Nitrate leaching and adsorption in a Kenyan Nitisol 期刊名称： Soil Use and Management
anna nalick
作者： G.P.,Warren,F.M.,Kihanda
年份： 2006年
期号： 第4期
关键词： Nitrate;anion exchange capacity;nitrogen
fertilizers;leaching;sorption;tropical soils;Nitisols
摘要：15N labelled NH4NO3 (fertilizer N) was applied at a rate of 50 kg N ha–1
to an Ando-Humic Nitisol and two maize crops grown on it. About 20 months later, soil cores were taken to a depth of 2.5 m. Leached fertilizer N was found between 1.4 m and 1.8 m deep and was delayed relative to net drainage by between 4.2 and 4.9 pore volumes. Anion exchange capacity (AEC) increased ten-fold down the profile, up to 2.9 cmolckg–1. The delay to fertilizer N leaching was predicted to be betw
een 4.1 and 5.3 pore volumes when calculated from the AEC and from an equation relating delay due to AEC in laboratory columns of repacked soil obtained by Wong et al. (1990b). It was concluded that the nitrate leaching delay equation was also valid in undisturbed field profiles. Two concentration maxima for mineral N were found, which did not