What is in this article?:
- Field trials conducted by UCCE Cotton Specialist Bob Hutmacher suggest that water cutbacks via deficit drip irrigation can save 3-4 or more inches of water.
- Research by UCCE Farm Advisor Steven Wright indicates that Pima cotton can be defoliated a week-plus earlier without much impact on lint yield and quality.
University of California (UC) researchers are unlocking new management practices which could help cotton growers save water through deficit drip irrigation, plus better manage weather challenges in the fall months.
At the 2014 Beltwide Cotton Conferences in New Orleans, La. in January, UC Cooperative Extension (UCCE) Cotton Specialist Bob Hutmacher discussed ongoing research on deficit irrigation in drip-irrigated cotton to save water with minimum crop yield and quality losses.
UC Cooperative Extension Farm Advisor Steven Wright, Tulare and Kings counties, discussed tweaks in the fall defoliation process which could allow Pima cotton growers to harvest earlier and reduce the threat of damage and harvest delays associated with fall rains and the related fog and dew.
Last year, California cotton growers produced about 300,000 acres of cotton, mostly in the San Joaquin Valley (SJV). Two-thirds of the crop (200,000 acres) was Pima with the remaining 100,000 acres in Acala.
Hutmacher says a fast-growing trend over the last five years in the SJV is to grow cotton with drip irrigation (surface- or subsurface-placed systems) to improve the water application efficiency and reduce the crop’s water needs.
He says as much as 25 percent of the crop may be irrigated with drip today with the 75-percent balance watered by furrow, border, or level basin irrigation.
At Beltwide, Hutmacher discussed several field trials conducted in Fresno County on drip irrigated cotton and the impact that deficit irrigation can have on cotton yield and quality.
“Drip irrigation in cotton can do a pretty effective job of applying water and during some targeted periods the water can be successfully applied at a deficit level,” Hutmacher said. “Basically the grower irrigates in amounts less than peak plant water use rates.”
The unused water from deficit irrigated cotton can be used for other crops in the grower’s overall water and crop management systems.
The timing of Hutmacher's deficit sdrip irrigation research is perfect, though somewhat coincidental. After several consecutive years of drought, California Governor Jerry Brown in mid-January declared a drought emergency in the Golden State Overall, this will mean less water available for crop production, including annual crops like cotton.
Hutmacher’s research findings are good news for cotton growers using deficit drip irrigation.
“Relatively mild water stress created with a 15-25 percent cutback in irrigation water in the mid-to-late season from peak bloom on had a relatively limited impact on yield (5-10 percent less yield) and no significant impact on fiber length and strength,” Hutmacher said.
He warned though not to cutback water any further. A 40-percent reduction in applied water, for example, could result in more than a 25-percent yield loss.