Response of Maize to Different Levels of Sulfur

Abstract

A field experiment was conducted to assess the effect of different levels of sulfur (S) on yield and yield components of maize crop grown on silt loam soils at the Agriculture Research Station Baffa, district Mansehra. The soil contained 1.17% organic matter, 10% CaCO3, and 39 mg SO4‐S kg−1. Sulfur was applied at 0, 20, 40, 60, 80, 100, and 120 kg ha−1 as gypsum along with 120 kg N, 90 kg P2O5, 60 kg K2O ha−1 replicated thrice in RCB design. Soil samples at silking and harvesting stage from each treatment plot along with leaf samples were collected for the determination of S. Yield and yield components of maize were significantly (p<0.05) enhanced with the application of S compared with control. Sulfur at 60 kg ha−1 produced highest yield of fresh matter, dry matter, stover, 1000‐grain and total grain, resulting in increases of 41, 55, 58, 5, and 43%, respectively. Application of S above 60 kg S ha−1 reduced yield and yield components, suggesting a classical yield response curve. The analysis of soil samples at silking and harvesting stage from each treatment plot revealed that soil SO4‐S concentration increased significantly by S application reaching the level of 108.4 and 99.7 mg kg−1, respectively, with 120 kg S ha−1. Sulfur concentration of leaves was significantly increased with the application of S compared with the control. Application of sulfur at 60 kg ha−1 produced leaf S concentrations of 0.46%, which is less than the critical level of 0.5%, whereas higher treatments increased S concentration ranging from 0.67 to 0.94%, which exceeded the value considered as high (0.5%) and excessive (0.8%). Elevated tissue sulfate concentrations induced by treatments greater than 60 kg ha−1 corroborate with the corresponding yield decreases of maize. Maize growers of the area may add S up to 60 kg ha−1 to obtain maximum yield.