Post on 13-May-2015
transcript
Ramanjaneyulu
Rainfed Agriculture needs special dispensation
• Limitations of rainfed areas– Moisture– Soil fertility– infrastructure– Other income generating options
• Lack of public policy support– Technology development– Marketing– subsidies
What we should think of ….
• Integrated farming systems integrating livestock, trees etc
• Building soil organic matter
• Conserving moisture
• Rainwater harvesting
• Locally adopted crops and varieties
• Contingence planning
Rainwater management
Combination of practices
Vermicomposting
Mixed croppingPlanting on bunds
Soil productivity Management• Plants as nutrient mining systems• Soil is understood as strata to hold plants• Only available nutrients are measured• External nutrient application-no measure of
utilisation• Soil-chemical, biological and physical properties• Biomass application is also seen as external
nutrient application…so measures only the content
KPN
Ca SMg
Fe ClMnZn Cu
O HC
B Mo
Major and micro nutrients Micro Nutrients
Source Air Water Soil Soil
Carbon Hydrogen Nitrogen Manganese
Oxygen Phosphorus Molybdenum
Nitrogen Potash Copper
Calcium Boran
Magnesium Zinc
Sulfur Chlorine
Iron
Essential Nutrients of PlantsElement Chemical symbol Atomic Wt. Ionic forms absorbed by
plantsApproximate dry concentration
Macronutrients
Nitrogen N 14.01 NO3-, NH4
+ 4.0 %
Phosphorus P 30.98 PO43-, HPO4
2-, H2PO4- 0.5 %
Potassium K 39.10 K+ 4.0 %
Magnesium Mg 24.32 Mg2+ 0.5 %
Sulfur S 32.07 SO42- 0.5 %
Calcium Ca 40.08 Ca2+ 1.0 %
Micronutrients
Iron Fe 55.85 Fe2+, Fe3+ 200 ppm
Manganese Mn 54.94 Mn2+ 200 ppm
Zinc Zn 65.38 Zn2+ 30 ppm
Copper Cu 63.54 Cu2+ 10 ppm
Boron B 10.82 BO32-, B4O7
2- 60 ppm
Molybdenum Mo 95.95 MoO42- 2 ppm
Chlorine Cl 35.46 Cl- 3000 ppm
Essential But Not Applied
Carbon C 12.01 CO2 40 %
Hydrogen H 1.01 H2O 6 %
Oxygen O 16.00 O2, H2O 40 % Plant tissues also contain other elements (Na, Se, Co, Si, Rb, Sr, F, I) which are not needed for the normal growth and development
Liebig principle
Plant growth is influenced by a nutrient at lowest concentration as a denominator
Healthy crop
Good nutrient managementGood tilth
Improving soil biota
Good cropping patterns
Mulching
Plough across the slope
In sandy soils add tank silt to increase water holding capacity and fertility
Application of at least 10 tonnes of tank silt per acre once in 3 years increases soil productivity considerably
Water harvesting
Water Management
Modern agriculture: irrigation, drip, sprinkler
Sustainable Agriculture: focuses more on conserving soil moisture, increasing organic matter, mulching, cover crops, cropping patterns etc…
Rainwater conservation measures
Conservation of the entire rain water in the field itself
•3.19 lakh acres of 1.46 lakh SC/ST farmers 2009-10•10 lakh acres in 2010-11
Components include Trench, Conservation furrows, Farm Pond, compost pit , tank silt application. Rs. 48,000 per acre - MGNREGS
Glimpses of insitu water harvesting CMSA
Critical Stages of crop growth
• Paddy: tillering stage, flowering, milking• Maize/jowar: flowering, panicle initiation, milking• Groundnut: flowering, prop root stage, pod
formation• Cotton: flowering, boll formation• Soybean/redgram/greengram/blackgram:
flowering, grain formation• Sunflower: bud formation, flowering, grain
formation
Factors influencing soil fertility and moisture
Rainwater
Organic Matter
Soil depth
Soil Structure
Water flow Nutrient release
Soil depth
Groundwater Basic minerals
Minerals
Living beings
Soil Organic matter The soil organic matter has declined from about 1.43 and 1.21 %
in red and black soils in the 1950’s to about 0.80 to 0.86 percent respectively at present.
Soil organic matter performs Hydrological, Biological and Nutrient related functions, which are both interrelated and distinct.
The OM helps tide over dry spells and in reducing runoff. Soil moisture and organic matter is essential even for improving the efficiency of biofertilisers and chemical nutrients.
For better decomposition Maintain C:N ratio in the range of 30-40:1 Application of water regularly to maintain around 60% moisture
'Organic Matter is Possible
Biomass source Biomass per Year (kgs/ ac) Remarks
Gliricidia/ Cassia 3000 to 4000 30kgs/ plant – from 5th year of planting
Sunhemp sown on bunds/ borders
350 @1.3 kgs/ sqm. 50% of bund length of 280 m
Biomass yielding trees` 450 @150 kgs/ tree, two loppings
Weeds 200 - 300
Crop residues 500 - 1000
Legume inter-crop 500
T O T A L 4000 - 5000
Green manure (legumes) crops when integrated as intercrops, would add about 1.5 to 3 tons/ ha of fresh biomass in situ.
Studies have shown that legume intercrops can add 0.30 to 2.4 tons of leaf litter per ha even in a drought year; with 4.1 to 35.6 kg N per ha.
Gobar Parva
Gobar Parva
Gobar Parva
Aakulu tokke panduga – KK Tanda
Aakulu tokke panduga – KK Tanda
Micro organismsDecomposition by microorganisms releases NutrientsProtect plants from diseasesImproves soil structure
Macro organisms•Incorporate organic matter in soil•Makes capillary pores in the soil to increase water infiltration and air circualtion
In factoryIn roots
Nitrates to plants
‘P’ for Plants
• Applied water soluble ‘P’ is, on an average, used @ 12-9-6-3% from year of application
• Considerable (70%) part of applied ‘P’ is locked in the soil first as tricalcium phosphate (TCP) and finally as apatite
• in paddies, under heavy soils, considerable part of applied ‘P’ gets converted into apatite
• P in TCP is unavailable but can be used by plants in association with Mycorrhizae and to some extent by Phosphobacteria
Factors limiting P availability and uptake
• Amongst the nutrients, nitrogen is universally limiting and in most trials this aspect is given due attention.
• But more often, the widespread Zinc deficiency is ignored and it could as well be a limiting factor in showing response to applied P
• At lower levels or production, the native phosphorus itself may be adequate and thus no response to applied P
• Some elements may become toxic (e.g. Boron). Subsoil salinity could be another factor
• With temporary or transient water logging or wet regime, Fe3+ iron may be reduced to Fe2+ leading to possible precipitation of phosphates
• The organic acids released by the legumes (Pscidic acid from pigeonpea roots) would solubilise phosphates or chelate metal irons like Ca2+, Fe2+ liberating part of the bound phosphorus. The VAM fungi may also accentuate the availability of phosphorus.
• VAM and other fungal bodies associated with roots improve the availability of difficulty available phosphates
• Method of application is important in enhancing fertiliser P use efficiency. Placement, in association with ammonical nitrogen is very effective.
Level of P requirement
Crop group Critical level
of P (P2 O5)
Low Pastures, grasses, small grains, field corn, soybean, etc.
35
Moderate Cotton, sweet corn, tomato etc.
60
High Potato, onion etc. 90
Soil critical values for phosphorus for different groups of crops
Organic matter increases P availability in four ways.First, organic matter forms complexes with organic phosphate which increases phosphate uptake by plants.Second, organic anions can also displace sorbed phosphate.Third, humus coats aluminum and iron oxides, which reduces P sorption.Finally, organic matter is also a source of phosphorus through mineralization reactions.
Flooding the soil reduces P-sorption by increasing the solubility of phosphates that are bound to aluminum and iron oxides and amorphous minerals.
In natural forestsa fistful of soil contains600-800 bacteria3000 fungi which are miles longer10000 unicellular organisms20-30 nematodes
Living in soil, making soil fertile and avoiding disease causing organisms
Soil where chemical fertilisers are used
Organically managed soils
How to increase soil organic matter
Leaving crop residues in field
Using organic manure with and mulching with crop residues
Practicing good tillage
Composting
Green manure crops and Good cropping patterns
Other important resources
subabool
Calatropis Glyrecidia
Cassia
seethafal
Functional pool Turnover time (yrs)
Composition
Decomposable
Metabolic litter 0.1-0.5 Cellular contents, cellulose
Structural litter 0.3-2.1 Lignin, polyphenol
Soil organic matter
Mulching
Crop Choices
• Market demand• Soil and growing conditions
Crop duration Water requirement crops
One season (< 4 months
Low Greengram, blackgram, chickpea, kharif groundnut
Medium Jowar, maize, rabi groundnut,
More than one season (6-8 months)
More Cotton, chillies
Year or longer Very high Sugarcane, banana
Based on soil depth
• Shallow roots (60 cm): ragi, sama, korra, onion, cauliflower, cabbage, potato
• Medium deep roots (90 cm): groundnut, chillies, wheat, tobacco, castor
• Deep roots (120 cm): maize, sugarcane, jowar, bajra, safflower, soybean, tomato, carrot, cucumber
Crop Management in Rain-fed areas• Low water consuming crops• Perennials on conservation furrows including green leaf
manure plants.• 7 tiered crop canopy ( 36*36 model ) near farm pond.
Probiotics
PanchagavyaJeevamrutAmrutjal
Cow/BuffaloIndegenous/improved
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