Abstract:It is of great significance for the sustainable development of agriculture in the arid and semiarid region to seek effective straw resources returned to the farmland. A twoyear field experiment was conducted to evaluate the effects of different pretreated straw returned to the farmland on the dynamics of several ecophysical characteristics of plant shoot height, leaf area index (LAI), aboveground biomass, canopy cover (CC), corn yield, soil water content, evapotranspiration and water use efficiency (WUE) so as to investigate the optimal scheme of the pretreated straw practices in 2014 and 2015. The experiments included two ammoniated straw levels (A0: no ammoniated straw; A1: ammoniated straw) and two straw length levels (L0: wheat straw was crushed into straw debris; L1: length of wheat straw was greater than 50mm). The results indicated that the average volumetric soil water contents of ammoniated short wheat straw (wheat straw was crushed into straw debris) plowed into the soil (A1L0) were significantly higher than those of long wheat straw (length of wheat straw was greater than 50mm) plowed into the soil (A0L1) by 10.7% in 2014 and 6.4% in 2015 during the summer maize growing season, respectively. Meanwhile, the treatment of ammoniated short wheat straw (wheat straw was crushed into straw debris) plowed into the soil (A1L0) could significantly increase average green canopy (CC) than other treatments by 3.7%~10.7% during the filling stage in two years, consecutively. Compared with other treatments, the treatment of A1L0 could significantly enhance average biomass, average corn yield and water use efficiency (WUE) by 2.1%~9.5%, 2.8%~9.1% and 1.7%~7.4% during the maturity stage in two years, respectively. The treatment of A1L0 could significantly increase the average corn yield and water use efficiency of summer maize. The average volumetric moisture content at 0~160 cm soil layers of ammoniated treatments were significantly higher than that of A0L0 and A0L1 treatments, and the ammoniated treatments (A1L0 and A1L1) significantly increased the crop water use efficiency in different growth periods. While the tendency between different treatments of water consumption was not significant, therefore, the treatment of ammoniated short wheat straw plowed into the soil (A1L0) can effectively promote the growth and yield of summer maize, which was a better measure for keeping soil water, promoting corn yields and enhancing water use efficiency (WUE).
