Effects of Straw Mulching on Soil Water-salt Transportation and Water Use Efficiency of Maize under Furrow Irrigation

In order to explore the characteristics of water and salt migration of the ridge-back plastic film and straw mulch on the ditch section of the typical saline soil in Hetao Irrigation District, and clarify the changes in crop yield and water use efficiency, the field experiment was carried out in 2019 with ridge-back stalks (0.3 kg/m2, 0.6 kg/m2, 0.9 kg/m2 and 1.2 kg/m2, recorded as P0.3, P0.6, P0.9 and P1.2) and the plastic mulching (DM) and bare land (CK) furrow irrigation test, the comparison and analysis of different straw coverages on the changes of soil water and salt distribution, crop yield and water use efficiency in the ditch section before and after maize growth period were made. Results showed that before maize jointing, film mulching and straw mulching can significantly reduce the ineffective water consumption of crops and ensure the water demand in the later growth period. During the heading grouting period, the temperature increase effect of film mulching promoted the growth of crops, which made treatment DM of maize intensive water consumption and the lowest soil water storage. The soil water movement in the vertical direction at the end of growth was weaker than that in the previous period. In general, the treatments of P1.2 and P0.9 was better than CK in water storage and moisture retention (P<0.05). Due to the small quota of furrow irrigation, the salt leaching effect was poor, and it was affected by soil evaporation and groundwater replenishment, resulting in accumulation of salt in the root layer. Both plastic and straw mulching can effectively inhibit the accumulation of salt, and the salt content of the soil treated with P1.2 and P0.9 was increased the least than the initial soil salt, only 14.10% and 24.74%. The yield and water use efficiency of P0. 9 and DM treatment was increased the largest, compared with CK, it was increased by 20.01%, 25.46% and 11.32%, 15.29%, respectively. Excessive straw mulch would cause low soil temperature during sowing period, reduce maize emergence, make maize yield and water use efficiency of P1. 2 treatment slightly reduced compared with DM treatment, but the difference was not significant (P>0.05). The principal component analysis method was used to comprehensively evaluate the effects of soil moisture retention and salt suppression, maize emergence, yield, and water use efficiency under furrow irrigation straw cover, and it was recommended to use 0.9~1.2 kg/m2 of ridge-back straw coverage instead of conventional plastic film to reduce the environmental impact of plastic film residues. The research result can provide some reference for agricultural cultivation techniques in irrigation areas. © 2021, Chinese Society of Agricultural Machinery. All right reserved.