Improving productivity of Sesbania pea in saline soils by enhancing antioxidant capacity with optimum application of nitrogen and phosphate combination

Abstract

Salinity stress is one of the major constraints to plant growth and crop production. Optimum fertilizer management is essential for promoting crop growth and productivity in saline soils. A field experiment was conducted to study the effects of nitrogen and phosphate combination on sesbania pea (Sesbania cannabina (Retz.) Poir.) growth and associated physiology in saline soils. Three N rates (N1: 240 kg·ha-1, N2: 360 kg·ha-1, N3: 480 kg·ha-1) and two P rates (P1: 120 kg·ha-1, P2:180 kg·ha-1) were arranged in this study using a RCBD with 3 replicates. The application of N and P fertilizers significantly improved plant growth and associated physiological traits of sesbania pea. Plant height (P=0.0001), fresh biomass weight (P=0.0006), dry biomass weight (P=0.0006), relative growth rate (RGR) (P=0.005), chlorophyll (P=0.002), peroxidase (POD) (P=0.0003), catalase (CAT) (P=0.0001), superoxide dismutase (SOD) (P=0.0001) and soluble protein (P=0.0053) were significantly increased, and the maximum values were consistently produced under N2P2 combination at each growth stage. On the contrary, malondialdehyde (MDA) was prominently decreased by N and P fertilizer application (P=0.0029), and the lowest values were all produced under N2P2 combination. The highest values of plant height, fresh biomass weight and dry biomass weight were recorded on the 163rd day after seeding (DAS). The highest RGR and MDA content were determined on the 141st DAS. The highest chlorophyll content, CAT and SOD activity, and soluble protein content were recorded on the 110th DAS, and the highest POD activity was at 47 DAS. This study suggested that the optimum N and P fertilizer combination was N2P2 (360 kg·hm-2 N + 180 kg·hm-2 P), which was superior in promoting growth and biomass yield with enhanced antioxidant capacity of sesbania pea in saline soils.