Biodynamics of microbial biomass nitrogen and sulfur in soil amended with organic matter and fertilizer (1): soil biomass

抄録

A pot experiment was carried out in a vinyl house with treatments of three organic materials and one fertilizer to assess the biodynamics of microbial biomass nitrogen and sulfur in organic matter amended and fertilizer treated soils. The organic materials were dustbin waste, poultry litter and rice straw. The organic materials were added at a rate of 2% of the dry weight of the soil. In the fertilizer treatment, nitrogen was applied at a rate of 200 μg N g^-1 soil as NH₄NO₃ and sulfur were applied at a rate of 15 μg S g^-1 soil as MgSO₄.7H₂O. A basal dressing of 150 μg P and 188μg K g^-1 soil as KH₂PO₄ and 10 μg Zn g^-1 soil as ZnO was added to each pot. The wheat variety Shatabdi was planted in the pots where necessary. The data was recorded periodically up to 128 days of crop growing. Organic matter amended soils induced higher amount of biomass-C, -N and -S formation than that of the fertilizer treated unplanted soils. Higher amounts of biomass-C, -N and -S were found in the planted soils from day 30 and onwards compared to the unplanted soils. Rice straw showed higher contribution to biomass-C, -N and -S formation than that of poultry litter and dustbin waste. Fertilizer contributed the highest amount of inorganic N, which was significantly higher than that of dustbin waste and poultry litter. Dustbin waste induced the highest amount of SO₄-S which was significantly higher than that of fertilizer treated and poultry litter amended soils. In rice straw amended soils, inorganic N and SO₄-S rapidly decreased by day 5 due to N and S immobilization and then remained constant.