Most growers would likely expect higher yields from conservation-tillage in drought years. With the ground covered and more organic material in the soil, better water usage would be expected. In corn, during the drought years of 1998-2001, conservation-tillage produced a 4 percent yield advantage.

In a soybean and wheat double-crop, it was a different story, Bauer notes. During the same time frame soybeans planted directly into wheat straw in the conservation-tillage plots produced a five percent decrease in soybean yields and three percent decrease in wheat yields.

“During that same time period and on a different area of the research farm, I had a test comparing the effects of no-till versus conventional-tillage on the exact same kind of soil on cotton, and we saw a 22 percent yield increase on the no-till plots,” Bauer notes.

Cotton is grown in 30 countries around the world, under sometimes dramatically different climatic conditions and on many different soil types. The one common denominator in yield and quality of cotton grown anywhere in the world is water.

USDA researchers recently documented the genes that help regulate water flow through a cotton plant. This study combined with the long-term tillage study, dating back to 1978 offer a near perfect environment to study how to best manage the water carrying capabilities of cotton.

A major facilitator of water movement through cell membranes of cotton and other plants are the aquaporin proteins. Aquaporin proteins are present as diverse forms in plants, where they function as transport systems for water and other small molecules.

 “We now know, based on results of these recent tests, that there are 71 genes in cotton that regulate how water moves through the cells of a cotton plant. And, we know that certain microbes in the soil can turn on the genes in the cells that help regulate water in the cotton plant,” Bauer says.

The USDA study presents a comprehensive identification of 71 cotton aquaporin genes. Phylogenetic analysis of amino acid sequences divided the large and highly similar multi-gene family into the known 5 aquaporin subfamilies.

Lead researcher on the project and USDA-ARS scientist Wonkeun Park says, “Together with expression and bioinformatic analyses, our results support the idea that the genes identified in this study represent an important genetic resource providing potential targets to modify the water use properties of cotton.

“The significance of the multi-gene family of aquaporin transmembrane proteins is emerging from studies aimed at optimizing water and nutrient use efficiency.

“This large gene family has been shown to be highly diversified in plants and thus likely harbors functionally multifaceted behaviors in plants under various growth circumstances.

“Since the global importance of cotton as a primary natural fiber source in production agriculture is well established, our goal in this study was to identify all the members of the aquaporin family in the cotton genome,” he says.    

Bauer adds that over the next few years, researchers at the PeeDee Station will look at cotton in comparison to corn to determine the different amounts of these microbes that occur in conventional versus long-term tillage.       

“We want to know better ways to manage the soils in the two different crops,” the USDA researcher says.

rroberson@farmpress.com