还原剂对四种土壤碱解氮测定的影响

利用扩散法测定草甸土、淡黑钙土、草甸黑钙土及盐碱土碱解氮含量,结果表明:添加与不添加还原剂测定的土壤碱解氮含量,在8～24 h之间,呈上升态势,在24～30 h之间有所下降,但在30～48 h之间又呈现明显上升趋势,在扩散时间为24 h时氮含量测定值达到最好。添加与未添加还原剂所测得的土壤碱解氮含量相关极显著,进而证明两种方法都适用于这4种土壤的测定。还原剂对草甸土、淡黑钙土、草甸黑钙土碱解氮含量的测定影响不大,但在测定盐碱土碱解氮含量时采用添加还原剂的方法更加准确。

The effect of reductant on the available nitrogen measurement of four soils

The available nitrogen was determined by the diffusion method for meadow soil,light chernozem,meadow chernozem and saline soil.Results showed that: the available nitrogen measured both with and without reductant increased between 8～24 h,decreased between 24～30 h,and increased between 30～48 h.The optimal measurement was occurred at 24 h diffusion time.There were significant correlations between measurements with and without reductant,indicating these two methods were suitable for the four kinds of soil.The effect of reductant on the measurement of available nitrogen was insignificant for the meadow soil,light chernozem,and meadow chernozem.However,the measurement was more accurate with reductant for the saline soil.