In Punjab’s cotton-wheat cropping system, cotton is harvested in November-December, which often delays wheat sowing beyond the recommended time period (November 1-20). Late sowing of wheat after cotton significantly reduces wheat yield and food security. Punjab grows cotton on almost 2.5 million hectares, and wheat is planted on almost all of this land after cotton is harvested. Cotton picking often continues until late November, and because of this delay, many farmers sow wheat in December or even January. Every week of delay reduces wheat yield by 5- 10%. This delay affects the food security of the whole country.
Causes of late sowing of Wheat
Cotton is picked by hand in 4-6 rounds, in which each round takes several days. The last round often finishes in late November or December. Farmers cannot sow wheat until all cotton is removed from the field. This is the biggest reason for the delay.
After the removal of cotton, the field needs ploughing, levelling, and irrigation. If the farmer does not have a tractor or labour ready, this takes many more days. Hard soil after cotton needs deep ploughing, which is slow and expensive.
Impacts on Wheat
Yield loss is the most serious impact of late sowing. Timely sown wheat in November gives 45-50 maunds per acre. Wheat sown in December gives 30-35 maunds per acre. If sown in late December, yield may drop to 25-30 maunds per acre. This happens because late-planted wheat does not get the cool temperature needed for tiller development. Fewer tillers mean fewer spikes and lower yield.
Late-planted wheat enters the grain-filling stage in March or April when temperatures rise above 35ºC. High temperatures damage the developing grains, making them small and shrivelled. This reduces both yield and grain quality, so farmers get a lower price in the market.
Management Strategies
- Zero Tillage
This is the most practical solution for late sowing. Zero tillage means planting wheat directly into the field without ploughing, harrowing or preparing the seedbed. The soil is not disturbed at all. Farmers use a special machine called a zero-till drill or happy seeder to cut through the previous crop residue and place wheat seeds into the soil. This saves 7-10 days of land preparation. Research shows that zero tillage wheat can produce equal to or better than conventional tillage, especially when sowing is delayed.
Under the zero tillage technique, wheat is sown using residual moisture with no or minimum tillage without irrigating the fields, with the aim of sowing wheat in time after the previous crop. The ZT ferti-seed drill places seeds at a depth of only 3–5 cm directly into the cotton stubble field — no ploughing, harrowing, or planking is needed.
In wheat, it is employed for planting in standing stubble of the previous crop. It thus avoids preparatory tillage and so reduces the cost of crop production. By eliminating field preparatory tillage, it facilitates early wheat planting. Timely wheat planting is a critical factor in wheat yield maximization.
- Increased Seed Rate
Late-sown wheat produces fewer tillers per plant because warm weather reduces tillering. To compensate, farmers should increase the seed rate from the normal 50 kg per acre to 60-70 kg per acre. This ensures enough plants in the field to maintain population density and achieve reasonable yield despite poor tillering.
In the cotton zone of southern Punjab, where wheat is routinely sown in late November to December, researchers recommend 150 kg/ha as the baseline and up to 175 kg/ha for very late sowings.
Increasing seed rates demonstrated a significant influence on initial plant population, shoot numbers, plant height, and dry matter production. The 140 kg/ha seed rate led to increased spike counts, longer spikes, more grains per spike, and heavier grains, with yield averaging 4.25 t/ha — surpassing the 100 kg/ha rate at 3.85 t/ha.
A seed rate of 150 kg/ha with row spacing of 20 cm was more efficient in influencing yield and yield-contributing traits — including plant population, productive tillers, grains per spike, 1000-grain weight, biological yield, and grain yield — compared to 125 kg/ha with any row spacing. Higher seed rate can be useful to compensate yield losses due to delayed sowing of wheat.
- Relay Cropping
Relay cropping is another effective method for late sowing of Wheat. In this method, wheat is sown between cotton rows while cotton is still standing. This is usually done during the last picking of cotton in mid-November. The wheat seeds are drilled into the soil between cotton rows, and by the time cotton is fully picked, wheat has already germinated and established itself. This method saves more time than zero tillage.
The conventional cotton-wheat system delays wheat sowing by 20–30 days beyond the optimum time of 1–15 November due to late pickings in cotton and the time involved in subsequent tillage operations for seedbed preparation. This delay reduces wheat yield by 1.5–2.0 t/ha compared to timely sowing. Relay cropping directly attacks this problem by decoupling wheat sowing from cotton harvest.
Conclusion
Every year in Punjab, cotton picking drags into December, and wheat sowing gets delayed. Zero tillage is the simplest solution. Relay cropping also works well. Farmers can also increase the seed rate to prevent yield loss due to delayed sowing, or farmers can use early varieties like Faisalabad-2008. However, these methods only work if farmers learn about them. Government extension services should set up village-level demonstrations and encourage farmer-to-farmer sharing of results.
Rukhsar Saleem1, Sarmad Ali Sajjad2, Hunain Ahmad3, Sana sharif4
Department of Agronomy, University of Agriculture Faisalabad, Pakistan.