灌溉对农田土壤有机碳影响研究进展

Effects of irrigation on soil organic carbon in farmland: a review

土壤有机碳(SOC)是地球陆地生态系统最重要和活跃的碳库,同时又是土壤肥力和基础地力的重要的物质基础,它对于提高作物产量,减缓温室气体排放具有重要作用。灌溉农业对世界农业发展至关重要,灌溉是SOC含量变化的重要驱动因素之一。通过总结国内外有关SOC研究,在综合阐述农田SOC积累的影响因素基础上,重点探讨了灌溉对SOC的影响,分析了影响机理,指出影响SOC变化的因素很多,灌溉主要从降低土壤水分限制,改变土壤理化性质,影响微生物活动、淋滤作用及对土壤盐分的影响等方面对SOC产生作用,但不同土壤类型及发育阶段、不同灌溉水质、不同灌溉年限、不同气候以及其他环境条件下作用结果不同。目前大多数灌溉对SOC影响的研究缺乏机理之间内在关系的认识,模型模拟缺乏验证数据。未来应综合研究各影响因子的相互作用机理,以流域和气候区的划分为基础,选择合适的时间尺度,明确灌溉水质、气候、土壤类型等因素的综合影响,注重实测数据的积累,获得长期监测数据以期对长期灌溉地区SOC进行评价。

Soil organic carbon （SOC） is the most important and active C pool of terrestrial ecosystem and it is the most important component of soil fertility. On one hand, SOC play a key role in improving crop yields; on the other hand, it is conducive to reduce greenhouse gas emissions. Irrigation plays a critical role in agricultural development around the world; meanwhile, irrigation is an important driving factor for the variation of SOC. This paper reviewed recent studies on SOC, the influential factors of farmland SOC accumulation are outlined, and the effects of irrigation on SOC, in addition, their mechanisms were discussed in detail. Many factors affect change in SOC, irrigation greatly affects SOC mainly resulted from lowering soil moisture limit, altering soil physical and chemical properties, affecting microbial activity, and reducing soil salinity. Moreover, impact of irrigation on SOC are different with various soil types, soil development stage, irrigation water quality, years of irrigation, climate variation, and other environmental conditions. Most of researches regarding impact of irrigation on SOC are lack of in-depth tmderstanding of interactions between mechanisms while application of model is lack of data for validation. In the near future, more studies considering multiple driving factors should be conducted to understand the interaction mechanisms among most factors; furthermore, effort should be taken to obtain long-term monitoring data on irrigation and SOC in order to evaluate variation in SOC at a large spatial and temporal scale.