【摘要】 基于15年石灰性潮土长期定位施肥试验,用水浸提法、Olsen法、Mehlich3法研究土壤磷素有效性。结果表明:长期不施磷的处理,土壤磷素有效性常年维持在本底的极低水平;施磷均能增加水溶性磷、Olsen-P、Mehlich3-P的含量,但磷钾配施及大量施用有机肥的效果最明显,其次是有机肥与NPK配施,只施无机肥(NPK,NP)增加的幅度相对较小;然而,在当前的施磷水平下,土壤“不缺磷”,但不能建立较大的有效磷库,并且以Olsen-P、Mehlich3-P的临界点为标准,土壤磷素流失的风险不大;水溶性磷、Olsen-P、Mehlich3-P的比值约为1¨10¨25,用幂函数、指数方程、对数方程能较好地模拟3种浸提磷之间的转化关系;水溶性磷、Olsen-P、Mehlich3-P与作物地上部吸磷量均达到极显著正相关,相关系数分别为0.563,0.854和0.930,表明用水浸提法、Olsen法、Mehlich3法研究长期定位试验中土壤磷素的有效性均可行。更多还原

【Abstract】 Based on the 15-year long-term fertilization experiment in calcareous fluvo-aquic soil,three extraction procedures(water,Olsen and Mehlich3) were used to study soil phosphorus availability.The results showed that: ①Soil phosphorus availability maintained at the wondrously low level as background soil without phosphorus fertilization;②The contents of water soluble phosphorus(WSP),Olsen-P and Mehlich3-P increased significantly with the application of PK and organic manure,followed by combined application of organic manure with inorganic fertilizer,but application of inorganic fertilizer alone(NPK,NK) showed a relatively lower effect;③However,inputting phosphorus fertilizer with current amount could result in soil phosphorus to the level as "non-deficiency" but far from setting up a large available phosphorus pool,while soil phosphorus loss risk was low with the criterion values of Olsen-P and Mehlich3-P;④The ratio of WSP,Olsen-P and Mehlich3-P was 1∶10∶25;Power function,exponential function and logarithmic equation were optimum indications to simulate their converted relationships,respectively;⑤WSP,Olsen-P and Mehlich3-P were positively correlated to phosphorus accumulation in the shoot of crops,correlation coefficients were 0.563,0.854 and 0.930,respectively;Which indicated that these three extraction procedures were feasible approaches to study soil phosphorus availability under the long-term experiment.更多还原