不同磷源对橡胶树幼苗生长及土壤磷素组分特征的影响

通过盆栽试验及Hedley土壤磷素分组法研究了海南省玄武岩发育砖红壤上施用不同磷源对橡胶树幼苗生长的影响及土壤磷素组分变化。磷肥处理分别为不施磷处理、施用昆阳磷矿粉100 mg/kg(以全P计,下同)、施用昆阳磷矿粉250 mg/kg和施用普通过磷酸钙100 mg/kg。结果表明:施用磷矿粉和普通过磷酸钙均显著增加了橡胶树幼苗干物重、株高、茎粗和吸磷总量,但高磷矿粉处理和普通过磷酸钙处理橡胶树幼苗叶片磷含量显著降低;高磷矿粉处理取得了与普通过磷酸钙相当的肥效;磷矿粉施用后,土壤树脂提取态磷(Resin-P)、碳酸氢钠提取态无机磷(NaHCO_3-Pi)、氢氧化钠提取态无机磷(NaOH-Pi)、盐酸提取态磷(HCl-P)和残余态磷(Residual-P)等组分含量均显著增加,但碳酸氢钠提取态有机磷(NaHCO_3-Po)和氢氧化钠提取态有机磷(NaOH-Po)不受施磷影响;干物质重和吸磷总量均与土壤Resin-P、NaHCO_3-Pi和Na OH-Pi呈显著的正相关关系;磷矿粉施用11个月后,平均33.1%磷矿粉溶解在土壤中,平均43.5%的磷矿粉残留在土壤Residual-P组分中。为改善玄武岩发育砖红壤上有效磷及橡胶树磷素营养状况,应选择施用高活性磷矿粉以降低磷矿粉颗粒被大量包被的风险。

Effect of Different Sources of Phosphorus Fertilization on Rubber Tree Seedlings Growth and Soil Phosphorus Fractions

The effects of different sources of phosphorus fertilizer application on rubber tree seedling growth and soil phosphorus fractions on Latosol derived from basalt were studied in a pot experiment. Hedley's sequential extraction method was used to investigate the effect of different P fertilization on the changes of the inorganic and organic P fractions. The Kunyang Phosphate Rock(KPR, as P)was added to obtain rates of 0 mg/kg soil(CK), 100 mg/kg soil(PR100), and 250 mg/kg soil(PR250)and superphosphate at 100 mg/kg soil(SSP100). The results showed that the application of phosphate rock(PR)and superphosphate significantly increased the rubber tree seedling dry weight, plant height, stem diameter, and total phosphorus uptake, and leaf P concentration of the rubber tree seedling under PR250 and SSP100 treatments significantly decreased. After PR application, soil Resin-P, NaHCO3-Pi and NaOH-Pi, HCl-P and Residual-P were significantly increased, and NaHCO3-Po and NaOH-Po were stable and not affected. Plant dry weight and total phosphorus uptake were both positively correlated with soil Resin-P, NaHCO3-Pi and NaOH-Pi at 0.05 level. At the end of the experiment, it was found that 33.1% of KPR was dissolved into soils, and 43.5% of the KPR existed in the soil as the form of Residual-P under the two rates of the KPR applications. In order to improve soil P availability and P nutrition status of rubber tree on soils derived from basalt, it is highly recommended to select and use high reactive PR for direct application, which may reduce the risk of coating of PR particles by soil iron, aluminum and manganese oxide.