SOIL BIOLOGICAL ACTIVITY

  • Good biological activity is central to all farming system including organic farming.
  • Soil organisms : Bacteria, fungi, earthworms and a whole range of organisms
  • Essential part of the organic farming system
  • Play vital roles in nutrient cycling, soil structural development and pest and disease control.

Encourage biological diversity/activity in soils by:

  • Provide comfortable living conditions – good soil structure.
  • Provide a food (energy) source – fresh organic matter.
  • Specialized micro-organisms such as N fixing bacteria and mycchorizal fungi provide large benefits to organic systems.
  • Plan rotations and management to encourage them.
  • Avoid the application of materials that are antagonistic to biological activity.
  • In organic agriculture the maintenance of soil fertility may be achieved through the recycling of organic material whose nutrients are made available to crops through the action of soil micro-organisms and bacteria.
  • Organic farming always encourages use of on-farm inputs for nutrient management.
  • Factors such as contamination, risk of nutritional imbalances and depletion of natural resources shall be taken into consideration.
  • Soil testing to know the physical structure, texture, nutrient status and microbial status of the soil.
  • Improvement in soil physical structure and soil biological activity will improve the nutrient status of the soil.
  • ‘Feed the soil’ not ‘Feed the plants’.
  • If organic nutrient recommendation is not available, calculate the required dose of organic manure equivalent to recommended nitrogen dose. The remaining phosphorus and potassium should be met using different organic manure rich in P and K, respectively.
  • Organic manure should be applied as basal during land preparation.
  • Biofertilizers can be applied as seed treatment (along with biopesticides) or as soil application during planting. Biofertilizers can also be applied in split doses.
  • Concentrated organic manures can be applied to meet certain nutrient deficiency.
  • Organic formulations can be used as seed treatment as well as foliar spray.
  • Incorporation of legumes in the cropping system is always advised.
  • Green manuring / cover cropping during nutrient depletion stage are essential.
  • Consult with certification agency prior to use any restricted source of nutrients.
  • The living organisms in the soil are at the heart of organic farming.
  • Organic matter is central to good soil fertility management.
  • Earthworms à Most visible soil organisms à Organic matter breakdown.
  • Fresh organic matter (crop residues) à Provides carbon in a form more easily processed by micro-organisms than composted organic matter à Short-term stimulatory effect.
  • Minimum cultivation just to break up soil clods à Exposing organic matter à aerates the soil à beneficial for soil microorganism.
  • Vigorous cultivation à (a) Kills earthworms, (b) Disrupts soil microbial activity by exposing organisms and (c) Disrupts mycorrhizae.

NUTRIENT BUDGETING

  • A nutrient budget is a measure of the nutrient balance of a farming operation.
  • It takes into account all the nutrient inputs on a farm and all those removed from the land.
  • Nutrient budget gives a draft picture about the nutrient flow in the organic farm.
  • It helps in determining nutrient surplus/deficit in the soil and facilitate nutrient management.