Effect of Liquid Mulch on the Transpiration Rate and Water Use Efficiency of Drip-irrigated Cotton

This study was carried out to address the ever severer white pollution issue in the cotton fields of arid areas and to primarily stop the increase of film residuals in cotton fields. The feasibility of replacing plastic films with liquid mulch in combination with drip irrigation was evaluated. A bucket experiment was conducted to investigate the effects of liquid mulch on the transpiration rate and water use efficiency (WUE) of drip-irrigated cottons. A total of 5 treatments were set up: liquid mulch (1900 kg/hm2) coupled with drip irrigation (LFD1), liquid mulch (2200 kg/hm2) coupled with drip irrigation (LFD2), liquid mulch (2500 kg/hm2) coupled with drip irrigation (LFD3), plastic film coupled with drip irrigation (PFD) and drip irrigation without mulch (NFD or control). The results showed that in the bud stage, the peak value of cotton leaf transpiration rate in LFD3 was 0.95 mmol•m-2•s-1 (or 21.99%) higher than that in control but 0.39 mmol•m2•s-1 (or 6.89%) lower than that in PFD. The WUE in LFD3 was the highest in any cotton growth stage among the treatments. The peak value of WUE in the seedling and bud stages was 16.90% and 15.03%, respectively higher in LFD3 than in control. When used at an appropriate dosage, liquid mulch can lower the transpiration rate and significantly raise the WUE of drip-irrigated cottons, thus paving the way towards high yields. In addition, liquid mulch has no negative effects on the soil environment and thus is of important research value and good application prospect in light of drip-irrigated cottons in arid areas.