| Not enough to go around
New Delhi, Dec. 4: An unprecedented stagnation in India’s wheat output has triggered concern among top agricultural scientists whether India will be able to meet its wheat demand over the next decade.
Unusually high winter temperatures, improper fertiliser applications and a slowdown in international exchange of elite plant material have contributed to unanticipated yield stagnation over the past five years, the scientists have said.
India’s wheat output climbed steadily over the past three decades to peak at 76 million tonnes during the year 2000. But over the past five years, production has dropped by 1.1 million tonnes per year. The average yield since 2000 has been 70 million tonnes.
Scientists fear that if this negative trend continues, India may not be able to meet the projected demand of 109 million tonnes for the year 2020. “We just cannot be complacent about our grain basket any more,” said Subrahmaniam Nagarajan, the chairman of the Protection of Plant Varieties and Farmers Rights Authority in New Delhi.
“There are some new realities we must learn to face,” Nagarajan told The Telegraph.
Across the grain basket states in the northern Gangetic plains, the improper use of fertilisers has led to widespread deficiency of micronutrients such as zinc, magnesium and sulphur -- elements that are crucial for successful plant growth.
Farmers in Punjab, Haryana, and Uttar Pradesh have tended to use excess of urea, ignoring the need for other micronutrients, Nagarajan said. The continued use of urea year after year has depleted micronutrients on farmland.
“If the level of micronutrients drops below a certain critical level, no amount of urea would be able to boost the crop yields,” he said.
While the ideal ratio of the three fertilisers --- nitrogen, phosphorus and potassium --- should be 4:2:1, in some parts of Punjab the ratio is now 35:7:1, said Mangala Rai, director general of the Indian Council of Agricultural Research.
In a report published in the latest issue of the journal Current Science, Nagarajan has also cautioned that high temperatures during the wheat harvesting period have caused “yield depression” in recent years.
A single day of growth reduction can mean a 35 kg per hectare loss of grain. If wheat matures a week ahead of schedule because of high temperatures, the yield can drop significantly.
Scientists believe that the drop in wheat production during 2003-04 was primarily caused by heat stress on the plants. “Winters don’t seem to be what they used to be. Is this an early signal of global warming' We’re not sure,” Nagarajan said.
But wheat yields have also remained stuck because new high-yielding varieties aren’t available to farmers any more. During the Green Revolution, India depended on imports of elite, high-yielding varieties from public-funded international agricultural networks.
But with changing research priorities worldwide and new patent regimes, the flow of such material has reduced, Nagarajan said. No new variety of wheat introduced over the past decade in India has been able to outperform the “PBW343” variety that was acquired through such exchange of plant material. This overdependence on the exotic, elite plant material is a point of great concern, Nagarajan wrote in the journal.
Rai, director general of agricultural research, said that wheat productivity may also be affected by a drop in use of green manure and farmyard manure on the cultivated land. “This has also contributed to changes in soil characteristics,” Rai said.
Agricultural scientists say there are also economic factors that have pushed farmers away from wheat. As the input costs of water pumping, fertilisers, and pesticides have gone up, the minimum support price has remained static.
Low profits from wheat have driven farmers towards other crops, Nagarajan said.