Straw strips mulch on furrows improves water use efficiency and yield of potato in a rainfed semiarid area

Potato (Solanum tuberosum L.) production in semiarid regions is always constrained by water availability. This study was to evaluate the effects of straw strips mulch to potato growth, yield and economic benefits. The field experiment was conducted in northwest China in 2016 and 2017, including four treatments: (1), alternating narrow and wide ridges both mulched by black polyethylene film (PM); (2) alternating large ridges and small furrows with maize straw strips mulched only on the furrows (RS); (3) alternating the strips mulched with maize straw and bare plots with no ridges (PS); (4) traditional flat planting without mulching (CK). Results indicated that mulched treatments significantly (P < 0.05) increased tuber yield and WUE of potato compared with CK. The magnitude of yield in mulched treatments increase were 36.9-61.2% in 2016 and 38.7-45.5% in 2017, respectively, compared with CK. PM and RS treatments produced the highest tuber yield and enhanced water use efficiency by up to 74.8%, compared with CK. Soil water storage (0-2 m depth) was 21.5-39.9 mm in 2016 and 16.7-41.2 mm in 2017, respectively, greater in the mulched treatments, which significantly (P < 0.05) reduced evapotranspiration from sowing to seedling stages, compared with CK. Greater water availability was associated with greater biomass accumulation in above- and below-ground components, and plant height gain, during the growing season. PM significantly (P < 0.05) increased soil temperature (5-25 cm depth), which advanced the duration whole growth period by 6 days on average. RS and PM treatments experienced lower soil temperature (5-25 cm depth), which prolonged the duration whole growth period by 10 days on average, and increased the mass and percentage of Grade 1 tubers and the commodity rate (P < 0.05). As straw strips mulch application has lower input and labor costs than plastic film mulch, it produced the greatest economic benefits during this study, and it should be considered as an environmentally-friendly alternative to plastic film mulch for potato production in semiarid areas.