中文摘要：

红壤固磷能力强,普遍存在缺磷现象。以云南红壤为试验材料,研究了草酸和柠檬酸对红壤磷素活化效果及其影响因素。结果表明：红壤经过草酸和柠檬酸处理后土壤中磷素的活化作用是明显存在的,在相同浓度下,草酸活化效果明显好于柠檬酸;随着有机酸处理浓度的增加,磷的活化率基本上呈增加趋势。但草酸在浓度2~10 mmol L-1间有效磷含量呈下降的趋势。而柠檬酸则刚好相反,总体随着处理浓度的增加,其有效磷含量呈增加的趋势;在不同固液比下,草酸对红壤磷素的影响比柠檬酸要大,红壤在固液比为1∶1时比1∶5时的活化效果好,在试验浓度范围内,柠檬酸对红壤A1-P、Fe-P以及磷酸二钙和八钙的活化能力强于草酸,对O-P的活化能力弱于草酸。

英文摘要：

Red soil has the high capacity of fixed phosphorus,so the content of phosphorus in red soil is very poor.Yunnan red soil treated with oxalic acid and citric acid was tested to study active effect and impacting factors of Red Soil phosphorus.The results showed that：（1） Soil Available phosphorus（AP） value of Red soil after oxalic acid and citric acid treatment was higher than the control;at the same concentration,active effect of oxalic acid on soil phosphate was better than citric acid.（2） With the concentration of organic acid increasing,the active effect on soil phosphorus in Yunnan red soil was also better.But when the concentration of oxalic acid was in the range from 2 mmol L-1 to 10 mmol L-1,the available phosphorus contents decreased,but the trend in citric acid treatments changed in the opposite way.（3） The experiment set the solid-liquid ratios respectively at 1∶1 and 1∶5t,he results showed that 1∶1 had the better effect on release of fixed phosphate than 1∶5.Among the experiment,active effect of citric acid was better than oxalic acid to Al-P,Fe-P,Ca2-P and Ca8-P,but was lower to O-P.