Editorial

3 pages, 633 KiB

Open AccessEditorial

Plant–Soil Interactions in Karst Regions

by Hao Zhang and Wei Zhang

Forests 2023, 14(5), 922; https://doi.org/10.3390/f14050922 - 29 Apr 2023

Cited by 1 | Viewed by 827

Karst regions have a shallow soil layer, discontinuous soil cover, high rock exposure rate, calcium-rich and alkaline soil, and a fertile but small total soil [...] Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

Research

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16 pages, 2650 KiB

Open AccessArticle

Changes in Plant Diversity and Soil Factors under Different Rocky Desertification Degrees in Northern Guangdong, China

by Mingyu Lan, Chunquan Xue, Jiazhi Yang, Ning Wang, Chuanxi Sun, Guozhang Wu, Hongyu Chen and Zhiyao Su

Forests 2023, 14(4), 694; https://doi.org/10.3390/f14040694 - 28 Mar 2023

Cited by 4 | Viewed by 1182

Abstract

Revegetation is an important restoration strategy for the control of rocky desertification. However, few studies have focused on the effects of different rocky desertification degrees (RDDs) on plant diversity and soil fertility in northern Guangdong over long periods of time. In this study, [...] Read more.

Revegetation is an important restoration strategy for the control of rocky desertification. However, few studies have focused on the effects of different rocky desertification degrees (RDDs) on plant diversity and soil fertility in northern Guangdong over long periods of time. In this study, variance analysis, correlation analysis, and canonical correlation analysis (CCA) were used to examine plant diversity, soil physicochemical properties, and their correlations in various rocky desertification areas in northern Guangdong. The results showed that the Pinaceae, Lauraceae, and Fagaceae species were relatively abundant in the rocky desertification areas of northern Guangdong. Additionally, Cinnamomum camphora, Schima superba, Pinus massoniana, Quercus stewardiana, and Acer camphora could be used as indicators for rocky desertification. There were significant differences in plant community compositions and diversity characteristics between the five RDDs, and the vegetation exhibited the trend of initial destruction and then gradual improvement and stabilization. There were significant differences in soil bulk density, mechanical composition, organic matter, total nitrogen, alkaline hydrolysis nitrogen, and available potassium between the different RDDs. Except for pH, the soil chemical characteristics all had clear aggregation effects. Soil organic matter, total nitrogen, total potassium, and alkaline hydrolysis nitrogen all exhibited degradation–improvement cycles. The correlation analysis revealed that there was a significant correlation between soil physicochemical properties and species diversity. The CCA analysis showed that the most important soil factors affecting plant community structures were total phosphorus and available phosphorus. In conclusion, some achievements have been made in the restoration of rocky desertification in northern Guangdong; while the plant community structure improved, some soil nutrients also improved. Vegetation and soil have a strong coupling relationship. In the later stages of recovery, suitable species for rocky desertification could be considered in varying degrees and P and K could be supplemented appropriately. Our study will have implications for the revegetation of rocky desertification. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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16 pages, 4842 KiB

Open AccessFeature PaperArticle

Diversity and Assembly of Bacteria Community in Lime Soil under Different Karst Land-Use Types

by Xiaoxiao Zou, Kai Yao, Fuping Zeng, Chen Zhang, Zhaoxia Zeng and Hao Zhang

Forests 2023, 14(4), 672; https://doi.org/10.3390/f14040672 - 24 Mar 2023

Cited by 4 | Viewed by 1604

Abstract

Bacteria play an important role as decomposers in karst ecosystems, which can be associated with karst soil and plants, promoting the cycling of nutrients between plants and soil. To reveal the diversity and structure of soil bacterial communities in some karst land-use types [...] Read more.

Bacteria play an important role as decomposers in karst ecosystems, which can be associated with karst soil and plants, promoting the cycling of nutrients between plants and soil. To reveal the diversity and structure of soil bacterial communities in some karst land-use types after the Grain for Green pattern, soil samples were collected from different land-use types (crops, grasses, and plantations) for analysis. Changes in the structure and assembly of karst soil bacteria were examined using 16S rRNA Illumina sequencing and soil chemical properties. We found that 18 years after the Grain for Green program, the soil chemical properties of available nitrogen (AN), total phosphorus (TP), total nitrogen (TN), and soil organic matter (SOM) of grassland were significantly different from those of farmland. The soil chemical properties in plantations were also significantly lower than those in farmlands. Different land-use types did not significantly affect the soil bacterial community structure. Actinobacteria, Proteobacteria, Chloroflexi, and Acidobacteria were the dominant phyla in all the plots. The relative abundance of Proteobacteria was higher in grasslands and plantations than in farmlands, whereas that of Actinobacteria was lower in grasslands. Furthermore, no significant correlations were observed between the soil chemical factors and soil bacterial groups at the genus level. The null model analysis indicated that dispersal limitations in stochastic processes predominated for the different land-use systems. Combined with previous analyses of the factors driving bacterial core species diversity in karst soils, we speculated that stochastic processes play a more important role in the construction of core bacterial species in restored karst soils at the plot scale. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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17 pages, 3254 KiB

Open AccessArticle

Study on Soil Moisture Characteristics in Southern China Karst Plant Community Structure Types

by Xing Gu, Kangning Xiong, Chenxu Wu and Ding Luo

Forests 2023, 14(2), 384; https://doi.org/10.3390/f14020384 - 14 Feb 2023

Cited by 3 | Viewed by 1497

Abstract

An understanding of soil moisture variation patterns under different plant community structures is crucial for the restoration of vegetation in southern China karst regions. Therefore, four plant community structure types: arbor + herb (AH), shrub + herb (SH), arbor + shrub + herb [...] Read more.

An understanding of soil moisture variation patterns under different plant community structures is crucial for the restoration of vegetation in southern China karst regions. Therefore, four plant community structure types: arbor + herb (AH), shrub + herb (SH), arbor + shrub + herb (ASH), and herb (H), were selected as the research objects. A soil moisture sensor was used to monitor the soil moisture content in the 0–70 cm soil layer, to analyze the variation characteristics of soil moisture content and to explore the differences under different plant community structure types. The results indicate that: (1) A total of 31 plant species in 31 genera and 18 families were recorded, among which herbs were the most abundant. There were significant differences in diversity indexes for ASH and H. The differences between Shannon–Wiener index and Simpson index of AH and H were significant, and between AH and SH in Pielou index and Simpson index were statistically significant. The Pielou index between SH and H was significantly different. (2) There were significant differences in soil water content among the four plant community types, showing SH > AH > H > ASH. The variation of soil moisture was consistent with the trend of rainfall, with the surface soil moisture more sensitive to rainfall events, and the deeper soil moisture had a lag. The Shannon–Wiener index was significantly and positively correlated with the Simpson index and the Margalef index. There was a highly significant positive correlation between Margalef index and Simpson index. The 20–30 cm soil layer was highly negatively correlated with the Margalef index and significantly and negatively correlated with the Shannon–Wiener index and the Simpson index. (3) The response of soil moisture of plant community structure types to light rain event was not obvious. The growth rates of soil water content in the 30–50 and 50–70 cm layers of the SH were higher in moderate rain event than that in heavy rain event, and H, AH, and ASH had larger growth rates in heavy rain events. The results provide a reference for the effective utilization of soil and water resources and the restoration of vegetation, as well as for plant community structure configuration decisions in the southern China karst region. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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13 pages, 2986 KiB

Open AccessArticle

Lower Sensitivity of Soil Carbon and Nitrogen to Regional Temperature Change in Karst Forests Than in Non-Karst Forests

by Yunfan Li, Rong Yang, Peilei Hu, Dan Xiao, Zhongcheng Wang, Wei Zhang and Kelin Wang

Forests 2023, 14(2), 355; https://doi.org/10.3390/f14020355 - 10 Feb 2023

Cited by 1 | Viewed by 1537

Abstract

Lithology has such an important effect on the sustainability of soil carbon (C) pools. Forests are an important part of terrestrial C sinks; yet, it is unclear whether their soil carbon sensitivity to temperature changes is regulated by lithology, especially in karst ecosystems, [...] Read more.

Lithology has such an important effect on the sustainability of soil carbon (C) pools. Forests are an important part of terrestrial C sinks; yet, it is unclear whether their soil carbon sensitivity to temperature changes is regulated by lithology, especially in karst ecosystems, which are widely distributed globally. Along a climate gradient in the subtropical region of southwest China, we compared the contents of soil organic C (SOC) and total N (TN) in karst and non-karst forests. The data were analyzed and processed using ANOVA, regression analysis, and random forest. The results showed that the karst forests had significantly higher SOC and TN contents but lower ratio of SOC to TN (C:N) than non-karst forests, mainly because of the higher soil calcium (Ca) content and microbial biomass. With rising mean annual temperature (MAT), SOC and TN contents in non-karst forests significantly decreased, whereas in karst forests they were not correlated with MAT; while, the opposite was true for C:N. In karst forests, soil Ca constrain warming induced decomposition of SOC and TN by forming stable complexes with SOM through exchangeable Ca, and by promoting aggregate stability through the role of calcium carbonate. The correlation between δ¹³C and the logarithm of SOC concentration also supported that conclusion. In karst forests compared to non-karst forests, soil C pools are larger and less sensitive to regional temperature change. Nevertheless, climate warming may still accelerate soil C loss in karst forests by increasing microbial C limitation. Thus, soil C sequestration potential and loss risk coexist in karst areas. The ratio of SOC to TN (C:N) is regulated through appropriate management measures in the process of karst vegetation restoration, thus promoting long-term stable sequestration of soil carbon pools. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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13 pages, 3287 KiB

Open AccessArticle

Plant Functional Trait Responses to Dolomite and Limestone Karst Forests in Southwest China

by Hua Zhou, Xuelei Xu, Xia Jiang, Bo Ding, Peng Wu and Fangjun Ding

Forests 2022, 13(12), 2187; https://doi.org/10.3390/f13122187 - 19 Dec 2022

Cited by 7 | Viewed by 1558

Abstract

Southwest China is distributed with the largest area of limestone and dolomite karst landscapes in the world, and its ecological environment is very fragile; the problem of rock desertification is particularly prominent. Karst lithological differences make habitats and soil heterogeneity more complex, and [...] Read more.

Southwest China is distributed with the largest area of limestone and dolomite karst landscapes in the world, and its ecological environment is very fragile; the problem of rock desertification is particularly prominent. Karst lithological differences make habitats and soil heterogeneity more complex, and vegetation has developed certain morphological and physiological structural characteristics to adapt to these special environments, which will most likely lead to differentiation in vegetation functional characteristics, such as seed size, wood density, life type and flowering time, thus affecting the number and growth of seedlings and young trees and the future succession potential of forest stands in karst-vegetation restoration. Therefore, it is important to understand the differences in species composition and the functional characteristics of dolomite and limestone karst forests. Over a 2-year period, we investigated a total of 3170 individuals from 123 species and analyzed the relationship between the species compositions and the functional characteristics of two karst-forest areas with different lithology (i.e., limestone and dolomite karst). It was found that the average number of species with medium-diameter seeds and medium wood density in dolomite plots was obviously greater than the average number of species in limestone plots, but this reached no significant difference. However, with the gradual restoration of each forest, the height and carbon sequestration capacity of the trees began to diverge, with the relative abundance of species with tall trees and high wood density being significantly higher in limestone plots than in dolomite plots. The species richness of evergreen trees was significantly higher in the limestone plots than in the dolomite plots. There was no significant difference in the relative species richness of flowering plants in the two karst-forest areas during spring–summer and winter–spring seasons; however, the species richness of flowering plants in the limestone karst forests was significantly higher than that of flowering plants in the dolomite karst forests during summer and autumn seasons. These significant traits were very closely related to the species richness of the understory plants. Further insight into the temporal aspects of karst-forest succession is needed to grasp how functional traits affect the restorations of different lithological karst forests to their primary states. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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14 pages, 5129 KiB

Open AccessArticle

Carbon, Nitrogen and Phosphorus Stoichiometry and Its Influencing Factors in Karst Primary Forest

by Chen Zhang, Fuping Zeng, Zhaoxia Zeng, Hu Du, Lijin Zhang, Liang Su, Mengzhen Lu and Hao Zhang

Forests 2022, 13(12), 1990; https://doi.org/10.3390/f13121990 - 25 Nov 2022

Cited by 4 | Viewed by 1917

Abstract

The stoichiometric characteristics of C, N, and P in plants result from long-term adaptation to environmental conditions. In this study, we analyzed leaf, branch, and soil C, N, and P stoichiometry in a karst primary forest plant community in China. The results showed [...] Read more.

The stoichiometric characteristics of C, N, and P in plants result from long-term adaptation to environmental conditions. In this study, we analyzed leaf, branch, and soil C, N, and P stoichiometry in a karst primary forest plant community in China. The results showed that N and P content in leaves was higher than that in branches, while C content in the latter was higher than in leaves. Moreover, the coefficient of the variation in C, N, and P content in branches was greater than that in leaves but there was no significant difference in said coefficients in soil. The values of the C:N and C:P ratios were both branch > leaf > soil, whereas the value of the N:P ratio was leaf > branch > soil. There was also a significant positive correlation between leaf nitrogen (LN), leaf phosphorus (LP), branch nitrogen (BN), and branch phosphorus (BP) concentrations but no significant correlation between leaf carbon (LC), branch carbon (BC), and other element concentrations. We found that leaf stoichiometry was strongly influenced by species diversity, whereas branch stoichiometry was mainly influenced by leaf and species diversity; the environmental factors influencing the stoichiometric characteristics of leaves and branches were mainly altitude, soil pH, and total soil P. Finally, these results are relevant as they are helpful to understand the adaptation mechanisms and eco-geochemical processes in karst forest plants and they can also provide a scientific basis for vegetation restoration and reconstruction in these degraded ecosystems. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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11 pages, 1492 KiB

Open AccessArticle

The Relative Importance of Niche and Neutral Processes for the Community Assembly of Subtropical Karst Forest Communities at Different Spatial Scales

by Yan He, Shichu Liang, Yong Jiang and Wenyan Ning

Forests 2022, 13(11), 1930; https://doi.org/10.3390/f13111930 - 16 Nov 2022

Cited by 2 | Viewed by 1367

Abstract

As spatial scale changes, the ecological processes and mechanisms that determine community patterns change. To understand these spatial effects, we established a medium-sized forest plot in an evergreen and deciduous broad-leaved mixed forest in Guilin, Guangxi, southwestern China. Here, we compared the fit [...] Read more.

As spatial scale changes, the ecological processes and mechanisms that determine community patterns change. To understand these spatial effects, we established a medium-sized forest plot in an evergreen and deciduous broad-leaved mixed forest in Guilin, Guangxi, southwestern China. Here, we compared the fit of niche and neutral models to the observed species abundance distributions (SADs) at three sampling scales (10 m × 10 m, 20 m × 20 m, 50 m × 50 m). We also performed a PER-SIMPER analysis to further evaluate the relative contribution of niche and neutral processes based on taxon occurrence data. Our results showed that niche-based selection and dispersal-based neutral processes are simultaneously expressed at the 10 m × 10 m and 20 m × 20 m sampling scales. Additionally, dispersal-based neutral processes were predominant at each sampling scale. From these results, we found that the dispersal-based neutral process is the prominent driver for forest community structure in a typical karst forest environment. Ultimately, our work will be useful for future restoration and reconstruction efforts in karst forest communities, showing that environmental heterogeneity, inter-species relationships, and geographic spatial differences should be considered in these efforts. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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13 pages, 1531 KiB

Open AccessArticle

Stoichiometric Variation in Soil Carbon, Nitrogen, and Phosphorus Following Cropland Conversion to Forest in Southwest China

by Mengzhen Lu, Kunping Liu, Lijin Zhang, Fuping Zeng, Tongqing Song, Wanxia Peng and Hu Du

Forests 2022, 13(8), 1155; https://doi.org/10.3390/f13081155 - 22 Jul 2022

Cited by 14 | Viewed by 1662

Abstract

Soil organic carbon (SOC), nitrogen (N), and phosphorus (P) are three essential soil nutrients for plant growth, and their stoichiometric ratios are already important indices of elemental balance and the soil fertility status in soil ecosystems. The evolution mechanism of the SOC, Total [...] Read more.

Soil organic carbon (SOC), nitrogen (N), and phosphorus (P) are three essential soil nutrients for plant growth, and their stoichiometric ratios are already important indices of elemental balance and the soil fertility status in soil ecosystems. The evolution mechanism of the SOC, Total Nitrogen (TN), Total Phosphorus (TP), and stoichiometry following the “conversion of cropland to forest program” (CCFP) in southwest China is not yet clear. Seven different CCFP restoration models, including Zenia insignis (RD), Toona sinensis (XC), Castanea mollissima (BL), Citrus reticulate (GJ), Zenia insignis and Guimu-1 elephant grass (RG), Guimu-1 elephant grass (GM), and abandoned cropland (LH), were chosen to explore changes in the concentration and stoichiometry of the SOC, TN, and TP, and their recovery times, at a depth of 0–100 cm. The results indicate that the SOC and TN concentrations in different restoration models all increased with restoration years in the topsoil, whereas the soil TP concentration remained relatively stable. The soil C:N and C:P ratios increased with increasing restoration years in the topsoil, whereas the N: P ratio was relatively stable over time. After ten years of reforestation, the SOC and TN concentrations decreased as the soil layer increased. The effects of the restoration model on the C: N ratios were greater in shallow soils. Our results suggest a complex reaction of SOC, soil TN, and soil TP concentrations and stoichiometry to the vegetation restoration mode, particularly in the topsoil. This research further improves the understanding of SOC, N, and P interactions and restricted nutrition, and provides relevant theoretical support for vegetation restoration in the southwest karst region. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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15 pages, 2187 KiB

Open AccessArticle

Impact of Selected Environmental Factors on Variation in Leaf and Branch Traits on Endangered Karst Woody Plants of Southwest China

by Chen Zhang, Fuping Zeng, Zhaoxia Zeng, Hu Du, Liang Su, Lijin Zhang, Mengzhen Lu and Hao Zhang

Forests 2022, 13(7), 1080; https://doi.org/10.3390/f13071080 - 09 Jul 2022

Cited by 8 | Viewed by 1656

Abstract

We explored the adaptability of endangered plants in degraded karst habitats through functional trait variation, using three endangered woody plants (E. cavaleriei, H. bodinieri and K. septentrionalis) in karst peak-cluster depression. We investigated the variation decomposition and correlation analysis of [...] Read more.

We explored the adaptability of endangered plants in degraded karst habitats through functional trait variation, using three endangered woody plants (E. cavaleriei, H. bodinieri and K. septentrionalis) in karst peak-cluster depression. We investigated the variation decomposition and correlation analysis of 13 branch and leaf functional traits using a mixed linear model, variance decomposition, Pearson’s correlation analysis, random forest regression, and generalized linear regression. The degree of variation in phosphorus concentration in the branches was the highest, while that in the carbon concentration in the leaves was the smallest. The variation in the carbon concentration in the branches and leaves, and the dry matter concentration in the leaves was mainly within species, while the variation in other functional traits was mainly between species. We found significant correlations among leaf traits, branch traits, and leaf–branch traits to different degrees; however, there were no significant correlations among branch traits in H. bodinieri. The significant correlations were higher in E. cavaleriei and K. septentrionalis than in H. bodinieri. Plant functional traits were influenced by soil and topographic factors, and the relationship between them varied by species. Our findings will enhance our understanding of the variation in leaf and branch traits in karst endangered plants and the adaptative strategies of endangered plants in degraded habitat, and will provide a scientific basis for vegetation conservation in the karst region of southwest China. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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15 pages, 4904 KiB

Open AccessArticle

Spatial Variations in Fine Root Turnover, Biomass, and Necromass of Two Vegetation Types in a Karst Ecosystem, Southwestern China

by Fujing Pan, Qian Qian, Yueming Liang, Kelin Wang and Wei Zhang

Forests 2022, 13(4), 611; https://doi.org/10.3390/f13040611 - 14 Apr 2022

Cited by 6 | Viewed by 1922

Abstract

Revealing the patterns of fine root turnover traits can aid our understanding of the mechanisms of fine roots in adapting to soil nutrient changes. In a karst ecosystem of southwest China, the fine root turnover rate, production, biomass, necromass, biomass/necromass ratio, as well [...] Read more.

Revealing the patterns of fine root turnover traits can aid our understanding of the mechanisms of fine roots in adapting to soil nutrient changes. In a karst ecosystem of southwest China, the fine root turnover rate, production, biomass, necromass, biomass/necromass ratio, as well as the soil total and available nitrogen (N) and phosphorus (P) concentrations, and root carbon (C) and N concentrations were analyzed in upper, middle, and lower slope positions of two vegetation types (shrubland and forest). The results showed that the soil total and available N and P and fine root production, biomass, and necromass were significantly higher in upper slope positions than those in lower slope positions in both vegetation types. However, the fine root turnover rates were slightly higher in upper positions than those in lower positions. In addition, fine root necromass was significantly lower in shrubland than that in forest, while the biomass/necromass ratio was the opposite. Therefore, fine root production and biomass were significantly affected by slope position, while the fine root biomass/necromass ratio was significantly influenced by vegetation type. Additionally, fine root necromass was significantly influenced by the slope position and vegetation, but the turnover rate was slightly impacted by the two factors. It was also found that fine root production, biomass, and necromass had significant positive correlations with the soil total and available N and P and root C concentrations, and had significant negative correlations with root N concentrations. Moreover, the biomass/necromass ratio was positively and negatively related to the root N concentrations and C/N ratios, respectively. Thus, the variations in these five parameters of fine root turnover were mainly explained by fine root nutrients and the interactive effects between fine root and soil nutrients. The above results indicated that these variations in fine roots responding to soil and root nutrient changes might be an adaptive mechanism to enhance plant nutrient acquisition in nutrient-poor karst ecosystems. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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15 pages, 10022 KiB

Open AccessArticle

Low Frequency of Plants Associated with Symbiotic Nitrogen-Fixers Exhibits High Frequency of Free-Living Nitrogen Fixing Bacteria: A Study in Karst Shrub Ecosystems of Southwest China

by Yueming Liang, Xunyang He, Xiangbi Chen, Yirong Su, Fujing Pan and Lening Hu

Forests 2022, 13(2), 163; https://doi.org/10.3390/f13020163 - 21 Jan 2022

Cited by 2 | Viewed by 1961

Abstract

Plants associated with symbiotic nitrogen-fixers and soil free-living nitrogen-fixing bacteria are good indicators for detecting the source of nitrogen in natural ecosystems. However, the community composition and diversity of plants associated with symbiotic nitrogen-fixers and soil free-living nitrogen-fixing bacteria in karst shrub ecosystems [...] Read more.

Plants associated with symbiotic nitrogen-fixers and soil free-living nitrogen-fixing bacteria are good indicators for detecting the source of nitrogen in natural ecosystems. However, the community composition and diversity of plants associated with symbiotic nitrogen-fixers and soil free-living nitrogen-fixing bacteria in karst shrub ecosystems remain poorly known. The community composition and diversity of soil free-living nitrogen-fixing bacteria and plants, as well as the soil physical–chemical properties were investigated in 21 shrub plots (including different topographies and plant types). The frequency of plants associated with symbiotic nitrogen-fixers was found to be low in the 21 shrub plots. The soil free-living nitrogen-fixing bacterial community structure varied among the 21 shrub soils. Based on a variance partitioning analysis, topography, plant type, and soil pH explained 48.5% of the observed variation in bacterial community structure. Plant type had a predominant effect on community structure, and topography (aspect and ascent) and soil pH had minor effects. A negative correlation between the abundance of the soil free-living nitrogen-fixing bacterial community and the richness index for plants associated with symbiotic nitrogen-fixers was observed. The result of the low frequency of plants associated with symbiotic nitrogen-fixers highlights the importance of sources of fixed nitrogen by soil free-living nitrogen-fixing bacteria in the nitrogen limitation shrub ecosystem of the karst regions. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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21 pages, 4963 KiB

Open AccessArticle

Mechanism and Evolution of Soil Organic Carbon Coupling with Rocky Desertification in South China Karst

by Xingfu Wang, Xianfei Huang, Kangning Xiong, Jiwei Hu, Zhenming Zhang and Jiachun Zhang

Forests 2022, 13(1), 28; https://doi.org/10.3390/f13010028 - 27 Dec 2021

Cited by 9 | Viewed by 2344

Abstract

To study the spatial distribution characteristics of soil organic carbon (SOC) coupled with rocky desertification, 1212 soil samples from 152 soil profiles were sampled from different karst landforms, including karst low hills/virgin forest (KLH) in Libo County, a karst peak-cluster depression (KPCD) in [...] Read more.

To study the spatial distribution characteristics of soil organic carbon (SOC) coupled with rocky desertification, 1212 soil samples from 152 soil profiles were sampled from different karst landforms, including karst low hills/virgin forest (KLH) in Libo County, a karst peak-cluster depression (KPCD) in Xingyi County, a karst canyon (KC) in Guanling County, a karst plateau basin (KPB) in Puding County and a karst trough valley (KTV) in Yinjiang County. The spatial distribution characteristics of the responses of SOC, SOC density (SOCD), rocky desertification and soil bulk density (SBD) to different influencing factors were analyzed. The relationships among SOC, SOCD, rocky desertification and SBD were analyzed using Pearson correlation analysis. The SOC storage capacity was characterized by using SOCD, and then the SOC storage capacity in different evolution stages of karst landforms was assessed. The SOC contents of KLH, KPCD, KC, KPB and KTV ranged from 6.16 to 38.20 g·kg⁻¹, 7.42 to 27.08 g·kg⁻¹, 6.28 to 35.17 g·kg⁻¹, 4.62 to 23.79 g·kg⁻¹ and 5.24 to 37.85 g·kg⁻¹, respectively, and their average SOCD values (0–100 cm) were 7.37, 10.79, 7.06, 8.51 and 7.84 kg·m⁻², respectively. The karst landforms as ordered by SOC storage capacity were KPCD > KPB > KLH > KTV > KC. The SOC content was negatively correlated with the SBD; light rocky desertification may lead to SOC accumulation. The rocky desertification degree and SBD were closely associated with slope position and gradient. Rocky desertification first increased, then decreased from mountain foot to summit, and increased with increasing slope gradient. However, the SBD decreased from mountain foot to summit and with increasing slope gradient. The SOC contents on the northern aspect of the mountains were generally higher than the other aspects. In summary, rock outcrops controlled the SOC contents in the studied regions. The slope position, gradient and aspect influenced the composition and distribution of vegetation, which influenced the evolution of rocky desertification. Therefore, these factors indirectly affected the SOC content. Additionally, the SOCD decreased with increasing rocky desertification. During the different evolution stages of karst landforms, the SOC storage capacity first decreases, then increases. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Karst Regions)

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