Burning of paddy stubble by farmers in fields after harvesting made headlines last month, even as the National Green Tribunal directed the Punjab, Haryana, Rajasthan and Uttar Pradesh governments to ban this practice, seen as a major cause of air pollution in the national capital.
But a few enterprising farmers in Punjab, seeing the writing on the wall, have adopted technologies — zero-tillage and direct seeded rice (DSR) — that not only enable sowing of wheat without any burning of crop residue, but also save water by doing away with transplanting operations in paddy.
Punjab grows paddy in 28 lakh hectares (lh) in kharif season (transplanting in June and harvesting in Oct-Nov) and wheat in 35 lh in rabi (sowing in Nov and harvesting in April). The two crops together produce an estimated 38 million tonnes (mt) of straw annually, of which over half is from paddy.
While 70 per cent of wheat straw is used as dry fodder and the rest burnt, the extent of burning is as high as 70-75 per cent in paddy straw. One reason being high silica content in paddy straw, making it unsuited for feeding directly to animals. Importantly, the spike in temperatures during March noticeable in recent times, results in premature ripening of grains. It has led to early sowing of wheat, towards mid-November, by farmers. But with paddy being harvested in October, it leaves little time for field preparation and planting of the wheat. So, rather than recovering the 14-15 inch left-over stalks after paddy harvesting, farmers simply set their fields on fire. The cleared fields they plough using a disc plough or rotavator, which crushes the straw roots into small pieces, followed by one irrigation and planking or levelling to prepare the seedbed for sowing.
Narinder Singh Bajwa, however, has eschewed the above practice for the last 6-7 years. This 10-acre farmer from Chaura village in Dera Baba Nanak tehsil of Gurdaspur district harvests his paddy around October 10. During the interval before wheat sowing by mid-November, he also plants seeds of Dhaincha — Sesbania aculeata, a green manure crop — in between the paddy stubbles. The wheat seeds he, then, directly sows with a tractor-mounted zero-tillage machine, which also ploughs the Dhaincha growing in the field enhancing its soil fertility.
Traditionally, the total cost of field preparation and sowing using tractor-powered tillers comes to Rs 3,500 per acre — Rs 1,200 for rotavator/disc plough operations, Rs 500 for planking, Rs 1,000 for seed and Rs 800 for sowing. “Here, my cost is limited to Rs 800 per acre for running the zero-till machine and Rs 1,000 on seed. Even if I spend another Rs 500-600 per acre for a chopper machine to shred the paddy straw further for their easier absorption into the soil, it translates into savings of over Rs 1,000,” says Bajwa.
His views are shared by Ravinder Singh Brar, who farms 65 acres in Kauni village of Muktsar’s Gidderbaha tehsil. The latter uses the Happy Seeder, a modified version of the zero-till machine that cuts, lifts and throws the paddy straw and sows the wheat seeds about 2-3 inches deep (against digging up to 6-7 inches in conventional tillage). Brar started zero-till cultivation in 2009 and has been modifying his Happy Seeder machine, adding more blades to cut the paddy straws into smaller pieces at the time of sowing.
Brar claims his wheat yields, at 26-27 quintals per acre, are at least two quintals more than in the traditional method. This, he attributes to the improved soil fertility from the incorporation of straw residue matter, which isn’t possible with burning. This advantage comes on top of lower production cost and, of course, no pollution from burning of stubble. A zero-tillage machine costs Rs 25,000-35,000, while ranging from Rs 1.25 to Rs 1.50 lakh for a Happy Seeder. Both are manufactured locally and amenable to modification as per the demand of farmers.
Bajwa and Brar have also taken to DSR technology in paddy. In the traditional cultivation method, paddy seeds are first sown in a nursery. After about four weeks, the young saplings are uprooted and transplanted in the main field. Prior to that, the field is also puddled or wet-tilled using tractor-drawn disc harrows. All these consume lot of water. For the first 60 days or so following transplantation, the paddy has to be given irrigation every 2-3 days to ensure continuous standing water at 1.5-2 inches above the ground. The underlying purpose is to prevent growth of weeds by denying them oxygen in submerged conditions. The weed threat recedes only once the plants have crossed the tillering stage. Transplanting is, moreover, a highly labour-intensive affair. About four labourers are required to transplant an acre, costing Rs 2,800-3,000.
With DSR, there is no need for transplanting, puddling or raising of nursery. The paddy seeds are directly planted in moist fields using a DSR machine, costing Rs 500-600 per acre. The DSR machine — which itself comes for about Rs 40,000 — can sow 5-6 acres area in a single day. Farmers, in this case, have to spend money basically on ‘real’ weedicides, as opposed to water. The total cost of these — mainly oxadiargyl, bispyribac sodium and fenoxaprop-p-ethyl — works out to Rs 2,000 per acre. This, along with the Rs 500-600 per acre DSR sowing charges, is much less than the expenditure on water and labour in the conventional route. Brar estimates only 12-14 irrigations are necessary under DSR, as compared to 25-27 in the traditional method. The savings are more if one takes the free power made available for irrigation. “The day the Punjab government stops giving power subsidy, no farmer can afford transplanted paddy cultivation”, points out Brar.
Today, about 8 lh wheat area in Punjab is being grown using zero-tillage/Happy Seeder and 1.60 lh under DSR paddy. Bajwa and Brar are among those who have adopted both technologies proven to be environment-friendly, cost-effective and labour- and energy-saving. It will take some time to convince other farmers, too, that they needn’t burn paddy straw to sow wheat or growing paddy is possible even without nursery preparation and transplanting.