Effects of Nitrogen Fertilizer Types and Application Rates on Fertilizer Utilization Efficiency and Yield of Dryland Maize

Dry farming areas are pivotal to agricultural production in China, and agronomic measures, such as tillage and fertilization, markedly influence crop yields. Ditch rain-harvesting planting, an effective water conservation technique, has proven beneficial for enhancing grain production in these regions. Because of the topographical changes from ridges and ditches, combined with moisture retention by mulching films, rainwater harvesting planting technology significantly influences soil water and heat dynamics, promoting temperature and moisture. In this study, "Xianyu 335" was used as the experimental material. Eight different fertilization regimens were tested: no fertilization (control, CK), nitrogen and phosphorus (NP), phosphorus and potassium (PK), nitrogen and potassium (NK), nitrogen (N: diammonium phosphate 24%, ordinary urea 76%), phosphorus potassium fertilizer (NPK1), nitrogen application (N: slow-release urea 40%, diammonium phosphate 20%, ordinary urea 40%), phosphorus-potassium fertilizer (NPK2), nitrogen application (70%N: slow-release urea), urea release 40%, diammonium phosphate 26%, ordinary urea 34%), phosphorus and potassium fertilizer (NPK3), and nitrogen (85%N: slow-release urea 40%, diammonium phosphate 23%, ordinary urea 37%), phosphorus, and potassium fertilizer (NPK4). These treatments were used to investigate their effects on maize grain yield, agronomic efficiency, and fertilizer utilization rate under full-film-covered ridge and furrow rainwater harvesting. The results from 2015 to 2016 indicated that the distinct fertilization methods significantly affected the physiological metrics and leaf area index of maize throughout the growth period, as well as grain yield and dry matter accumulation. Notably, the NPK3 treatment, which employed slow-release fertilizers, outperformed the other treatments. Its average grain yield stood at 8.66 t·hm -2 , demonstrating an increase of 2.15 t·hm -2 (or 28.8%) compared with the control group. Moreover, NPK3 exhibited superior agronomic efficiency and fertilizer utilization. The findings indicate that integrating slow-release fertilizers into ridge and furrow rainwater harvesting systems can enhance maize growth and yield.