缓/控释复合肥料不同形态氮素释放特性研究

【目的】探讨缓/控释复合肥料不同形态氮素养分（NH4+-N、NO3－-N、Urea-N、DON和Total N）在不同介质中释放的动力学特性及生物效应。【方法】采用水中溶出法、土壤恒温培养法和盆栽生物试验。【结果】不同培养介质中，缓/控释复合肥5种形态氮素养分的累积释放量随时间的动态变化可用一级动力学方程Nt=N0(1-e-kt）、Elvoich方程qt=a+blnt、抛物线扩散方程qt=a+bt0.5表征，并以一级动力学方程拟合效果最好（r＝0.9569**～0.9999**），E1ovich方程次之（r＝0.7705**～0.9933**）。缓释复合肥料不同形态氮素最大释放量（N0值）与其氮素累积释放量的变化规律一致，在水中以Total N＞DON＞Urea-N＞NH4+-N＞NO3--N，在土壤中则以Total N＞NH4+-N＞DON＞Urea-N＞NO3--N。以水为介质时，缓释复合肥料不同形态氮素释放速率常数（k值和b值）的变化序列均以Total N＞DON＞NH4+-N＞NO3--N；以土壤为介质时，k值大小为Urea-N＞DON＞NH4+-N＞Total N＞NO3--N，b值则为Total N＞NH4+-N＞DON＞NO3--N＞Urea-N。与普通复合肥料相比，缓/控释复合肥的氮素利用效率（NUE）、氮素农学效率（NAE）及氮素生理效率（NPE）分别提高了11.4%、8.32 kg·kg-1和5.17 kg·kg-1。相关分析发现，5种形态氮素养分占总氮量的比值（Nx/NT）与水稻不同生育期吸收氮素养分之间呈显著或极显著正相关。【结论】定量描述氮素养分释放的动力学方程中以一级动力学方程评价更具有实效性。与普通复合肥料以单一尿素态氮养分为主相比较，缓/控释复合肥料的不同形态氮养分更有利于水稻对氮素的吸收利用。

Study on Release Characteristics of Different Forms of Nitrogen Nutrients of Slow/Controlled Release Compound Fertilizer

【Objective】This paper was to explore the release characteristics of different forms of N nutrients (NH4+-N, NO3--N, urea-N, DON and total N) of uncoated slow/controlled-release compound fertilizer (CRF) and N uptake and use efficiency of rice.【Method】Water dissolution, soil leaching and pot experiment methods were started. 【Result】Results showed that the dynamics of N release of CRF could be quantitatively described by three equations: the first-order kinetics equation (Nt =N0 (1-e-kt)), Elovich equation (Nt＝a+blnt) and parabola equation (Nt＝a＋bt0.5). However, the imitation of the first-order kinetics equation was the best for different forms of N nutrient（r＝0.9569**～0.9999**）. By Nt =N0 (1-e-kt) equation, the release potentials of different forms N (N0 values) in the CRF were in accord with the accumulated nitrogen release amount and in the order of Total N＞DON＞Urea-N＞NH4+-N＞NO3--N in water, and Total N＞NH4+-N＞DON＞Urea-N＞NO3--N in soil. The rate constants of N release (k values and b values) of different forms of N was in the order of Total N＞DON＞NH4+-N＞NO3--N in water. However, the k values was in the order of Urea-N＞DON＞NH4+-N＞Total N＞NO3－-N; and the b values was Total N＞NH4+-N＞DON＞NO3--N＞Urea-N in soil. Compared to the common compound fertilizer (CCF), the N use efficiency, N agronomic efficiency and N physiological efficiency of CRF increased by 11.4%, 8.32 kg·kg-1 and 5.17 kg·kg-1, respectively. The correlation analysis indicated that the ratios (between different forms of N and Total N in CRF) and N uptake by rice were positively significant of very significant. 【Conclusion】The imitationof the first-order kinetics equation (Nt =N0 (1-e－kt)) is the most practical for the release characteristics of different forms of N nutrients. Compared to the only Urea-N of common compound fertilizer, different forms of N nutrients of CRF is in favor of rice.