Cotton Water Use Efficiency under Two Different Deficit Irrigation Scheduling Methods

Agronomy

Jeffrey T. Baker¹  Dennis C. Gitz²  John E. Stout²  Robert J. Lascano² 

[1] USDA-ARS, Plant Stress and Water Conservation Laboratory, 302 West I-20, Big Spring, TX 79720, USA;USDA-ARS, Plant Stress and Water Conservation Laboratory, 3810 4th Street, Lubbock, TX 79415, USA; E-Mails:

关键词: deficit irrigation;    canopy temperature;    cotton;    yield;    water use efficiency;   

DOI  :  10.3390/agronomy5030363

来源: mdpi

【 摘 要 】

Declines in Ogallala aquifer levels used for irrigation has prompted research to identify methods for optimizing water use efficiency (WUE) of cotton (Gossypium hirsutum L). In this experiment, conducted at Lubbock, TX, USA in 2014, our objective was to test two canopy temperature based stress indices, each at two different irrigation trigger set points: the Stress Time (ST) method with irrigation triggers set at 5.5 (ST_5.5) and 8.5 h (ST_8.5) and the Crop Water Stress Index (CWSI) method with irrigation triggers set at 0.3 (CWSI_0.3) and 0.6 (CWSI_0.6). When these irrigation triggers were exceeded on a given day, the crop was deficit irrigated with 5 mm of water via subsurface drip tape. Also included in the experimental design were a well-watered (WW) control irrigated at 110% of potential evapotranspiration and a dry land (DL) treatment that relied on rainfall only. Seasonal crop water use ranged from 353 to 625 mm across these six treatments. As expected, cotton lint yield increased with increasing crop water use but lint yield WUE displayed asignificant (p ≤ 0.05) peak near 3.6 to 3.7 kg ha⁻¹ mm⁻¹ for the ST_5.5 and CWSI_0.3 treatments, respectively. Our results suggest that WUE may be optimized in cotton with less water than that needed for maximum lint yield.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.