Phosphorus leaching through column study to evaluate P movement and vertical distribution in black, red and alluvial soils of India.

Abstract

Phosphorus leaching from soils is a major environmental concern leading to eutrophication of water bodies. Three different soil types namely black, red and alluvial soils from Nagpur, Raipur and Kanpur were taken for the study. Soil column leaching experiment was conducted during 2014–15 with different levels of P (0, 50, 100, 150, 300, 600 mg L−1) application with the objective to evaluate P buildup and vertical distribution in different soil types. Soluble reactive P (RP) content in three soils increased slowly with P application rates and decreased with increase in number of leaching events. Total P in leachate followed the similar trend. Phosphorus leaching mainly occurred during the initial seven leaching events accounting to 50–60% of total P leached over whole period. Among the various soil types RP content in leachate followed the order alluvial (0.01–0.23 mg l−1) followed by red (0.01–0.17 mg l−1), and black (0–0.1 mg l−1) soil. Soluble reactive P (RP) accounting for 75–80% leaching mainly during initial 10 leaching events with alluvial soil leached highest P followed by red and black soils. Vertical distribution and movement of Olsen and bray P content in all the soils were higher beneath 0–10 cm depth and increased with P application and decreased in untreated column section. Environmental test like water extractable P (WEP) and CaCl2 P content were higher in alluvial soil, suggesting the greater potential of P leaching loss under chemical P fertilization. The result of the study can further be extended at field level for efficient P management in various soil types and thus could quantify the contribution of P from different sources to P leaching in agricultural land.