中文摘要：

通过根箱试验比较了根系不分隔与分隔2种处理方式下玉米—大豆套作体系作物地上部生物量、籽粒产量及植株吸磷量。采用Hedley磷分级方法,测定根际土壤水溶性磷、NaHCO3-Po、NaHCO3-Pi、NaOH-Po、NaOH-Pi、HCl-P和残留磷7种磷素形态,力图阐明玉米—大豆套作模式下作物根际土壤磷素形态转化机制及其有效性。结果表明,玉米籽粒产量不隔根处理比隔根处理高12.6%,大豆籽粒产量在隔根与不隔根处理间差异不显著。不隔根处理与隔根处理下,玉米对磷肥的回收率分别为57.1%和54.7%,大豆对磷肥的回收率分别为127%和98.3%。磷素分组结果显示,与隔根处理相比,不隔根处理显著提高了玉米成熟期和大豆成熟期水溶性磷含量、玉米灌浆期NaHCO3-Po和NaHCO3-Pi含量、大豆分枝期V4和成熟期R8NaHCO3-Po含量;显著降低了玉米成熟期NaHCO3-Pi含量、大豆分枝期V4NaHCO3-Po含量及分枝期V12和成熟期R8NaHCO3-Pi含量;显著提高了玉米灌浆期NaOH-Po含量、大豆分枝期V4 NaOH-Po含量及分枝期V12 NaOH-Pi含量,显著降低了玉米灌浆期和成熟期NaOH-Pi含量、大豆分枝期V12NaOH-Po含量及分枝期V4NaOH-Pi含量。除大豆分枝期V12外,玉米和大豆各生育时期根际土HCl-P和残留磷均表现为隔根处理显著高于不隔根处理。无论隔根与否,随生育时期的推进,玉米根际土NaOH-Po、NaOH-Pi、HCl-P含量呈现出明显的降低趋势,而残留磷呈升高趋势;大豆根际土NaOH-Po含量略有升高,NaOH-Pi、HCl-P含量呈明显的降低趋势,残留磷呈先升高后降低的趋势。

英文摘要：

The crop aboveground biomass,grain yield and plant phosphorus（P）uptake in a maize-soybean relay intercropping system were studied in a root-box cultivation experiment with 2treatments of root barrier and non root barrier.7phosphorus fractions including water soluble P,NaHCO3-Po,NaHCO3-Pi,NaOH-Po,NaOH-Pi,HCl-P,and residue P in crop rhizosphere soil were determined according to the Hedley method of phosphorus fractionation,in order to clarify the transformation mechanism and bioavailability of rhizosphere soil phosphorus fractions in maize-soybean relay intercropping system.The results showed that maize grain yield under treatment without root barrier were 12.6% higher than that under treatment with root barrier,whereas no significant difference were observed on soybean grain yield under different treatments.The P fertilizer recovery rate by maize were 57.1%and 54.7%respectively,under treatments of root barrier and non barrier,and the P fertilizer recovery rate by soybean were 127% and 98.3% respectively.The phosphorus fractionation results showed that in rhizosphere soil,water soluble P content during maize and soybean maturity stage,NaHCO3-Poand NaHCO3-Picontent during maize grain filling stage,and NaHCO3-Pocontent during soybean branching（V4）and maturity（R8）stages were improved significantly under treatment without root barrier compared with treatment with root barrier;but NaHCO3-Picontent decreased significantly during maize maturity stage,the same as NaHCO3-Pocontent in soybean branchingstage（V4）,and NaHCO3-Picontent in soybean branching（V12）and maturity（R8）stages.Treatments without root barrier significantly increased NaOH-Pocontent in rhizosphere soil during maize grain filling stage and soybean branching stage（V4）,and NaOH-Picontent during soybean branching stage（V12）,while significantly decreased the NaOH-Picontent during maize grain filling and maturity stage,NaOH-Po content during soybean branching stage（V12）and NaOH-Picontent during soybean branching stage（V4）.Exc