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土壤盐分类型与含量对土壤生物活性和功能结构多样性会产生重要影响。本文模拟新疆北疆典型硫酸盐盐土,通过设置不同盐分浓度梯度(3、6、10、20和40 g kg-1),研究了土壤5种主要功能酶、土壤微生物量和土壤呼吸等生物性状的变化特征。结果表明:过氧化氢酶、蔗糖酶、β-葡萄糖苷酶和多酚氧化酶4种酶对盐分梯度响应非常敏感,其中过氧化氢酶、蔗糖酶和β-葡萄糖苷酶这3种酶活性与盐分浓度呈负相关,当盐分浓度达到40 g kg-1时,以上3种酶分别较对照降低25.7%、69.6%、30.0%;在3~6 g kg-1盐分浓度范围,多酚氧化酶随盐分浓度而升高,但在10~40 g kg-1时却显著降低,表现出“低盐促进,高盐抑制”的效应;纤维素酶对盐分浓度变化不敏感。土壤盐分与微生物量和微生物商呈显著负相关,与土壤基础呼吸和呼吸商则显著正相关,如40 g kg-1的盐分浓度导致土壤微生物量和微生物商分别较对照降低73.0%和69.5%,呼吸商升高了6.4倍。土壤过氧化氢酶、蔗糖酶、土壤微生物量、微生物商和呼吸商等可作为硫酸盐盐土早期预警生物指标。在40 g kg-1的含盐量下土壤生物功能结构明显区别于其他处理,且多样性指数显著下降。
The type and content of soil salinity have a significant impact on soil biological activity and functional structure diversity. In this paper, we simulated the typical sulphate salt in northern Xinjiang. By setting different salt concentration gradients (3, 6, 10, 20 and 40 g kg-1), five main functional enzymes, soil microbial biomass and soil respiration The changing characteristics. The results showed that the four enzymes catalase, sucrase, β-glucosidase and polyphenol oxidase were very sensitive to the salt gradient response, of which catalase, sucrase and β-glucosidase activity And negatively correlated with the salt concentration. When the salt concentration reached 40 g kg-1, the above three enzymes decreased by 25.7%, 69.6% and 30.0% respectively compared with the control; in the range of 3 ~ 6 g kg-1, Enzyme increased with the salt concentration, but decreased significantly at 10-40 g kg-1, showing the effect of “low salt promotion and high salt inhibition”; and cellulase was insensitive to salt concentration change. Soil salinity was significantly negatively correlated with microbial biomass and microbial quotient, and positively correlated with soil basic respiration and respiratory quotient. For example, 40 g kg-1 of salt concentration decreased soil microbial biomass and microbial quotient by 73.0% and 69.5% , Respirators increased by 6.4 times. Soil catalase, invertase, soil microbial biomass, microorganism quotient and respiratory quotient can be used as biomarkers for early warning of sulphate saline soil. Under the 40 g kg-1 salinity, the soil biofunctional structure was significantly different from other treatments, and the diversity index decreased significantly.