包膜控释肥料在土壤中养分释放特性的测试方法与评价

Evaluation of determination methods for nutrient release characteristics of coated controlled-release fertilizer under soil and water incubation conditions

在土壤培养基础上,着重研究了包膜控释肥料养分释放率的三种测定方法以及在土壤中测得的包膜控释肥料养分释放率与在水中测得的养分释放率间的相关性。结果表明,在土壤培养中,采用肥料养分化学测定法、肥料养分称量法和土壤无机氮增量法都能直接或间接表征包膜控释肥料在土壤中的养分释放率及其相关性状。包膜控释肥料在土壤与水两种体系中所测得的养分释放率之间相关性显著,其相关关系符合一元一次线型回归方程,相关系数(r)大于0.920。

The basic property of controlled-release fertilizer （CRF） is its release-delay of nutrients from fertilizer. A series of soil and water incubation trials were conducted to compare three methods of determining nutrient release rate and characteristics of coated fertilizer, including chemical analysis method, coated fertilizer weighting method, and total soil mineral nitrogen method. In addition, the relationship between nutrient release rates of CRF in soil and water was discussed. The results showed that each method could represent nutrient release rate of CRF in soil. Chemical method is very complicated and more suitable for study and development of coated fertilizer. On the other hand, the fertilizer nutrient weighting method is suitable for rapid online monitoring under coated fertilizer production and it is simple, rapid, reliable and inexpensive. Total soil mineral nitrogen method is applicable to evaluation of fertilizer efficiency and crop response. The nutrient release rates of CRF under soil and water conditions were comparable. There was a significant positive linear correlation between accumulative nutrient release rate of CRF in soil and that in water, and its correlation coefficient （r） was greater than 0.920.