Frances Gould, Arender, Tammi, McClure, Olivia J. | 10/13/2016 6:55:01 PM
Syam Dodla, LSU AgCenter agronomist, is studying the effectiveness of skip-row furrow irrigation. Photo by Tammi Arender
The most common way that farmers irrigate their crops in Louisiana is furrow irrigation — pumping water into the field to flood rows. While its cost is low, furrow irrigation is also inefficient, with much of the water running off the field.
But if farmers skip rows when irrigating, this may improve efficiency and still give crops enough water and nutrients, according to Syam Dodla, an agronomist at the LSU AgCenter Red River Research Station.
“Due to agriculture being the major consumer of freshwater and the long-term perspective of a shortage of freshwater resources, there is an urgent need to develop new strategies to conserve water,” Dodla said. “Furrow irrigation is still a dominant type of irrigation due to its low cost, but the water use efficiency is as low as 40 percent.”
The effectiveness of skip-row irrigation depends on a number of factors, including soil and crop type, which can affect how water flows down the field, he said. Heavy clay soils, for example, have better lateral seepage than lighter sandy soils.
Ryan Kirby, who farms corn, cotton and soybeans in Belcher in Caddo Parish, said many farmers have been using skip-row irrigation on clay soils. The heavy texture of the clay holds water well, while more water is required to spread through sandy soils that drain faster.
Most farmers have 38- or 40-inch rows, but Kirby now uses 30-inch rows and skip-row irrigation for crops grown in both clay and sandy soils.
More research is needed to determine if skip-row irrigation affects crop yields and if farmers can afford to cut back on the amount of water they use, said Kirby, a member of the Soybean and Grain Research and Promotion Board. But one benefit of skipping rows is that farmers have only half as many holes to punch in poly pipe, which saves time and labor, Kirby said.
“The objectives of this research are to evaluate and quantify the effect of soil texture on water use efficiency and crop yield with skip-row irrigation as compared to regular furrow irrigation,” Dodla said. He is also studying how irrigation frequency and amount should be adjusted when skipping rows, and how the practice may affect soil health and plant nutrient uptake.
Dodla, who began the study in 2015, so far has found that skip-row irrigation doesn’t seem to cause a significant decrease in corn yield in either light- or heavy-textured soils. But skipping rows with irrigation did cause a significant soybean yield drop in a field with very fine sandy loam, he said.
“Part of the differences in the results of soybeans and corn could be due to differences in the growing season — amount and distribution of rainfall and average temperature — rather than crop type,” he said.
Olivia McClure and Tammi Arender