Yield and water use efficiency of dryland potato in response to plastic film mulching on the Loess Plateau

Water shortage is a key factor limiting potato yield in dryland farming regions, and the practice of soil mulching with plastic film has proven to be effective for increasing crop yield and improving soil and water conservation. This study investigated the effects of plastic mulching on potato yield and water use efficiency (WUE) on the Loess Plateau of China based on a synthesis of 44 publications (1987-2016) from 17 sites. Our results indicated that relative to no mulching, plastic mulching significantly increased the yield and WUE by 29.2% and 31.7%, respectively. The effects on yield under different mulching methods were ranked as follows: ridge-furrow mulching (RFM) > flat mulching (FM), and the effects on yield with different mulching extents were ranked full-area mulching (FAM) > partial-area mulching (PAM). The effects of plastic mulching on the yield using different colors of film were ranked as white plastic mulching (WPM) > black plastic mulching (BPM) and under different rainfall levels as (precipitation < 400mm) > (precipitation > 400mm). The rankings of the effects of plastic mulching on WUE were the same as for potato yield. The yield-evapotranspiration (ET) relationship could be described using a quadratic polynomial, and the yield response curve to ET under plastic mulching fell above the no-mulching curve, indicating that plastic mulching can result in higher yields than no mulching when ET is equal. The yield-ET relationship indicated that potatoes required an ET of 334 and 360mm to achieve the highest yield under plastic mulching and no mulching, respectively, and potato WUE increased linearly with yield under both plastic mulching and no mulching. This study indicated that RFM, FAM and WPM are better potato management measures and that there is potential to improve the yield and WUE on the Loess Plateau.