长期施肥下旱地红壤剖面磷素的形态变化与累积特征

Morphological changes and accumulation characteristics of phosphorus in dry land of red soil profile under long-term fertilization

依托长期(1989―)定位试验,田间试验设置5个处理:氮磷钾(NPK)、氮磷钾+花生秸秆(NPK+PS)、氮磷钾+绿肥(NPK+FR)、氮磷钾+腐熟猪粪(NPK+PM)、只施氮钾(CK),研究不同施肥措施对旱地红壤剖面磷素形态变化与累积特征的影响。结果显示:长期施磷肥显著增加红壤中全磷和速效磷的含量,提升土壤磷活化系数(PAC);相关分析表明,中等活性有机磷(MAOP)和无机磷中的磷酸铝盐(Al-P)、磷酸铁盐(Fe-P)与有效磷呈显著相关(P<0.05)。对照处理土壤中无机磷以闭蓄态(O-P)为主(64.54%),但在不同施肥处理下外源性磷更易以Al-P和Fe-P形式积累,其中NPK+PM处理最为明显(Al-P,CK:6.27%、NPK+PM:27.58%;Fe-P,CK:17.28%、NPK+PM:37.35%)。NPK+PS、NPK+FR处理对土壤中磷素的影响主要集中于耕层,但NPK+PM处理对20 cm以下土层磷含量仍有较大影响,在底层(60~100 cm)土壤中依然有少量有效磷积累。研究结果表明,磷肥及其与有机肥的配施明显促进了土壤磷素的积累与活化,以猪粪为原料的腐熟粪肥尤为显著。

Based on long-term(1989-)location experiment,the effects of different fertilization measures on morphological changes and accumulation characteristics of phosphorus in dry land of red soil profile were studied.Five treatments including nitrogen,phosphorus and potassium fertilizer(NPK),nitrogen,phosphorus and potassium fertilizer plus peanut straw(NPK+PS),nitrogen,phosphorus and potassium fertilizer plus green manure(NPK+FR)and nitrogen,phosphorus and potassium fertilizer plus pig manure(NPK+PM),and only nitrogen and potassium fertilizer(CK)were set up in the field experiment.The results showed that long-term application of phosphorus fertilizer significantly increased the contents of total phosphorus and available phosphorus in red soil and increased the soil phosphorus activation coefficient(PAC).The results of the correlation analyses showed that medium active organic phosphorus(MAOP),aluminum phosphate(Al-P)and iron phosphate(Fe-P)in inorganic phosphorus were significantly correlated with available phosphorus(P<0.05).In the control treatment,the soil inorganic phosphorus was mainly in closed storage(O-P)(64.54%).But under different fertilization treatments,exogenous phosphorus was easier to accumulate in aluminum phosphorus(Al-P)and iron phosphorus(Fe-P),especially in NPK+PM treatment(Al-P,CK:6.27%,NPK+PM:27.58%;Fe-P,CK:17.28%,NPK+PM:37.35%).The effects of NPK+PS and NPK+FR treatments on phosphorus in soil were mainly concentrated in the plough layer,but NPK+PM treatment still had a great impact on the phosphorus content in the soil layer below 20 cm.There was still a small amount of available phosphorus accumulation in the bottom layer(60-100 cm).Phosphorus fertilizer and its combined application with organic fertilizer significantly promoted the accumulation and activation of soil phosphorus,especially the decomposed manure with pig manure as raw material.