Effect of soil water and fertilizer on soybean yield on loess slopeland
黄绵土坡耕地大豆的水肥产量效应

Studies on the effect of soil water and fertilizer on soybean yield on loess slope farmland showed that soybean yield (Y) increased linearly with the increase of water use efficiency (WUE). Soybean yield and WUE increase with the increase of P fertilizer when P fertilizer was applied alone, but increased firstly and then decreased with the increase of N fertilizer when N fertilizer was applied alone. Therefore, N fertilizer should be applied with P fertilizer. Compared to no fertilizer, fertilizer could significantly increase soybean yield and WUE by 86.76%-470.16% and 69.64%-438.47%, respectively. A combined application of N and P fertilizers could increase more soybean yield and WUE than applied each of them alone, and the rational ratio of N and P (P2O5) was 1.3:1.