Effect of Nitrogen Fertilization on Organic Carbon Mineralization in Soils at Tea Plantations

A laboratory incubation experiment was conducted to study the effect of the varied nitrogen (N) inputs, i.e., 0mg·kg-1 (N0) , 100mg·kg-1 (N1) , 200mg·kg-1 (N2) and 400mg·kg-1 (N3) , on the organic carbon mineralization (OCM) in the yellow and red soils at tea plantations.The results indicated that under N0 the cumulative OCM of the yellow soil was 586.58mg·kg-1, which was significantly higher than that of the red soil (298.84mg·kg-1) .But, the rate and constant kof mineralization were significantly lower for the yellow soil than those for the red soil.Increasing exogenous N resulted in the increase of the cumulative OCM in the yellow and red soils by 20.90%-91.88% and 48.52%-113.88%, respectively.The first-order kinetics equation appeared to adequately describe the dynamics of OCM in the soils.N fertilization made the easily mineralizable organic carbon (C1) in soil increased significantly with an exponentially increased k, raised the initial potential mineralization rate (Cok) , and lowered the half-life.The results suggested that a short term N treatment could promote the OCM turnover, which was conducive to the carbon/N transformation and fertility improvement of the soil.