长期施肥对红壤磷素持续供应能力的影响

EFFECTS OF LONG-TERM FERTILIZATION ON SUSTAINED P SUPPLY CAPACITY OF RED SOIL

以长期施肥(始于1988年)的旱地红壤为研究材料,通过对历史数据的统计与分析,讨论了红壤全磷累积量与有效供磷量之间的相互关系,同时,通过有效磷的连续提取实验研究了红壤的持续供磷能力。研究结果表明:在长期施肥的过程中约有76.9%～86.8%的磷素积累在旱地红壤中,有效磷水平是红壤磷素肥力高低的直观表现,随着土壤全磷累积量的增大而增加;土壤磷素的纯盈余量又决定着全磷与有效磷的供应水平。由连续提取实验结果可以初步推测,如果现在减少或停止施用磷肥,红壤现有的供磷水平至少可以满足3～4季作物的磷素需求。因此,应在兼顾土壤磷素的农业效应和环境安全的前提下,建立新的施肥制度,使磷素资源的利用更加合理化。

Relationship between total phosphorus （TP） and available phosphorus （P） in a red soil under a longterm fertilization experiment beginning from 1988, was discussed through statistical analysis of its historical data. At the same time, sequential Olsen-P extraction was carried out to examine sustained P supply capacity in the red soil. Results show that the content of available soil P was a direct indicator of P fertility in the red soil and increased with the accumulation of TP; the supply levels of TP and available P in the red soil were determined by the amount of P surplus. According to the findings, the P content in the soil is adequate to meet the P need of at least 3 - 4 crops, if P fertilization decreases or ceases now. Consequently a new fertilization system should be worked out by taking into account both the agricultural effects and environment safety of soil P, to further rationalize the use of P resources.