Micronutrient Status in Commercial Sugarcane-growing Alfisols at <em>Sevanagala</em>, Sri Lanka

Abstract

The continuous mono-culture cropping without organic matter addition could deplete the plant available micronutrient reserves in sugarcane-growing soils. This study attempted to investigate the current status of micronutrient availability in commercial sugarcanegrowing Alfisols at Sevanagala, Sri Lanka, and to assess the potential of these soils to become micronutrient deficient in the future. Sugarcane-growing Alfisols at Sevanagala, covering both irrigated and rain-fed cropping systems, and low humic gley (LHG) and reddish-brown earth (RBE) soils were included in this study. A stratified random sampling technique, covering both cropping systems and soil orders, was employed to obtain 263 samples. Soils were analyzed for available Fe, Mn, Zn, and Cu contents using the standard DTPA procedure. Available Fe and Zn contents exhibited significant differences among cropping systems and soil orders. They were significantly higher under RBE soil (75 mg/kg and 1.1 mg/kg in Fe and Mn, respectively) when compared to those under LHG soil (43 mg/kg and 0.6 mg/kg in Fe and Mn, respectively). Available Fe and Mn contents were at sufficient levels for sugarcane in most soils. In contrast, Zn and Cu contents exhibited deficient patches (< 0.1 mg/kg) within the cropping systems and great soil groups in the studied area. The results indicate that appropriate nutrient management practices are required to overcome Zn and Cu deficiencies in Sevanagala sugarcane-growing Alfisols and to mitigate any negative effects on crop yield and quality in the future.