不同无机矿物应用于包膜复合肥的氮素释放特征及其评价

探讨了不同无机矿物用于膜材料后的包膜复合肥氮素养分释放特性、生物效应和评价方法。采用了土壤淋溶和土壤盆栽试验两种方法。试验方法的不同造成土壤盆栽与淋溶试验中各处理养分释放拟合曲线的差异 。两种方法的试验结果都能说明:无机矿物材料能有效地保持Ｎ素养分较长时间处于NH4＋-N形态，减少了因转化为NO3－-N形态造成的养分淋溶损失，但是各种材料彼此间存在一定的差异。盆栽试验中养分累计释放量与释放速率虽然快于作物的生理需求，但是受矿物材料和土壤缓冲作用的影响，作物氮素供应状况良好。与普通复合肥相比，各无机矿物用于包膜肥后能显著提高氮素利用率。蒙脱土效果最好，其次为高岭土，且差异显著。滑石粉、硅粉、硅藻土与前两者相比效果稍差，差异显著，但三者间差异不显著。无机矿物材料的耐水程度，养分吸附、固定能力和离子交换量等理化性质会影响包膜肥的养分释放性能。对于膜层疏松、耐水性差、主要靠养分吸附和固定机理控释的包膜肥来说，采用土壤作为养分释放介质更接近真实释放性能。评价包膜肥料的性能应该充分考虑养分形态、膜材特性、包膜工艺、土壤环境、供试作物等各方面因素，重点在“肥料–土壤–作物”系统中考查，从多种角度制定不同方案、通过多种方法综合评价其缓释效果。

N-release characteristics of compound fertilizers coated with various minerals and its evaluation

This paper was to explore the N nutrient release characteristics, N uptake and use efficiency of Chinese cabbage and evaluation method of compound fertilizers coated with different minerals. Soil leaching and pot experiment methods were adopted. An inconsistent dynamics curve was observed using different methods. However, the results obtained under both methods showed that the using inorganic minerals could keep N as NH₄^＋-N for a long time，consequently reduce the risk of NO₃^－-N losses. But the effects of all the materials were not consistent. Although the accumulated amount or releasing rate of N was faster than the requirement of Chinese cabbage, the nutrients supplied was quite rational owing to the mineral and soil buffer capacity. Comparing to the common compound fertilizer，the N use efficiency of all the mineral-coated fertilizer was improved significantly. The effiect of applying Montmorillonite on N efficiency was the best, followed by Kaolinite. The effects of French chalk, Microsilica and Kieselgur on N efficiency were significantly lower than that of Montmorillonite and Kaolinite, but there were not significant different from each other. The physicochemical properties of mineral materials, such as water resistance, nutrient absorption and fixation, ion exchange capacity affected the nutrients release efficiency of coated-fertilizer. Using soil as release media might be closer to the truly release properties for the coated fertilizers depending on nutrient absorption and fixation mechanisms. All the factors, including nutrient forms, coated material properties, making technology, soil condition, tested plant etc, should be considered thoroughly for the slow/controlled fertilizers evaluation.