3-Crop Residue Retention

Transcript

We are discussing about another component of CASI which is residue retention. What is residue retention? Before getting into the topic, we must understand how crop biomass can be managed? There are different methods like crop residue which is left in the field; crop removal which is taken out of the field; third one is crop incorporation which is mixed with the soil in the same field; and the fourth one is crop burning in which farmers usually burn the residue in the field which causes environmental pollution. Among all these methods, the most beneficial one is crop retention.

We can also opt for crop incorporation, but this method consumes a lot of energy and the field needs to be tilled several times. This is a very difficult, time consuming and expensive process for farmers. Now what is crop retention? When we harvest crop, generally Combiner is used. These days SMS (Straw Manager System) is attached to the Combines which helps in equal distribution and forms a mulch in the field. We do not disturb that mulch rather continue seeding in to the mulch. This retention of the mulch is called crop retention.

As mentioned, there are different methods of residue retention and we need to understand its importance. If we take 1 ton of residue, we can find 5.5 kg of nitrogen, 25 kg of potassium, 2.5 kg of Phosphorus, 1.2 kg of Sulphur, 70%- 80% of micronutrients that can absorb and around 400 kg of carbon. When we burn the residue, the nutrients are lost and so, the soil is deteriorated. And if we incorporate it, usually nitrogen and carbon get mineralized and decomposed during the process and the nutrients are lost in form of gases. So, in retaining the residue we get maximum benefit from all the plant nutrients.

Now we deal with comparative advantages of crop residue retention. The first advantage is it increases the organic carbon of soil and catalyzes the secretion of carbon. The second benefit is it improves soil fertility and releases nutrients. It also improves structure of soil and helps in soil aggregation. Besides, permeability of soil or infiltration- an ability to absorb water, increases. This consequently increases the recharge and improves water-holding capability.

It’s been found that if we mulch, the moisture in soil is conserved and soil temperature remains balanced. In extreme cold, mulch keeps the temperature of soil from dropping. And in extreme heat, it keeps the temperature of soil cooler by 3- 4 degrees. Overall, it moderates soil temperature and balances by 5- degrees due to which microbial properties increases.

If we mulch the entire season, the conservation of soil moisture remains highest throughout. We have measured it as you can see clearly in the graph, where there is residue, there is less soil tension and vice versa.

With residue retention, the relation between soil, plant and water also improves. This also boosts up plants’ physiological activities like increase in photosynthesis, balance in canopy temperature, better respiration etc. So overall, plants get healthier. Mulching also controls decomposition and mineralization of nutrients in the soil. The nutrients are released gradually throughout the season which helps plants to prosper across the season.

One of the benefits that we are losing in conventional agriculture is soil biodiversity. When we mulch, organic matter is decomposing in the soil due to which soil bacterial, fungal, actinomycetes and overall the population of micro- fauna and macro-fauna, overall soil microbial properties improve. This will improve soil health and hence, rises soil quality index. The overall improvement in soil brought by residue retention improves soil’s health which will result in healthier plants, healthier produce and nutritious diet. These are the benefits of residue retention which plays very important role in making soil healthy