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Decomposition and Products of Wheat and Rice Straw from a FACE Experiment Under Flooded Conditions

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Pedosphere 2009年第3期19卷 389-397页

作者： LIU Juan HAN Yong cai zu-cong State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China） Graduate University of the Chinese Academy of Sciences Beijing 100049 （China） School of Environmental Science and Technology Zhejiang Forestry University Lin＇an Hangzhou 311300 （China）

Winter wheat and rice straw produced under ambient and elevated CO2 in a China rice-wheat rotation free-air CO2 enrichment （FACE） experiment was mixed with a paddy soil at a rate of 10 g kg^-1 （air-dried）, and the mixture was incubated under flooded conditions at 25℃ to examine the differences in decomposition as well as the products of crop residues produced under elevated CO2. Results showed that the C/N ratio and the amount of soluble fraction in the amended rice straw grown under elevated CO2 （FR） were 9.8% and 73.1% greater, and the cellulose and lignin were 16.0% and 9.9% lesser than those of the amended rice straw grown under ambient CO2 （AR）, respectively. Compared with those of the AR treatment, the CO2-C and CH4-C emissions in the FR treatment for 25 d were increased by 7.9% and 25.0%, respectively; a higher ratio of CH4 to CO2 emissions induced by straw in the FR treatment was also observed. In contrast, in the treatments with winter wheat straw, the CO2-C and CH4-C emissions, the ratio of straw-induced CH4 to CO2 emissions, and the straw composition were not significantly affected by elevated CO2, except for an 8.0% decrease in total N and a 9.7% increase in C/N ratio in the wheat straw grown under elevated CO2. Correlation analysis showed that the net CO2-C and CH4-C emission from straw and the ratio of straw-induced CH4 to CO2 emissions were all exponentially related to the amount of soluble fraction in the amended straw （P 〈0.05）. These indicated that under flooded conditions, the turnover and CH4 emission from crop straw incorporated into soil were dependent on the effect of elevated CO2 on straw composition, and varied with crop species. Incorporation of rice straw grown under elevated CO2 would stimulate CH4 emission from flooded rice fields, whereas winter wheat straw grown under elevated CO2 had no effect on CH4 emission.

关键词： carbon cycle CH4 CO2 emissions soluble fraction

Effects of Long-Term Application of Inorganic Fertilizers on Biochemical Properties of a Rice-Planting Red Soil

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Pedosphere 2007年第4期17卷 419-428页

作者： ZHONG Wen-Hui cai zu-cong ZHANG He State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China）. College of Chemistry and Environmental Science Nanjing Normal University Nanjing 210097 （China）

A long-term experiment was set up in Yingtan of Jiangxi Province to investigate the effects of long-term application of inorganic fertilizers on the biochemical properties of a rice-planting soil derived from Quaternary red earth. Noncultivated soils are extremely eroded and characterized by a low pH and deficiencies in available nutrients, in particular P and N. After 13 years of inorganic fertilization in cultivation for double-cropped rice, the biochemical properties of the soil were changed. The nitrification potential and urease activity were higher in the treatments with N application than those without N application, Acid phosphatase activity and dehydrogenase activity were also higher in the treatments with P application than in those without P application. The dehydrogenase activity correlated well with the concentrations of both total P and hydrolysable N and with rice crop yield, suggesting that dehydrogenase activity might be a suitable indicator for improvement in soil fertility.

关键词： enzyme ergosterol inorganic fertilizer nitrification potential rice-planting red soil

Relationship between light and heavy fractions of organic matter for several agricultural soils in China

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Journal of Environmental Sciences 2005年第6期17卷 917-920页

作者： YIN Yun-feng cai zu-cong LU Jia-long State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China College of Geographical Sciences Fujian Normal University Fuzhou 350007 China College of Resourcesand Environment Northwest Sci-Tech University of Agriculture and Forestry Yangling 712100 China

Although numerous studies about the nature and turnover of soil organic matter（SOM） in light and heavy fractions（ LFOM and HFQM, respectively） have been made, little information is available in relation to the relationship between LFQM and HFOM, and no attempts have been made to quantify a general relationship between LFQM and HFQM for agricultural soils under field condition. Qur hypothesis is there may be an inherent relationship between LFQM and HFQM for agricultural soils under certain unaltered management practices for a long period, to this end, we therefore studied typically soils taken from different parts in China by using a simple density fractionation procedure. The results indicated that LFQM was positively correlated with LFOM/HFOM ratio for three typical soils. This information will be of particular use not only in deepening our understanding of the dynamics of SQM fractions but also in evaluating the potential of agricultural soils to sequestrate C under different management practices in a long term.

关键词： soil organic matter light fraction heavy fraction agricultural soils

Effects of long-term amendment of organic manure and nitrogen fertilizer on nitrous oxide emission in a sandy loam soil

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Journal of Environmental Sciences 2007年第2期19卷 185-193页

作者： DING Wei-xin MENG Lei cai zu-cong HAN Feng-xiang State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China College of Agriculture South China University of Tropical Agriculture Danzhou 571737 China Department of Plant and Soil Sciences Mississippi State University StarkviUe MS 39759 USA

To understand the effects of long-term amendment of organic manure and N fertilizer on N2O emission in the North China Plain, a laboratory incubation at different temperatures and soil moistures were carried out using soils treated with organic manure （OM）, half organic manure plus half fertilizer N （HOM）, fertilizer NPK （NPK）, fertilizer NP （NP）, fertilizer NK （NK）, fertilizer PK （NK） and control （CK） since 1989. Cumulative N2O emission in OM soil during the 17 d incubation period was slightly higher than in NPK soil under optimum nitrification conditions （25℃ and 60% water-filled pore space, WFPS）, but more than twice under the optimum denitrification conditions （35℃ and 90% WFPS）. N2O produced by denitrification was 2.1-2.3 times greater than that by nitrification in OM and HOM soils, but only 1.5 times greater in NPK and NP soils. These results implied that the long-term amendment of organic manure could significantly increase the N2O emission via denitrification in OM soil as compared to NPK soil. This is quite different from field measurement between OM soil and NPK soil. Substantial inhibition of the formation of anaerobic environment for denitrification in field might result in no marked difference in N2O emission between OM and NPK soils. This is due in part to more rapid oxygen diffusion in coarse textured soils than consumption by aerobic microbes until WFPS was 75% and to low easily decomposed organic C of organic manure. This finding suggested that addition of organic manure in the tested sandy loam might be a good management option since it seldom caused a burst of N2O emission but sequestered atmospheric C and maintained efficiently applied N in soil.

关键词： denitrification N fertilizer nitrification N2O emission organic manure

Methane Emission from Natural Wetlands in China:Summary of Years 1995-2004 Studies

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Pedosphere 2007年第4期17卷 475-486页

作者： DING Wei-Xin cai zu-cong State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China）.

From studies undertaken during 1995-2004, annual budgets of CH4 emissions from natural wetlands and its temporal and spatial variations were examined throughout China, and various factors influencing CH4 emissions were also evaluated. The seasonal variation in CH4 emissions that increased with increasing plant growth reached its peak in August; decrease in the emissions was found in freshwater marshes but not in peatlands. Emissions were mainly controlled by temperature and depth of standing water. Low CH4 emissions at the early plant growing stages were not because of deficiency of organic C for CH4 production but because of low temperatures. Low temperatures not only reduced CH4 production but also stimulated CH4 oxidation by lowering the activity of other aerobic microbes which left more 02 in the rhizosphere for methanotrophs. Low summer temperatures （below 20 ℃） in the Qinghai-Tibetan Plateau lowered CH4 production and CH4 emission resulting in little or no seasonal variation of emissions. Diel and spatial variation in CH4 emissions depended on plant species. For plants that transport CH4 using the pressure-driven convective through-flow mechanism, diel variation in CH4 emissions was governed by diel variation of solar energy load （that produces temperature and vapor pressure differences within various plant tissues） and stomatal conductance. For plants that transport gases using the molecular diffusion mechanism only, the diel variation of CH4 emissions was because of differences in the magnitude of O2 produced through photosynthesis and then delivered into the rhizomes and/or rhizosphere for CH4 oxidation. Emergent plants could transport more CH4 than submerged plants because the former transport CH4 directly into the atmosphere rather than into water as do submerged plants where CH4 can be further be oxidized during its diffusion from water to the atmosphere. Emergent plants with high gas transport capacity could not only transport more CH4 into the atmosphe

关键词： diel variation methane emission seasonal variation temporal variation wetland

Effects of long-term fertilization on soil gross N transformation rates and their implications

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Journal of Integrative Agriculture 2017年第12期16卷 2863-2870页

作者： DAI Shen-yan WANG Jing CHENG Yi ZHANG Jin-bo cai zu-cong School of Geography Sciences Nanjing Normal University Nanjing 210023 P.R. China State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 P.R.China State Key Laboratory of Cultivation Base of Geographical Environment Evolution (Jiangsu Province) Nanjing 210023 P.R.China Key Laboratory of Virtual Geographic Environment (Nanjing Normal University) Ministry of Education Nanjing 210023 P.R. China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023 P.R.China

Application of fertilizer has been found to significantly affect soil N cycling. However, a comprehensive understanding of the effects of long-term fertilization on soil gross N transformation rates is still lacking. We compiled data of observations from 10 long-term fertilization experiments and conducted a meta-analysis of the effects of long-term fertilization on soil gross N transformation rates. The results showed that if chemical fertilizers of N, P and K were applied in balance, soil p H decreased very slightly. There was a significantly positive effect of long-term fertilization, either chemical or organic fertilizers or their combinations, on gross N mineralization rate compared to the control treatment（the mean effect size ranged from 1.21 to 1.25 at 95% confidence intervals（CI） with a mean of 1.23）, mainly due to the increasing soil total N content. The long-term application of organic fertilizer alone and combining organic and chemical fertilizer could increase the mineralization-immobilization turnover, thus enhance available N for plant while reduce N losses potential compared to the control treatment. However, long-term chemical fertilizer application did not significantly affect the gross NH4＋ immobilization rate, but accelerated gross nitrification rate（1.19; 95% CI： 1.08 to 1.31）. Thus, long-term chemical fertilizer alone would probably induce higher N losses potential through NO3– leaching and runoff than organic fertilizer application compared to the control treatment. Therefore, in the view of the effects of long-term fertilization on gross N transformation rates, it also supports that organic fertilizer alone or combination of organic and chemical fertilizer could not only improve crop yield, but also increase soil fertility and reduce the N losses potential.

关键词： chemical fertilizer organic fertilizer gross N transformation rate long-term fertilization experiment meta-analysis

Straw Application Altered CH_4 Emission,Concentration and ^(13)C-Isotopic Signature of Dissolved CH_4 in a Rice Field

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Pedosphere 2012年第1期22卷 13-21页

作者： ZHANG Xiao-Yan ZHANG Guang-Bin JI Yang MA Jing XU Hua cai zu-cong State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008(China) Graduate University of Chinese Academy of Sciences Beijing 100049(China)

CH4 emission and the concentration of dissolved CH4 in soil solution and floodwater in a rice field and their stable carbon isotopic signatures as affected by straw application were investigated in 2009 in a field experiment at Jurong, Jiangsu Province, China. Straw application increased CH4 emission and CH4 concentration in the soil solution and floodwater. A positive seasonal correlation was also observed in the variation between CH4 flux and CH4 concentration in soil solution. The seasonal total CH4 emission （51.6 g CH4 m^-2） in Treatment WS （straw applied） was about 168% higher than that in Treatment CK （without straw）. The emitted CH4 and CH4 in soil solution were initially relatively enriched, then depleted and finally enriched again in 13C in both treatments, while CH4 in floodwater became isotopically heavier. The carbon isotopic signature of emitted CH4 and CH4 in floodwater averaged around -62%o and -45%0 for both treatments, respectively, and was not significantly influenced by the application of straw. However, straw application caused the CH4 in soil solution to be significantly depleted in lac during the middle of the rice season, and the mean δ13C value was lower in WS （-57.5‰） than in CK （-49.9‰）. Calculation from the isotopic data showed that straw application increased the fraction of CH4 oxidized, causing no significant difference in the δ13C value of the emitted CH4 between the two treatments.

关键词： δ13CH4 CH4 flux CH4 oxidation floodwater soil solution

Soil Respiration During a Soy bean-Growing Season

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Pedosphere 2006年第2期16卷 192-200页

作者： YANG Lan-Fang cai zu-cong State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China）. School of Resources and Environmental Science Hubei University Wuhan 430062 （China） School of Environmental Studies China University of Geosciences Wuahn 430074 （China）

Soil respiration induced by soybean cultivation over its entire growing season and the factors influencing soil respiration were investigated to examine the seasonal pattern of soil respiration induced by soybean cultivation, explore soybean growth and photosynthesis on soil respiration, and determine the temperature dependence on soil respiration. Soil respiration in a pot experiment with and without soybean plants was sampled using the static chamber method and measured using gas chromatograph. Air temperature was a dominant factor controlling soil respiration rate in unplanted soil. Additionally, rhizosphere respiration comprised 62% to 98% of the soil respiration rate in the soybean-planted soil varying with the soybean growth stages. Harvesting aerial parts of soybean plant caused an immediate drop in the soil respiration rate at that stage. After harvesting the aerial parts of the soybean plant, a highly significant correlation between soil respiration rate and air temperature was found at the flowering stage （P 〈 0.01）, the pod stage （P 〈 0.01）, and the seed-filling stage （P 〈 0.05）. Thus, rhizosphere respiration during the soybean-growing period not only made a great contribution to soil respiration, but also determined the seasonal variation pattern of the soll respiration rate.

关键词： photosynthesis rhizosphere soil respiration soybean plant temperature effect

Progress in Significant Soil Science Fields of China over the Last Three Decades: A Review

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Pedosphere 2011年第1期21卷 1-10页

作者： ZHAO Qi-Guo HE Ji-Zheng YAN Xiao-Yuan ZHANG Bin ZHANG Gan-Lin cai zu-cong State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 (China) State Key Laboratory of Urban and Regional Ecology Research Centre for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 (China) Key Laboratory of Plant Nutrition and Nutrient Cycling of the Ministry of Agriculture of China Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Beijing 100081 (China)

Due to continuous decreases in arable land area and continuous population increases,Chinese soil scientists face great challenges in meeting food demands,mitigating adverse environmental impacts,and sustaining or enhancing soil productivity under intensive *** the aim of promoting the application of soil science knowledge,this paper reviews the achievements of Chinese scientists in soil resource use and management,soil fertility,global change mitigation and soil biology over the last 30 *** this period,soil resource science has provided essential support for the use and exploitation of Chinese soil resources,and has itself developed through introduction of new theories such as Soil Taxonomy and new technologies such as remote *** fertility science has contributed to the alleviation and elimination of impeding physical and chemical factors that constrain availability of essential nutrients and water in soils,the understanding of nutrient cycling in agroecosystems,and the increase in nutrient use efficiency for sustainable crop *** soil scientists have contributed to the understanding of the cropland's role in global change,particularly to the understanding of methane and nitrous oxide emission from rice fields and the effect of elevated carbon dioxide and ozone on rice-wheat *** biology research has progressed in biological N fixation,distribution of fauna in Chinese soils,and bioremediation of polluted soils.A new generation of soil scientists has arisen in the last three *** gaps between research and application in these soil science fields are also discussed.

关键词： global change soil biology soil fertility soil resources