Correlation between Nitrogen Mineralization and Properties of Various Types of Soils at Tea Plantations

For this study,5types of soils at tea plantations,i.e.,yellow,red,moist sandy,alpine meadow and purple soils,collected from Wuyishan City in Fujian were incubated at 28℃with a 60% water holding capacity for 35 days.The nitrogen(N)mineralization and its correlation with the properties of the soils were analyzed.A firstorder kinetic model derived from the experimental data was obtained:Ni=N0(1-e-kt)(R2=0.65-0.98),where Niis the cumulative mineralized N at incubation time t;N0,the potential mineralizable N pool;and k,the first order rate constant.N0 for the soils ranged from 4.15 to 52.46mg·kg-1(averaging 33.22mg·kg-1);kfrom0.019 to 0.343mg·kg-1·d-1(averaging 0.15mg·kg-1·d-1);N0×kfrom 0.32 to 16.82 mg·kg-1·d-1(averaging 33.22mg·kg-1·d-1);and the N mineralization rate(Nr)from 2.32 to 6.00%(averaging 3.73%).All parameters of the N mineralization in the alpine meadow and yellow soils were significantly higher than those in the others.They were followed by the moist sandy and purple soils,while the red soil was the lowest.△N,N0,k and N0×k were significantly correlated with the soil organic carbon,as well as the total N,NH+4-N and NO-3N.They also significantly correlated reversely with the soil bulk density,but not significant correlated with C/N or pH.The sand and silt contents in the soil significantly correlated with kand N0×k,but not with other indicators.