Effects of Different Film Types on Cotton Growth and Yield under Drip Irrigation

To address residual plastic film in fields in which mulched drip irrigation technology is applied, a sprayable degradable film (consisting of 1–5% clay, 5–20% humic acid, 0.5–5% crosslinker, and 0.5–5% auxiliary and water) can be used as a superior alternative to the plastic film applied in drip-irrigated fields. A field experiment was conducted in Xinjiang, Northwest China, to test the impacts of five different mulching treatments (SF1, sprayable degradable film applied at 1900 kg ha −1 ; SF2, sprayable degradable film applied at 1900 kg ha −1 ; SF3, sprayable degradable film applied at 2500 kg ha −1 ; PF, plastic film; and NF, no film mulching) on cotton growth and development, yield, and water use efficiency. The results showed that, compared to the NF treatment, sprayable degradable film mulching (SF1, SF2, and SF3) positively impacted the soil hydrothermal environment, promoted root growth, significantly increased plant height and leaf area, and enhanced physiological characteristics, which, in turn, increased yield and water use efficiency by 11.79–15.00% and 21.88–30.21%, respectively. The maximum yield and water use efficiency were observed in the PF treatment, amounting to 5345 kg ha −1 and 1.28 kg m −3 , respectively, and they had no significant differences from those in the SF3 treatment. In general, applying moderate amounts of sprayable degradable film at a rate of 2500 kg ha −1 represents an effective agronomic strategy for managing residual film contamination while maintaining stable cotton yields.