【作者】 龙攀；

【导师】 高旺盛； 陈源泉； 隋鹏；

【作者基本信息】 中国农业大学 ， 作物栽培学与耕作学， 2014， 博士

【摘要】 针对我国农业废弃物类多、数量大、利用低、污染重的现实问题,以循环农业理念为指导,选择代表农田内循环的秸秆、代表农牧循环的猪粪、代表农沼循环的沼渣、代表农菌循环的菌渣、代表农工循环的酒渣5种有机物料进行等碳量还田,通过麦玉两熟农田定位试验,重点对土壤有机碳及其组分变化、团聚体固碳机制、土壤温室气体排放进行监测与分析,研究不同物料还田对农田系统的碳平衡的影响及其机制。试验开始于2010年6月,本论文主要分析2012-2013年的数据。取得的主要进展主要有：(1)五种物料还田均能不同程度促进麦玉两熟集约化农田土壤总有机碳积累,增强系统固碳潜力。与单施无机肥相比,5种物料还田3年后的土壤有机碳(TOC)含量平均提高44%,周年系统固碳量分别增加4.22～6.30t C ha-1。与不施肥(NF)和撂荒地(FL)相比,物料还田的TOC含量分别高出63%和32%,系统固碳量平均增加8.78t C ha-1和6.82t C ha-1。综合表明,循环农作模式对土壤TOC积累正贡献最大,非循环农作模式(无机肥)与原始农作模式(不施肥)对TOC积累呈现负贡献,撂荒模式TOC相对稳定。(2)五种物料中,猪粪、沼渣和菌渣更有利于土壤有机碳的积累和系统固碳潜力的提高。猪粪、沼渣、菌渣和酒渣的TOC含量分别比秸秆处理高29%、27%、27%和16%,表明经过其他系统“循环”利用的有机物还田比秸秆直接还田更有利于有机碳在土壤中积累。猪粪、沼渣和菌渣还田3年后分别比秸秆直接还田多积累1.26tCha-1,0.76tCha-1,0.26tCha-1。(3)有机物料还田促进土壤团聚体的形成,有利于对土壤有机碳的保护,其中猪粪、沼渣和菌渣大幅提高有机碳的稳定性。有机物料还田的微团聚体结合态TOC以及大团聚体包裹的微团聚体结合态TOC含量分别比撂荒、非循环农作模式及原始农作模式高54%,115%,128%。菌渣、猪粪、沼渣和酒渣还田的土壤微团聚体结合态TOC以及大团聚体包裹的微团聚体结合态TOC含量分别比秸秆高49%、23%、22%和7%,说明经过农田系统外循环回来的物料还田有利于TOC稳定性的提高。(4)有机物料还田虽促进了土壤温室气体排放,但同时也提高了系统碳输入,最终表现出系统固碳能力增强,是温室气体的“汇”。五种物料还田的土壤温室气体排放增温潜势平均比无机肥高出58%,但同时也提高了系统生产力、增加系统固碳,弥补所促进的温室气体排放量,从而使整个系统的表现为碳汇,系统净碳平衡高出264%。研究结果表明,农田有机废弃物经过农牧循环、农沼循环、农菌循环之后回田,具有更强的固碳优势,又能提高系统生产力,说明发展循环农业,促进农业节能减排具有重要意义。更多还原

【Abstract】 A large number of agricultural organic wastes are produced in China every year from various agricultural systems. The low utilization of these organic wastes leads to serious potential pollution to the environment. To resolve these problems, five types of organic wastes were applied to a wheat-maize cropping system based on the concept of circular agriculture, including crop straw (CS) representing the inner farmland circulation, pig manure (PM) representing the farming-stockbreeding circulation, biogas residue (BR) representing the farming-biogas circulation, mushroom residue (MR) representing the farming-mushroom circulation, and wine residue (WR) representing farming-processing circulation. The organic wastes were incorporated at an equal rate of carbon. Total organic carbon (TOC) and its components, soil aggregate, and soil greenhouse gases (GHGs) emission were investigated and analyzed to explore the effects of organic waste on soil organic carbon and net carbon balance of the farming system. This experiment began in June2012, data in the period of2012to2013were analyzed in this dissertation. The main results were as follows.(1) Incorporation of the five organic wastes could promote the accumulation of TOC in the wheat-maize intensive farming system, and improve the retention of C in the system. In comparison with CF, TOC was increased by44%on average after three years of organic waste incorporation, the amount of C retention in the system increased4.22-6.30t C ha-1. When compared with the no-fertilization (NF) and fallow (FL), TOC were increased by63%and32%, respectively, and the amount of C retention were increased8.78t C ha-1and6.82t C ha-1. On the whole, the largest positive contribution to the accumulation of TOC was derived from the circular farming mode, and the negative contribution were showed in the acyclic farming mode (CF) and primeval farming mode (NF), whereas a stable TOC was showed in the fallow mode.(2) Among the five orgaic wastes, pig manure, biogas residue and mushroom residue are more benefit to the accumulation of TOC and improvement of C retention. In comparison with CS, the TOC of PM, BR and WR were increased by29%,27%,27%and16%respectively, which indicated that it was more conducive to soil C accumulation by incorporating organic wastes recycling from other systems than crop straw. The amount of C retention in the system raised by1.26tC ha-1,0.761C ha-1,0.261C ha-1in PM, BR and MR when compared to CS.(3) Incorporating organic wastes promotes the formation of soil aggregate, and is beneficial for the protection of TOC, among the organic wastes, PM, BR and MR greatly increase the stability of soil organic C. In comparison with FL, CF and NF, the microaggregate associated TOC and microaggregate-within-macroaggregate associated TOC content were increased by54%,115%and128%in organic wastes treatments. The microaggregate associated TOC and microaggregate-within-macroaggregate associated TOC contents in MR, PM, BR and WR were49%,23%,22%and7%higher than that of CS, which indicated that the returning back of organic wastes from the outside systems were more conducive to the improvement of the TOC stability.(4) Although organic wastes incorporation promote GHGs emissions, it also increases carbon input of farming system, and ultimately presents an enhancement in C retention capacity of the system which served as greenhouse gases "sinks". The soil greenhouse gas warming potential (GWP) of the five organic waste treatments was58%higher than CF, the fact that the net primary production (NPP), system C retention were also improved, could easily offset the promoted GHG emissions, so that the whole system turned out a sink of C, and the net carbon balance (NECB) was increased by264%.The results showed that advantages of C retention and system production can derive from the returning back of organic wastes from the farming-stockbreeding circulation system, the farming-biogas circulation system and the farming-mushroom circulation system. This indicated that it is of great importance to develop circular agriculture, to promote the energy-saving and emissions reduction.更多还原