聚磷酸铵在土壤中有效性的变化及其影响因素

The availability of ammonium polyphosphate in soil and the impacting factors

【目的】明确聚磷酸铵在土壤中有效性的变化及影响因素,为聚磷酸铵的合理高效施用提供参考。【方法】选用pH不同的两种供试土壤进行室内恒温培养试验和盆栽试验。培养试验总时长331 h(14天),设置4个磷肥处理:不施磷肥处理(CK),及分别施磷酸二氢铵(MAP)、聚合度4的聚磷酸铵(APP-4)和聚合度6的聚磷酸铵(APP-6)处理;除CK外,其他3个处理均施用P2O583.8 mg/kg,每个处理重复4次。于施肥后第0、3、24、96、144、240和331 h采样测定土壤有效磷含量。盆栽试验以玉米为供试材料,设置5个磷肥处理:不施磷肥处理(CK),及分别施磷酸二氢铵(MAP)、过磷酸钙(SSP)、聚合度4的聚磷酸铵(APP-4)和聚合度6的聚磷酸铵(APP-6)处理;除CK外,其他处理均以每盆(2 kg土)施N 0.400 g、P2O50.764 g、K2O 0.386g,玉米苗移栽后第30天收获植株,测定地上部与地下部干重和全磷含量,同时测定土壤pH和有效磷含量。【结果】相比于MAP处理,APP处理能在较长时间内维持土壤中的有效磷含量。在酸性土中,APP-4和APP-6处理的磷肥利用率较SSP处理分别提高了49.5%和84.3%,在碱性土中较SSP处理分别提高了307.3%和316.2%。在酸性土中,APP处理的玉米地上部全磷含量较SSP处理提高了7.9%~12.4%,APP-6处理的玉米地下部全磷含量较SSP处理提高了13.5%;在碱性土中,APP处理的玉米地上部全磷含量较SSP处理提高了175.0%~177.6%,玉米地下部全磷含量提高了111.2%。APP-4和APP-6处理的玉米植株吸磷量在酸性土中较SSP处理提高了43.3%和74.0%,在碱性土中分别提高了244.6%和251.7%。与SSP处理相比,APP处理玉米地上部干重显著提高了17.2%~51.9%,地下部干重显著提高了13.3%~49.5%。【结论】聚磷酸铵比普通磷酸二氢铵能在更长的时间范围内维持土壤有效磷的含量,显著增加玉米对磷素的吸收利用效果,从而促进玉米的生长。聚合度和土壤酸碱性对聚磷酸铵的肥效响应显著,聚合度6的聚磷酸铵肥效显著优于聚合度4的聚磷酸铵,聚磷酸铵在碱性土壤中施用的效果好于酸性土壤。

【Objectives】The purpose of this study is to clarify the changes of available P when ammonium polyphosphate is applied into soil and the impacting factors to phosphorus availability,and provide a reference for the reasonable and efficient application of ammonium polyphosphate.【Methods】A cultivation experiment and a pot experiment were carried out using two types of soil in different pH value and maize as test material.The cultivation experiment lasted 331 hours(14 days).At the equal nutrient supply(P2O583.8 mg/kg),the cultivation experiment included four treatments:no phosphate application(CK),mono-ammonium phosphate(MAP),ammonium polyphosphate with polymerization degree of 4(APP-4)and 6(APP-6).Soil available P was determined at 0,3,24,96,144,240 and 331 h after fertilization.At the equal nutrient supply(N 0.400 g/pot,P2 O50.764 g/pot,K2 O 0.386 g/pot)in the pot experiment,five phosphorous fertilizer treatments were setup:no phosphate application(CK),mono-ammonium phosphate(MAP),superphosphate(SSP),ammonium polyphosphate with polymerization degrees of 4(APP-4)and 6(APP-6).The plants were harvested after transplanting 30 days for the determination of dry weight and total phosphorus contents.The soil was sampled for measurement of the pH and Olsen-P content.【Results】Compared with the MAP,APP increased the content of Olsen-P in soil.In acid soil,the phosphate utilization rates in APP-4 and APP-6 treatment were 49.5%and84.3%higher than that in the SSP.Compared with the SSP,the APP-4 and APP-6 increased the phosphate utilization rate by 307.3%and 316.2%in alkaline soil,the APP increased the total phosphorus content of aboveground part of maize by 7.9%–12.4%and the APP-6 increased the total phosphorus content of underground part of maize by 13.5%in acid soil.In alkaline soil,the total phosphorus content of aboveground and underground part of maize in APP treatment were 175.0%–177.6%and 111.2%higher than those in the SSP treatment.The phosphorus uptake by maize in the APP-4 and APP-6 treatment were increased by 43.3%and 74.0%relative to the SSP treatment in acid soil and increased by 244.6%and 251.7%in alkaline soil.The application of APP increased the dry weight of maize significantly.Compared with the SSP,APP increased the dry weight of aboveground and underground part of maize by 17.2%–51.9%and 13.3%–49.5%.【Conclusions】Ammonium polyphosphate can maintain a relatively higher content and longer period of soil available phosphorus compared with mono-ammonium phosphate,so could promote the growth of maize and use efficiency of phosphorous significantly.The degree of polymerization and soil pH affect the availability of ammonium polyphosphate greatly.Polymerization degree of 6 is better than that of 4,and the availability of ammonium polyphosphate performs better in alkaline soil than that in acid soil.