Reversion of Fertilizer Nitrogen in Soils1
- F. E. Broadbent and
- T. Nakashima2
The term nitrogen reversion is suggested as applying to the conversion of fertilizer nitrogen to organic forms, which become progressively less available as a function of time. In greenhouse pot experiments with several soils, nitrogen availability ratios were found to decrease with successive cuttings of sudangrass Sorghum vulgare var. sudanensis This ratio is defined as the percentage of tagged N in the crop divided by the percentage of tagged N in the so l at the onset of crop growth. Similarly, the time required for mineralization of 1% of the residual fertilizer N in soil was found to increase with successive cuttings of grass.
Where straw was added to promote immobilization as much as two-thirds of the fertilizer N remained in soil after nearly 1.5 years of continuous cropping.
It is suggested that nitrogen reversion cannot be accounted for solely on the basis of biological interchange, and that a non-biological mechanism of N stabilization may be involved.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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