水稻对苏打盐碱土锌形态转化的驱动作用研究

为了揭示种稻对苏打盐碱土中Zn形态转化的驱动作用及其机理,采用Tessier连续提取法研究了松嫩平原不同种稻年限苏打盐碱地水田土壤中不同形态Zn含量及其在剖面中的分布特征。结果表明:盐碱地种稻改良后,可显著提高土壤剖面各层次中的有效Zn、交换态Zn及有机结合态Zn等生物有效态Zn的含量,降低碳酸盐结合态Zn、氧化物结合态Zn及残渣态Zn等非生物有效态Zn的含量。这种作用在种稻后的第1年表现的最为显著,第5年之后进入平缓上升阶段;种稻对有效Zn、交换态Zn及有机结合态Zn等生物有效态Zn含量提升的促进作用是随剖面层次的加深而减弱的。相关分析表明,交换态Zn和有机结合态Zn分别与pH呈显著负相关关系,而与有机质含量呈显著正相关关系;碳酸盐结合态锌和氧化物结合态锌与pH呈显著正相关;与有机质含量呈显著负相关关系。说明盐碱土种稻改良后,土壤pH降低和有机碳含量的提升是驱动不同形态Zn转化的主要因素。

Driving Effect of Rice on Form Transformation of Zn in Soda-saline-alkali Soil

To reveal the driving effect of rice on form transformation of Zn in soda-saline-alkali soil and its mechanism, Tessier continuous extraction method was used to study the content of Zn in different forms in soda-saline-alkali soil and its distribution characteristics in soil profile in Songnen Plain under different planting years. The results showed that the improvement of saline-alkali soil by planting could significantly enhance the contents of available Zn, exchangeable Zn and organism combined Zn, and other bio-available Zn in all soil profile, but reduce the contents of carbonate combined Zn, oxide combined Zn, residual Zn and other non-bio-available Zn. The effect was the most significant in the first year after planting, and then entered the gentle rising stage after the fifth year. The promoting effect of planting on the contents of available Zn, exchangeable Zn, organism combined Zn and other bio-available Zn weakened with the deepening profile level. Correlation analysis showed that exchangeable Zn and organism combined Zn had a significant negative correlation with pH, but a significant positive correlation with organic matter content respectively. Carbonate combined Zn and oxide combined Zn showed a significant positive correlation with pH but a significant negative correlation with the organic matter content, indicating that after saline-alkali soil improvement by planting, the decrease in soil pH and increase in organic carbon contents were the main factors for driving the transformation of Zn in different forms.