Effects of Straw Strip Covering on Yield and Water Use Efficiency of Potato cultivars with Different Maturities in Rain-Fed Area of Northwest China

The strip mulch of corn straw planting technique is widely used in the Northwest rain-fed agricultural region of China due to the region's good soil moisture-temperature properties. However, the hydrothermal properties and yield effects of this planting technique on different potato varieties are not clear. Therefore, a field experiment was conducted for two years (2015 and 2016) in the rain-fed area of Northwest China, to study the effects of different mulching treatments on the yield and water use efficiency (WUE) of potato with different maturation characteristics (potato varieties Longshu 7 and LK99). A split-plot experimental design was used. The experiment included corn straw strip flat cover planting (SMF), plastic film mulching (PMF), corn straw strip ditch mulching and ridge planting (SMFR), straw flat fully covered (SMWF), and uncovered and flat planting (CK). The results showed that straw mulch and plastic film mulch had significant effects on yield and WUE (p < 0.05). Compared with CK, SMF significantly increased the yield by 3.75-63.17% in the late-maturing varieties, and increased the yield by 24.96-79.02% in the early-maturing varieties. Among the mulching treatments, compared with SMF, PMF made no significant difference in the yield and WUE between the late-maturing varieties in the normal year and the early-maturing varieties in the dry year, but the yield and WUE of the early-maturing varieties in the normal year significantly decreased by 17.25% and 18.44%, respectively, and the yield and WUE of the late-maturing varieties in the dry year significantly increased by 27.57% and 29.26% respectively. Compared with SMF, SMFR reduced yield by 1.44-13.62%; SMWF decreased the yield of late-maturing varieties by 25.94% (p < 0.05), and WUE decreased by 7.65-23.44% (p < 0.05). It can be seen that under this experimental condition, SMF is more suitable for early-maturing varieties and PMF is more suitable for late-maturing varieties.