ABSTRACT

Determining how soil-crop management practices affect phosphorus partition and lability in soil may further our understanding of the soil P cycle. The objective of the work was to assessed the long-term effect of P fertilization on different soil P fractions. This study evaluated changes in soil P fractions as affected by long-term P fertilization under conventional tillage. Different P level applied soil samples were sequentially extracted to separate P into distilled deionized water-extractable, 2 M KCl solution-extractable, 0.1 M NaOH-extractable, 4. 0.1 M HCl-extractable, 0.5 M NaOH-extractable, and HCl: HNO3 mixture (2:5) fractions. Changes of all soil P fractions were indicating the occurrence of soil P transformation and movement over the time. The resin-extractable P, H₂O-extractable and NaOH-extractable P were significantly increased under long-term P fertilization. The highest P applied soil had the highest total phosphorus (PT) contents. Also the percent distribution of Ca and Mg‐bound P CaMgP, humic HaP and fulvic acid, and FaP increased with P fertilizer level increases. The other extraction P level did not increase vary consistently with increasing levels of P fertilization. Also soil P lability except soluble reactive phosphorus (SRP), KCl extractable phosphorus (EP), and particulate organic phosphorus (POP) increased consistently by P fertilization. Increasing P fertilization significantly (p < .001) increased the phosphorus management index (PMI) of extracted P fractions except for EP. The work demonstrated that P under long-term corn-wheat treated soils changed as a result of changes in labile P fractions probably due to the solubilization of residual fertilizer P joined with corn/wheat crop rotation factors. The highest P applied soil had the highest total phosphorus (PT) contents.

摘要

确定土壤作物管理方式如何影响土壤中磷的分配和不稳定性可能会进一步加深我们对土壤磷循环的理解。这项工作的目的是评估磷肥对不同土壤磷组分的长期影响。这项研究评估了常规耕作下长期施磷对土壤磷组分的影响。依次提取不同P含量的土壤样品，将P分离为蒸馏去离子水提取物，2 M KCl溶液提取物，0.1 M NaOH提取物，4。0.1 M HCl提取物，0.5 M NaOH提取物和HCl：HNO3混合（2：5）馏分。所有土壤磷组分的变化表明随着时间的推移发生了土壤磷的转化和迁移。树脂可萃取的P，H ₂长期施用磷肥后，可O提取和NaOH可提取的P显着增加。施磷量最高的土壤具有最高的总磷（PT）含量。Ca和Mg结合的P CaMgP，腐殖酸HaP和富勒酸和FaP的百分比分布也随着P肥水平的提高而增加。磷的其他提取水平并未提高，但随着磷肥水平的提高而变化。施肥使土壤可溶性磷（SRP），氯化钾可提取磷（EP）和有机磷（POP）稳定增加。显着增加磷的施肥量（p<.001）增加了提取的P馏分（EP除外）的磷管理指数（PMI）。这项工作表明，长期玉米小麦处理过的土壤中磷的变化是不稳定的磷含量变化的结果，这可能是由于残留的肥料P和玉米/小麦作物轮作因子的溶解所致。施磷量最高的土壤具有最高的总磷（PT）含量。