不同聚合度的聚磷酸铵对土壤磷动态转化及有效性的影响

以石灰性土壤和砖红壤为供试土壤,进行土壤培养试验,研究不同聚合度组成的聚磷酸铵(APP)对土壤有效磷和磷分级的影响。试验共设置5个处理:CK,不施磷肥;MAP,施用磷酸一铵;APP_L,施用以低聚合度为主的APP;APP_M,施用以中聚合度为主的APP;APP_H,施用以高聚合度为主的APP。结果显示:在石灰性土壤中,试验初期(5 d)APP_H处理的土壤有效磷含量显著(P<0.05)低于MAP处理,但至50 d时,APP_H处理的土壤有效磷含量较MAP处理显著(P<0.05)增加了23.92%。在砖红壤中,试验初期(5~10 d),APP_H处理的土壤有效磷含量显著(P<0.05)低于MAP处理,但在15~50 d却显著(P<0.05)高于MAP处理;APP_L处理5~15 d的土壤有效磷含量显著(P<0.05)高于MAP处理,但在后期却与MAP处理无显著差异。在石灰性土壤中,APP_L和APP_H处理的Resin-P含量在整个试验期间均较MAP处理高,APP_H处理后期的NaHCO₃-P含量随培养时间延长不断升高,高于其他磷肥处理。在砖红壤中,APP_L和APP_H处理的Resin-P和NaHCO₃-P含量虽然在试验初期稍低于MAP处理,但随着时间延长均逐渐高于MAP处理。在石灰性土壤中,APP_L和APP_H处理相较MAP处理可提高土壤磷的有效性,减少磷的固定;在砖红壤中,APP_L处理土壤前期磷的有效性高,说明其适合作基肥施用,而APP_H处理后期土壤中磷的有效性高,有效减少了酸性土壤对磷的固定。

Conversion dynamics and effectiveness of ammonium polyphosphate with different polymerization degrees to soil phosphorus

In the present study, calcareous soil and laterite soil were selected as test materials, and soil culture experiment was carried out to explore the effect of ammonium polyphosphate (APP) with different polymerization degrees on the dynamic transformation and availability of soil phosphorus. Five treatments were set up: CK, no phosphate fertilizer; MAP, application of monoammonium phosphate; APP_L, application of low polymerization degree APP; APP_M, application of medium polymerization degree APP; APP_H, application of high polymerization degree APP. It was shown that, in calcareous soils, the available phosphorus content under APP_H was significantly (P<0.05) lower than that under MAP at 5 d, yet it was significantly (P<0.05) higher than that under MAP by 23.92% at 50 d. In laterite soil, the available phosphorus content under APP_H was significantly (P<0.05) lower than that under MAP in 5-10 d, yet it was significantly (P<0.05) higher than that under MAP in 15-50 d. The available phosphorus content under APP_L was significantly (P<0.05) higher than that of MAP in 5-15 d, yet there was no significant difference between the two treatments in 30-50 d in laterite soil. In calcareous soils, the content of Resin-P under APP_L and APP_H was higher than that under MAP during the whole experiment, while the content of NaCHO₃-P under APP_H increased with the prolongation of culture time, which was higher than that under other treatments. In laterite soil, the contents of Resin-P and NaHCO₃-P under APP_L and APP_H were lower than those under MAP initially, yet they got higher than those under MAP with the increasing culture time. In calcareous soil, APP_L and APP_H could increase the availability of soil phosphorus as compared with MAP, and reduce phosphorus fixation. In laterite soil, APP_L exhibited high availability of phosphorus in the early stage, which was suitable for basal application, yet APP_H showed high availability of phosphorus in the later stage, and reduced phosphorus fixation in acidic soils.