According to a new technique successfully tried out by researchers led by AS Brar of the Department of Agronomy at Punjab Agricultural University (PAU) on the university’s experimental farms, early wheat sowing and adopting drip irrigation technology could result in a 50 per cent reduction in water usage and improved yields, researchers at the PAU in Ludhiana have found. It could emerge as a major boon for Punjab, where 110 of 138 water blocks were found to be overexploited, with groundwater tables dipping steeply. Since the wheat is sown at the same land as of paddy, problems arises for farmer which can be weeded off by replacing it with maize for one section. The government may have to offer better prices for maize so that farmers may opt for the crop instead of paddy.
In a paper published in the journal Agriculture, Ecosystems & Environment last week, Brar and his doctoral student Eajaz Ahmad Dar showed that this could yield great savings in water budget, if widely adopted. The third author of the paper is KB Singh, a scientist at PAU’s University Seed Farms in Ladhowal. Further, the study has shown that the yields can be enhanced by about 10 per cent if the sowing is advanced by 15 days from the normal date of November 10, said Dar, who is the first author of the study. Advancing the crop cycle by a few days will not be difficult, he said.
Conventionally, rabi wheat crop in the State requires close to 50 cm of irrigation. This comes down to 26-27 cm if the drip irrigation technique is deployed, said Dar.
However, Brar admitted that implementing drip irrigation in wheat crop may face some challenges. Farmers normally grow wheat in the same field where their cultivate paddy in kharif. As of now, flooding the field is needed for paddy cultivation and hence farmers will not find it attractive to go for drip irrigation for wheat crop alone.
A way out, however, is to lure at least a section of farmers to grow maize in kharif, and subsequently use the land to grow wheat. Maize is grown over one lakh hectares in the State already, Brar said. The government may have to offer better prices for maize so that farmers may opt for the crop instead of paddy, he added.“We have already developed drip irrigation protocols for maize and cotton and they are found to be working wonderfully,” he said.Brar’s team is also exploring the possibility of using sub-surface drip irrigation. Once the pipes are laid beneath the soil, they won’t be destroyed even if the farmers grow paddy in kharif. “We also want to see whether drip irrigation will work for paddy as well, as we recently received funds for such a study,” Brar said.
According to him, drip irrigation offers other benefits as well. It improves nutrient efficiency and therefore brings hdown the input cost. Moreover, it helps prevent yield loss if there is a sudden raise in temperature closer to the time of harvest. Dar, who hails from Kashmir, said typically the field where wheat is to be grown is first flooded with 10 cm of water. Wheat crop , which has a duration of over 150 days, would require another five rounds of irrigation — each with an average of 7.5 cm water — before it is ready for harvest.
The first heavy irrigation is required for the new cultivation method too. But the water required for subsequent irrigation rounds comes down to just one-fifth. Even though the frequency of irrigation goes up two to three times depending on the rainfall received in a season, there is a substantial saving in the water used, he said. The number of irrigation cycles is decided by measuring the soil moisture content. When the rainfall is low, more irrigation rounds are required. For instance, in 2014-15, the PAU scientists irrigated the experimental fields 11 times as the region received 190 mm rainfall, but 2015-16 required 16 irrigation rounds as the precipitation was just 70 mm that year, Dar said.