The Effect of Soil Drainage on Phosphorus Status and Availability to Corn in Long-term Manure-amended Soils
1982
Kuo, S. | Baker, A. S.
The effect of soil drainage on phosphorus (P) transformation and availability in soils was examined in a field that received annual manure applications for more than 20 years. The soil in the field ranged from well-drained Briscot loam (Typic Fluvaquents) to poorly drained Schalcar muck (Terric Medisprists) and was planted with corn (Zea mays L.) in 1979. Ten weeks after planting, soil and plant tissue samples were collected for P analysis. Manure applications increased the P content of the soils considerably. Most of the added P from manure remained in the surface soils (0 to 30 cm), though some downward movement of P did occur. Poor soil drainage increased the accumulation of P in the organic matter (NaOCl-extractable) and in the amorphous Fe-Al oxide (oxalate-extractable) soil fractions, but reduced the amount of P in the acid (0.5N H₂SO₄)-soluble soil fraction. Drainage affected the P desorption and availability to corn plants as well. The poorly drained Schalcar muck soil, for instance, had less P extractable by dilute HCl-H₂SO₄ or NaHCO₃ solution than the well-drained Briscot loam soil, despite the higher total P content of the muck soil. The rate of P desorption by NaHCO₃ can be described by two zero-order rate equations after an initial rapid desorption. The rate constant of desorption for the poorly drained soil (0.058 µg ml⁻¹ min⁻¹) was lower than for the well-drained soil (0.082 µg ml⁻¹ min⁻¹). The marked influence of soil drainage on P availability and transformation in the manure-amended soils observed in this study suggests that the selection of appropriate soils for manure disposal is necessary for better recycling of this nutrient by plants.
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