土壤微生物与有机物料对盐碱土团聚体形成的影响

为了研究不同来源的微生物群落和不同类型的有机物料对盐碱土团聚体形成的影响,采用土培实验,接种不同来源的微生物群落(青海盐碱土或黄棕壤制备土壤悬液)到盐碱土中,并添加腐熟的有机肥或半腐熟的有机物料(玉米秸秆和牛粪)。土样在常温下培养45、90 d后,测定土壤相关指标。结果表明,各处理之间,在pH值下降、土壤团聚体形成及微生物数量等方面,接种土著微生物及添加半腐熟有机物料处理(SS+MS-CD)的效果最好。该处理土壤pH值下降幅度最明显,与对照相比降低了0.6个单位,且土壤团聚体形成效果优于其他处理,形成了0.62%的大团聚体(2 mm),而其他处理均未形成2 mm的大团聚体,并增加了小团聚体(2~0.25 mm)的形成比例。该处理亦显著提高了土壤酶活性及土壤呼吸强度。实验结果为制备盐碱土改良措施提供了理论参考。

Combined effects of soil microbes and organic matter on aggregate formation in saline-alkali soil

Saline-alkali soil is widely distributed in China. The saline-alkali properties of this soil are the primary factors affecting agricultural management. Promoting the formation of soil macro-aggregates is a key step for the improvement of saline-alkali soil. In this study, experiments were conducted to investigate the effects of adding various microbial communities and multiple types of organic matter on formation of soil aggregates in saline-alkali soil. The microbial communities were prepared in soil suspension of saline-alkali and yellow brown soil. In addition, decomposed organic or semi-decomposed organic matter were provided by inoculating maize straw and cow dung. Soil samples were cultured at room temperature for 45 or 90 days. The results showed that treatment with indigenous microorganisms plus semi-decomposed organic matter(SS+MS-CD) resulted in the greatest improvement in aggregate formation among all treatments. For example, aggregates of more than 2 mm were increased to 0.62%, whereas no aggregates of more than 2 mm formed in the other treatments. Additionally, the contents of 0.25~2 mm aggregates increased to 14.3%~23.9% from 0.5% of CK. Moreover, the pH value decreased around 0.6 pH units, and the population of microorganisms was significantly elevated. Furthermore, the treatment significantly improved the soil enzyme activities and soil respiration intensities. These findings provide insights into the promising applications of saline-alkali soil in agriculture.