Douse farm fires with innovation, incentives

Milkha Singh Aulakh and Kabal Singh Gill

WITH mechanised farming and assured irrigation, farmers of northwest India raise 2-3 crops/year, and rice (summer)-wheat (winter) has become the predominant cropping system. This has increased foodgrain production from 52 million tonnes in 1951-52 to 310 million tonnes in 2020-21. More than half of the dry matter produced by these crops is inedible for humans; it remains in the fields as crop residue (CR). Farmers remove some CR for animal feed and household fuel. The rest is burnt in the fields or incorporated into the soil. In Punjab, 80-90% of wheat straw is removed for animal feed. However, 80-90% rice/paddy straw is burnt in the fields as high silica and oxalate content makes it less digestible for livestock.

*Source: Ministry of Agriculture and Farmers’ Welfare, Government of India (Indiastat.com) #Calculated by using CR/paddy Ratio of 1.3. $Proportion of Paddy straw burnt varies due to its use as animal feed and for other purposes in different States. data for 2016-17

Farmers face difficulties dealing with paddy straw because its tremendous amount is very expensive to evenly spread and work into the soil. It needs labour, time and 3-5 tillage operations with different equipment. Farmers are unable to complete seedbed preparation for timely sowing of wheat within the 2-4 weeks’ window. They also want to control insects, diseases, mice, etc. harbouring in CR, and avoid possible yield reduction by weeds and nutrient immobilisation. Small farmers are unable to bear over Rs 3,000/acre incorporation or removal costs, and hence burn CR.

When worked into the soil, CR is a source of organic matter (OM) and plant nutrients, improves soil health and reduces nutrient leaching. Soil OM —main storehouse of plant nutrients — and water help circulate air, water and nutrients, like blood in our body. Field studies at Punjab Agricultural University (PAU) illustrated that up to 21% of CR-organic carbon could be sequestered into soil OM, and returning all CR to the soil could replace 30-50% of chemical fertilisers. Total nitrogen (N) and phosphorus (P) removed by CR in India is equivalent to 30% and 34% of these applied as chemical fertilisers. Potassium removal by CR represents five times of that supplied by fertilisers. Burning of CR causes loss of OM, all nitrogen and some other nutrients, kills friendly insects and microorganisms, and deteriorates the soil structure. About 90% of agricultural carbon dioxide emissions in India are from burning CR, predominantly paddy straw in the fields.

In North American and Europe, conservation tillage has widely replaced conventional tillage. Indian researchers have developed several eco-friendly on-farm technologies for managing paddy straw. PAU researchers found that maize and several other crops’ production during the hot and dry summer substantially increased with paddy straw mulching. Straw Chopper-cum-Spreader or Straw Management System attachment with Combine Harvesters minimises difficulties in tilling residue-laden fields. Then, wheat is seeded using Happy Seeder or Zero-till Drill. However, wheat yield losses sometimes occur due to poor crop stand, rat infestation, weeds, etc.

The Super Seeder, which combines cutting, distribution and incorporation of straw into the soil plus drilling fertiliser and seeding wheat, seems a feasible technique. Crop establishment is excellent and damages due to pests, diseases, weeds, etc. are minimised. However, it requires 60-70 HP tractors compared to commonly used 20-35 HP tractors. Few farmers can afford over Rs 10-lakh tractor plus Rs 3-lakh Super Seeder, and about Rs 1,500/acre operational cost. Thus, rental units are a must for small farmers (86%).

Off-field, paddy straw could be used for several purposes. Biomass, cardboard and paper-making plants are being developed for CR as raw material. However, high cost of collection & bailing, transporting and processing prohibit utilising substantial proportions of annually produced paddy straw.

Another eco-friendly approach is recycling animal waste-enriched CR as manure, which can substantially reduce fertiliser use. This practice is successful in several countries. For instance, during a visit to a 200-acre rice farm in Japan, the farmer described how his nearby dairy farmers pick up paddy straw from fields for animal bedding, and after a few weeks he transports nutrient-rich straw back to his fields. This practice has established a sustainable system and he does not apply any fertiliser or manure to raise two rice crops annually. These farmers have developed a sustainable win-win system for themselves and the environment. Also, dairy and beef cattle farmers in Europe and North America often use CR as bedding material from own fields or bought from nearby grain farmers.

India has the largest number of cattle in the world. Unfortunately, a considerable portion of dung and almost all urine go waste and cause environmental pollution. About 90% of the nutrient intake by animals is excreted as urine (almost all N) and dung (most of P, K-potassium and other nutrients). Eco-friendly approaches could be developed according to local conditions to drastically reduce pollution and fertiliser use by recycling animal waste-enriched CR manure.

Each eco-friendly approach has severe economic constraints. Rather than punishing the farmers already reeling under heavy debts, they should be provided meaningful incentives on required equipment and/or compensation for operational costs for minimising CR burning. Alternatively, cooperative, agro-industries or other government-owned machines and support systems must be provided at subsidised, affordable rent. The Union Budget 2022-23 proposes to facilitate CR management, mandates thermal plants to use biomass pellets, and promote fertiliser-free natural and organic farming. Sufficient funds should be allocated for appropriate incentives and support infrastructure.

Minimising paddy straw burning needs multi-pronged, eco-friendly approaches immediately. There is no single solution to manage its massive quantities. All on-field and off-field technologies have limitations. Combined, they would improve soil health, grain production and fertiliser-use efficiency, reduce fertiliser need and pollution, and ensure long-term agriculture sustainability. While further technological refinements continue, concerted efforts are required to make the eco-friendly techniques economically viable, especially for small farmers. Overall, the provision of appropriate incentives is a must to replace CR burning with eco- and farmer-friendly ways to benefit the economy.

Aulakh is former Dean (Agriculture), PAU; Gill is former Soil Scientist, ICRISAT