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ARS Home » Midwest Area » Columbia, Missouri » Cropping Systems and Water Quality Research » Research » Publications at this Location » Publication #178934
Title: PLANT RESPONSE TO IRRIGATION TREATMENTS IN ARKANSAS COTTON

Author
item BAJWA, SREEKALA - UNIV OF ARKANSAS
item Vories, Earl

Submitted to: Agricultural Experiment Station Publication
Publication Type: Experiment Station
Publication Acceptance Date: 3/25/2005
Publication Date: 10/1/2005
Citation: Bajwa, S., Vories, E.D. 2005. Plant response to irrigation treatments in arkansas cotton. PP. 126-133. In D.M Oosterhuis (ed) Summaries to Arkansas Cotton Research 2004. Agricultural Experiment Station Research. Series 533.

Interpretive Summary: Irrigation of cotton has been increasing throughout the mid-South, and remote sensing is a potentially valuable method for water quantity management. A furrow-irrigated cotton field at the University of Arkansas Northeast Research and Extension Center in Keiser was used for a study to investigate the sensitivity of remotely sensed data to crop water stress. A relatively wet crop season prevented development of significant water stress in the crop for much of the season, with excess water causing a decrease in yield. However, during the periods of water shortage, the study showed that crop canopy response has the potential to be an effective indicator of water stress. This indicates we can develop an irrigation scheduling strategy that could incorporate real-time monitoring into irrigation scheduling.

Technical Abstract: Irrigation of cotton has been increasing throughout the mid-South. Remote sensing is potentially the best method for water quantity management based on a site-specific, time-critical and need-based application. The objectives of this project included validating light reflectance from a cotton canopy and canopy temperature as early indicators of water stress, and developing and validating an irrigation strategy on an as-needed basis by incorporating season-to-season or within-season variability in crop development indicated by canopy reflectance/temperature. A furrow-irrigated cotton field at the University of Arkansas Northeast Research and Extension Center in Keiser was used for the irrigation study. The study was designed as a randomized complete block split plot design with four replications. The whole plot factor was irrigation and the split plot factor was cultivar. Three irrigation treatments were based on the Arkansas Irrigation Scheduler: a well watered (WW) treatment was irrigated at a 1.75-inch allowable deficit; a moderately stressed (MS) treatment was irrigated at a 3.5-inch allowable deficit; and a severely stressed (SS) treatment received no irrigation. Two cultivars were FM 960RR, a standard, mid-South cultivar and FM 819RR an okra-leaf cultivar of similar maturity. The subplots were 5.8 m wide and approximately 244 m long, with 4 rows (3.9 m) between each set of irrigation treatments. Data collection included soil grid sampling prior to planting, soil moisture tension, canopy temperature, crop canopy reflectance, and yield. A relatively wet crop season prevented development of significant water stress in the crop to allow for field data collection for much of the season. Seed cotton yield was significantly affected by the treatments, with excess water showing a decrease in yield. Both crop reflectance and canopy temperature showed potential to indicate water stress in cotton. The study showed that crop canopy response (temperature, reflectance) has the potential to be an effective indicator of water stress to develop a modified irrigation scheduling strategy. Such a strategy could have the potential to incorporate real-time monitoring with irrigation scheduling.