关键词: 降水年型, 休闲期覆盖, 旱地小麦, 耗水量, 产量, 水分利用效率

Abstract: 【Objective】Strategies and practices are required to increase yield of dryland wheat and improve water use efficiency. The objective of this study was to confirm the effects of mulching during fallow period on the yield of dryland wheat, and to provide a solution to soil water retention.【Method】Field experiments were carried out with a winter wheat cultivar Yunhan 20410 from 2010 to 2013 in Qiujialing Village, Wenxi, Shanxi, and soil water storage was observed during fallow period and different wheat growth periods, yield and yield components were observed in two treatments, with and without mulching during fallow period after deep plowing. Changes in soil water storage and consumption, wheat yield and water use efficiency were analyzed.【Result】The results showed that soil water storage in the 0-3 m depth was increased at sowing stage by 47 mm in humid year under mulching during fallow period, 55 mm in normal year and 63 mm in dry year, and more water was stored in deep soil layers in dry year. Soil water storage efficiency was increased significantly, which was increased by 35% in humid year under mulching during fallow period, 48% in normal year and 101% in dry year, and its effect was still significant on the anthesis. The effects of water consumption during different growth periods were different under mulching during fallow period, which was increased significantly in the wheat growth period, but reduced significantly during fallow period, thus the annual water consumption did not change much. While the percentage of water consumption before jointing stage was decreased significantly under mulching during fallow period, water consumption and daily water consumption after jointing stage were increased significantly. The percentage of water consumption after jointing stage was also increased, especially the regulatory effect of water consumption at later growth stage of wheat in dry year. Wheat yield and yield components were increased significantly under mulching during fallow period, especially spike number, and wheat yield was increased by 30% in humid year, 35% in normal year and 50% in humid year. In dry year, spike number was increased by 19%, grain number per spike and 1000-grain weight also received a large effect. In addition, water consumption at each growth stage had close correlation with wheat yield under mulching during fallow period, especially after jointing stage. In mulching during fallow period treatment, soil water storage increased by 1 mm at sowing stage could improve wheat yield by 17-26 kg·hm^-2, soil water consumption in growth period increased by 1 mm could improve wheat yield by 22-26 kg·hm^-2. Rainfall productive efficiency and water use efficiency were increased significantly under mulching during fallow period, especially in dry year.【Conclusion】It could benefit the soil water storage from the fallow period to anthesis under mulching during fallow period. The annual precipitation was regulated by reducing water consumption at earlier growth stage, and increasing water consumption at middle and later growth stage under mulching during fallow period. In addition, the yield components were optimized, especially the spike, through the method, which was favorable for increasing production, and ultimately to achieve efficient use of rainfall. The effect of mulching during fallow period was better in dry year.

Key words: rainfall years, mulching during fallow period, dryland wheat, water consumption, yield, water use efficiency