Assessing the Utility of Primed Acclimation for Improving Water Savings in Cotton using a Sensor‐Based Irrigation Scheduling System

Abstract

This study addressed the potential of reduced prebloom irrigation, referred to as primed acclimation (PA), to increase agricultural water-use efficiency (WUE) using a soil-moisture-based irrigation scheduling system in cotton (Gossypium hirsutum L.). To address this, a study was conducted near Camilla, GA, under a variable-rate, center-pivot irrigation system using a Watermark-based automated soil moisture sensing approach to measure soil water potential (SWP) and impose varying irrigation scheduling treatments during the prebloom stage of development. Early season thresholds were −20 (Treatment 1), −40 (Treatment 2), −70 (Treatment 3), to −100 kPa (Treatment 4) prior to flowering. Reductions in prebloom irrigation of up to 17% were noted in this study for the driest thresholds (−100 kPa) with no reduction in lint yield relative to the −20 and −40 kPa thresholds. In some cases, prebloom irrigation was eliminated completely in the drier prebloom threshold treatments with no appreciable yield reductions. In rainfed treatments, episodic drought during flowering (2014) limited plant growth and node production, hastened cutout, decreased boll numbers per plant, produced a more compact boll distribution on the plant, and decreased yield and WUE relative to irrigated treatments. In contrast, season-long rainfed treatments exhibited the highest WUE in 2015 (a wet season). The results of this study conclude that prebloom irrigation thresholds between −70 and −100 kPa appear to be viable for use in a sensor-based PA irrigation scheduling system, whereas episodic drought coinciding with flowering represents a major threat to yield stability and WUE for cotton production in the southeastern United States.

Evaluating the Mechanisms of Photosynthetic Inhibition under Growth‐Limiting, Early‐Season Water Deficit Stress in Cotton

“…(Lawlor and Tezara, 2009;Tezara et al, 1999). Although we do not presume that greenhouse experiments will provide identical results to field conditions, these findings highlight the possibility of lasting, negative impacts of drought stress during the prebloom period and illustrate the importance of carefully managing irrigation during the early season based on actual measures of crop water status (Meeks et al, 2017) to minimize drought risk. In the first experiment, when the chlorophyll content was measured, total chlorophyll content per unit leaf area responded positively to increasing drought stress duration, indicating that reductions in chlorophyll content are not associated with drought stress as has been observed in other crop species (Pilon et al, 2018).…”

“…5 illustrates substantial declines in reproductive DW for all four drought-stressed treatments in 2016, whether water was withheld for 3 wk (followed by a 7-wk recovery) or 6 wk (followed by a 2-wk recovery). Although we do not presume that greenhouse experiments will provide identical results to field conditions, these findings highlight the possibility of lasting, negative impacts of drought stress during the prebloom period and illustrate the importance of carefully managing irrigation during the early season based on actual measures of crop water status (Meeks et al, 2017) to minimize drought risk. Overall, these observations are similar to those of Loka et al (2011) and Loka and Oosterhuis (2012) in which early-season drought stress led to abscission of young squares.…”

Forty Years of Increasing Cotton’s Water Productivity and Why the Trend Will Continue

“…This was attributed to reduced early season evaporation losses and reduced early season plant growth that could not be supported with available irrigation late in the season. Meeks et al (2017) also found that cotton yields were less sensitive to water stress prior to flower bloom in a humid environment. However, this does not mean cotton is completely insensitive to early season water stress.…”

“…Researchers have evaluated the use of electronic monitoring systems for irrigation scheduling under a variety of environmental, cropping, and cultural conditions (Phene et al, 1989;Jones, 2006;Gutiérrez et al, 2013;Haule and Michael, 2014;Soulis et al, 2015;Payero et al, 2017;Fisher et al, 2018Fisher et al, , 2020. Work undertaken explicitly for cotton production has also been reported (Bockhold et al, 2001;Thomson et al, 2002;Bellamy et al, 2009;Leib et al, 2015;O'Shaughnessy et al, 2015;Meeks et al, 2017). Many of these efforts have dealt with development of the electronic systems, field implementation issues, wireless and cellular data transmission, and methods to interpret sensor data and develop scheduling strategies.…”

Defining physiological contributions to yield loss in response to irrigation in cotton

“…At the same time, the fraction of PAR intercepted by the canopy (IPAR f ) was similar between the various irrigation treatments. In addition to the effect of RUE and IPAR f , total biomass can also be reduced because water deficit hastens maturity (Chastain et al., 2016; Meeks et al., 2017), reducing the number of days over which PAR is intercepted. Regarding excessive irrigation, a study by Bange et al.…”