摘要
土壤碳固存在缓解全球气候变化、维持农田生态系统生产力中起着十分重要的作用.农田土壤碳固存的决定因子包括气候因子(温度、降雨)、生物因素(微生物活性、酶活性)和非生物因素(土壤理化性质、团聚体组成及含量等),农田生态系统通过增加碳输入、减少碳输出和增加碳在土壤中持留时间三种途径强化土壤碳的固存.绿肥具有固定土壤碳、氮和调节土壤微生物群落结构等多重功能,将绿肥纳入作物生产中可通过减少有机碳矿化、增加土壤有机碳来源、调控土壤团聚化过程、促进微生物量及残体累积、改善微生物群落组成及代谢活性等多种方式协同提升土壤碳的固存,其作用可归纳为团聚体物理保护的物理固定机制、矿物化学结合的化学固定机制和微生物固定机制.目前采用的强化绿肥提升农田土壤碳固存的关键技术包括:1)选用适宜的绿肥品种;2)构建与区域土壤和气候资源相匹配的"主作物+绿肥"种植模式;3)配套绿肥与其他肥源协同增效的养分管理技术;4)优化耕作措施等.但还需进一步深入开展以下几方面的研究,包括:1)明确不同类型绿肥介导下的农田土壤碳固存机制的差异;2)强化高效固碳绿肥种质资源的选育;3)建立强化绿肥固存土壤碳的长效研究体系;4)构建基于绿肥的土壤有机碳管理框架.
Abstract
Soil carbon sequestration plays an important role in mitigating global climate change and maintaining farmland productivity.There are many determinants for soil carbon sequestration in cropland,such as climate(precipitation,temperature),soil biotic property(microbial communities and enzyme activities),and soil abiotic properties(physiochemical properties,agronomic management practices,aggregates).Cropland became carbon sink(positive sequestration)through increasing carbon input,reducing carbon output,and increasing carbon retention time in the soil.Green manures show multiple functions in such as nitrogen fixation,carbon sequestration,and regulation of soil microbial community structure.Incorporating green manure into crop production system could reduce the mineralization of soil organic carbon,increase the sources of soil organic carbon,regulate the process of soil aggregation,promote the accumulation of microbial biomass and residues,and improve the composition and metabolic activity of microbial communities,and these functions could be concluded into physical fixation(physical protection of aggregates),chemical fixation(chelating with soil minerals),and microbial carbon pump.The currently used key technologies to strengthen soil carbon sequestration efficiency of green manures mainly include:1)Selecting appropriate green manure varieties;2)Construction of'main crop+green manure'planting pattern to match the regional soil and climate conditions;3)Nutrient management technology to form synergic effect of green manure and other fertilizers;4)Optimized tillage methods.In the future,more researches should be focused on:1)The mechanism of soil carbon sequestration mediated by green manure;2)Breeding of high-efficiency carbon-fixing green manure germplasm resources;3)Establishing a long-term research system for the utilization of green manure;4)Construction of organic carbon management framework based on the application of green manure.
基金项目
国家重点研发计划项目(2021YFD1700204)
国家绿肥产业技术体系项目(CARS-22-G-12)
甘肃省优秀研究生"创新之星"项目(2022CXZX-646)
国家科技期刊平台
NSTL
万方数据