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Distribution of organic carbon fractions in Soil aggregates in Chinese fir plantations with different stand ages

Ecological Processes 2021年第1期10卷 646-658页

作者： Xinxin He Yongzhen Huang Qianchun Zhang Shaoming Ye Shengqiang Wang Forestry College Guangxi UniversityNanning 530004China

Background:Revealing the variations in soil aggregate-related organic carbon(OC)and labile organic carbon(LOC)fractions in a chronosequence of Chinese fir plantations plays an important role in better understanding the impact of soil carbon sink or source on the Chinese fir plantation ecosystem.In this study,soil samples in a depth of 0–20 cm were collected from Chinese fir plantations at different stand ages(0,9,17,and 26 years old)in Guangxi,China.With the optimal moisture sieving method adopted,the Soil aggregates of 4 different sizes were obtained,including>2-mm,2–1-mm,1–0.25-mm,andaggregates.soil OC and LOC fractions were measured in the aggregates of different sizes.The LOC fractions included readily oxidizable carbon(ROC),particulate organic carbon(POC),microbial biomass carbon(MBC),water-soluble organic carbon(WOC),and mineralized organic carbon(MOC).Results:soil aggregate stability,as indicated by the mean weight diameter(MWD),was the highest in the 17-yearold Chinese fir plantations and was significantly positively related(psoil OC and LOC fractions were significantly increased as the aggregate size decreased.Consequently,there were more OC and LOC fractions distributed in theaggregates.During the stand development,the concentrations of soil OC and LOC fractions first increased and then decreased,with the highest levels detected in the 17-year-old Chinese fir plantations,indicating that the 17-year-old Chinese fir plantations were conducive to the accumulation of soil OC and LOC fractions.Conclusion:After 17 years of planting,promoted soil carbon(especially for the POC)accumulation contributes significantly to enhancing soil aggregate stability for the Chinese fir plantations in Guangxi,China.

关键词： Chinese fir plantation Soil aggregates Organic carbon Labile organic carbon fractions

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The distribution and availability of phosphorus fractions in restored cut slopes Soil aggregates:a case study of subalpine road,Southwest China

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Frontiers of Environmental Science & Engineering 2023年第4期17卷 27-39页

作者： Mengke Zhu Bocong Huang Shenghao Ai Zongyang Liu Xiaoyan Ai Meihua Sheng Yingwei Ai Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education College of Life SciencesState Key Laboratory of Hydraulics and Mountain River EngineeringSichuan UniversityChengdu 610065China Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China

The distribution and availability of phosphorus(P)fractions in restored cut slope Soil aggregates,along altitude gradients,were analyzed.Samples were collected at 3009,3347,3654 and 3980 m of altitude.We examined Soil aggregates total phosphorus(TP),available phosphorus(AP)and phosphorus activation coefficient(PAC),and discovered that there was no significant difference in TP levels between all four altitudes samples(p>0.05).However,there was a significant difference in AP at 3009,3347 and 3980 m of altitude(paggregates was more advantageous.Overall,PAC dropped steadily as Soil aggregates sizes increased,as shown:PAC(3654 m)>PAC(3347 m)>PAC(3009 m)>PAC(3980 m).In all particle size Soil aggregates,the distribution of the P fractions was as follows:total inorganic phosphorus(TPi)>total organic phosphorus(TPo)>residual phosphorus(R-P),at 3009,3347 and 3654 m,but a different registry was observed at 3980 m of altitude:TPo>TPi>R-P.Through correlation and multiple stepwise regression analysis,it was concluded that active NaHCO_(3)-Pi was the main AP source.It was also suggested that more attention should be given to the ratio of small particle size aggregates to increase soil AP storage.In order to improve the activation capacity and supply of soil P,along with promotion of the healthy development of soil ecosystem on slope land,it was suggest that inorganic P fertilizer and P activator could be added to soil at both low(3009 m)and high altitudes(3980 m).

关键词： Altitude gradient Restored cut slopes Soil aggregates Phosphorus fraction Available phosphorus

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Fragmentation process of Soil aggregates under concentrated water flow in red soil hilly region with different land use patterns

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Journal of Mountain Science 2023年第11期20卷 3233-3249页

作者： WEN Li-li WANG Jin-yue DENG Yu-song DUAN Xiao-qian Guangxi Key Laboratory of Forest Ecology and Conservation College of ForestryGuangxi UniversityNanning 530004China Guangxi Key Laboratory of Agricultural environment and Agricultural product safety College of AgricultureGuangxiUniversityNanning 530004China

The hilly area of red soil in the central subtropical region of China has a long history of severe soil erosion due to its abundance of water,heat,and intense agricultural and forestry activities.The Sandshale red soil area is hot and rainy,the local land utilization rate and replanting index are high,and the soil easily weathers and erodes,resulting in infertile and sandy soils,extensive soil erosion and large erosion,with far-reaching impacts.In this study,the stability of Soil aggregates was studied by the wet sieving method and Le Bissonais(LB)method in six land use patterns in the Sandshale red soil area,including natural forest(NF),Pinus massoniana(PM),Eucalyptus urophylla×E.grandis(EU),orchard(OR),wasteland(WL)and arable land(AL).The transport damage characteristics of the Soil aggregates under concentrated water flow were analyzed by using the Soil aggregates to simulate the soil surface roughness in the field using a steel scouring flume with a variable slope.The results showed that:(1)the total soil porosity of the natural forest was the highest,with 56.51%in A layer,which was 4.99%higher than the B layer,and the organic matter content ranged from 10.69 to 29.94 g.kg-1 and was highest in NF and lowest in AL;(2)the maximum mean weight diameter(MWD)obtained by the wet sieving method was 4.81 mm for natural forest,and the MWD was the lowest in OR and AL at 2.45-2.77mm.The MWD measured by the LB method was also highest in NF and lowest in AL.The contents of Fed and Ald have a strong correlation with the stability parameters of Soil aggregates;(3)the Wr/Wi results for the six land use patterns were NF>PM>EU>WL>OR>AL;the NF had the strongest soil aggregate stability,followed by WL,PM and EU,and AL and OR had the weakest;the stability of Soil aggregates gradually weakened as the soil depth increased.Comprehensive analysis shows that forest land has high soil stability and obvious advantages in soil erosion resistance.Strengthening the construction of artificial forests can be an important means to reduce soil

关键词： Soil aggregates Land use Aggregate stability Fragmentation process

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Effects of organic matter on the distribution of rare earth elements in red Soil aggregates during ecological restoration

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Journal of Mountain Science 2021年第11期18卷 2915-2928页

作者： OU Xiao-lin CHEN Zhi-biao CHEN Zhi-qiang LIANG Mei-xia CHEN Hai-bin Key Laboratory for Humid Subtropical Eco-geographical Processes of the Ministry of Education Fujian Normal UniversityFuzhou 3500007China School of Geographical Sciences Fujian Normal UniversityFuzhou 3500007China

Rare earth elements(REEs)are widely applied in high-tech fields.However,their increasing presence in the food chain poses significant risks to human health.At present,little is known about the effects of organic matter on the distribution of ion-adsorbed REEs in Soil aggregates during ecological restoration.Red soil derived from coarse-grained granite in Southern China is both prone to ecosystem degradation from soil erosion and rich in REEs.Understanding the distribution of REEs in Soil aggregates undergoing ecological restoration is helpful to formulate effective measures for controlling the environmental migration of REEs.Four sites that had undergone different durations/degrees of ecological restoration were selected in the areas to analyze.REEs concentration of six different aggregates sizes(5 mm)were analyzed and the enrichment coefficients were calculated in 4 sample sites of severe-degraded ecosystem in Changting County,Fujian Province,Southern China.The results showed that the total rare earth elements(TREEs)concentration in the aggregates increased from 213 mg kg^(-1) to 528 mg kg^(-1) with the extension of the ecological restoration time.At the initial stages of ecological restoration,there was no significant difference in the TREEs concentration among the six aggregates sizes.However,in the middle and late stages of restoration,the concentration of TREEs increased significantly with the decrease of aggregate size.The concentration of individual REEs showed three changing trends with sizes of aggregates during ecological restoration,respectively:1)no obvious regular change(S1),2)a V-shaped change trend(S2),and 3)increasing concentration with the decrease of aggregate size(S3 and S4).Ce and Eu showed a positive and negative anomaly in the Soil aggregates,respectively.Moreover,the light rare earth elements(LREEs)were enriched,while the heavy rare earth elements(HREEs)were depleted during the initial stages,and the HREEs were enriched during the middle and late stages of r

关键词： Rare earth elements Soil aggregates Ecological restoration Red soil

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Application of fractal theory in assessing Soil aggregates in Indian tropical ecosystems

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Journal of Forestry Research 2012年第3期23卷 355-364页

作者： S.K.Tripathi C.P.Kushwaha S.K.Basu Computer Science Department Banaras Hindu UniversityVaranasi-221005India Department of Forestry Mizoram UniversityAi-zawl-796009India Centre for Env.Sci.&Tech. Banaras Hindu UniversityVaranasi-221005India

soil aggregation varies according to climatic and manage- ment factors, and is difficult to measure because of irregular shapes and sizes of Soil aggregates. We applied fractal theory to assess soil aggrega- tion as affected by （1） land use change from forest to savanna, （2） nutri- ent additions in forest, ecotone, and savanna ecosystems, and （3） tillage practice and residue treatments in an agro-ecosystem. We used fractal dimensions nonlinear （D,o,-lin） and linear （Dlin） based on number of ag- gregates （N） and mass of aggregates （M）（the range of values were 2.6-2.89 and 2.694.41, respectively） to capture the variations in the sizes of Soil aggregates due to land use and treatments/management in these ecosystems. The variation in the values of non-linear fractal dimension based on mass （DMnon-lin） was smaller in forest and savanna ecosystems with and without nutrient additions, while the variation was wider in agro-ecosystems with different management practices. Linear fractal dimensions based on number （Dr^i,） and mass （DMlin） of aggregates var- ied marginally in these ecosystems and did not capture the variations in Soil aggregates well. The variations in non-linear fractal dimension indi- cate that continued nitrogen loading in forest accelerates the formation of macro-aggregates, whereas in savanna the situation was reversed. The values of non-linear fractal dimensions did not show significant change after 6 years of nutrient additions in the ecotone; reflecting a buffering mechanism of this system in soil aggregate formation. On the basis of non-linear fractal dimension values, we conclude that residue retention and minimum tillage are appropriate for proper maintenance of soil ag- gregate stability for sustained crop production in the Indian dry land agro-ecosystems

关键词： Soil aggregates fractal tillage practice ecosystem Indian dry tropics

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Preliminary Study on the Effect of Different Ecological Cultivation Modes on the Water Stability of Soil aggregates in Rubber Based Agroforestry Systems

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Open Journal of Ecology 2023年第11期13卷 782-793页

作者： Shiyun Zhan Fengyue Qin Dongling Qi Zhixiang Wu Chuan Yang Yingying Zhang Qingmao Fu Rubber Research Institute Chinese Academy of Tropical Agricultural Sciences Danzhou China Hainan Danzhou National Field Scientific Observation Research Station of Tropical Agricultural Ecosystem Danzhou China College of Ecology and Environment Hainan University Haikou China

Rubber trees (Hevea brasiliensis Müll. Arg.) have been commercially cultivated for a century and a half in Asia, particularly in China, and they constitute a common element of plantation ecosystems in tropical regions. soil health is fundamental to the sustainable development of rubber plantations. The objective of the study is to explore the influence of different complex ecological cultivation modes on the stability of Soil aggregates in rubber based agroforestry systems. In this study, the ecological cultivation mode of rubber—Alpinia oxyphylla plantation, the ecological cultivation mode of rubber—Phrynium hainanense plantations, the ecological cultivation mode of rubber—Homalium ceylanicum plantations and monoculture rubber plantations were selected, and the particle size distribution of Soil aggregates and their water stability characteristics were analyzed. The soil depth of 0 - 20 cm and 20 - 40 cm was collected for four cultivation modes. soil was divided into 6 particle levels > 20 cm. soil was divided into 6 particle levels > 5 mm, 2 - 5 mm, 1 - 2 mm, 0.5 - 1 mm, 0.25 - 0.5 mm, and 0.053 - 0.25 mm according to the wet sieve method. The particle size proportion and water stability of Soil aggregates were determined by the wet sieve method. The particle size proportion and water stability of Soil aggregates under different ecological cultivation modes were analyzed. The results showed that under different ecological cultivation modes in the shallow soil layer (0 - 20 cm), the rubber—Alpinia oxyphylla plantation and the rubber—Phrynium hainanense plantation promoted the development of dominant Soil aggregates towards larger size classes, whereas the situation is the opposite for rubber—Homalium ceylanicum plantation. In soil layer (20 - 40 cm), the ecological cultivation mode of rubber—Phrynium hainanense plantation developed the dominant radial level of Soil aggregates to the diameter level of large aggregates. Rubber—Alpinia oxyphylla plantation and rubber—Homalium ceylanicum plantation, three indicators

关键词： Ecological Complex Cultivation Rubber Plantation Soil aggregates soil Aggregate Water Stability Rubber Based Agroforestry Systems

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MICROBIAL NECROMASS WITHIN aggregates STABILIZES PHYSICALLY-PROTECTED C RESPONSE TO CROPLAND MANAGEMENT

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Frontiers of Agricultural Science and Engineering 2023年第2期10卷 198-209页

作者： Ranran ZHOU Jing TIAN Zhengling CUI Fusuo ZHANG College of Resources and Environmental Sciences National Academy of Agriculture Green DevelopmentKey Laboratory of Plant-Soil Interactions(Ministry of Education)China Agricultural UniversityBeijing 100193China

The interactions of soil microorganisms and structure regulate the degradation and stabilization processes of soil organic carbon(SOC). Microbial necromass is a persistent component of SOC, and its magnitude of accumulation dependent on management and aggregate sizes. A meta-analysis of 121 paired measurements was conducted to evaluate the management effects on contributions of microbial necromass to SOC depending on aggregate fractions. Results showed that the contribution of fungal necromass to SOC increased with aggregate sizes, while bacterial necromass had a higher proportion in silt and clay. Cropland management increased total and fungal necromass in large macroaggregates(47.1% and 45.6%), small macroaggregates(44.0% and 44.2%), and microaggregates(38.9% and 37.6%).Cropland management increased bacterial necromass independent of aggregate fraction sizes. Greater fungal necromass was increased in macroaggregates in response to manure(26.6% to 28.5%) and no or reduced tillage(68.0% to 73.5%). Cover crops increased bacterial necromass by 25.1%in small macroaggregates. Stimulation of microbial necromass was proportional to the increases of SOC within Soil aggregates, and the correlation was higher in macroaggregates. Increasing microbial necromass accumulation in macroaggregates can, therefore, be considered as a central component of management strategies that aim to accelerate C sequestration in agricultural soils.

关键词： cropland management microbial necromass Soil aggregates soil carbon sequestration soil organic matter

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Ecological Processes 2020年第1期9卷 378-386页

作者： Hu Cui Yang Ou Duian Lv Lixia Wang Aizhen Liang Baixing Yan Yingxin Li Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China Jilin Provincial Engineering Center of CWs Design in Cold Region&Beautiful Country Construction Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China University of Chinese Academy of Sciences Beijing 100049China Second Institute of Oceanography Ministry of Natural ResourcesHangzhou 310012China

Ecological stoichiometry is an important indicator presenting multiple elements balance in agro-ecosystems.However,information on microbial communities and nutrient stoichiometry in soil aggregate fractions under different croplands(rice,maize,and soybean fields)remains limited.Thus,this study investigated water-stable aggregate structure and their internal nutrient stoichiometry under different croplands and ascertain their interaction mechanism with microbial communities.The results showed that no significant difference on the carbon-to-nitrogen ratio(C:N)in soil aggregate fractions was observed,while the carbon-to-phosphorus ratio(C:P)and the nitrogen-to-phosphorus ratio(N:P)were ranked as rice field>maize field>soybean field,and were higher in mega-aggregates(ME,>1 mm).General fatty acid methyl ester(FAME),Gram-positive bacteria(G+),and Gramnegative bacteria(G−)were predominant microbial communities in all croplands and tented to condense into coarse-aggregates.Redundancy analysis(RDA)demonstrated that N:P ratio was primary environmental controls on the distribution of soil microorganisms.In the Sanjiang Plain,N was the nutrient element limiting agro-ecosystem productivity,and rice cultivation is expected to improve the N-limited nutrient status.

关键词： Sanjiang Plain Croplands Soil aggregates Microbial communities Ecological stoichiometry

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Straw return increases crop production by improving soil organic carbon sequestration and soil aggregation in a long-term wheat-cotton cropping system

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Journal of Integrative Agriculture 2024年第2期23卷 669-679页

作者： Changqin Yang Xiaojing Wang Jianan Li Guowei Zhang Hongmei Shu Wei Hu Huanyong Han Ruixian Liu Zichun Guo Institute of Industrial Crops Jiangsu Academy of Agricultural Sciences/Key Laboratory of Cotton and RapeseedMinistry of Agriculture and Rural AffairsNanjing 210014China College of Life Sciences and Food Engineering Huaiyin Institute of TechnologyHuai’an 223003China College of Agriculture Nanjing Agricultural UniversityNanjing 210095China Cotton Research Institute Xinjiang Academy of Agricultural and Reclamation ScienceShihezi 832000China Institute of soil Science Chinese Academy of Sciences/State Key Laboratory of Soil and Sustainable AgricultureNanjing 210008China

Straw return is a promising strategy for managing soil organic carbon(SOC)and improving yield stability.However,the optimal straw return strategy for sustainable crop production in the wheat(Triticum aestivum L.)-cotton(Gossypium hirsutum L.)cropping system remains uncertain.The objective of this study was to quantify the long-term(10 years)impact of carbon(C)input on SOC sequestration,soil aggregation and crop yields in a wheat-cotton cropping system in the Yangtze River Valley,China.Five treatments were arranged with a single-factor randomized design as follows:no straw return(Control),return of wheat straw only(Wt),return of cotton straw only(Ct),return of 50%wheat and 50%cotton straw(Wh-Ch)and return of 100%wheat and 100%cotton straw(Wt-Ct).In comparison to the Control,the SOC content increased by 8.4 to 20.2%under straw return.A significant linear positive correlation between SOC sequestration and C input(1.42-7.19 Mg ha^(−1)yr^(−1))(Paggregates of sizes>2 and 1-2 mm at the 0-20 cm soil depth were also significantly elevated under straw return,with the greatest increase of the aggregate stability in the Wt-Ct treatment(28.1%).The average wheat yields increased by 12.4-36.0%and cotton yields increased by 29.4-73.7%,and significantly linear positive correlations were also detected between C input and the yields of wheat and cotton.The average sustainable yield index(SYI)reached a maximum value of 0.69 when the C input was 7.08 Mg ha^(−1)yr^(−1),which was close to the maximum value(SYI of 0.69,C input of 7.19 Mg ha^(−1)yr^(-1))in the Wt-Ct treatment.Overall,the return of both wheat and cotton straw was the best strategy for improving SOC sequestration,soil aggregation,yields and their sustainability in the wheat-cotton rotation system.

关键词： straw return crop yields SOC Soil aggregates wheat-cotton cropping system

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Effects of sediment characteristics on the sediment transport capacity of overland flow

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International soil and Water Conservation Research 2023年第1期11卷 75-85页

作者： Chenguang Liu Suhua Fu Zhanbin Li Zeyu Zhang Jianhui Zeng Institute of soil and Water Conservation Northwest A&F UniversityYanglingShaanxi712100PR China State Key Laboratory of soilErosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationChinese Academy of Sciences and Ministry of Water ResourceYanglingShaanxi712100PR China Beijing Key Laboratory of Environmental Remote Sensing and Digital City Faculty of Geographical ScienceBejing Normal UniversityBejing100875PR China

The transport of sediments is a crucial part of soil erosion.Accurately calculating the sediment transport capacity is key to the construction of soil erosion process models.Research on Tc has focused mainly on the dynamics of a single particle of sediment and hydraulic variables.There have been few studies of the impact of Soil aggregates on the Tc.To clarify how sediment characteristics,including those for single particles and aggregates,affect the Tc of overland flow with no raindrop import,flume experiments were implemented at slope gradients varying from 5.24%to 26.80%and flow discharges ranging from 0.68 to 5.41×10^(-3)m^(2)s^(-1).The experimental materials were five typical soils in China.The results indicated that the correlation between the measured Tc and sediment mechanical composition indexes of the five soils was indistinctive in this study.The sediment settling velocity with aggregates has a significant corre-lation with the measured Tc.New equations,including for the sediment settling velocity with aggregatesωud75,were established to calculate the Tc.The empirical equation that includedωud75,slope gradient and unit discharge performed greatly in predicting Tc(R^(2)=0.93,NSE=0.90).ωud75 can effectively improve the calculation accuracy of Tc.The new equation including flow and sediment properties obtained through dimensional analysis performed well in predicting Tc(R^(2)=0.99,NSE=0.91),and the calculation accuracy was better than that of the empirical model derived in this study.These findings indicate that the sediment settling velocity is an important variable in the equation for predicting sediment transport capacity of overland flow.

关键词： Sediment transport capacity soil mechanical composition Soil aggregates Sediment settling velocity Dimensional analysis

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