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Accueil du site → Doctorat → Chine → 2021 → Study on Ecosystem Carbon Balance and Stability of Soil Organic Carbon Pool in Dryland Corn Farmland of the Loess Plateau of Central Gansu Province under Different Fertilization Measures

Gansu Agricultural University (2021)

Study on Ecosystem Carbon Balance and Stability of Soil Organic Carbon Pool in Dryland Corn Farmland of the Loess Plateau of Central Gansu Province under Different Fertilization Measures

王晓娇

Titre : Study on Ecosystem Carbon Balance and Stability of Soil Organic Carbon Pool in Dryland Corn Farmland of the Loess Plateau of Central Gansu Province under Different Fertilization Measures

Auteur : 王晓娇

Grade : Doctoral Dissertation 2021

Université : Gansu Agricultural University

Résumé partiel
The Intergovernmental Panel on Climate Change(IPCC)launched"the Special Report on Global Warming of 1.5℃"in its Sixth Assessment Report,which emphasized"limiting global warming at 1.5°C instead of 2°C or any higher temperature".Excessive emission of Greenhouse Gases such as carbon dioxide caused by human activities is one of the main causes of global warming.Farmland soil carbon pool is the most active part of the global carbon pool,and fertilization measures have a great impact on it,so it is of great significance to clarify the impact of different fertilization measures on the carbon cycle of the farmland ecosystem.Dry farming in the Loess Plateau plays a very important strategic role in China’s agriculture.At present,the main fertilization measures for dry farming are to increase nitrogen application and organic fertilization.However,the effects and their formation mechanism of different fertilization measures on carbon balance and the stability of soil carbon pool in dry-farming cornfields has been seldom analyzed thoroughly,and the effect of organic fertilization mode on soil carbon emissions at regional scale has been still unclear,and how to comprehensively evaluate the effect of fertilization measures from the perspective of environmental and economic benefits has not been studied completely.Based on above scientific issues,firstly,the effect and mechanism of organic fertilization measures on soil CO2 emissions at regional scale were discussed with Meta-analysis method.Secondly,relying on two long-term positioning experiments including the fertilization experiment of organic materials with equal amount of nitrogen input in corn farmland[no fertilizer(CK),nitrogen fertilizer(NF,200 kg N·m-2),organic fertilizer(OM,6000 kg·hm-2),straw(ST,28500 kg·hm-2),and organic fertilizer combined with inorganic fertilizer(OMNF,3000 kg·hm-2+100 kg N·hm-2)]and the split-plot experiment of different levels of nitrogen fertilizer[principal factor,N0(0 kg N·hm-2),N1(100 kg N·hm-2),N2(200 kg N·hm-2),N3(300kg N·hm-2)]combined with different nitrogen application methods[side factor,T1(1/3 base fertilizer+2/3 jointing stage fertilizer),T2(1/3 base fertilizer+1/3 jointing stage fertilizer+1/3large trumpet stage fertilizer))in the dry farming area of the Loess Plateau in central Gansu in2012,and by measuring the relevant indicators in 2017 and 2018,combining with the yield data from 2014 to 2018,this study researched the effects of different fertilization measures on soil CO2 emissions and net carbon balance of farmland ecosystem,and analysed the response of soil carbon fractions,soil carbon pool stability and soil carbon pool management index to different fertilization measures.The study also expounded the mechanism of soil carbon pool stability and soil CO2emissions,and clarified the yield stability and ecological service value of different fertilization measures.The research results of the study can provide data supports for carbon sequestration and emission reduction in the farmland ecosystem and the formulation of ecological compensation policies,and provide a theoretical basis for the promotion of"chemical fertilizer reduction and organic fertilizer replacement"environmentally friendly agriculture.The main conclusions are as follows:1.Meta-analysis showed that organic fertilization measures increased soil CO2 emissions,so it was suggested to apply organic-inorganic fertilizer combination or the combined application of nitrogen fertilizer,organic fertilizer and slow-release fertilizer in Northern China.Organic fertilizer application significantly increased the CO2 emissions in farmland soil than the non-fertilizer and inorganic fertilizer application during the growth period,and there had no significant difference in soil CO2 emissions among northeast,north and northwest regions(P>0.05)

Mots clés : Soil carbon emission ;Carbon pool stability ;Yield stability ;Ecological service value ;Fertilization measures ;the Longzhong Loess Plateau ;

Présentation (CNKI)

Page publiée le 20 octobre 2021