短链聚磷酸磷肥对土壤无机磷转化及铁锰锌有效性的影响

明确聚磷酸形态磷在土壤中的转化及其对土壤磷有效性的影响是聚磷酸类磷肥合理施用的前提.本研究通过盆栽试验比较了施用磷酸一铵和聚磷酸类磷肥对石灰性土壤和酸性红壤有效磷、无机磷转化和土壤微量元素活化的影响,同时研究了不同磷源在油菜上的施用效果.结果表明: 聚磷酸磷肥可显著提高石灰性土壤磷的有效性.与磷酸一铵(MAP)处理相比,聚磷酸处理的土壤水溶性磷和有效磷平均含量分别提高了19.0%和25.4%;对土壤无机磷连续浸提试验表明,Resin-P(树脂磷)和NaHCO₃-P(高活性磷)较MAP处理分别提高了22.8%和43.3%,NaOH-P(中活性磷)较MAP处理提高了33.8%,说明聚磷酸磷肥可显著减少石灰性土壤对磷的固定.在酸性红壤上,施用聚磷酸类磷肥对提高土壤磷的有效性及减少磷的固定效果不明显.聚磷酸磷肥可显著提高石灰性和酸性土壤Fe、Mn、Zn的有效性.与MAP处理相比,聚磷酸肥料处理下石灰性土壤有效Fe、Mn、Zn分别提高了2.1%、16.2%和20.8%,红壤的有效Fe、Mn、Zn含量分别高了6.6%、11.9%和9.2%.聚磷酸磷肥显著提高了石灰性土壤上油菜干物质、吸磷量和磷肥利用率,但在酸性红壤上聚磷酸磷肥处理肥料效应却低于MAP处理.总之,聚磷酸磷肥在提高石灰性土壤中磷的有效性、减少磷的固定、活化Fe、Mn、Zn等微量元素以及改善油菜磷素营养方面均具有显著效果,是在石灰性土壤上能有效替代正磷酸磷肥的新型磷肥.

Effects of short-chain polyphosphate fertilization on inorganic P transformation and mobilization of Fe,Mn and Zn in soils.

Understanding the transformation of P in polyphosphate form in the soil and its effect on P availability is the prerequisite for reasonable polyphosphate fertilizer application. A pot experiment was conducted to explore the effects of polyphosphate fertilizers and MAP on soil available-P, inorganic P transformation in soils, soil micro-nutrient availabilities of Fe, Mn and Zn. Meanwhile, the effects of different P fertilizer on rape P nutrition and PUE in both calcareous and acid soils were investigated. Compared with the MAP treatment, polyphosphate fertilizers significantly increased plant available P concentrations in calcareous soil. Soil water soluble-P and Olsen-P were increased by 19.0% and 25.4%, respectively, and soil resin-P and NaHCO₃-P (high labile P) and NaOH-P (medium labile P) increased by 22.8%, 43.3% and 33.8%, respectively. Those results implied that polyphosphate could reduce the fixation of P in calcareous soil. However, there was no significant effect of polyphosphate fertilization on improving P availability and reducing P fixation in acid soil. In comparison with MAP treatment, polyphosphate treatments significantly mobilized micronutrient in soils and increased the uptake of Fe, Mn and Zn by rape plants. In the calcareous soil, the available Fe, Mn, and Zn increased by 2.1%, 16.2% and 20.8%, respectively. In acid soil, the available Fe, Mn, and Zn increased by 6.6%, 11.9% and 9.2%, respectively. In addition, polypho-sphate treatments significantly increased dry mass, P uptake concentrations and P use efficiency (PUE) of rape in calcareous soil, but not in acid soil. In conclusion, polyphosphate fertilizer could significantly increase P availability and micronutrient availability, plant P nutrition and PUE, especially in calcareous soil. Thus, polyphosphate could be used as alternative of P source substituting the orthophosphate-based P fertilizer in calcareous soil.