Effects of different fertilizer strategies on soil water utilization and maize yield in the ridge and furrow rainfall harvesting system in semiarid regions of China

Shortages of water resources and low soil fertility are two key factors that limit crop production in semiarid areas. The ridge and furrow rainfall harvesting (RFRH) system is an effective method for enhancing the efficiency of rainfall water use and fertility. In this study, we conducted a field experiment over five years (2012-2016) to determine the effects of different fertilizer application rates on the soil water consumption properties, water use efficiency, and maize yield under RFRH. We found that the evapotranspiration (ET), maize dry matter (DM), water consumption strength (CD), and soil water use rate (SP) increased with the fertilizer application rate. Compared with the no fertilizer treatment (RCK), ET, DM, CD, and SP increased significantly by 7.2%, 38.3%, 16.4%, and 37.6% under high fertilizer (RH) treatment, respectively, by 6.7%, 35.8%, 18.0%, and 39.1% with medium fertilizer (RM) treatment, and by 5.5%, 31.1%, 16.1%, and 32.6% with low fertilizer (RL) treatment. RM achieved the highest average yield of 11.3 t ha-1 and the lowest coefficient of variation at 12.9%. The yield, DM, and water use efficiency did not differ significantly between RH and RM. Regression analysis showed that the highest yield could be obtained by applying nitrogen at 265.0 kg ha-1 combined with P2O5 at 132.5 kg ha-1. The yield and water use efficiency were significantly higher under RL compared with RH and RM in wet year. However, in both normal and drought years, the grain yield and water use efficiency was significantly higher under RM. These results indicate that the RFRH system can promote crop use of fertilizers by regulating soil moisture. The best fertilization strategy for planting maize with RFRH system was 265.0 kg ha-1 of pure nitrogen combined with 132.5 kg ha-1 of P2O5 in the semiarid area of the Loess Plateau, in China.