Abstract: 【Objective】 To cope with the drought, lower water storage and unreasonable fertilization of dry-land wheat in the Loess Plateau, the best technology way of water conservation of sub-soiling at fallow period and phosphorus fertilization at sowing stage of dry-land wheat was explored. 【Method】 Field experiments were carried out from 2012 to 2016 in Qiujialing village, Wenxi, Shanxi, the main plots were dealt with two tillage methods of sub-soiling and no tillage during fallow period, the subplots were dealt with six pure phosphorus fertilization amount of 0, 75,150, 225, 300, 375 kg·hm^-2,in order to make clear the effect of sub-soiling during fallow period and phosphorus fertilization on yield, water use efficiency of dry-land wheat in different years. 【Result】 The results showed that soil storage efficiency was improved by 20%-86% during fallow period. Under sub-soiling during fallow period, soil water storage of 3 m soil layer was improved by 24-90 mm significantly, spike number was improved by 1%-18%, yield was improved by 3%-25%, water use efficiency was improved by 4%-20% in 2012-2013. The results also showed that phosphorus levels affected dry-land wheat soil water storage of 0-300 cm soil layer, which was the lowest at 150 kg P·hm^-2 under the range of 0-225 kg·hm^-2 phosphorus amount, and was decreased under the long-term phosphorus application (4 year positioning test), and the difference was significant the fourth year. The difference of soil water because of different water consumption of phosphorus was restored through precipitation during fallow period, in the third and fourth year, soil moisture is not balanced, annual soil water consumption was different between phosphorus of 150 kg·hm^-2and0. In the end, with the phosphorus fertilizer amount (0-225 kg·hm^-2) increasing, average yield and WUE of four years were largest under phosphorus of 150 kg·hm^-2, and the differences of yield were significant among different treatments, differences of WUE were significant between 150 kg·hm^-2and0. In addition, the F value test showed that years had the greatest influence on yield and water use efficiency, the yield increase effect of sub-soiling was higher than that of phosphorus fertilizer. The sowing water storage of 0-300 cm layer with more than 550 mm combined with the phosphorus amount of 75 kg·hm^-2, or below 550 mm combined with the phosphorus amount of 150 kg·hm^-2, made the spike number, yield and WUE higher. 【Conclusion】 Sub-soiling during fallow period is conducive to the accumulation of the precipitation and the improvement of the sowing water storage. Phosphorus fertilizer increased soil water consumption of dry-land wheat, decreased soil water storage of 0-300 cm during growth stages, increased annual water consumption. Yield was increased by 2-31 kg·hm^-2 with increase of 1 mm water storage of sub-soiling during fallow period, yield increased by 2-13 kg·hm^-2 with increase of 1 kg·hm^-2 phosphorus amount. The sowing water storage below 550 mm of 0-300 cm combined with the phosphorus amount of 150 kg·hm^-2, or the sowing water storage more than 550 mm combined with the phosphorus amount of 75 kg·hm^-2 could achieve higher yield, water and fertilizer efficiency.

Key words: dry-land wheat, sub-soiling during fallow period, phosphorus fertilizer, yield, water use efficiency