Abstract

                                The addition of fresh plant material to soil has been reported to accelerate the decom- position of indigenous organic matter. In some studies this claim has been disproved. This was tested using C labelled tissues of leaves, stems and roots of maize plants of different maturity stages in a laboratory study on a clay loam soil containing 0.49 percent. organic carbon. Plant materials added to the soils accelerate the decomposition of indi- genous organic matter; plant. leaves and stems decomposa more rapidly than the roots: increased loss of soll organic matter was obtained in the case of only 14-day old plant materials. Similar trends were observed in case of experiments conducted with moisture for 14 days. Considerably less soil organic matter decomposition was found in a compa- rable time after the addition of the plant materials in the preincubation experiments than in the non-preincubation experiments.

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