Effects of straw mulching and sowing methods on water consumption characteristics and yield of potato in arid region of Northwest China

In order to clarify the evapotranspiration, water use efficiency, and yield of potatoes under different straw mulching planting patterns in rainfed agricultural areas of Northwest China, four straw strip mulching patterns (D40:40 cm wide of planting and coverage strips, single row planting; S40:40 cm wide of planting and coverage strips, double-row planting; D50:50 cm wide of planting and coverage strips, single row planting; S50:50 cm wide of planting and coverage strips, double-row planting), plastic film mulching (DM), and traditional flat planting (CK) were set to study the potato evapotranspiration, water-use efficiency, and yield of each treatment. The results showed that under four straw mulching treatments, the average potato yield increased by 34.0% and water-use efficiency increased by 21.5% compared with CK; while they significantly reduced averagely by 31.3% and 25.0%, respectively compared with DM treatment. The yield and water-use efficiency of 40 cm planting structures increased by 4.5% and 6.8%, respectively compared with 50 cm planting structures. The yield of double-row planting was 4.4% higher than that of single row planting, however, water-use efficiency had no significant differences. The amount, intensity, and model coefficient of water consumption during the sowing-budding period decreased under straw strip mulching conditions by 14.5%, 15.2%, and 15.4%, respectively compared with CK, but they increased by 20.9%, 19.0%, and 31.5%, respectively compared with DM. During the budding to tuber bulking period, there were no significant differences in water consumption, water intensity, and water modulus coefficient between the straw mulching treatments and CK; however, compared with DM a significant reduction in water consumption (20.7%), water intensity (22.2%), and water modulus coefficient (13.9%) in the four straw mulching patters. The averages under straw mulching treatments increased during tuber bulking to mature peirod by 51.7% (water consumption), 52.4% (water intensity), and 50.0% (water modulus coefficient), respectively, compared with CK. Under the four straw mulching treatments, the weight per tube and the commodity rate of potato significantly increased by 17.3% and 31.8%, respectively, while the tubers number per plant and the small tuber rate decreased by 7.5% and 17.6%, respectively, compared with CK. It can be seen that cultivation using straw strip mulching can alleviate the water shortage of potato plants in the later stages, by reducing the water consumption before bud growth stage and increasing the water consumption after tuber enlargement stage, extending the duration of plant photosynthesis after tuber enlargement, improving the accumulation of organic matter, and thus improving yield. In the four straw strip mulching patterns, the yield of double row planting treatment was 4.4% higher than that of single row planting, while the water use efficiency had no significant difference between them. In this study, single row planting with the planting band︰mulching band=40 cm︰40 cm, and double row planting with the planting band︰mulching band=50 cm︰50 cm were more suitable straw strip mulching planting mode of potato in the rainfed agricultural areas of Northwest China.