环境胁迫对不同水分管理措施下稻田土壤功能稳定性的影响

随着全球变化和人类活动干扰的加剧,维持和提高土壤生态功能具有重要意义.本研究以室内模拟干扰下土壤功能稳定性为核心,研究环境胁迫(干燥、高温和干燥高温)对常规淹水、裸地旱作、秸秆覆盖旱作3种水分管理措施下土壤功能稳定性(抵抗力和恢复力)的影响.结果表明:相对于单一的干燥或高温胁迫,复合胁迫虽然显著增加了土壤可溶性有机碳和铵态氮含量,但是降低了胁迫1 d后的土壤真菌和细菌生物量、土壤呼吸、土壤功能抵抗力,同时也显著降低了56 d后的土壤功能恢复力.相关性分析结果表明,细菌生物量和真菌生物量与土壤功能抵抗力和土壤功能恢复力均呈显著相关.不同水分管理措施能够调节环境胁迫对土壤功能稳定性的影响,无论是单一胁迫还是复合胁迫条件下,秸秆覆盖旱作均显著增加了可溶性有机碳、铵态氮含量和真菌、细菌生物量,其功能抵抗力和功能恢复力均高于常规淹水和裸地旱作.总之,在多种胁迫存在的条件下,秸秆覆盖旱作能够提高土壤生态系统在环境胁迫下的功能稳定性,是稻田节水旱作适宜的农业管理措施.

Effects of environmental stresses on soil functional stability under different water management measures in a paddy field

With the increase of global environmental changes and intensive anthropogenic activities, it is important to maintain and improve soil function. Here, we evaluated the effects of environmental stress (i.e., drying, high temperature and the combination of drying and high temperature) on soil functional stability (resistance and resilience) under three kinds of water management mea-sures, which included conventional-flooded cultivation, non-flooded with uncovered cultivation and non-flooded with straw mulching. Results showed that, compared to single environmental stress (drying or high temperature), combined stress led to lower soil fungal biomass, bacterial biomass, basal respiration, and soil functional resistance, and higher contents of dissolved organic carbon (DOC) and NH₄⁺-N after one day treatment of stress. Combined stress significantly decreased soil functional resilience after 56 days treatment of stress. Results from the correlation analysis showed that bacterial and fungal biomass were significantly related to soil resistance and resilience. Different water management measures could regulate the effects of environmental stress on soil functional stability. Non-flooded with straw mulching treatment significantly increased the contents of soil DOC, NH₄⁺-N, fungal biomass and bacterial biomass, resulting in higher soil functional resistance and resilience compared with conventional-flooded cultivation and non-flooded with uncovered cultivation under both single and combined stress. In summary, non-flooded with straw mulching could improve soil functional stability under environmental stress, and it could be a suitable agricultural management for non-continuously flooded rice cultivation under multiple stresses.