Progress on evaluation methods for nutrient release characteristic of coated controlled release fertilizers

Controlled release fertilizers (CRFs) have become a hotspot in fertilizer research in both domestic and abroad, but the researches in evaluation methods for nutrient release characteristic of CRFs are relatively backward. Up to now, there has not been perfect method and unified testing standard. This paper reviewed the present evaluation methods: water (or solution) dissolution rate method, soil dissolution rate method, infiltrate method, permeability method, isotopic tracer method and electroultrafiltration method , analyzing the merit, the shortcoming and the improving way of them and prospecting the direction of the evaluation methods in the future.