Movement of Phosphorus in a Calcareous Soil as Affected by Humic Acid
2013
DU, Zhen-Yu | WANG, Qing-Hua | LIU, Fang-Chun | MA, Hai-Lin | MA, Bing-Yao | MALHI, S.S.
When humic acid (HA) and phosphorus (P) fertilizer are simultaneously applied to soil, HA may affect the movement of P. A laboratory incubation experiment was conducted to quantify the effects of a commercial HA product co-applied with monocalcium phosphate (MCP) on the distance of P movement and the concentration of P in various forms at different distances from the P fertilizer application site in a calcareous soil from northern China. Fertilizer MCP (at a rate equivalent to 26.6 kg P ha−1) was applied alone or in combination with HA (at 254.8 kg HA ha−1) to the surface of soil packed in cylinders (150 mm high and 50 mm internal diameter), and then incubated at 320 g kg−1 moisture content for 7 and 28 d periods. Extraction and analysis of each 2 mm soil layer in columns showed that the addition of HA to MCP increased the distance of P movement and the concentrations of water-extractable P, acid-extractable P and Olsen P in soil. The addition of HA to MCP could enhance P availability by increasing the distance of P movement and the concentration of extractable P in soil surrounding the P fertilizer.
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