不同有机物料还田对农田系统净温室气体排放的影响

    Effects of different organic wastes application on net greenhouse gas emission in farmland system

    • 摘要: 农业有机物料的循环利用不但能解决自身对环境的污染问题、为农田提供养分,而且对增加土壤碳库、减少温室气体(GHG)排放和应对气候变化也发挥着重要作用。该文选用来自5个涉农系统的有机物料(秸秆、沼渣、菌渣、酒渣和猪粪)进行还田,以单施化肥为对照,基于田间定位试验,研究不同有机物料还田对农田土壤碳库、土壤温室气体排放的影响,在此基础上采用土壤碳库法对农田系统净温室气体排放(NGHGE)进行综合评价。2013-2015年的结果表明:1)与无机肥对照相比,有机物料还田均不同程度地提高农田土壤固碳能力,2013-2015年平均提高0-20cm土壤碳储量63.52%,其中秸秆、沼渣、菌渣、酒渣和猪粪分别比无机肥提高33.13%、86.34%、75.97%、52.66%和69.48% ,来自农田系统外的几种有机物料还田效果优于秸秆,更有利于土壤碳储量的增加。2)除秸秆外,有机物料还田均不同程度地增加土壤温室气体排放,与无机肥对照相比,土壤增温潜势(GWPsoil)平均增幅达到67.23%,其中,沼渣、菌渣、酒渣和猪粪处理的土壤GWPsoil分别比秸秆还田处理高30.23%、27.84%、62.10%和52.55%,秸秆还田低于酒渣和猪粪处理(P<0.05)。3)各处理的NGHGE均为正值,代表各处理均为温室气体的源,但是,除了菌渣还田处理的NGHGE高于无机肥之外,其他有机物料还田的NGHGE显著低于无机肥处理(P <0.05),秸秆、沼渣、酒渣和猪粪的NGHGE分别比无机肥低52.78%、56.30%、54.19%和90.35%,说明猪粪、沼渣和酒渣经过农田系统外循环后还田之后减少温室效应效果优于直接还田的秸秆。综合显示,农业有机物料的循环利用有利于土壤碳储量的增加,除了菌渣之外,猪粪、沼渣、酒渣和秸秆还田虽均增加了土壤温室气体排放,综合土壤固碳和排放,整个农田系统的净温室气体排放还是减少了。

       

      Abstract: Abstract: The recycling of agricultural organic wastes not only can mitigate its pollution to the environment, provide nutrients for farmland, but also increase soil carbon storage and reduce greenhouse gas (GHG) emissions, which play an important role to climate change. Five kinds of agricultural organic wastes were selected to the wheat-maize rotation system, including crop residue, biogas residue, mushroom residue, wine residue and pig manure, with chemical fertilizer as control. Based on the field trials, the effects of soil carbon storage, soil GHG emissions and net greenhouse gas emissions (NGHGE) were measured. The results from 2013-2015 showed that: 1) Compared with chemical fertilizer control, returning organic materials improved the ability of soil carbon sequestration by 63.52% of 0-20 cm soil during 2013-2015 years of observation, crop residue, biogas residue, mushroom residue, wine residue and pig manure increased by 33.13%、86.34%、75.97%、52.66% and 69.48% in 2013-2015, respectively.Except the treatment of mushroom residue returning, organic material outside the croplands were more conducive to the increasing of soil carbon storage than crop residue. 2) Except crop residues returning, organic materials returning increased soil GHG emissions, soil GWP of crop residues were the lowest one, which was significantly lower than wine residue and pig manure (p<0.05), compared with biogas residue, mushroom residue, wine residue and pig manure, crop residue reduced emissions by 30.23%、27.84%、62.10% and 52.55%, respectively. 3) The values of NGHGE of each treatment were positive, which means all of the treatments were GHG emission sources. Compared with inorganic fertilizer control, except the treatment of mushroom residue returning, other organic amendments reduced GHG emissions and increased soil carbon pool s of the system(p<0.05), crop residues, biogas residues, wine residues and pig manures decreased NGHGE by52.78%、56.30%、54.19% and 90.35%, respectively. Organic materials from outside had a better NGHGE than crop residues. In conclusion, recycling organic wastes is beneficial to the soil carbon storage, although increasing soil GHG emissions, it ultimately presents an enhancement of NGHGE, which reduced total GHG emissions of the whole system. Returning organic amendments such as crop residues, biogas residues, wine residues and pig manures far beyond the croplands had better effects of mitigating GHGs than crop residues.

       

    /

    返回文章
    返回