importance. (ii) Field- strip Cropping : Planting o f farm crops in more or less parallel strips across fairly uniform slopes but not on ex­ act contours. H ere care of land slope is taken. It is useful for soils o f regular slope and o f high infiltration rates. Erosion a n d S o il /61  (iii) W in d S rtip C ro p p in g : Planting of tall growing crops.such as jowar, maize etc and low growing crops in alternately arranged straight and long, but relatively narrow, parallel strips laid out right across the direction of the prevailing wind, regardless o f contour: Here wind direction is cared. Objective is to control wind erosion rather than water erosion. (iv ) P e rm a n e n t o r T e m p o ra ry B u ffe r S trip C ro p p in g : T o take care of critical i.e. steep or highly eroded,slopes in.Tfields under contour strip - cropping.lt does not from part o f crop rotation unlike others. Strips of perennial legumes, grasses or shrubs on a permanent or temporary basis.Buffer strips are counter strips o f grass or other erosion resisting vegetation between or below cultivated strips or fields. Th e width o f the strips o f erosion resisting crops and erosion permitting crops depends upon slope, soil texture, type o f crops and rainfall characteristics. Strip cropping is riot adopted in India on a large scale because o f the small size holdings: (e ) Cropping systems like crop rotations, strip cropping, inter­ cropping and Crop mixtures. (B ) M echanical M e a s u r e s are adopted to supplement the agronomical practices and when land slope is more than 2%. Objectives : (i) to increase the time of concentration by intercepting the runoff and thereby providing an opportunity for the infiltration of water. (ii) to divide a long slope into several short ones so as to reduce the velocity o f runoff and thus prevent erosion. (a) Basin —Lisitng : Making o f small interrupted basin along the contour; effective on retentive soils having mild slopes. (b ) S u b -so ilin g : Breaking of hardpan by the sub soiler at 30-60 cm depth and 90-180 cm interval. (c) Cotltoiir bunding : making a comparatively narrow based embankment at intervals across the land slope on a level that is along the contour,Contour bunding is adopted in arid and semi Hrosfon and S oil Con serva tion / 6 2  arid areas with high infiltration and permeability and slope o f about 6%. Spacing between bunds should not exceed 150 cm vertical drop or 67.5 cm horizontal spacing, (d ) G ra d e d b u n d in g/ c h a n n e l te rra c e s : recommended where rain water is not readily absorbed either due to high rainfall or low intake o f the soil e.g. in areas'receiving rainfall o f more than 800 mm per year irrespect