EFFECTS OF FERTILIZATION ON SOIL WATER USE EFFICIENCY AND CROP YIELD ON THE LOESS PLATEAU, CHINA

The selection of appropriate fertilizers influences agricultural production, especially in water limited conditions such as those on the Loess Plateau (China). In this study, we aimed to determine the optimum method for the fertilization of dryland crops. In a two-year split-plot experiment, we tested eight fertilization treatments with different combinations of organic and inorganic fertilizers and a no-fertilizer control. Crop yield, soil water storage, and soil water use efficiency (WUE) were assessed pre-sowing and post-harvest in 2017 and 2018. The results showed that soil water storage was decreased by fertilization, while the WUE and crop yield were both increased: compared to the control, WUE was 6-39% higher in 2017 and 8-39% higher in 2018, while crop yield was 3-21% higher in 2017 and 1-19% higher in 2018. The maximum effect on WUE and crop yield was achieved when a combination of organic fertilizer and either nitrogen or phosphate fertilizer was applied. Linear regression analysis revealed that soil water consumption (ET) was significantly positively correlated with crop yield. Our results provide a scientific basis for rational crop fertilization on the Loess Plateau and suggest that a combination of organic and inorganic fertilizers is the most appropriate.