Increasing cotton lint yield and water use efficiency for subsurface drip irrigation without mulching.

Area of Science:

• Agricultural Science
• Agronomy
• Environmental Science

Background:

• Plastic film mulching in arid region cotton fields causes pollution and reduces water use efficiency (WUE).
• Subsurface drip irrigation and nighttime irrigation offer potential solutions to improve hydrothermal environments and WUE without mulching.

Purpose of the Study:

• To evaluate the effects of reduced irrigation amounts via subsurface nighttime irrigation on cotton growth and WUE in arid regions.
• To determine optimal irrigation levels that balance soil moisture, leaf temperature, and crop productivity without mulching.

Main Methods:

• A two-year field experiment (2019-2020) with five irrigation treatments (I1-I5) using subsurface drip irrigation.
• Evaluation of soil volumetric moisture content, soil temperature, leaf relative water content (RWC), gas exchange parameters, lint yield, and WUE.

Main Results:

• Reduced irrigation increased soil temperature and leaf temperature but decreased leaf RWC, net photosynthetic rate (Pn), and transpiration rate (Tr).
• Optimal irrigation (3201-3477 m³ ha⁻¹) significantly increased lint yield (2.8-12.2%) and WUE compared to higher irrigation levels.
• Positive correlations were found between leaf hydrothermal environment, Pn, soil temperature, and WUE during specific daytime periods (10:00-16:00).

Conclusions:

• Subsurface nighttime irrigation without mulching, with an optimal water application of 3201-3477 m³ ha⁻¹, enhances cotton lint yield and WUE in arid environments.
• This approach mitigates the negative impacts of plastic film pollution while improving soil and leaf hydrothermal conditions for better crop performance.