2. 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
3. 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
4. Rainwater management Vermicomposting
Combination of Planting on bunds
Mixed cropping practices
5. 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
7. 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
8. Essential Nutrients of Plants
Element Chemical symbol Atomic Wt. Ionic forms absorbed by Approximate dry
plants concentration
Macronutrients
Nitrogen N 14.01 NO3-, NH4+ 4.0 %
Phosphorus P 30.98 PO43-, HPO42-, 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-, B4O72- 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%
Plant tissues also contain other elements16.00 Se, Co, Si, 2Rb,O F, I) which are not %
Oxygen O (Na, O , H2 Sr, 40 needed for
the normal growth and development
9. Liebig principle
Plant growth is influenced
by a nutrient at lowest
concentration as a
denominator
14. Application of at least 10
tonnes of tank silt per acre
once in 3 years increases
soil productivity
considerably
In sandy soils add tank silt to increase water holding capacity and fertility
16. Water Management
Modern agriculture: irrigation, drip,
sprinkler
Sustainable Agriculture: focuses more on
conserving soil moisture, increasing organic
matter, mulching, cover crops, cropping
patterns etc…
17. Rainwater conservation measures
Conservation of the
entire rain water in the
field itself
Components include Trench,
Conservation furrows, Farm Pond,
compost pit , tank silt application.
Rs. 48,000 per acre - MGNREGS
•3.19 lakh acres of 1.46
lakh SC/ST farmers 2009-
10
•10 lakh acres in 2010-11
21. Factors influencing soil fertility and moisture
Rainwater
Organic Matter
Living beings
Soil Structure
Soil depth Minerals
Soil depth
Water flow
Nutrient release
Basic minerals Groundwater
22. 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
23. '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/ 350 @1.3 kgs/ sqm. 50% of
borders 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
TOTAL 4000 - 5000
24.
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.
30. Micro organisms
Decomposition by microorganisms releases
Nutrients
Protect plants from diseases
Improves soil structure
Macro organisms
•Incorporate organic matter in soil
•Makes capillary pores in the soil to
increase water infiltration and air circualtion
32. ‘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
33. 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, Fe 3+ 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 Ca 2+, 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.
34. 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.
Soil critical values for phosphorus for different groups of crops
Level of P Crop group Critical level
requirement of P (P2 O5)
Low Pastures, grasses, 35
small grains, field
corn, soybean, etc.
Moderate Cotton, sweet corn, 60
tomato etc.
High Potato, onion etc. 90
35.
36. In natural forests
a fistful of soil contains
600-800 bacteria
3000 fungi which are miles longer
10000 unicellular organisms
20-30 nematodes
Living in soil, making soil fertile and avoiding disease
causing organisms
39. How to increase soil organic matter
Leaving crop residues in field
Composting
Using organic manure with
and mulching with crop residues
Green manure crops and
Practicing good tillage
Good cropping patterns
48. Crop duration Water requirement crops
One season (< 4 Low Greengram,
months blackgram, chickpea,
kharif groundnut
Medium Jowar, maize, rabi
groundnut,
More than one season More Cotton, chillies
(6-8 months)
Year or longer Very high Sugarcane, banana
49. 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
50. 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.