Wheat that can beat the heat

He hasn’t looked back since. “In conventional tillage, I have to first spend some Rs 500 per acre to chop the paddy stubble, without which burning isn’t possible. The field has to, then, be tilled twice using harrow (costing Rs 550 per operation) and given a pre-sowing irrigation (Rs 800, including labour and water charges). This is followed by one planking (smoothening the soil surface; Rs 300), two more harrowings (Rs 1,100), a second planking (Rs 300) and one final ploughing with rotavator (Rs 1,100). The total comes to roughly Rs 5,200 per acre, with sowing by seed-drill adding another Rs 900,” states Chaudhary.

Zero-till, by contrast, entails virtually no seedbed preparation cost. The Happy Seeder simply cuts and lifts the standing paddy stubble, drills the wheat seeds into the bare soil, and deposits the straw over the sown area as a mulch cover.

But for Chaudhary, the real gains from “conservation agriculture” or CA — cultivation that involves minimum soil disturbance through no-tillage and direct seed-cum-fertiliser placement — have come only in the last couple of years. “I started zero-tillage with DBW 17 and DPW 621-50 in 2010-11. After 2012-13, I also planted the newer high-yielding wheat varieties such as HD 2967 and HD 3086 using CA. The drawback with these varieties, however, was that they were not bred specifically for CA,” he notes.

Breeding for CA would have required a wheat variety suitable for planting immediately after harvesting of paddy around mid-October. Zero-tillage technology, on paper, allowed paddy to be harvested and wheat sown the very same day, since the farmer did not have to expend time or money on field preparation. But for that, there had to be wheat varieties that could be seeded before November.

The usual “ideal” time to plant wheat in Haryana and Punjab is from about November 5 to 15. “If you sow before that, the crop tends to prematurely flower; the earheads (containing the flowers) emerge fully from the tillers (the side stems that grow from the initial parent shoot) much earlier than desired. For the wheat that is sown on November 15, heading (50 per cent or more of the earheads coming above the leaf sheath) takes place in 90-95 days. This could be 10-15 days earlier, if you plant in the second half of October,” explains Rajbir Yadav, principal scientist (genetics division) at the Indian Agricultural Research Institute (IARI), New Delhi.

Yadav’s team at IARI have bred a wheat variety HDCSW 18, which has a mild “vernalisation requirement” or the need for a certain minimum period of low winter temperatures for initiation of flowering. So, whether sown in October or November, the transition from the vegetative to reproductive stage — when the earheads fully emerge and pollination (transfer of pollen from the male anther to the female stigma part of the same flower) starts — will not happen till the plant’s basic vernalisation requirement is met during the whole of December and January.

“The crop, therefore, comes to heading 10 days late: 100-105 days, instead of the normal 90-95 days. Since the crop has more time for vegetative growth, it tillers better, which can contribute to higher yields,” observes Yadav. Moreover, being amenable to sowing by October 20-25, instead of November 5-15, means there is a longer window now available for grain-filling as well.

If the wheat seeded in October 25 completes flowering and pollination by February 5-10, which is followed by another 25 days of early kernel formation (“milk” stage), the main grain-filling or “dough” stage can commence around March 5. This is as against the usual time of mid-March, which makes the crop vulnerable to terminal heat stress and the grains not accumulating enough starch matter. While day temperatures during the 15 days or more of grain-filling should ideally be in the early-thirty degrees range, there has been an increasing tendency, though, for the mercury to soar well beyond those levels towards the second half of March.

“HDCSW 18 is the perfect wheat variety, not only for sowing early and reducing yield loss risk from surge in March temperatures, but also for CA. Previously, even if paddy was harvested by mid-October, I couldn’t plant wheat before November 4-5. Now, I can sow using the residual moisture from the paddy itself. The leftover straw deposited as mulch, too, promotes moisture retention and dispenses with the need for any pre-sowing irrigation. Further, the plants are less prone to lodging (falling) with CA, as there is no loosening of soil from repeated tilling and the roots establish themselves deeper,” claims Chaudhary.

Chaudhary has planted the HDCSW 18 variety on 25 out of his total 55-acre holding — 35 own and the rest leased — in the current rabi season. On the remaining land also, he has mainly sown wheat — 11 acres under HD 3226, five acres under HD 2967, and four acres each under HD 3117 and DBW 173 — and a few acres under mustard and berseem fodder.

“This is my third season of growing HDCSW 18. Last year, my average yield from it was 27 quintals per acre, more than the 25 quintals from HD 3117, 24 quintals from HD 3086 and 22 quintals from HD 2967. This time, the winter has been great so far, but if temperatures shoot up in the next 10 days, I know my yields from HDCSW 18 at least will not suffer,” he adds.

Chaudhary has also ensured that nearly 400 acres out of Taraori’s 2,400-acre agricultural land — which includes 600 acres under vegetables and 200 acres under other crops — has been covered under HDCSW 18 this year. The village today has 16 Happy Seeders, for which he was again the prime mover. Now, that’s what a progressive farmer is and can do for technology diffusion.