Study on nutrient release characteristics of compound slow release fertilizer and the biological response of Chinese goldthread

Continuous constant temperature incubations and field experiments were adopted to study the nutrient release characteristics of four compound slow release fertilizers and the effect on yield and medical qualities of rhizome of Chinese goldthread. The results indicated that the nitrogen, phosphorus and potassium had good slow release capability of four compound slow release fertilizers incubated under the simulation conditions(20℃). The dynamical processes of nutrient release were described correctly by Elovich equation (St=a+blnt), double constant equation (lnSt=a+blnt) and parabola diffuse equation(St=a+bt0.5) and nutrient release rate could be described by parameter b of all equations. Rhizome yields and berberine and alkaloid contents of Chinese goldthread were increased significantly used four compound slow release fertilizers, and the maximum biological response of rhizome of Chinese goldthread, which growing third to fifth years, were SRF2, SRF1　and SRF3, respectively.