土地利用变化与施肥管理方式对黑土碳库的影响
2010-1
科学出版社
Han Xiaozeng，Li Haibo 著
257
Human activity（fossil fuel combustion and land-use change）consumed large amounts of energy resources leading to C02 and other greenhouse gases emitted into atmosphere，which escalated and changed natural processes resulting in greenhouse effect and global warming，and it is estimated that atmospheric has increased from a pre.industrial concentration of about ppm to about 380 ppm.The global carbon cycle is defined as the processes of carbon flow and ex-change through the biosphere，atmosphere，hydrosphere，and geosphere being one of the most complex，interesting and important global element cycles.The cycle is usually thought of as four major pools of carbon interconnected by pathways ofexchange.These pools include the atmosphere，the terrestrial biosphere，the oceans and the sediments fincluding fossil fuels）.Soil carbon pool is the largest carbon reservoir in the terrestrial biosphere，and its carbon storage is twice that of the atmosphere and three times that of the vegetation including forest，grassland and arable land.Soil carbon p001 can be either sink or source depending on the carbon input and output through soil-plan tatmosphere interface.Thus，globally，not only scientists and government leaders，but common people are concerned about to what extent global soils can sequester the increasing atmospheric.
On the basis of the long-term position experiments established in the National Field Research Station of Agroecosystem in Hailun, and Key Laboratory of Black Soil Ecology of Chinese Academy of Sciences, this research aims to examine the impact of land-use change and long-term fertilization on soil carbon stocks, the physically protected SOC, and carbon emissions from black soil as well as carbon budget through the ecosystems and soil-plant-atmosphere interface. The stability mechanism of black soil carbon pool was defined, and carbon sequestration capacity of black soil was also evaluated.
Foreword1 Carbon cycling and SOM pool 1.1 Introduction 1.2 Global and terrestrial ecosystem carbon cycling 1.2.1 Introduction and history 1.2.2 Processes of carbon flow in the terrestrial realm 1.3 The composition of soil carbon pool 1.3.1 SOM fractions affected by land use 1.3.2 SOM pool as affected by long-term fertilization 1.4 Physical protection mechanism of SOM 1.4.1 Density separated fractions 1.4.2 Aggregate stability 1.5 Isotope technique protocd 1.5.1 SOM turnover 1.5.2 Carbon efflux 1.6 Summary 1.7 References2 Description of the black soil zone in the northeast China 2.1 Ecological and environmental conditions of the black soil zone 2.1.1 Meteorological and hydrologic conditions 2.1.2 Parent material of black soil 2.1.3 Topography 2.1.4 Vegetation 2.1.5 Evolution and development of Mollisol 2.1.6 Land-use change and fertilization in black soil region 2.2 The common characteristics of black soil 2.2.1 The morphological characteristics 2.2.2 The physical properties 2.2.3 The seasonal dynamics of soil water 2.2.4 Clay minerals and chemical properties 2.3 Experimental sites--introduction to Hailun station 2.4 Experiment setup 2.4.1 Grass land and bareland 2.4.2 Long-term fertilization 2.4.3 Continuous and rotation cropping system 2.5 Summary 2.6 References3 Experiment methodology 3.1 Study site description 3.2 SOM stocks estimation 3.2.1 Soil sampling 3.2.2 Analysis method 3.3 Density fractionation and extraction of humic substance 3.3.1 Soil sampling 3.3.2 Density fractionation 3.3.3 Chemical extraction of humus 3.3.4 Some soil properties 3.4 Wet sieving of aggregate 3.4.1 Study site description 3.4.2 Physical fractionation 3.4.3 Organic carbon determination of soil samples and isolated fractions 3.5 POM isolation from water-stable aggregate 3.6 SOM and aggregate stability of rhizosphere soils differing in continuous cropping patterns and vegetation cover 3.6.1 Soil and plant sampling 3.6.2 Aggregate wet-sieving 3.6.3 Organic carbon determination of soil samples and aggregate separates 3.7 Determination of C emission 3.7.1 Study site description 3.7.2 Experimental methods 3.8 Carbon budget 3.8.1 Sampling and determination 3.8.2 Carbon balance estimated through soil-crop-atmosphere systems 3.9 Statistical analysis 3.10 Summary 3.11 References4 SOM stocks differing in land use and long-term fertilization 4.1 Introduction 4.2 Carbon distribution in soil profile 4.3 N distribution in soil profile 4.4 Soil bulk density in profile 4.5 C/N ratio in profile 4.6 SOM stocks 4.6.1 SOC densityand stocks 4.6.2 Nitrogen stocks 4.7 Conclusions 4.8 Summary 4.9 References5 SOM in density fractions differing in land use and fertilization 5.1 Introduction 5.2 Soil properties analysis 5.3 Organic carbon and nitrogen contents in bulk soil 5.4 Carbon and nitrogen in density fractions 5.5 C/N ratio 5.6 Organic carbon in combined humus 5.7 The elemental composition and spectroscopic properties of humic substances extracted from a black soil 5.8 Conclusions 5.9 Summary 5.10 References6 SOM distribution and aggregate stability differing in land use and long-term fertilization 6.1 Introduction 6.2 SOC and nitrogen at o-1o and lO-2O cm soil layer 6.3 Distribution of water-stable aggregates 6.4 C storage in water-stable aggregates 6.5 C distributed in density separated fractions from aggregates 6.6 Conclusions 6.7 Summary 6.8 References7 SOM distribution and aggregate stability of rhizosphere soils differing in continuous cropping patterns and vegetation cover 7.1 Introduction 7.2 SOM and bulk density 7.3 Root density of crops and grasses 7.4 Mass distribution of water-stable aggregates 7.5 SOC in aggregates and correlation analysis 7.6 Conclusions 7.7 Summary 7.8 References8 Aggregate stability and POM distribution: impacts of land-use change and long-term fertilization 8.1 Introduction 8.2 SOM in the whole soil and density fractions and related soil properties 8.3 Distribution of aggregates and SOM 8.4 POM content within the aggregates and in the whole soil 8.5 MOC content in aggregates and whole soil 8.6 C/N ratio of POM and MOC 8.7 Distribution of SOM fractions in the whole soil 8.8 Conclusions 8.9 Summary 8.10 References9 CO2 emission characterization and carbon budget estimation through different ecosystems differing in land use and long-term fertilization 9.1 Introduction 9.2 Soil properties 9.3 Soil temperature and precipitation 9.4 Seasonal variations of CO2 emission 9.5 Related environmental factors to CO2 emission and Q,o estimation 9.6 Rhizosphere and native soil respiration 9.7 Cumulative CO2 emission and its relationship with SOC fractions 9.8 Plant biomass under different land use and fertilization 9.9 Carbon budget through soil-plant-atmosphere system 9.10 Carbon balance of soil ecosystem 9.11 Conclusions 9.12 Summary 9.13 References
Soil carbon flux comprises three biological processes：soil microbial respiration．plant root respiration and soil fauna respiration，and a non-biological process：the oxidation and decomposition of matters containing carbon（Raich and Tufek cioglu，2000）．In general，soil fauna respiration and C02 emission as a result of non-biological process can be negligible due to the very small amount detected．Inaddition，C02 emissions from soil can be divided into plant root respiration，mi．crobial decomposition of plant derived organic carbon．and microbial decomposi．tion of native soil organic matter,iemicrobial autotrophic respiration；in gen-eral，the combination of root respiration and microbial decomposition of plantderived organic matter is defined as rhizosphere respiration（Kuzyakov and Cheng，2001；Cheng and Kuzyakov，2005；Yang and Cai，2005）．The substrates for rhizosphere respiration come from carbon recently fixed through photosynthesis，whereas SOM decomposition is primarily a function of soil heterotrophic activi-ties using soil carbon．This two processes act simultaneously and are also linkedthrough rhizosphere interactions，which may exert a stimulative（priming effect）or a suppressive influence on SOM decomposition（Cheng，1999a，1999b；Chengand Kuzyakov,——005）． Roots of higher plants，as a key functional component of belowground systemsand one of the main soil forming agents，interact with virtually all soil compo-nents．The processes largely controlled or directly affected by roots and often OC-curring in the vicinity of the root surface are commonly referred to rhizosphere processes．These processes may include root production through growth and death（root turn over），rhizodeposition，root respiration and rhizosphere micro-bial respiration as a result of microbial utilization of rhizodeposits．Rhizosphere processes play a critical role in the global carbon cycle．
