Soil specific enzyme stoichiometry reflects nitrogen limitation of microorganisms under different types of vegetation restoration in the karst areas

ABSTRACT A portable, handheld gluten detection device, the Nima sensor, is now available for consumers wishing to determine if gluten is present in food. By U.S. regulation, gluten-free foods should contain <20 ppm of gluten. Thirteen gluten-free foods (muffins, three different types of bread, three different types of pasta, puffed corn snack, ice cream, meatballs, vinegar and oil salad dressing, oatmeal, and dark chocolate) were prepared; each food was spiked on a weight to weight basis with gluten levels of 0, 5, 10, 20, 30, 40, and 100 ppm before processing or preparation. Unprocessed and processed foods were tested with the handheld gluten sensor and by two gluten-specific enzyme-linked immunosorbent assays (ELISAs) on the basis of the R5 and G12 monoclonal antibodies, respectively. The portable gluten detection device detected gluten in all food types at the 30-ppm addition level, failing to detect gluten in only 5 (6.4%) of 78 subsamples. At the 20-ppm addition level, the portable gluten detection device failed to detect gluten in one type of pasta but detected gluten residues in 63 (87.5%) of 72 other subsamples. The device was able to detect gluten at the 10-ppm addition level in 9 of the 13 food matrices (41 of 54 subsamples, 75.9%) but not in the three types of pasta and the puffed corn snack. The gluten-sensing device did not perform reliably at the 5-ppm addition level in 11 of 13 food matrices (exceptions: ice cream and muffins). In contrast, the ELISA methods were highly reliable at gluten addition levels of ≥10 ppm in all food matrices. The portable gluten detection device yielded a low percentage of false-positive results (4 of 111, 3.6%) in these food matrices. Thus, this handheld portable gluten sensor performed reliably in the detection of gluten in foods having ≥20 ppm of added gluten with only 18 (5.9%) of 306 failures, if results of the one type of pasta are excluded. The device worked with greater reliability as the gluten levels in the foods increased.

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Effects of Grass and Forests and the Infiltration Amount on Preferential Flow in Karst Regions of China

10.5194/egusphere-egu2020-47 ◽

2020 ◽

Author(s):

Xiaoqing Kan ◽

Jinhua Cheng

Keyword(s):

Organic Matter ◽

Preferential Flow ◽

Water Movement ◽

Vegetation Restoration ◽

Water Infiltration ◽

Rocky Desertification ◽

Restoration Planning ◽

Karst Areas ◽

Matrix Flow ◽

Natural Grassland

<p>&#160; Preferential flow is an important water infiltration phenomenon in karst regions because it can quickly transport surface water to deep soil and increases available water for underground root growth. The response of preferential flow to vegetation restoration requires urgent investigation due to the special soil structure of karst regions. In order to study the effect of vegetation restoration on water movement in karst regions, four kinds of ponded water infiltration experiments were carried out in Pinus Yunnanensis plantation forestland, secondary forestland, and natural grassland. A brilliant blue dyeing experiment was conducted to visualize the distribution of water infiltration in soil (a total of 150 stained images from vertical soil slices). Results showed that the average depth of matrix flow in natural grassland was approximately six times those in plantation and secondary forestlands. An increase in matrix flow will have a negative effect on the development of preferential flow. Water transported in preferential flow paths affects the distribution of nutrients and organic matter in the soil. However, preferential flow in grassland can promote the accumulation of available nutrients, and preferential flow in plantations can inhibit the loss of organic matter. Preferential flow in grasslands and forest plantations is less than that in native forests soils. The results of SEM showed that preferential flow increases the percolation of water in soils. The effect is that preferential flow can obstructs water uptake by the roots under low rainfall conditions, and decreases surface runoff before soil saturation under high rainfall conditions. In the process of nutrient element migration, preferential flow has a good contribution, which is conducive to the migration and accumulation of elements required for surface vegetation growth. The contribution of preferential flow needs to be considered in studies on vegetation restoration planning and land degradation. Reasonable allocation of plantation forests has a certain mitigation effect on soil erosion in Karst areas, and preferential flow under this special geomorphological type is worth studying. Preferential flow can transport nutrients to deeper soil for roots according to the data of this study. Therefore, plantation is feasible under karst landform conditions, but it is better to combine herbaceous plants in a plantation. The results could provide suggestions for the restoration of rocky desertification and the advantages or disadvantages of vegetation restoration engineering in karst areas.</p>

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Calcium content and high calcium adaptation of plants in karst areas of southwestern Hunan, China

Biogeosciences ◽

10.5194/bg-15-2991-2018 ◽

2018 ◽

Vol 15 (9) ◽

pp. 2991-3002 ◽

Cited By ~ 4

Author(s):

Xiaocong Wei ◽

Xiangwen Deng ◽

Wenhua Xiang ◽

Pifeng Lei ◽

Shuai Ouyang ◽

...

Keyword(s):

Plant Species ◽

Calcium Content ◽

Vegetation Restoration ◽

Plant Functional Groups ◽

Ecological Problem ◽

Rocky Desertification ◽

Exchangeable Ca ◽

High Calcium ◽

Karst Areas ◽

Ecosystem Reconstruction

Abstract. Rocky desertification is a major ecological problem of land degradation in karst areas. In these areas, the high soil calcium (Ca) content has become an important environmental factor that can affect the restoration of vegetation. Consequently, the screening of plant species that can adapt to high Ca soil environments is a critical step in vegetation restoration. In this study, three grades of rocky desertification sample areas were selected in karst areas of southwestern Hunan, China (LRD: light rocky desertification; MRD: moderate rocky desertification; and IRD: intense rocky desertification). Each grade of these sample areas had three sample plots in different slope positions, each of which had four small quadrats (one in rocky-side areas, three in non-rocky-side areas). We measured the Ca content of leaves, branches, and roots from 41 plant species, as well as soil total Ca (TCa) and exchangeable Ca (ECa) at depths of 0–15, 15–30, and 30–45 cm in each small quadrat. The results showed that the soil Ca2+ content in rocky-side areas was significantly higher than that in non-rocky-side areas (p<0.05). The mean soil TCa and ECa content increased gradually along with the grade of rocky desertification, in the order IRD > MRD > LRD. For all plant functional groups, the plant Ca content of aboveground parts was significantly higher than that of the belowground parts (p<0.05). The soil ECa content had significant effects on plant Ca content of the belowground parts but had no significant effects on plant Ca content of the aboveground parts. Of the 41 plant species that were sampled, 17 were found to be dominant (important value > 1). The differences in Ca2+ content between the aboveground and belowground parts of the 17 dominant species were calculated, and their correlations with soil ECa content were analyzed. The results showed that these 17 species can be divided into three categories: Ca-indifferent plants, high-Ca plants, and low-Ca plants. These findings provide a vital theoretical basis and practical guide for vegetation restoration and ecosystem reconstruction in rocky desertification areas.

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Response of soil specific enzyme activity to vegetation restoration in the Loess hilly region of China

CATENA ◽

10.1016/j.catena.2020.104564 ◽

2020 ◽

Vol 191 ◽

pp. 104564 ◽

Cited By ~ 3

Author(s):

Hongwei Xu ◽

Qing Qu ◽

Bingbing Lu ◽

Peng Li ◽

Sha Xue ◽

...

Keyword(s):

Enzyme Activity ◽

Vegetation Restoration ◽

Specific Enzyme ◽

Specific Enzyme Activity ◽

Hilly Region ◽

Loess Hilly Region

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Calcium content and high calcium adaptation of plants in karst areas of southwestern Hunan, China

10.5194/bg-2017-392 ◽

2017 ◽

Author(s):

Xiaocong Wei ◽

Xiangwen Deng ◽

Wenhua Xiang ◽

Pifeng Lei ◽

Shuai Ouyang ◽

...

Keyword(s):

Plant Species ◽

Calcium Content ◽

Vegetation Restoration ◽

Plant Functional Groups ◽

Ecological Problem ◽

Rocky Desertification ◽

Soil Calcium ◽

High Calcium ◽

Karst Areas ◽

Ecosystem Reconstruction

Abstract. Rocky desertification is a major ecological problem of land degradation in karst areas. Its high soil calcium (Ca2+) content has become an important environmental factor which can affect the restoration of vegetation in such rocky desertification areas. Consequently, the screening of plant species, which can adapt to soils high Ca2+ environment, is a critical step for vegetation restoration. However, the Ca2+ dynamics of plants and soil are not well understood. In this study, three different grades of rocky desertification samples areas (LRD, light rocky desertification; MRD, moderate rocky desertification; IRD, intense rocky desertification) were selected in karst areas of southwestern Hunan, China. Each grade of these samples areas had 3 sample plots in different slop positions, each of which had 4 small quadrats (1 in rocky side areas, 3 in non-rocky side areas). We measured the Ca2+ content of leaves, branches and roots from 41 plant species, as well as soil total Ca2+ (TCa) and exchange Ca2+ (ECa) at depths of 0–15, 15–30 and 30–45 cm under each small quadrat. The results showed that the soil Ca2+ content in rocky side areas was significantly higher than that in non-rocky side areas (p MRD > LRD. For all plant functional groups, the plant Ca2+ content of aboveground parts was significantly higher than that of the underground parts (p 1) and their correlations with soil ECa content, these 17 species can be divided into three categories: Ca-indifferent plants, high-Ca plants and low-Ca plants. Our results can provide a vital theoretical basis and practical guide for vegetation restoration and ecosystem reconstruction in rocky desertification areas.

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Karst environments and disturbance: evaluation of the effects of human activity on grassland and forest naturalness in dolines

Biologia ◽

10.2478/s11756-020-00518-7 ◽

2020 ◽

Vol 75 (10) ◽

pp. 1529-1535 ◽

Cited By ~ 1

Author(s):

Dianne Joy Aguilon ◽

András Vojtkó ◽

Csaba Tölgyesi ◽

László Erdős ◽

Péter János Kiss ◽

...

Keyword(s):

Sustainable Forest Management ◽

Anthropogenic Disturbances ◽

Conservation Strategies ◽

Generalist Species ◽

Warming Climate ◽

Open Questions ◽

Karst Areas ◽

Different Types ◽

Specialist Species ◽

Disturbed Habitats

Abstract Karst depressions (dolines) have the potential to act as safe havens for a high diversity of valuable species. We showed that local anthropogenic disturbances play a significant role in determining the naturalness of dolines. We compared the number of specialist species, competitor species, generalist species and species of disturbed habitats between natural and disturbed dolines in two Hungarian karst areas, where different types of anthropogenic disturbances have been shaping the vegetation for centuries. We found that these disturbances have the potential to negatively influence the naturalness of dolines, reducing the number of valuable species, thus affecting the conservation value of dolines. To maintain the naturalness of vegetation in these doline habitats, the populations of ruderal competitors should be eliminated, and sustainable forest management should be adapted. However, there are still open questions about the effects of different disturbances on the naturalness in dolines that need to be answered to determine which conservation strategies will be particularly suitable for valuable species in a warming climate.

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The effects of different types of vegetation restoration on wind erosion prevention: a case study in Yanchi

Environmental Research Letters ◽

10.1088/1748-9326/abbaff ◽

2020 ◽

Vol 15 (11) ◽

pp. 115001

Author(s):

Qi Luo ◽

Lin Zhen ◽

Yu Xiao ◽

Haiyan Wang

Keyword(s):

Wind Erosion ◽

Vegetation Restoration ◽

Different Types ◽

Erosion Prevention

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Spatial Variations in Microbial Compositions in a Karst Critical Zone in Samcheok, Republic of Korea

Applied Sciences ◽

10.3390/app10144714 ◽

2020 ◽

Vol 10 (14) ◽

pp. 4714

Author(s):

Heejung Kim ◽

Jiwook Jang ◽

Sangwook Park ◽

Chang-Seong Kim ◽

Han-Sun Ryu ◽

...

Keyword(s):

Water Samples ◽

Bacterial Communities ◽

Flow System ◽

Bacterial Species ◽

Karst Area ◽

Spatiotemporal Variations ◽

Flow Conditions ◽

Karst Areas ◽

Different Types ◽

Seawater Inundation

The effects of the unpredictability of the flow system in a karst area, with respect to bacterial communities in the aquatic environment, were evaluated. Bacterial communities from two different types of flow conditions (spring and sinkhole) were characterized and compared in the karst area. Proteobacteria, Bacteroidetes, and Verrucomicrobia were the major phyla present in the sampled spring and sinkhole waters. The water samples from the spring points were heavily loaded with Actinobacteria, especially Firmicutes, which accounted for 4.3% of the bacterial content. Furthermore, Actinobacteria were prevalent in some water samples, serving as indicators of the effects of seawater inundation. The richness and diversity of bacterial species were evaluated at the spring and sinkhole water points. The spring waters showed a higher bacterial richness and diversity compared to the sinkhole waters. Our results provide valuable information for the evaluation and investigation of microbial compositions in karst areas, which are characterized by heterogeneous hydrological conditions. The microbial species in karst areas are already exposed to changing hydrogeological conditions, and are likely to be confronted with future changes; thus, their spatiotemporal variations reflect the shifting baselines of physicochemical and ecosystem processes.

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Effects of Vegetation Restoration on Regional Soil Moisture Content in the Humid Karst Areas—A Case Study of Southwest China

Water ◽

10.3390/w13030321 ◽

2021 ◽

Vol 13 (3) ◽

pp. 321

Author(s):

Xiaocha Wei ◽

Qiuwen Zhou ◽

Mingyong Cai ◽

Yujuan Wang

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Soil Moisture Content ◽

Southwest China ◽

Vegetation Restoration ◽

Data Set ◽

Karst Areas ◽

Increasing Trend ◽

Drying Trend

Soil moisture is one of the restricting factors in the humid karst areas, which feature strong spatial heterogeneity. However, current research about the effects of vegetation restoration on soil moisture content have mainly focused on plot scale and slope scale, while these effects still remain unclear at regional scale in this area. Taking Southwest China as a case study and based on the land parameter data record (LPDR) and enhanced vegetation index (EVI) data set during 2002–2018, this study analyzed the spatiotemporal variation characteristics of vegetation and soil moisture content, and evaluated the effects of vegetation restoration on regional soil moisture content dynamics in paired years with similar precipitation conditions. The results showed that the EVI generally increased at a rate of 0.035/10a during 2002–2018, while the soil moisture was dominated by a drying trend at a variation rate of −0.0006 (cm3/cm3)/10a. The increasing trend of EVI accounted for 90.90% across the study area, whereas the decreasing trend of soil moisture accounted for 51.66%, and the increasing trend of soil moisture accounted for 48.34%. In addition, the decreasing trend of soil moisture coupled with an increasing trend of EVI distributed in most of the study area, especially in the homogenous limestone area. Our results demonstrate that there were remarkable vegetation restoration efforts in a series of ecological restoration projects, which resulted in a drying trend of the regional soil moisture content in the humid karst areas. The results suggest that it is necessary to consider reasonable vegetation planting density and suitable revegetation types to balance the relationship between vegetation water consumption and soil moisture supplementation in vegetation restoration practice in the humid karst areas.

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Effects of vegetation restoration on soil quality in fragile karst ecosystems of southwest China

PeerJ ◽

10.7717/peerj.9456 ◽

2020 ◽

Vol 8 ◽

pp. e9456

Author(s):

Huiling Guan ◽

Jiangwen Fan

Keyword(s):

Soil Quality ◽

Juglans Regia ◽

Soil Layer ◽

Vegetation Restoration ◽

Pennisetum Purpureum ◽

Toona Sinensis ◽

Prunus Salicina ◽

Karst Areas ◽

Restoration Time ◽

Karst Ecosystems

Soil quality assessment is important for karst ecosystems where soil erosion is significant. A large amount of vegetation restoration has been implemented since the early 21st century in degraded karst areas across southwestern China. However, the impacts on soil quality of different restoration types rarely have been compared systematically. In the current study, we investigated the soil quality after a number of vegetation restoration projects as well as their adjacent cropland by analyzing soil samples. Six vegetation restoration types were evaluated, including one natural restoration (natural shrubland, protected for 13 years), three economic forests (4 years Eucalyptus robusta, 4 years Prunus salicina and 6 years Zenia insignis) and two mixed forests (1 year Juglans regia–crop and 13 years Toona sinensis-Pennisetum purpureum ). We evaluated the benefits of different restoration types more accurately by setting each adjacent cropland as the control and setting the variation between the corresponding restored and control site as the evaluation object so that the background differences of six sites could be eliminated. The results indicated that natural shrubland, Toona sinensis-Pennisetum purpureum and Zenia insignis were effective in improving soil quality index (SQI) in degraded karst cropland largely due to their higher SOC and TN content. The variation of SQI (VSQI) of natural shrubland was significantly higher than that in Eucalyptus robusta, Prunus salicina and Juglans regia-crop in total soil layer (0–30 cm) (P < 0.05), indicating natural shrubland had better capacity to improve soil quality. The boosting regression tree model revealed that vegetation restoration type explained 73.49% and restoration time explained 10.30% of the variation in VSQI, which confirmed that vegetation restoration type and restoration time are critical for achieving soil reserves. Therefore, it is vital to select appropriate vegetation type in restoration projects and recovery for a long time in order to achieve better soil quality. The current study provides a theoretical basis on which to assess the effects of different vegetation restoration types on the heterogeneous degraded karst areas.

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