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N-cycle gene abundance determination of N mineralization rate following re-afforestation in the Loess Plateau of China

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Soil Ecology Letters 2024年第1期6卷 97-106页

作者： Yaping Zhao Yuqing Zhao Shuohong Zhang Yulin Xu Xinhui Han Gaihe Yang Chengjie Ren College of Agronomy Northwest A&F UniversityYangling 712100China Shaanxi Engineering Research Center of Circular Agriculture College of AgronomyNorthwest A&F UniversityYangling 712100China

afforestation effectively improved soil microbial communities and significantly increased soil nitro-gen mineralization rate(Rm).Soil microorganisms drive Rm by regulating soil N-cycling genes.Soil nitrification genes had a major effect on soil Rm than denitrification genes after afforestation.Assessing the function of forest ecosystems requires an understanding of the mechanism of soil nitrogen mineralization.However,it remains unclear how soil N-cycling genes drive soil nitrogen mineralization during afforestation.In this study,we collected soil samples from a chrono-sequence of 14,20,30,and 45 years of Robinia pseudoacacia L.(RP14,RP20,RP30,and RP45)with a sloped farmland(FL)as a control.Through metagenomic sequencing analysis,we found significant changes in the diversity and composition of soil microbial communities involved in N-cycling along the afforestation time series,with afforestation effectively increasing the diversity(both alpha and beta diversity)of soil microbial communities.We conducted indoor culture experiments and analyzed correlations,which revealed a significant increase in both soil nitrification rate(Rn)and soil nitrogen mineralization rate(Rm)with increasing stand age.Furthermore,we found a strong correlation between soil Rm and soil microbial diversity(both alpha and beta diversity)and with the abundance of soil N-cycling genes.Partial least squares path modeling(PLS-PM)analysis showed that nitrification genes(narH,narY,nxrB,narG,narZ,nxrA,hao,pmoC-amoC)and denitrification genes(norB,nosZ,nirK)had a greater direct effect on soil Rm compared to their effect on soil microbial communities.Our results reveal the relationships between soil nitrogen mineralization rate and soil microbial communities and between the mineralization rate and functional genes involved in N-cycling,in the context of Robinia pseudoacacia L.restoration on the Loess Plateau.This study enriches the understanding of the effects of microorganisms on soil nitrogen mineralization rate during afforestation and provides a ne

关键词： afforestation soil N mineralization rate denitrification genes nitrification genes the Loess Plateau

大规模人工造林是否会加剧中国北方土壤水分亏缺?

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Science Bulletin 2024年第10期69卷 1506-1514页

作者：王秋铭刘鸿雁梁博毅石亮伍露曹静 College of Urban and Environmental Sciences and PKU Saihanba StationPeking UniversityBeijing 100871China College of Forestry Precision Forestry Key Laboratory of BejingBejing Forestry UniversityBeijing 10083China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China China Meteorological Administration Training Center Beijing 100081China State Key Laboratory of Environmental Criteria and Risk Assessment State Environmental Protection Key Laboratory of Regional Eco-process and Function AssessmentChinese Research Academy of Environmental SciencesBeijing 100012China

Trading water for carbon has cautioned large-scale afforestation in global drylands.However,model simulations suggested that the consumption of soil water could be partially offset by increasing precipitation due to vegetation feedback.A systematic meta-analysis of long-term and large-scale field observations is urgently required to address the abovementioned limitations,and the implementation of large-scale afforestation since 1978 in northern China provides an ideal example.This study collected data comprising 1226 observations from 98 sites in northern China to assess the variation in soil water content(SWC)with stand age after afforestation and discuss the effects of tree species,precipitation and conversions of land use types on SWC.We found that the SWC has been decreased by coniferous forest and broadleaf forest at rates of 0.6 and 3.2 mm decade-1,respectively,since 1978.There is a significant declining trend of SWC with the stand age of plantations,and the optimum growth stage for plantation forest is 0-20 a in northern China.However,we found increases in SWC for the conversion from grassland to forest and in the low-precipitation region,both are corresponding to the increased SWC in coniferous forest.Our study implies that afforestation might lead to a soil water deficit crisis in northern China in the long term at the regional scale but depends on prior land use types,tree taxa and the mean annual precipitation regime,which sheds light on decision-making regarding ecological restoration policies and water resource management in drylands.

关键词： Soil water afforestation Tree planting Land use changes Arid and semiarid area

Variation of soil organic carbon and bulk density during afforestation regulates soil hydraulic properties

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Journal of Mountain Science 2022年第8期19卷 2322-2332页

作者： GU Feng CHEN Xue-jiao SU Zheng-an ZHANG Xin-bao ZHOU Ming-hua Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China Sichuan Academy of Environmental Policy and Planning Chengdu 610093China School of Food and Bioengineering Xihua UniversityChengdu 610039China

Grain to Green program on arable land has been conducted for decades in semi-arid regions of North China.However,it remains uncertain how afforestation practices affect soil hydraulic properties(SHP).Two afforestation types,i.***.shrubland(SL)and woodland(WL),and the adjacent cropland(CL)were investigated to determine afforestation effects on SHP in this area.Disturbed and undisturbed soil cores were collected in three experimental sites.Soil field capacity(FC),wilting point(WP),and available water capacity(AWC)increased in SL compared to the CL.Soil saturated water content,however,decreased significantly in both SL and WL.Correlation and redundancy analysis identified that bulk density(BD)and soil organic carbon(SOC)were the main factors regulating SHP across different land uses.Lower saturated water contents in afforestation sites were likely driven by the higher BD,compared to the adjacent cropland.FC,WP,and AWC were positively correlated to SOC content.While afforestation may not increase the saturated water content of a landscape,our results indicate that it can improve soil water retention and could be an effective practice for soil and water conservation.

关键词： afforestation Bulk density Field capacity Soil hydraulic properties Soil organic carbon Soil water retention curve

Effects of cropland abandonment and afforestation on soil redistribution in a small Mediterranean mountain catchment

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International Soil and Water Conservation Research 2023年第2期11卷 339-352页

作者： Makki Khorchani Leticia Gaspar Estela Nadal-Romero Jose Arnaez Teodoro Lasanta Ana Navas Instituto Pirenaico de Ecologia(IPE CSIC)Campus de Aula DeiAvda.Montanana100550059ZaragozaSpain School of Natural Resources University of Nebraska-LincolnLincolnNEUSA Estacion Experimental Aula Dei(EEAD CSIC)Campus de Aula DeiAvda.Montanana100550059ZaragozaSpain University of La Rioja DCHPhysical GeographyLogronioSpain

In slopes of Mediterranean mid-mountain areas,land use and land cover changes linked to the aban-donment of cropland activity affect soil quality and degradation and soil redistribution;however,limited attention has been paid to this issue at catchment scale.This paper evaluates the effects of cropland abandonment and post-land abandonment management(through natural revegetation and afforesta-tion)on soil redistribution rates using fallout ^(137)Cs measurements in the Araguás catchment(0.45 km^(2),Central Spanish Pyrenees).A total of 52 soil core samples,distributed in a regular grid,from the first 30-40 cm and 9 sectioned reference samples were collected across the catchment and soil properties were analysed.Fallout ^(137)Cs was measured in a 5 cm sectioned references samples and in bulk grid samples.^(137)Cs inventories were used to estimate soil erosion and deposition rates across the catchment.Results show that the highest erosion rates were recorded under sparsely vegetated sites in the badland area,while the lowest rates were found in the afforested area,but no significant differences were observed between the different uses and covers in soil redistribution rates likely due to a long history of human intervention through cultivation in steep slopes and afforestation practices.However,the recovery of the soil organic matter in afforested areas suggest that afforestation can reduce soil degradation at long-term scale.The information gained achieve a better understanding of soil redistribution dynamics and provide knowledge for effective land management after cropland abandonment of agroecosystems in Mediter-ranean mountain areas.

关键词： Land use and land cover changes Caesium 137 Erosion and deposition rates afforestation Mediterranean mountain areas

Local and teleconnected temperature effects of afforestation and vegetation greening in China

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National Science Review 2020年第5期7卷 897-912页

作者： Yue Li Shilong Piao Anping Chen Philippe Ciais Laurent Z.X.Li Sino-French Institute for Earth System Science College of Urban and Environmental Sciences Peking University Key Laboratory of Alpine Ecology and Biodiversity Institute of Tibetan Plateau Research Chinese Academy of Sciences Center for Excellence in Tibetan Earth Science Chinese Academy of Sciences Department of Biology Colorado State University Laboratoire des Sciences du Climat et de l'Environnement/Institut Pierre Simon Laplace Commissariata l Energie Atomique et aux Energies Alternatives–CNRS–Universite de Versailles Saint-QuentinUniversite Paris-Saclay Laboratoire de Met eorologie Dynamique Centre National de la Recherche ScientifiqueSorbonne UniversiteEcole Normale Superieure Ecole Polytechnique

afforestation in China provides carbon sequestration and prevents soil erosion, but its remote impacts on climate in other regions via the coupling of forest energy fluxes with atmospheric circulation are largely unknown. Here, we prescribe inventory-based forest cover change and satellite-observed leaf area index from 1982 to 2011 in a coupled land-atmosphere model to simulate their biophysical climate effects. Both local and global surface air temperatures show a seasonal contrast in response to past vegetation cover expansion over China:a phenomenon we primarily attribute to a variation of seasonality of vegetation greening. A large cooling in spring results in concurrent decreases in geopotential height over China and zonal wind over Mongolia, causing a dipole structure in the upper troposphere over the Arctic. This accounts for～58%of simulated spring warming over the Russian Arctic and～61% of simulated spring cooling over the Canadian Artic. Our results imply that spring vegetation dynamics in China may affect climate in northern high latitudes.

关键词： afforestation vegetation greening China biophysical climate effect coupled land-atmosphere model

Evaluating the effect of plain afforestation project and future spatial suitability in Beijing

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Science China Earth Sciences 2020年第10期63卷 1587-1598页

作者： Tengyun HU Xuecao LI Peng GONG Wencheng YU Xiaochun HUANG Beijing Municipal Institute of City Planning and Design Beijing 100045China Department of Geological and Atmospheric Sciences Iowa State UniversityAmes 50011USA Ministry of Education Key Laboratory of Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing 100084China Tsinghua Urban Institute Tsinghua UniversityBeijing 100084China

Taking the"One Million-Mu(666 km^2)"Plain afforestation(PhaseⅠ)Project(Phase I afforestation)in Beijing city as an example,we monitored the growth status of planted forest using long-term remote sensing images,and evaluated the impacts of afforestation on land use change and vegetation growth.We found there is a large space for improvement regarding the ecological benefits of the project.Moreover,we found forest patches with decreasing greenness after the afforestation were mainly converted from farmland with high greenness and low heterogeneity in terms of the normalized difference vegetation index(NDVI).This implies that those farmland patches are inappropriate for afforestation.According to the results from PhaseⅠafforestation and the impact of urbanization on green space,we constructed a series of spatial variables and generated a suitability map for the next"New Round of One Million-Mu(666 km^2)afforestation project"(PhaseⅡafforestation).We then modeled the spatial distribution of PhaseⅡafforestation based on the derived suitability map.This study is crucial for the scientific evaluation of afforestation projects for space planning(e.g.,urban green space planning).The evaluation and modeling framework built in this study can be used to support the decision making and policy implementation of afforestation projects in China.

关键词： Urban land use afforestation Forest growth Suitability Segmentation Forest modeling

Perspectives on the role of terrestrial ecosystems in the ‘carbon neutrality' strategy

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Science China Earth Sciences 2022年第6期65卷 1178-1186页

作者： Shilong PIAO Chao YUE Jinzhi DING Zhengtang GUO College of Urban and Environmental Sciences Peking UniversityBeijing 100871China Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100101China Institute of Soil and Water Conservation Northwest A&F UniversityYangling 712100China Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China

The Chinese government has made a strategic decision to reach ‘carbon neutrality' before 2060. China's terrestrial ecosystem carbon sink is currently offsetting 7–15% of national anthropogenic emissions and has received widespread attention regarding its role in the ‘carbon neutrality' strategy. We provide perspectives on this question by inferring from the fundamental principles of terrestrial ecosystem carbon cycles. We first elucidate the basic ecological theory that, over the long-term succession of ecosystem without regenerative disturbances, the carbon sink of a given ecosystem will inevitably approach zero as the ecosystem reaches its equilibrium state or climax. In this sense, we argue that the currently observed global terrestrial carbon sink largely emerges from the processes of carbon uptake and release of ecosystem responding to environmental changes and, as such, the carbon sink is never an intrinsic ecosystem function. We further elaborate on the long-term effects of atmospheric CO_(2) changes and afforestation on China's terrestrial carbon sink: the enhancement of the terrestrial carbon sink by the CO_(2) fertilization effect will diminish as the growth of the atmospheric CO_(2) slows down, or completely stops, depending on international efforts to combat climate change, and carbon sinks induced by ecological engineering, such as afforestation, will also decline as forest ecosystems become mature and reach their late-successional stage. We conclude that terrestrial ecosystems have nonetheless an important role to play to gain time for industrial emission reduction during the implementation of the ‘carbon neutrality' strategy. In addition, science-based ecological engineering measures including afforestation and forest management could be used to elongate the time of ecosystem carbon sink service. We propose that the terrestrial carbon sink pathway should be optimized, by addressing the questions of ‘when' and ‘where' to plan afforestation projects, in order to effectively strengthen the terrestrial

关键词： Carbon neutrality Terrestrial ecosystem carbon sink CO_(2)fertilization effect afforestation Carbon sink pathway

Quantitative evaluation of eco-geotechnical measures for debris flow mitigation by improved vegetation-erosion model

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Journal of Mountain Science 2022年第7期19卷 2015-2026页

作者： LYU Li-qun XU Meng-zhen ZHOU Guan-yu WANG Zhao-yin School of Soil and Water Conservation Beijing Forestry UniversityBeijing100083China State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China

Eco-geotechnical measures for debris flow mitigation and control have attracted wide attention,but the mitigation effect is lack of quantitative evaluation of coordinated measures.In order to evaluate the debris flow mitigation effect in the combinations of geotechnical engineering and ecological engineering,this study investigated the different trends of debris flows behaviour based on the sediment deposition on the gully bed and the loose material on the hillslope.Besides,this research proposed a new model involving vegetation coverage,source gravity energy and debris flow volume based on vegetation-erosion model.The new model validated that the debris flow volume was proportional to the gravity energy of gravel and rock fragments on the hillslope and inversely proportional to the vegetation coverage in a dry-hot valley setting.Furthermore,a typical area in the valley of the Xiaojiang River in Yunnan Province,China was quantified with the new model.The results showed that under different gravity energy conditions,the implementation order of check dam construction and afforestation was important for debris flow mitigation.

关键词： Debris flow Vegetation coverage Source energy Incision and deposition afforestation Check dam Jiangjia Gully

Effects of afforestation of agricultural land with grey alder(Alnus incana(L.) Moench)on soil chemical properties, comparing two contrasting soil groups

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Forest Ecosystems 2020年第3期7卷 489-498页

作者： Oļģerts Nikodemus Dārta Kaupe Imants Kukuļs Guntis Brūmelis Raimonds Kasparinskis Iluta Dauškaneand Agita Treimane Faculty of Geography and Earth Sciences University of LatviaJelgavas iela 1RigaLV-1004Latvia Faculty of Biology University of LatviaJelgavas iela 1RigaLV-1004Latvia

Background: Natural afforestation of former agricultural lands with alder species is common in Europe. Symbiotic nitrogen fixation by actinomycetes associated with alder species has been widely used for improvement of soil properties of abandoned agricultural lands, but relatively little is known of the interactions of these processes with soil type and chemical composition. We conducted a space-for time study with soil sampling under and outside grey alder tree canopies on two different soil groups to explore effects of colonisation of former agricultural lands by alder on soil properties.Results: The results were analysed using analysis of variance. During the first 25 years after afforestation of former agricultural lands there was a significant increase in content of Ctot, Ntot, K+, Fe3+, Mn2+and available P in the topsoil(0–10 cm and 11–20 cm) of Dystric Arenosols soils, which are deficient in organic matter. Such trends were not evident in organic matter rich Endostagnic Umbrisols soils, in which exchangeable K+concentration decreased and exchangeable Fe3+and Al3+concentration increased.Conclusions: The results show that the effects of grey alder on soil chemical properties depend on initial soil properties. The invasion of agricultural land by grey alder leads to spatial variability of soil chemical properties creating a mosaic pattern.

关键词： afforestation Grey alder Soil properties Umbrisols Arenosols Topsoil