scholarly journals Evaluating the joint use of GPR and ERT on mapping shallow subsurface features of karst critical zone in southwest China

2021 ◽  
Author(s):  
Min Tao ◽  
Xi Chen ◽  
Qinbo Cheng ◽  
Andrew Binley
Keyword(s):  
Southwest China ◽  
Critical Zone ◽  
Shallow Subsurface

scholarly journals Soil organic carbon sequestration in soil aggregates in the karst Critical Zone Observatory, Southwest China

2019 ◽  
Vol 65 (No. 5) ◽  
pp. 253-259 ◽  
Author(s):  
Man Liu ◽  
Guilin Han ◽  
Zichuan Li ◽  
Qian Zhang ◽  
Zhaoliang Song
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Southwest China ◽  
Critical Zone ◽  
Soil Aggregation ◽  
Research Station ◽  
Land Uses ◽  
Farmland Abandonment ◽  
Critical Zone Observatory ◽  
Farmland Soils

Soil organic carbon (SOC) sequestration in aggregates under land use change have been widely concerned due to intimate impacts on the sink (or source) of atmospheric carbon dioxide (CO<sub>2</sub>). However, the quantitative relationship between soil aggregation and SOC sequestration under land uses change has been poorly studied. Distribution of aggregates, SOC contents in bulk soils and different size aggregates and their contributions to SOC sequestration were determined under different land uses in the Puding Karst Ecosystem Observation and Research Station, karst Critical Zone Observatory (CZO), Southwest China. Soil aggregation and SOC sequestration increased in the processes of farmland abandonment and recovery. SOC contents in micro-aggregates were larger than those in macro-aggregates in restored land soils, while the opposite results in farmland soils were obtained, probably due to the hindrance of the C-enriched SOC transport from macro-aggregate into micro-aggregate by the disturbance of agricultural activities. SOC contents in macro-aggregates exponentially increased with their proportions along successional land uses. Macro-aggregates accounted for over 80% on the SOC sequestration in restored land soils, while they accounted for 31–60% in farmland soils. These results indicated that macro-aggregates have a great potential for SOC sequestration in karst soils.

scholarly journals Variations and Indications of δ13CSOC and δ15NSON in Soil Profiles in Karst Critical Zone Observatory (CZO), Southwest China

2019 ◽  
Vol 11 (7) ◽  
pp. 2144 ◽  
Author(s):  
Man Liu ◽  
Guilin Han ◽  
Qian Zhang ◽  
Zhaoliang Song
Keyword(s):  
Southwest China ◽  
Crop Productivity ◽  
Critical Zone ◽  
Soil Profiles ◽  
Agricultural Lands ◽  
Farmland Abandonment ◽  
Surface Soils ◽  
Soil Layers ◽  
Critical Zone Observatory ◽  
Karst Soils

Soil carbon and nitrogen storage and stabilization are the key to solving the problems of mitigation of global warming and maintaining of crop productivity. In this study, the contents of soil organic carbon (SOC) and soil organic nitrogen (SON) and their stable isotope compositions (δ13CSOC and δ15NSON) in soil profiles were determined in two agricultural lands (including a farmland and an abandoned farmland) and four non-agricultural lands (including two shrub-grass lands and two shrub lands) in the karst critical zone observatory (CZO), Southwest China. The contents of SOC and SON were used for research on the effects of land use on SOC and SON storage, and the change of δ13CSOC and δ15NSON values in soil profiles were used to indicate SOC and SON stabilization. The results showed that agricultural activities reduced SOC and SON storage in the whole soil layers of farmland compared to non-agricultural lands, and farmland abandonment slightly increased SOC and SON storage. Crop rotation between peanut (C3) and corn (C4) affected the δ13CSOC in surface soils of agricultural lands (−21.6‰), which were intermediate between shrub lands (−22.7‰) and shrub-grass lands (−19.6‰). 15N-depleted SON in surface soils in farmland compared to those soil in other lands possibly associated with synthetic N fertilizer application. In soil layers below 30 cm depth the δ13CSOC deceased with depth, while the δ15NSON displayed irregular fluctuation. The change in δ13CSOC and δ15NSON through soil profiles in karst soils were more intensive than those in semiarid grassland soils indicating the less stabilization of SOC and SON in karst soils.

Main controls on the denitrification rates during cropland revegetation in the southwest China Karst Critical Zone Observatory

2021 ◽  
Vol 308 ◽  
pp. 107228
Author(s):  
Dandan Li ◽  
Xinyu Zhang ◽  
Jennifer A.J. Dungait ◽  
Sophie M. Green ◽  
Xuefa Wen ◽  
...  
Keyword(s):  
Southwest China ◽  
Critical Zone ◽  
Critical Zone Observatory

scholarly journals Geochemical Characteristics of Rare Earth Elements in Soils from Puding Karst Critical Zone Observatory, Southwest China

2019 ◽  
Vol 11 (18) ◽  
pp. 4963 ◽  
Author(s):  
Qian Zhang ◽  
Guilin Han ◽  
Man Liu ◽  
Lingqing Wang
Keyword(s):  
Rare Earth ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Rare Earth Elements ◽  
Southwest China ◽  
Clay Content ◽  
Critical Zone ◽  
Fe Content ◽  
Local Soil ◽  
Critical Zone Observatory

Soil samples from eight soil profiles under different land-use types were collected at the Puding Karst Critical Zone Observatory, Southwest China, to investigate the distribution, fractionation, and controlling factors of rare earth elements (REEs). The total REEs contents in topsoil ranged from 149.97 to 247.74 mg kg−1, the contents in most topsoil were higher than local soil background value (202.60 mg kg−1), and the highest content was observed in topsoil under cropland. The REEs contents in surface soils from lower slopes sites were higher than that of middle and upper slope sites, and the highest contents were observed in cropland. The PAAS-normalized REEs pattern in soils showed MREEs significantly enriched relative to LREEs and HREEs, and HREEs were enriched relative to LREEs. The results showed that clay content, pH, soil organic carbon, total phosphorus, and Fe content were the main factors influencing the distribution of REEs in karst soils, and soil organic carbon (SOC), Fe content showed better linear relationship with REEs.

Soil enzyme activity and stoichiometry along a gradient of vegetation restoration at the Karst Critical Zone Observatory in Southwest China

2019 ◽  
Vol 30 (16) ◽  
pp. 1916-1927 ◽  
Author(s):  
Zhiming Guo ◽  
Xinyu Zhang ◽  
Sophie M. Green ◽  
Jennifer A.J. Dungait ◽  
Xuefa Wen ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Southwest China ◽  
Soil Enzyme ◽  
Critical Zone ◽  
Vegetation Restoration ◽  
Soil Enzyme Activity ◽  
Critical Zone Observatory

scholarly journals Hydrogeochemical Dynamics and Response of Karst Catchment to Rainstorms in a Critical Zone Observatory (CZO), Southwest China

2020 ◽  
Vol 2 ◽  
Author(s):  
Caiqing Qin ◽  
Hu Ding ◽  
Si-Liang Li ◽  
Fu-Jun Yue ◽  
Zhong-Jun Wang ◽  
...  
Keyword(s):  
Surface Water ◽  
Southwest China ◽  
Critical Zone ◽  
Karst Water ◽  
Agricultural Activities ◽  
Carbonate Weathering ◽  
Hydrogeological Conditions ◽  
Surface Water And Groundwater ◽  
Critical Zone Observatory ◽  
Karst Catchment

Karst water is vital for local drinking and irrigation but is susceptible to contamination. Hydrochemistry, which is highly related to carbonate weathering in karst catchments, can affect water quality and respond rapidly to climate change. In order to explore hydrogeochemical sources, dynamics, and their responses to rainstorms, rainwater, throughfall, hillslope runoff, surface water, and groundwater were sampled synchronously during rainstorms at a karst Critical Zone Observatory (CZO), Southwest China. Results showed that the total dissolved solids (TDS) concentration in throughfall increased by 30.1 ± 8.0% relative to rainwater, but both throughfall and rainwater contributed little to TDS in surface water and groundwater compared with terrestrial sources. Hydrochemistry in surface water and groundwater was diluted by rainstorms but displayed chemostatic responses with different intensities to increasing discharge. This is possibly regulated by hydrogeological conditions, available sources of various solutes, and the difference between solute concentrations before and after rainstorms. Ca2+ and Mg2+ dynamics were mainly regulated by carbonate weathering, gypsum dissolution, and gypsum-induced dedolomitization (geological sources), which also affect Ca2+, Mg2+, and SO42- in deep confined groundwater draining a gypsum stratum. For HCO3-, CO2 from respiration and microbiologic activities is one dominant contributor, especially for spring. The chemostatic behaviors of NO3-, Cl−, and K+ were related to agricultural activities, especially in surface water. These controls on hydrochemistry may already exist as hillslope runoff occurs, which has be further demonstrated by principle component analysis (PCA). The heterogeneous permeability of epikarst can affect the mixture of groundwater from different sources and flowing pathways, enabling hydrochemistry at different hydrogeological conditions to display discrepant responses to rainstorms. The epikarst aquifer with high permeability is susceptible to changes in external environment, such as rainstorms and agricultural activities, increasing the potential risk of water environment problems (chronic pollution of nitrogen and high hardness of water) during a certain period. Drinking water safety thus deserves consideration in the agricultural karst catchment.

Assessment of multiple and interacting modes of soil loss in the karst critical zone, Southwest China (SWC)

Geomorphology ◽  
2018 ◽  
Vol 322 ◽  
pp. 97-106 ◽  
Author(s):  
Faming Zeng ◽  
Zhongcheng Jiang ◽  
Lina Shen ◽  
Wei Chen ◽  
Qiyong Yang ◽  
...  
Keyword(s):  
Soil Loss ◽  
Southwest China ◽  
Critical Zone

scholarly journals Critical Zone Science in the Anthropocene: Opportunities for biogeographic and ecological theory and praxis to drive earth science integration

2019 ◽  
Vol 44 (1) ◽  
pp. 50-69 ◽  
Author(s):  
Jesse Minor ◽  
Jessie K Pearl ◽  
Mallory L Barnes ◽  
Tony R Colella ◽  
Patrick C Murphy ◽  
...  
Keyword(s):  
Earth Science ◽  
Spatial Scales ◽  
Abiotic Factors ◽  
Climate Change Impacts ◽  
Critical Zone ◽  
Spatial And Temporal Scales ◽  
Shallow Subsurface ◽  
Rate Dependent ◽  
Patterns And Processes ◽  
Earth’S Critical Zone

Critical Zone Science (CZS) represents a powerful confluence of research agendas, tools, and techniques for examining the complex interactions between biotic and abiotic factors located at the interface of the Earth’s surface and shallow subsurface. Earth’s Critical Zone houses and sustains terrestrial life, and its interacting subsystems drive macroecological patterns and processes at a variety of spatial scales. Despite the analytical power of CZS to understand and characterize complicated rate-dependent processes, CZS has done less to capture the effects of disturbance and anthropogenic influences on Critical Zone processes, although some Critical Zone Observatories focus on disturbance and regeneration. Methodological approaches from biogeography and ecology show promise for providing Critical Zone researchers with tools for incorporating the effects of ecological and anthropogenic disturbance into fine-grained studies of important Earth processes. Similarly, mechanistic insights from CZS can inform biogeographical and ecological interpretations of pattern and process that operate over extensive spatial and temporal scales. In this paper, we illustrate the potential for productive nexus opportunities between CZS, biogeography, and ecology through use of an integrated model of energy and mass flow through various subsystems of the Earth’s Critical Zone. As human-induced effects on biotic and abiotic components of global ecosystems accelerate in the Anthropocene, we argue that the long temporal and broad spatial scales traditionally studied in biogeography can be constructively combined with the quantifiable processes of energy and mass transfer through the Critical Zone to answer pressing questions about future trajectories of land cover change, post-disturbance recovery, climate change impacts, and urban hydrology and ecology.

Bedrock-associated belowground and aboveground interactions and their implications for vegetation restoration in the karst critical zone of subtropical Southwest China

2020 ◽  
pp. 030913332094986
Author(s):  
Hongyan Liu ◽  
Jingyu Dai ◽  
Chongyang Xu ◽  
Jian Peng ◽  
Xiuchen Wu ◽  
...  
Keyword(s):  
Southwest China ◽  
Soil Formation ◽  
Critical Zone ◽  
Vegetation Restoration ◽  
Research Progress ◽  
Karst Region ◽  
Vegetation Ecology ◽  
Rocky Desertification ◽  
Vegetation Growth ◽  
Soil Features

The role of bedrock geochemistry in vegetation growth within karst areas has been examined in recent works, implying that the approach of the critical zone (CZ) extending from the canopy to the groundwater bottom enhances the understanding of vegetation ecology. In this paper, the research progress of vegetation ecology associated with bedrock features in the karst CZ in subtropical Southwest China is systematically reviewed. There are great differences in soil formation and soil features (water-holding capacity, particle size, and soil chemistry) between karst and non-karst regions, even between dolomite and limestone within a karst region. Water and soil are easily leached due to the connected underground crevices in karst, particularly in limestone-dominated regions, leading to water deficits in karst CZ plants in subtropical Southwest China. The development of plant roots in crevices affects the water and nutrient absorption by plants and microbial activities in the soil, which form the basis for vegetation distribution and growth in the karst CZ. The organic acids from plants also increase weathering rates. As extensive human activities have accelerated vegetation degradation and soil erosion and further led to rocky desertification characterized by increasing areas of rock exposure, state-of-the-art knowledge about the effects of bedrock-associated belowground and aboveground interactions can guide the implementation of vegetation restoration and the control of further rocky desertification in the subtropical karst CZ.

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