Effect of Application Rate of Nitrogen on Its Utilization in Wheat by Using 15N Tracer Technique The Effects of Split-nitrogen Application in Spring on Seed Yield and Nitrogen Use Efficiency in Russian Wildrye Analysis of single rice nutrition utilization by TechnoGIN——A case study of single-rice in Pujiang County The differences of nitrogen uptake and utilization in waxy corn Ⅰ.The difference genotypes in absorption and utilization of nitrogen Effects of nitrogen application rate and ratio of base and topdressing on nitrogen absorption,utilization,grain yield,and grain protein content in winter wheat Effect of controlled-release urea combined application with urea on nitrogen utilization efficiency of winter wheat