大沽河流域农田土壤磷有效性及全磷淋失影响因素试验

Experimental Study on Influencing Factors Affecting Phosphorus Availability and Total Phosphorus Leaching in Farmland Soil in Dagu River Basin

以青岛市大沽河流域砂壤、河潮土、砂姜土3种农田土壤为研究对象,开展室内土柱试验,研究土壤pH、温度、含水率等理化性质与生物炭和氮肥配施对土壤有效磷(Olsen—P)和全磷(TP)淋失的影响,以期为提高农田土壤磷素有效性、减少全磷淋失提供参考依据。结果表明:3种土壤的pH在偏中性或弱碱性时磷素有效性最高,pH偏酸性时,土壤全磷淋失量较大;3种土壤不同土层中的Olsen—P含量随含水率的增加表现为不同的变化规律;3种土壤的磷素有效性均随温度的升高逐渐增大,全磷淋失量随温度的升高逐渐降低;生物炭和氮肥配施(T1~T7)处理下均能够有效提高土壤磷素有效性,作用效果依次为生物炭和氮肥联合施加>单加生物炭>单加氮肥,当氮肥和生物炭比例为2∶1时,土壤磷素有效性最高。生物炭与氮肥联合施加对土壤全磷淋失的抑制效果优于单独施加生物炭,氮肥对全磷淋失的抑制效果不明显。

Taking sandy soil,fluvo-aquic soil and Shajiang soil in Dagu River Basin of Qingdao as research objects,the indoor soil column experiments was carried out to study the effects of soil temperature,pH,water content and other physical and chemical properties and combined application of biochar and nitrogen fertilizer on leaching of soil available phosphorus(Olsen—P)and total phosphorus(TP),so as to provide reference basis for improving soil phosphorus availability and reducing total phosphorus leaching.The results showed that the soil phosphorus availability was the highest when the pH was neutral or weakly alkaline,and the total phosphorus leaching loss was larger when the pH was weakly acidic.The Olsen—P content in different soil layers of the three soils showed different changes with the increasing of water content.The phosphorus availability of the three soils increased gradually with the increasing of temperature,while the leaching loss of total phosphorus decreased with the increasing of temperature.The combined application of biochar and nitrogen fertilizer(T1~T7)could effectively improve the availability of soil phosphorus,and the effect followed the order of combined application of biochar and nitrogen fertilizer>single addition of biochar>single addition of nitrogen.When the ratio of nitrogen fertilizer to biochar was 2∶1,the availability of soil phosphorus was the highest.The inhibition effect of biochar combined with nitrogen fertilizer on soil total phosphorus leaching was better than that of biochar alone,and the inhibition effect of nitrogen fertilizer on soil total phosphorus leaching was not obvious.