The Way and Amount of Straw Mulching Impact Water Consumption and Yield of Potato

【Objective】 Straw mulching and ridge tillage is an improved agronomic technology to sustain crop production in the loess plateau in northwestern China. How their combination impacts water uptake and crop yield is not well understood. This paper is to fill this knowledge gap. 【Method】 The experiment was conducted in a potato field and compared ridge tillage and traditional flatten tillage. For the ridge tillage, there were three mulching treatments: film mulching (PM), locally high straw mulching (RSM9), and locally low straw mulching (RSM6). For the traditional flatten tillage, there were also three treatments: locally high straw mulching (PSM9), locally low straw mulching (PSM6), and full straw mulching (FC). The control is flatten tillage without mulching. 【Result】 ①Compared with CK, mulching increased the yield and WUE of the potato by 11.8%~21.7% and 15.9%~26.7%, respectively. Compared with PSM treatments, RSM treatments increased the yield and WUE of the potato by 1.5% and 1.7%, respectively. Compared with the locally high straw mulching (9 000 kg/hm2), the locally low straw mulching (6 000 kg/hm2) increased the yield and WUE by 6.1% and 6.5%, respectively. ② Compared with CK, local straw mulching increased soil moisture in some regions and reduced it in other regions, but overall, it increased soil water content. The increased soil water storage under different treatments was ranked in the order of RSM6 >PSM6 >RSM9 >PSM9 treatment. ③ Compared with CK, partial straw mulching increased total water consumption, daily water consumption, and water consumption coefficient for potato tuber formation and starch accumulation by 4.6 mm, 0.11 mm/d and 2.7%, respectively. Water consumption during tuber expansion and harvest was greater in RSM than in PSM, while the opposite was true during soil-tuber expansion. 【Conclusion】 Straw mulching can reduce water consumption before tuber expansion, increase water consumption after tuber expansion, balance water consumption and demand during key growth stages, and promote potato growth and development. For all treatments we compared, ridge tillage coupled with partial straw mulching at 6 000 kg/hm2 was most effective.