土壤酸化对樱桃番茄养分积累和分配的影响

为研究土壤酸化对土壤养分有效性以及植物吸收、积累、分配养分的影响,采用盆栽试验,以酸性红壤(pH 5.05)、樱桃番茄(Lycopersivon esculentum Mill)为试验材料,浇施柠檬酸-磷酸氢二钠缓冲液和碳酸钠-碳酸氢钠缓冲液调节土壤pH,使土壤pH下调至4.0,5.0及上调至6.0和7.0,试验共4个处理,每处理5个重复,测定了土壤酸化对樱桃番茄植株生长、植株体内养分含量和积累分配的影响。结果显示,通过缓冲液调节,实测土壤pH为4.35、4.92、5.89、6.85;土壤酸化显著降低樱桃番茄叶面积、生物量尤其是根系生物量,降低植株根冠比;土壤酸化严重抑制氮、磷、钾、镁、铁在番茄根系的积累,而促进铁、锰在茎秆和钙、镁在叶片的积累分配,使根系氮、磷、钾、钙、镁、铁积累量显著降低,茎秆积累氮、钾、铁、锰较多,叶片积累磷、钙、镁较多,特别是植株各部位锰含量显著提高。结果表明,根系是樱桃番茄植株受土壤酸化抑制最严重、最敏感的部位,并因此导致多数养分被根系吸收,迁移受阻,积累显著下降。

Simulation study on copper and zinc release from contaminated sandy soils due to acidification

Afforestation in sandy soils can cause soil acidification and affect Cu and Zn release. The behaviors of Cu and Zn release from contaminated arable sandy soils were investigated in the laboratory with the methods of simulated acidification of the soils. The results showed that soil acidification could change chemical forms of Cu and Zn in the soils, impel the transformation of Cu and Zn from carbonate associated fractions to exchangeable, organic matter and oxides associated fractions, and thus increase the release potential of Cu and Zn in the soils. The effect of the acidification on Zn leaching was more significant than that of Cu. Water solubility of Cu and Zn in the soils was increased with decreasing pH, and the solubility of Cu and Zn was increased exponentially at pH 3.8-4.5, and 6.2-6.5, respectively.