根箱法解析大豆苗期根际养分分布及吸收特征

Inspection of nutrients uptake and distribution across rhizosphere at seedling stage of soybean by rhizobox method

植物影响根际微生态系统特征．应用根箱法对2个大豆基因型的苗期养分（N、P、K、Ca、Mg、Fe、Mn、Zn和Cu）吸收及其在根际分布特征进行了研究．结果表明，高产基因型北丰11对N、P、K、Ca、Mg、Mn、Zn和Cu的吸收量均显著高于低产基因型海9731，其单位根长、根表面积吸收N、P、Ca和Mg的量亦较高，其根系吸收活力较强．土壤有效养分在根际的分布趋势不同，有效N和Mn在0～4mm范围内的含量高于非根际区（〉10mm），而P、K、Mg和Cu在根面区表现一定程度的亏缺．2个基因型间根际养分差含量异较大，除K和Fe外，其他营养元素在北丰11根面和近根面区的含量均不同程度地高于海9731．北丰11根际0～6mm的范围内pH较低．

Plants affect micro-ecological characteristics of the rhizosphere. The nutrients（N, P, K, Ca, Mg, Fe, Mn, Zn and Cu）uptake and its distribution across the rhizosphere at the seedling stage in two soybean genotypes were investigated by the rhizobox method. The results showed that the uptakes of N, P, K, Ca, Mg, Mn, Zn and Cu in a high yielding genotype, i.e. Beifeng 11, were higher than that in a low yielding genotype, i.e. Hai 9731, and the greater absorptions of N, P, Ca and Mg per root length and per root surface area were found in Beifeng 11, which indicated that Beifeng 11 had a relatively high root activity. The distribution characteristics of nutrients across the rhizosphere were different. The soluble N and Mn concentration within 0 - 4 mm of the rhizosphere was higher than bulk soil（ 〉 10 mm）, whereas a negative trend was found for the P, K, Mg and Cu. The difference of nutrient concentration in the rhizosphere between the two genotypes was obvious. The nutrients in the central compartment and the near zone for Beifeng 11 were higher than Hai 9731, except for K and Fe. Beifeng 11 had lower pH within 0 - 6 mm of the rhizosphere.