Grain Yield, Nitrogen Use Efficiency and Antioxidant Enzymes of Rice under Different Fertilizer N Inputs and Planting Density

Nitrogen fertilizer and planting density are key factors affecting rice yield nitrogen utilization efficiency. There is still a need to optimize management for high yield. We studied the effects of different quantities application (N0 0 kg ha−1, N1 120 N2 180 ha−1) (low-density: 18.8 hills m−2; high-density: 37.5 m−2) on yield, photosynthetic characteristics, antioxidant system, use ANOVA results indicated that most tested traits were affected by environment, density, N application, their interactions. Comparing low-density planting, high-density increased panicle number 21.12% but decreased grain per 3.97% 22.48%, respectively. Similarly, superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate (APX) activities PFPn (partial factor productivity nitrogen) 8.20%, 6.99%, 16.41%, 14.28%, 5.73%, respectively, while HIn (N harvest index) 1.32%. Compared no treatments number, panicle, 9.92%, 17.64%, 37.83% in treatment; 17.15%, 29.09%, 128.94% treatment, significantly net rates enzyme antioxidases. with N1, REn (apparent recovery efficiency N), AEn (agronomic efficiency), 8.98%, 11.80%, 25.14%, while, compared N0, 8.50%. It was observed had an interaction effect rate, activities, HIn. Given comprehensive consideration, it best apply at rate ha−1 m−2 our experimental site.