Abstract
Effect of decomposition of city refuse compost on periodical changes of amino acids in soils were investigated accompanying with mineralization of nitrogen compounds. City refuse compost was applied to soils (Light-colored Andsol and Brown lowland soil) at the rate of 10 mg as nitrogen per 10 g dry soils in each plot. At the end of each incubation period, contents of amino acids in hot water soluble fraction (F-1) and residual fraction (F-2), and mineralization of nitrogen from city refuse compost were determined. The results obtained were as follows : 1) Two kinds of acidic amino acids (aspartic and glutamic acids) and neutral amino acids such as alanine and glycine were apparently dominant both in original soils and compost. 2) In F-1 fraction, city refuse compost was rich in basic amino acids compared with original soils, and these differences in amino acid composition showed the discrepancies of microflora. 3) Accumulation of amino acids in F-1 and F-2 at the early stage of incubation was more marked in Brown lowland soil compared with in Light-colored Andsol, and this result might be the difference in decomposition of city refuse compost in each soil. 4) In F-1 fraction, the ratios of serine and glycine in total amino acids were increased with the length of incubation period ; these results were also apparent in the mineralization process of nitrogen, especially, in the case of Brown lowland soil. 5) Total amino acid contents in F-2 were markedly high compared to those of F-1 ; however, it is suggested that F-1 was important fraction to investigated decomposition of organic waste and mineralization of nitrogen in soils.
