影响旱地红壤易解吸磷的因子分析

Influence Factor Analysis of Readily Desorbable Phosphorus in Upland Red Soil

在位于江西省鹰潭农田生态系统国家野外研究站内的肥料长期（始于1988年）定位试验中,选取了无机肥试验区的NPK和NK,有机肥试验区的对照（CK）、CK＋花生秸秆（SR）、CK＋绿肥（FR）、CK＋稻秆（RS）和CK＋猪厩肥（PM）等7个施肥处理.测定了长期施肥后旱地红壤中易解吸磷（Readily Desorbable Phosphorus,RDP）的含量,采用相关分析及通径分析方法,探讨了土壤pH及土壤有机质、铁铝氧化物、无机磷组分、黏粒等基质组分对红壤RDP的影响程度及其对红壤磷潜在淋失量的贡献率大小.结果表明：长期施肥的旱地红壤中RDP含量,随着土壤中有机质及各形态无机磷组分数量的增加而显著增加（p〈0.01）,却随着无定型氧化铁数量的增加而显著减少（p〈0.05）.通径分析进一步表明红壤各基本化学组分对RDP的直接贡献率（绝对值）大小依次为Al-P〉Fe-P〉Ca-P〉Oc-P〉游离氧化铁〉有机质〉游离氧化铝〉无定型氧化铁〉pH〉无定型氧化铝〉黏粒,可见,无机磷组分对旱地红壤RDP及磷素潜在流失量影响较大.因此,有效调控旱地红壤中Al-P、Fe-P、Ca-P的含量对降低土壤磷素的淋失及其对水体环境的污染具有重要作用.

Soil samples were collected from the 7 treatments of a long-term upland fertilization field experiment, which started in 1988 for determination of soil readily desorbable phosphorus （RDP）. The treatments include NPK and NK from the inorganic fertilization plot, and CK, CK＋ pig manure （PM）, CK＋ peanuts straw （SR）, CK＋ fresh radish （FR） and CK＋ rice straw （RS） from the combination of chemical and organic fertilizers. Combined with correlation analysis and correlation analysis, the relationship between RDP and soil organic matter （OM）, iron-aluminum oxides, various inorganic phosphates （Pi）, clay and soil pH were discussed in this study. Study results showed that soil organic matter, aluminum phosphate （Al-P）, occluded phosphate （Oc-P） were significant increased by the addition of organic fertilizers based on the chemical fertilization. RDP was negatively correlated with iron-aluminum oxides （r=-0.442, p〈0.05）, and also significant correlated with the Pi and OM, the correlation coefficients （p〈0.01） were in the order of Al-P（r=0.972） 〉 Ca-P（r =0.910） 〉 Fe-P（r=0.853） 〉 Oc-P（r=0.684） 〉 OM（r=0.570）. Path analysis showed that the direct influence of Fe-P, Al-P and Ca-P to RDP were large. Therefore, effective measures and managements should be taken to control the contents of accumulated Pi in upland red soils to avoid soil P leaching and polluted soil water body.