Establishment of Crop Water Stress Index for Sustainable Wheat Production under Climate Change in a Semi-Arid Region of Pakistan

Abstract

The Crop Water Stress Index (CWSI) is a useful tool for evaluating irrigation scheduling and achieving water conservation and crop yield goals. This study examined the CWSI under different water stress conditions for the scheduling of wheat crop irrigation and developed indices using the leaf canopy temperature in Faisalabad, Pakistan. The experiments were conducted using a randomized, complete block design and four irrigation treatments with deficit levels of D0%, D20%, and D40% from the field capacity (FC) and D100% (100% deficit level). The CWSI was determined at pre-heading and post-heading stages through the lower baseline (fully watered crop) and upper limit (maximum stress). These baselines were computed using the air temperature and canopy temperature of plant leaves and the vapor pressure deficit (VPD). The CWSI for each irrigation treatment was calculated and the average seasonal CWSI value for the whole season was used to develop the empirical relationships for scheduling irrigation. The relationships between the air canopy temperatures and the VPD resulted in slope (x) = −0.735 and interception (c) = −0.8731 as well as x = −0.5143 and c = −1.273 at the pre- and post-heading stages, respectively. The values of the CWSI for the treatment at deficit levels of Do%, D20%, D40%, and D100% were found to be 0.08, 0.61, 0.20, and 0.64, respectively. The CWSI values developed in this study can be effectively used to promote better the monitoring of irrigated wheat crops in the region.

Enhancing Wheat (Triticum aestivum L.) Crop Yield and Water Use Efficiency: A Study on Canopy Air Temperature Difference-Based Drip Irrigation Scheduling in a Semi-Arid Region of Western India

“…Consequently, during pre-heading, a given increase in air VPD induces more transpirational cooling than during post-heading. Similar findings were reported by Fritschen and Van Bavel (1964); Khan et al, 2022;and Liu et al, 2023 for wheat and sudangrass. They noted that headed crops exhibited lower evapotranspiration rates due to seed heads absorbing radiant energy, converting it to sensible heat, and acting as an aerodynamic barrier against sensible heat transfer.…”

“…The form of these relationships varies according to the type of leaf and how the reference surfaces are wetted (one side or two sides). Therefore, the application of CATD-based CWSI as an indicator of crop water stress is appropriate because it is non-destructive, rapid, non-contact, reliable, provides considerably precise estimation, and represents actual crop water demand (Gontia and Tiwari, 2008;Taghvaeian et al, 2014;Lena et al, 2020;Khan et al, 2022). In semi-arid western India, wheat is very important crop covering large acreage grown on irrigation applications.…”

Comparative Analysis of Water Sustainability Indices: A Systematic Review

“…These categories, however, may not align with the overall goals of creating comprehensive sustainability indices because they are narrow in focus and not designed to be holistic. Giving the example of water sustainability indices in the agricultural sector, such as Agricultural Water Poverty Index (AWPI) (Forouzani and Karami 2011) and Crop Water Stress Index (CWSI) (Khan et al 2022) emphasized e cient and sustainable water use in irrigation practices, crop production, and agricultural water management. Therefore, while these specialized indices are excellent for their speci c applications, they may not be suitable for assessing sustainability comprehensively across all sectors, as they do not encompass the broader range of factors that are relevant to sustainability in its entirety.…”

Comparative Analysis of Water Sustainability Indices: A Systematic Review

“…These categories, however, may not align with the overall goals of creating comprehensive sustainability indices because they are narrow in their focus and are not designed to be holistic. Examples of water sustainability indices in the agricultural sector, such as the agricultural water poverty index (AWPI) [86] and crop water stress index (CWSI) [45], emphasize efficient and sustainable water use in irrigation practices, crop production, and agricultural water management. Therefore, while these specialized indices are excellent for their specific applications, they may not be suitable for assessing sustainability comprehensively across all sectors, as they do not encompass the broader range of factors that are relevant to sustainability in their entirety.…”