Studies on the organic nitrogen becoming decomposable through the effect of drying a soil

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Abstract
Numerous experiments (2, 7, 9–14,16) have been reported that drying a soil and rewetting it results in a flush of decomposition of soil organic matter and a flush of ammonium and then of nitrates. And if the soil is taken through a number of such cycles of drying, rewetting and incubation, the amount of nitrogen to be mineralized falls off slowly as the number of cycles through which it is carried increases. The magnitude of the flush is larger in lowland soils than in upland ones. Among lowland soils it is largest in the ill-drained paddy. In rough figures, abut 10 per cent of the organic nitrogen is decomposed through one cycle of drying and rewetting in the ever-flooded paddy in Japan. No completely satisfying reason can yet be given for this flush of decomposition, nor is it known what fraction of the organic matter is involved.