Abstract:In order to explore the effects of tillage combined with straw mulching on soil water storage,crop water consumption characteristics and yield formation of upland potato growth period in different precipitation year types,the field experiment was conducted by setting different tillage methods (no-tillage,subsoiling,and ploughing tillage) combined with straw mulching after autumn crop harvest in dryland area for three consecutive years.The results showed that after three years of tillage and mulching treatment,no-tillage,subsoiling combined with straw mulching could significantly reduce soil bulk density and increase soil organic matter content in 0-40 cm layer.Conservation tillage combined with straw mulching could significantly improve soil water storage in 0-200 cm soil layer during potato growth period.The soil water storage in subsoiling with straw mulching treatment was the highest in the whole potato growth period in the relative less water year and the less water year,which was significantly increased by 15.80% and 20.80% than that of ploughing tillage without mulching,respectively.In the normal year,no tillage with straw mulching treatment was the highest,which was significantly increased by 14.78% than that of ploughing tillage without mulching.Among them,subsoiling with straw mulching treatment had the best soil water storage effect in 0—60 cm soil layer in early growth stage and 120—200 cm soil layer in middle growth stage of the relative less water year,20—100 cm soil layer in early normal year and 0—80 cm soil layer in growth stage of the relative less water year.Subsoiling or no-tillage with straw mulching treatment could significantly reduce the water consumption,water consumption modulus coefficient and water consumption intensity at the early stage of potato and significantly increase the water consumption,water consumption modulus coefficient and water consumption intensity at the middle and late stages of potato especially in the less water year.Compared with ploughing tillage without mulching,subsoiling with straw mulching was more conducive to the increase of dry matter mass of potato,especially in the middle growth stage of less water years and in the middle and late growth stages of normal years.In the relative less water year,potato yield and water use efficiency of no tillage with straw mulching treatment were the best,which were significantly increased by 51.82% and 50.52% than that of ploughing tillage without mulching respectively.In the normal year and the less water year,the effect of subsoiling with straw mulching treatment was the best,which were significantly increased by 36.69% and 29.48% than that of ploughing tillage without mulching in the normal year,and significantly increased by 87.46% and 62.31% respectively in the less water year.Subsoiling with straw mulching treatment had the best effect on increasing the commodity rate of potato in the relative less water year and the normal year,and no tillage with straw mulching treatment had the best effect on increasing the commodity rate of potato in the less water year,which was significantly increased by 12.88%,14.58% and 26.18%,respectively,compared with ploughing tillage without mulching.Correlation analysis showed that soil bulk density and organic matter content increased under the tillage with straw mulching,which improved soil water retention performance and the potato yield.The soil moisture characteristics played a crucial role in improving potato yield during the growth period of potato under different precipitation years,especially in the middle and late growth period of potato in relative less water years,soil moisture was significantly or extremely significantly positively correlated with the yield.It could be seen that no-tillage or subsoiling combined with straw mulching could improve the soil moisture status during potato growth period,regulate crop water consumption and increase the dry matter accumulation,which was beneficial to improve the potato yield and water use efficiency,and the subsoiling with straw mulching has the best effect.