Evaluation of Nitrate Leaching in Lateritic Soil under Saturated or Unsaturated Conditions in Soil Columns

Abstract

ABSTRACTNitrate () leaching is a leading process of nitrogen (N) loss in agricultural ecosystems. The present research focused on leaching and transport in soil from the packed soil columns at different depths (0–20, 0–40, 0–60 and 0–90 cm) under saturated or unsaturated conditions for a lateritic soil. The leached collected from the bottom of column was analyzed with colorimetric method and was assessed for its variance in concentration (mg/L) with variable depths (20–90 cm). The leaching of was more in saturated condition than in unsaturated conditions. The cumulative concentration detected were 23, and 17 mg/L in a saturated condition for two N applications 15 mg and 7.5 mg, respectively, and were 2.10, and 1.36 mg/L in an unsaturated condition for two N applications 19.5 mg and 9.5 mg, respectively. Depth-wise analysis of leached indicated that at a 20 cm depth leached 16, 29 and 43% higher in a saturated condition whereas 21, 38, 52% higher in the unsaturated condition in comparison to 40, 60 and 90 cm depths, respectively. The concentrations with variable depths for both conditions were analyzed with principal component analysis (PCA) and PC (Pearson correlation) scores of 99.93% and 76.41% for unsaturated and saturated conditions were obtained and clarified that N application with more water results in more being leached out. Further, the study suggests that leaching can be restricted even with limited amount of nutrient and water.