Abstract:Aiming to explore the effects of different improvement measures on hydrothermal carbon and sunflower yield in salinized soil, experiment was carried out by applying biochar (C, 22.5t/hm2), desulfurization gypsum (S, 37.5t/hm2), straw returning (J, 20.625t/hm2) and control (CK) in field. The results showed that three improvement measures can improve the soil hydrothermal environment, of which biochar had advantages. The soil moisture content of the soil layers of 0～20cm and 20～40cm during the whole growth period was significantly higher than that of the control. In the vertical distribution, the improvement effect of water conservation and water storage of 0~40cm soil layer was better than that of soil layer below 40cm. The spatial distribution pattern of soil moisture in each treatment section showed the characteristics of wet and dry. Compared with CK, each improved treatment had good temperature increase and heat preservation effect, both of which had “warming effect” at low temperatures, and “cooling effect” at high temperatures, and the regulation of temperature was mainly concentrated at 5～25cm soil layer, and weakened from 35cm. The application of three improvement measures can increase the soil organic carbon content and organic carbon density, among which the biochar effect was the most significant, and the organic carbon content was increased by 17.46% compared with the control. Compared with the control, the yield of C treatment was the highest, reached 32.28%, and the yield of J and S treatment was increased by 21.94% and 30.68%, respectively. The difference between the three was not significant. According to comprehensive analysis, the application of biochar of 22.5t/hm2 was more suitable for soil improvement in the process of planting sunflower in salinized farmland in Hetao Irrigation District.
