Effect of Applied Nitrogen and Potassium on Source and Sink Development of Maize Growing in Non-Calcic Brown Soils

Abstract

Maize is the second most important cereal crop grown in Sri Lanka. lt needs high amount of nitrogen and potassium for better growth and yield. However, Non-Calcic Brown (NCB) soil is poor in exchangeable potassium. Therefore, a study was conducted to find out the impact of increasing the amount of Nitrogen {N) and Potassium {K}on source and sink development of maize- Tl're experiment was conducted in split plot design where N was used as the main factor {150 and 2?5 kglha) and K (15, 30, 45 and 60 KzO kglha) tr'/as the sub factor, lncreasing of N increased developrnent of source components where chlorophyll content, above ground bio mass and leaf area; sink of plant where number of grains percob, 100 grain weight and the yield. Potassium significantly affected on sink except number of grains per cob. lnteraction of N and K was positively correlated on grains per cob, hundred grain weight and yield frorn 150 to 225 N kg/ha with all potassium levels. Hence, split application of N {225 kg/ha) with K (60 KzO kg/ha) would be the optimum level among tested fertilizer combinations for maize growing in NCB soils.