设施菜地利用强度对土壤磷形态分布及其有效性的影响——以江苏省水耕人为土和潮湿雏形土为例

Effects of Greenhouse Vegetable Cultivation on Fractionations and Bioavailability of Soil Phosphorus-A Case Study on Paddy Soil and Fluvo-aquic Soil in Jiangsu Province

以江苏省水耕人为土和潮湿雏形土两种土壤类型为对象,研究了设施菜地利用强度对土壤磷形态分布及其有效性的影响。结果表明:随利用强度增加,两种土壤类型的各磷形态含量均有所增加,以水溶态磷和铝结合态磷(Al-P)增加最为显著(P<0.05)。而水耕人为土闭蓄态磷(O-P)占总磷百分比和潮湿雏形土残渣态磷占总磷百分比随利用强度增加则表现出显著降低的趋势(P<0.05)。回归分析结果表明,水耕人为土有效磷主要来自于铁结合态磷(Fe-P)和Al-P;潮湿雏形土有效磷主要来自于水溶态磷和钙结合态磷(Ca-P),且以前者更为重要。另外,设施蔬菜生产增加了土壤磷淋失的风险,尤其是潮湿雏形土。水–旱轮作并结合减少施肥量可能是降低设施土壤磷淋失风险的一个有效措施。

In order to understand the influence of management strategies of greenhouse vegetable production(GVP)on the fractions and bioavailability of soil phosphorus(P),soil samples encompassing a wide range of P status were collected in two typical GVP bases in Jiangsu Province:one with paddy soil in Guli Village of Nanjing City and one with fluvo-aquic soil in Xiahu Village of Xuzhou City,and the basic physiochemical properties and P fractions of the soil samples were analyzed.It was shown that Fe-P,O-P and organic P predominated in the paddy soil,while Ca-P contributed the most in the fluvo-aquic soil.With the increase of utilization intensity,the concentrations of soil available P,soluble P,Al-P,Fe-P,organic P and residual P in the paddy soil,the concentrations of soil available P,soluble P,Al-P,O-P,Ca-P and organic P in the fluvo-aquic soil,the percentages of W-P and Al-P to total P for both soil types were increased significantly(P<0.05),but O-P in paddy soil and residual P in fluvo-aquic soil were decreased significantly(P<0.05).Stepwise regression analyses revealed that Olsen-P was mainly contributed by Fe-P and Al-P in paddy soil,while by W-P and Ca-P in fluvo-aquic soil.It was worth noting that intensive agricultural inputs in GVP might increase the risk of P loss,especially for fluvo-aquic soil.Therefore,appropriate management strategies,such as paddy-upland rotation and lower fertilizer rate,are necessary to improve the bioavailability of soil P and achieve a sustainable progress of GVP.