长期定位施肥对紫色土氮矿化特征的影响

Effects of Long-term Fertilization on Nitrogen Mineralization of Purple Soil

用长期定位试验的紫色土做40 d莴笋盆栽实验,测定盆栽实验前后土壤矿质氮、微生物量氮变化和植株氮总吸收量,根据土壤氮素收支平衡公式探讨了长期定位施肥处理对紫色土氮矿化特征的影响。结果表明:长期定位施肥对紫色土短期盆栽实验氮素矿化能力有一定影响;土壤碳氮比和植株氮吸收量、土壤微生物量氮呈线性关系,过量施用无机肥、土壤碳氮比下降,会影响土壤氮净矿化量和土壤有机氮矿化量增加;所以,需要无机肥和有机肥配合施用,避免因过度施肥造成的肥料浪费。

In order to explore the effect of long-term fertilization on nitrogen(N)mineralization of Purple soil,soil samples were taken from the Long-term National Monitoring Base for Purple Soil Fertility and Fertilizer Efficiency and a pot experiment was carried out for 40 days.Soil mineral N,microbial biomass N,and total content of N uptake by plant(Nplant)were determined before and after the pot experiment.A simplified mathematic equation was used to calculate soil N balance between input and output.The results showed that long-term fertilization had a certain effect on N mineralization of Purple soil in short-term pot experiment.Excessive application of inorganic fertilizer affected net N mineralization of soil organic matter,which might due to the change in soil C/N ratio.The soil C/N ratio had a linear relationship with Nplant and soil microbial biomass N.Under the low C/N ratio,the mineralized N source absorbed by plants was sufficient,which affected the N mineralization of Purple soil.Both organic and fertilizers should be applied appropriately to avoid the fertilizer waste.