Changes In Soil Quality Research Articles

Soil quality assessment and its response to water flow connectivity in different vegetation restoration types, eastern China

Vegetation restoration is the most widely used forest management practice for degraded soils, but the responses of soil quality in different vegetation restoration types may vary. In addition, the relationship between water flow paths connection and soil quality needs to be further explored. In this study, the soil quality index (SQI) and the index of water flow connectivity (IWFC) in the six water flow patterns (PFP, SSB, WSB, CPS, CPW, and CSW) were explored at three forest stands (oak, pine, and bamboo forests) with 50 years for enclosure. The results showed that the bamboo forest stand had the best soil quality as a whole (0.534 ± 0.135), followed by pine (0.530 ± 0.180) and oak forest stands (0.435 ± 0.205). The IWFC in PFP, CPS and CPW water flow patterns decreased gradually with increasing soil depth, while in SSB, WSB and CSB water flow patterns, the IWFC increased at first and then decreased. Finally, the IWFC in the CPW water flow pattern showed the largest positive correlation with the SQI (P < 0.05). The IWFC in the CPW water flow pattern driven by soil physical properties could mainly control the changes in the SQI indirectly (average IE = 0.825) by influencing soil nutrient (average IE = 0.447) and biological (average IE = 0.485) properties, while its direct effects could be ignored (average DE = −0.074), which demonstrated that the joint effects of preferential flow paths and weak stream buffer zones can dramatically reflect the changes in soil quality. The better soil improvement effect of bamboo and pine forest stands compared to the oak forest stand should be given more consideration. This study provided new insights for the assessment of the relationship between soil hydrology and soil quality.

Changes in soil quality during different ecological restoration years in the abandoned coal mine area of southern China

AbstractUnderstanding the effects of abandoned coal mine ecological restoration on soil quality and function is important to protect the regional ecological environment. This study aims to evaluate the ecological restoration effects of soil quality in abandoned coal mine area. Taking Fengcheng County, a typical coal‐rich area in southern China, as a case, this study took 120 soil samples to investigate the influence of restoration years on soil quality by using an integrated soil quality index (SQI). Results indicated that restoration years had significant effects on the saturated hydraulic conductivity (Ks) by affecting the soil bulk density, clay content, and soil water content. Furthermore, clay, soil organic matter, Ks, and pH were selected to assess the effect of ecological restoration years on soil quality. It was found that the ecological restoration 8 years (ER8) site had higher SQI value, indicating ecological restoration years showed a positive correlation with SQI in abandoned coal mine area. Since there was a 4‐year gap between ecological restoration 4 years site and ER8 site, the ecological restoration may be effective between 5 and 8 years. The results of this study are of great significance for improving the effects of ecological restoration and management in abandoned coal mine area.

An overview of soil and plant assessment for predicting site quality and recovery strategies of one the largest tailings dam failures worldwide.

Brazil's Fundão dam collapse is one of the world's largest disasters of tailing dam failures. Previous research has evaluated toxic metals and non-metals (Cd, Cr, Ni, Pb, As, Hg) in the same soil samples used in this study, and results have indicated that only Fe and Mn concentrations increased above the original baseline (Melo et al., 2023). Consequently, the present study's focus has shifted towards assessing and integrating changes in soil quality regarding chemical fertility and morphological, physical, and mineralogical attributes in the floodplains post-dam collapse. Soil samples from 0 to 0.2 and 0.2-0.4m depths, and samples of Urochloa sp. were collected along ten transects, spanning 100km perpendicular to the Doce River channel. This sampling strategy targeted specific landscape positions including areas affected by deposited iron tailings (DIT), soil tailing mixture (STM), and control soil (CS) devoid of iron tailing interference. Results showed no discernible alterations in Ca, Mg, K, and P concentrations in Urochloa sp., and the most severe negative impacts observed regarded the replacement of kaolinitic pre-disaster matrix for hematitic matrix, reduction in organic carbon, and the prevalence of sand and silt particles. These factors collectively contributed to triggering: (i) decrease in chemical fertility and cation exchange capacity and (ii) significant decline in physical quality, evidenced by increased density and reduced total porosity and macroporosity. Addressing these adverse effects would require the augment of organic matter levels and offset the dominance of the hematitic matrix in the DIT. Furthermore, it is imperative to decompact the DIT by mechanized or plant cultivation means.

Effects of Film Mulching on Soil Quality, Garlic Yield, and Garlic Quality

To determine the optimal film management technique for garlic planting, this study aimed to investigate the effects of various film cover methods on soil quality and garlic yield in garlic cropping systems. To achieve these goals, trials with different film cover methods were conducted at the Jiangsu Academy of Agricultural Sciences in Nanjing. To investigate the impact of changes in soil quality and garlic yield, we set up four treatments： no film treatment （CK）, black polyethylene film treatment （HPE）, black poly（butylene- adipate-co-terephthalate） （PBAT） with straw composite film treatment （HSJ）, and white PBAT film treatment （BJ） in a garlic cropping system. Our results indicated that specific mulch coverings had a positive effect on both soil quality and garlic yield. The film cover treatments resulted in significant changes in soil physicochemical properties and bacterial and fungal biomasses and indirectly improved soil quality. Compared to that under the no film treatment, the BJ treatment boosted soil quality by 70%, with the most significant impact, followed by that under the HPE and HSJ treatments, with improvements of 52% and 36%. Random forest modeling indicated that soil organic matter and total nitrogen were the most important factors influencing soil quality. The different film covers significantly increased the diameter of garlic bulbs and single quality. The HSJ treatment exhibited the most significant increase in garlic yield, with 46%, 19%, and 6% improvement compared to that in the CK, HPE, and BJ treatments, respectively. Correlation analysis showed that soil quality under film cover was significantly correlated with the starch content of garlic bulbs, garlic diameter, and single quality. This study highlights that selecting the appropriate mulch film aids in the production of garlic and helps to develop farmland that produces both high-quality and high-yield crops.

Temporal Variations in Fire Impacts on Characteristics and Composition of Soil-Derived Dissolved Organic Matter at Qipan Mountain, China.

Dissolved organic matter (DOM), the most reactive fraction of forest soil organic matter, is increasingly impacted by wildfires worldwide. However, few studies have quantified the temporal changes in soil DOM quantity and quality after fire. Here, soil samples were collected after the Qipan Mountain Fire (3-36 months) from pairs of burned and unburned sites. DOM contents and characteristics were analyzed using carbon quantification and various spectroscopic and spectrometric techniques. Compared with the unburned sites, burned sites showed higher contents of bulk DOM and most DOM components 3 months after the fire but lower contents of them 6-36 months after the fire. During the sharp drop of DOM from 3 to 6 months after the fire, carboxyl-rich alicyclic molecule-like and highly unsaturated compounds had greater losses than condensed aromatics. Notably, the burned sites had consistently higher abundances of oxygen-poor dissolved black nitrogen and fluorescent DOM 3-36 months after the fire, particularly the abundance of pyrogenic C2 (excitation/emission maxima of <250/∼400 nm) that increased by 150% before gradually declining. This study advances the understanding of temporal variations in the effects of fire on different soil DOM components, which is crucial for future postfire environmental management.

Moving toward a fairer access to land fostering agroecological transition? A decade of legal change and reframing of debates around soil and climate in France

Although farmland concentration receives narrower media coverage than land grab, it goes hand in hand with impactful environmental and demographic consequences. This article examines the case of France, one of the European countries with the highest level of farmland market control. It questions to what extent the regulation of access to land is adapted to initiate an agroecological and food transition. Its objective is to analyze why and how land concentration has been reframed in the past decade, by which types of stakeholders, building on which sources of legitimacy, and with which legal strategies and results. The theoretical framework combines the sociology of controversies and agenda-setting with a land justice-based approach. This article builds on a textual hermeneutics of 3 documental corpora encompassing a press review with 172 items, 112 documents (press releases, opinion pages, reports, notes, interviews, public speeches, amendment proposals, draft bills, laws, and decisions), and 3,409 tweets (those mentioning loi foncière or the #LoiFoncière hashtag, and those quoting, retweeting, or replying (to) them). These data were contextualized using sporadic participant observation. Since 2013, and more specifically since 2018, 2 networks of left-wing politicians, left-wing farmers’ unions, and civil society nongovernmental organizations have brought land justice concerns up-to-date to put farmland concentration on the political agenda. However, only minor progress has been made. A major factor in this is the chronological gap between, on the one hand, the successive reframings of the issue (from soil quality and climate change mitigation lenses), the proposed legal devices, the degree of projected legal change and, on the other hand, the pace at which the window of opportunity for a new land law has opened and closed. Indeed, the land imaginaries of land commons that underpin the agroecological transition are not yet sufficiently socially legitimate to be enshrined in law.

Anthropogenic shrub encroachment has accelerated the degradation of desert steppe soil over the past four decades

Anthropogenic and natural shrub encroachment have similar ecological consequences on native grassland ecosystems. In fact, there is an accelerating trend toward anthropogenic shrub encroachment, as opposed to the century-long process of natural shrub encroachment. However, the soil quality during the transition of anthropogenic shrub encroachment into grasslands remains insufficiently understood. Here, we used a soil quality assessment method that utilized three datasets and two scoring methods to evaluate changes in soil quality during the anthropogenic transition from temperate desert grassland to shrubland. Our findings demonstrated that the soil quality index decreased with increasing shrub cover, from 0.49 in the desert grassland to 0.31 in the shrubland. Our final results revealed a gradual and significant decline of 36.73 % in soil quality during the transition from desert grassland to shrubland. Reduced soil moisture levels, nutrient availability, and microbial activity characterized this decline. Nearly four decades of anthropogenic shrub encroachment have exacerbated soil drought conditions while leading to a decrease in perennial herbaceous plants and an increase in bare ground cover; these factors can explain the observed decline in soil quality. These findings emphasize the importance of considering soil moisture availability and potential thresholds when implementing revegetation strategies in arid and semiarid regions.

Polyaspartic calcium improved soil quality and altered nitrification process in saline‐sodic paddy soils

AbstractSaline‐sodic paddy soils in the Songnen Plain suffer from nitrogen loss due to nitrification. The purpose of the study is to explore soil saline improvement and nitrification mitigation effects of polyaspartic calcium (PASP‐Ca) by evaluating changes of soil quality, nitrification, and microbial communities. Four PASP‐Ca application treatments (additions of 0, 500, 1000, and 1500 kg hm−2) were studied in an experiment in saline‐sodic paddy soils of the Songnen Plain, China. Results showed that PASP‐Ca application significantly decreased soil pH, electrical conductivity (EC), and water‐soluble salt ions, and significantly increased soil total carbon (TC), total nitrogen (TN), urease activity (UA), and sucrase activity (SA). PASP‐Ca application significantly slowed down soil nitrification, which was manifested in a significant increase in ammonium nitrogen () and a significant decrease in nitrate nitrogen () and ammonia monooxygenase activity (AMO). The composition and distribution of soil nitrifying microbial communities were affected by soil salinity, nutrient, and enzyme activities. Ammonia‐oxidizing bacteria (AOB) plays an important role in the nitrification process of saline‐sodic paddy soils, while PASP‐Ca application significantly inhibited nitrification by suppressing AOB amoA gene abundance. This study shows that PASP‐Ca, as an effective amendment, can improve soil salinization and slow down nitrification, which has an important role and significance in improving nitrogen utilization and reducing nitrogen loss of saline‐sodic soils.

Assessment of Soil Enzyme Activities in Plant Root Zone of Saline Soil Reclaimed by Drip Irrigation with Saline Groundwater

Drip irrigation with saline water is frequently adopted to realize the sustainable utilization of saline–sodic soil with high water tables, and soil enzyme activities can be used to indicate changes in soil quality. In the current study, spatiotemporal changes in soil urease enzyme (URE), alkaline phosphatase (ALP) and invertase (INV) activities were investigated during consecutive growing seasons. Soil in beds was sampled before planting (0 y) and one, two, three and four years after the growing season (1 y, 2 y, 3 y, 4 y), and these samples were distributed at four horizontal distances from the drip line (0, 10, 20 and 30 cm) and four vertical soil depths (0–10, 10–20, 20–30 and 30–40 cm). The results showed that a distribution pattern of URE and ALP activities formed during the first growing season, while the distribution of INV activity formed until the third growing season. All three soil enzyme activities in the upper soil layers and positions close to the drip line were more greatly affected by planting year. The average URE activity of the soil profile decreased slightly during the first year and increased by about 220% and decreased by 20% after reclamation for two and three years, and finally, it increased to 4.9 μg NH4+·g−1·h−1 at the end of the fourth growing season. ALP activity remained stable during the first two years and rapidly increased in the following years; in particular, in the fourth year, it reached 32.7 μg ph(OH)·g−1·h−1. INV activity increased continually with the number of years after planting and reached 1009.0 μg glu·g−1·h−1 at the fourth season’s end. An analysis of variance indicated that URE, ALP and INV activities varied insignificantly among the time points of 0 y, 1 y, 2 y and 3 y (p &lt; 0.05), while they were significantly higher for 4 y than for 0 y and 1 y. In addition, all three enzyme activities of the soil profile had an exponentially increasing trend with the number of years after planting. These results indicated the soil quality in saline–sodic soils could be improved with time under drip irrigation with local saline groundwater, especially around the drip line.

Mixed planting mode is the best measure to restore soil quality in alpine mines

In ecologically fragile areas heavily affected by human disturbance, it is imperative to restore soil quality to preserve nutrient cycling and ensure ecosystem stability. However, our understanding about the underlying mechanisms of dynamic change in soil quality associated with revegetation in alpine areas remains incomplete. In this study, data from 96 plots were collected to reveal the response of soil quality to vegetation restoration in alpine mines. The soil quality index (SQI) was developed utilizing 19 measured indicators to assess differences in soil quality between various vegetation restoration modes (natural restoration (CK), planting with Elymus dahuricus (ED), Medicago sativa (MS), and multi-plant mixed (Avena fatua L. + Elymus dahuricus + Medicago sativa + Oxytropis coerulea, MM)) and restoration periods (1, 3, 4, and 6 years). A partial least squares structural equation model (PLS-SEM) was constructed to recognize the impact of 14 variables related to topographical features, plant biodiversity and community stability, aboveground plant productivity characteristics, root functional traits, and soil erosion on soil quality. The results revealed significant variations in soil quality among different vegetation restoration modes. Within the initial four years following vegetation restoration, the discernible discrepancies in SQI values were as follows: ED > MM > MS > CK; by the sixth year, the order shifted to MM > ED > MS > CK. Aboveground plant productivity characteristics and functional root traits significantly contribute to soil quality. In contrast, plant biodiversity and community stability had no significant effects on soil quality. Topographical features and soil erosion adversely affected soil quality, with soil erosion exerting the most prominent effect.

Soil microbiota resilience in a two-decade long-term experiment comparing an organic and a conventional cropping system

The effect of conventional and organic management in agriculture impacts not only economic and food quality aspects but potentially all biological components of the environment where these activities occur, including soil microorganisms. While there is generally positive appreciation for organic agriculture's role in organic matter accumulation, its beneficial effects on soil microbiota are a matter of debate, mostly due to the varying conditions in which the comparisons are made. To minimize the impact of distant locations, soils were sampled from nearby fields managed separately with the same rotation schemes for 18 years with conventional low-impact and organic agriculture methods. Samples from six different crops were compared using metabarcoding and metabolomic fingerprinting. The major differences were found between late summer and spring, whereas the variations between the beginning and the end of the spring were neither large nor significant. Some significant differences were found between the microbiota of organic vs. conventional management, particularly between r- and k-strategist microorganisms. While other studies found very little differences between microbiota of differently managed soils after shorter time periods, this work highlights that nearly two decades of separate management are necessary to induce significant variations in the microbiota. This suggests a strong resilience of soil populations and the need for very long-term strategies in agriculture to effect significant changes in soil quality.

Natural colonizers effectively restore heavy metal polluted wasteland

In India, ∼30% of total land is degraded due to pollution, salinization, and nutrient loss. Change in soil-quality at urban waste-dumping site prior and after cow-dung amendment was compared with control agriculture soil. The soil at waste-dumping site had elevated pH, EC, temperature and lowered OC and NPK concentrations when compared to control. Polymetallic pollution of Cr, Cd, Pb, and Ni beyond permissible limits was obtained. Cow-dung amendment restored soil physicochemical properties at the waste-dumping site, with increasing soil moisture, CEC and OC; however, a slight change in soil bulk-density and heavy-metal concentration post-amendment was noted. The seven natural colonizers present at the waste-dumping site accumulated more metals in roots than shoots. Datura innoxia had maximum bioaccumulation of Cr, Calotropis procera of Cd and Ni and Parthenium hysterophorus of Pb in roots. All these plants had Bioacccumulation factor (BAfroot )>1 and translocation factor (Tf) <1 for Cd and serve as its phytostabilizer except Calotropis procera which had BAfroot >1 and Tf >1 and is identified as a phytoextractor for Cd. Cow-dung amendment alone appeared to be insufficient and additionally the revegetation of natural colonizers is recommended for effective reduction in heavy metal load and improving overall soil health at wasteland. Such eco-restoration may also minimize risks to biodiversity in India.

Response of soil quality degradation to cultivation and soil erosion: A case study in a Mollisol region of Northeast China

Soil degradation is endangering agricultural and ecological sustainability in the Mollisol region of Northeast China. Cultivation and soil erosion are the primary drivers degrading soil quality. However, few studies have comprehensively quantified the effects of cultivation and soil erosion on soil quality degradation in Mollisols. Therefore, three sampling sites with similar landscapes, erosion environments and agricultural management practices were selected. The cultivation chronosequence was determined using a space-for-time substitution approach, including 1) forestland without cultivation (0 yr, stage I), 2) farmland with few cultivation years (< 20 yr, stage II), and 3) farmland with many cultivation years (> 80 yr, stage III). Soil erosion was quantified using the caesium-137 (137Cs) and black soil thickness. Sixteen soil physicochemical indicators were analyzed, and soil quality and its degradation were evaluated using an integrated soil quality index (SQI) and a soil degradation index (SDI), respectively. The results showed that soil erosion was profoundly accelerated by cultivation. Soil organic carbon (SOC), bulk density (BD), mean weight diameter (MWD) and soil erodibility (K) factor were selected to develop the SQI. The SQI was higher in stage I (0.61±0.05) than in stages II (0.49±0.06) and III (0.52±0.03) and decreased with increasing soil erosion rate, implying that cultivation and soil erosion exacerbated the degradation of soil quality. Furthermore, cultivation and soil erosion contributed 16.0–51.1% and 2.0–18.4% to the changes in soil quality, respectively, and their combination further amplified the impacts (8.4–61.5%). Cultivation and accelerated soil erosion driven by cultivation led to the degradation of soil quality; the former controlled the degradation processes mainly by decreasing the MWD, and the latter induced soil quality degradation by reducing the SOC and increasing the K factor. These findings are important for advancing our understanding of the driving forces and mechanisms of soil degradation in the Mollisol region.

Use of compost to improve Technosol properties and spontaneous plant-soil relationships of Mediterranean species potentially suitable for urban greening

Organic-based amendments are promising, eco-friendly solutions among soil requalification strategies. In this context, the current study explored the application of compost to Technosols (2 kg m-2) to improve soil quality, making the substrate suitable for plant growth. Changes in soil quality have been assessed before compost addition (time zero, T0) and plant transplanting and at 2, 4 and 11 months (T2, T4, and T11) after plant establishment. To test the soil suitability for plant growth, we monitored (at T2, T4, and T11) structural and functional ecological traits in the herbaceous spontaneous species Malva sylvestris L. and in transplanted Mediterranean sclerophyllous Phillyrea angustifolia L., and Quercus ilex L., often used in the urban greening, also considering plant and soil relationships. Our study demonstrated that compost increased soil nutrients availability over time, favoring M. sylvestris physiological performance in long-lasting, compared to sclerophyllous, since the beginning of the application. M. sylvestris exhibited high photosynthetic efficiency and carbon investment in photosynthetic tissues (higher leaf area and lower leaf mass per area) on compost-enriched soil. On the other hand, P. angustifolia and Q. ilex, even if they did not benefit from compost addition for photosynthetic efficiency, after 11 months, maintained higher leaf water content despite limited soil water availability. These results encourage the use of compost in ameliorating the quality of Technosols for urban greening, also evidencing that the species’choice is pivotal in obtaining benefits from plants and a period longer than one year is needed for sclerophyllous to see beneficial effects.

Early impacts of marginal land‐use transition to Miscanthus on soil quality and soil carbon storage across Europe

AbstractMiscanthus, a C4 perennial rhizomatous grass, is a low‐input energy crop suitable for marginal land, which cultivation can improve soil quality and promote soil organic carbon (SOC) sequestration. In this study, four promising Miscanthus hybrids were chosen to evaluate their short‐term potential, in six European marginal sites, to sequester SOC and improve physical, chemical, and biological soil quality in topsoil. Overall, no differences among Miscanthus hybrids were detected in terms of impacts on soil quality and SOC sequestration. SOC sequestration rate after 4 years was of +0.4 Mg C ha−1 year−1, but land‐use transition from former cropland or grassland showed contrasting SOC sequestration trajectories. In unfertilized marginal lands, cultivation of high‐yielding Miscanthus genotypes caused a depletion of K (−216 kg ha−1 year−1), followed by Ca (−56 kg ha−1 year−1), Mg (−102 kg ha−1 year−1) and to a lesser extent of N. On the contrary, the biological turnover of organic matter increased the available P content (+164 kg P2O5 ha−1 year−1). SOC content was identified as the main driver of changes in biological soil quality. High input of labile plant C stimulated an increment of microbial biomass and enzymatic activity. Here, a novel approach was applied to estimate C input to soil from different Miscanthus organs. Despite the high estimated plant C input to soil (0.98 Mg C ha−1 year−1), with significant differences among sites and Miscanthus hybrids, it was not identified as a driver of SOC sequestration. On the contrary, initial SOC and nutrients (N, P) content, as well as their elemental stoichiometric ratios with C, were the key factors controlling SOC dynamics. Introducing Miscanthus on marginal lands impacts positively soil biological quality over the short term, but targeted fertilization plans are needed to secure crop yield over the long term as well as the C sink capacity of this perennial cropping system.

Organic food has lower environmental impacts per area unit and similar climate impacts per mass unit compared to conventional

In recent years, interest in studying the climate and environmental impact of organic food has grown. Here, we compared the environmental impacts of organic and conventional food using data from 100 life cycle assessment studies. Most studies focused on climate impacts, with fewer addressing biodiversity loss and ecotoxicity. Findings revealed no significant differences in global warming, eutrophication potential, and energy use per mass unit. However, organic food showed lower global warming, eutrophication potential, and energy use per area unit, with higher land use. Additionally, organic farming showed lower potential for biodiversity loss and ecotoxicity. Challenges in life cycle assessment include evaluating biodiversity, toxicity, soil quality, and carbon changes. The choice of functional units influences results, highlighting the importance of considering multiple units in assessing organic food’s environmental footprint. This study emphasizes the necessity for comprehensive assessments at both product and diet levels to support informed decisions.

Plant Tissues as Biomonitoring Tools for Environmental Contaminants

Environmental toxins pose significant threats to ecosystems and human health. Monitoring and assessing these toxins are crucial for effective environmental management and public health protection. Recently, plant species have garnered increasing attention as potential bioindicators for identifying and evaluating ecological toxins. Since plants often come into touch with harmful compounds in soil, water, and the atmosphere, they are particularly valuable for analyzing how human activities influence the terrestrial ecosystem, the aquatic system, and the atmosphere. This review paper emphasizes using plant species as a resource for tracking environmental pollution and analyzing contaminants. We focused on plants because they are significant indicators of soil, water, and air quality changes. Many plants have been used as bio-indicators to assess and predict pollution, toxicity, and environmental changes. These include Allium cepa, Vicia faba, Pisum sativum, Zea mays, Nicotiana tabacum, lichens, and mosses. The idea of bioindicators is discussed in the current paper, with a focus on plants as possible candidates for bioindicators for toxin assessment and related outcomes.

Influence of Land Use Types on Soil Properties and Soil Quality in Karst Regions of Southwest China

Establishing a suitable and useful soil quality index (SQI) is the key to accurately evaluating changes in soil quality (SQ) under different land use types. In the present study, a suitable and useful SQI using a minimum data set (MDS) with two scoring methods (linear scoring method and nonlinear scoring method) and two additive models (simple additive model with same weighting value and weighted additive model with significant different weighting value) was established to compare SQ under different land uses in Longtan valley. Soil samples were collected under one dryland (DRYL), one paddy (PADD), one orchard (GRA), and one natural forest (FORE), and 13 soil properties were measured. The four land use types had the same soil type and similar environmental conditions. Land use types had significant effects on the measured 12 soil properties. The top two principal components in Principal Component Analysis were chosen, and their cumulative variance was more than 90%. Soil indicators of soil labile carbon, C/N ratio, and microaggregates were chosen as members of MDS in this study. Significant (p &lt; 0.001) positive correlations among the four establishing SQIs were found. The values of the sensitive index ranged from 47.17% to 82.12% for the four SQIs, and the SQI established using the nonlinear scoring method and weighted additive model (SQI-NLW) had the highest values. Among the four land use types, the four SQIs had similar change trends, and the average values of SQ under FORE (0.73) and PADD (0.68) were significantly higher than those under GRA (0.54) and DRYL (0.43). These results indicated that the SQI-NLW was an effective and precise tool to assess SQ under different land uses in similar regions, and the FORE and PADD were the suitable land use types for the sustainable use of soils in karst regions.

Quinoa growth and yield performance under salinity stress in arid West Texas

AbstractCrops such as quinoa (Chenopodium quinoa Willd.) that are both salinity and drought‐tolerant and with high seed value are needed to sustain agriculture in arid Far West Texas facing dual threat of freshwater scarcity and soil salinization. However, quinoa's growth and yield performance under arid conditions of Far West Texas has not been studied previously. This study evaluated growth and yield of a salt‐tolerant quinoa genotype under greenhouse conditions using a completely randomized experimental design with irrigation water salinity as the main factor having five different levels (freshwater, 5, 10, 15, and 20 dS m−1). Plant parameters (plant height, leaf SPAD, leaf tissue carbon, and nitrogen concentrations) and seed yield were measured for two growing seasons. Soil quality (salinity and sodicity) changes were also determined for the same time. Seed yields ranged between 747 and 6065 kg ha−1 across 2 years, indicating significant effects of water salinity. However, these yields were comparable to those reported in the literature. Increasing water salinity significantly affected all growth parameters with leaf C and N decreasing by an average of 20%, whereas reductions in plant height reached a high of 60% at 20 dS m−1. Similar reductions in leaf chlorophyll content were found with increasing water salinity. Soil salinity and sodicity significantly increased over time with irrigation water salinity. Importantly, we observed that quinoa has a much higher soil salinity threshold (∼12 dS m−1) above which yields declined rapidly. Higher salt tolerance threshold of quinoa makes it an alternative economically viable crop for the Trans‐Pecos Texas region.

The Diversity and Composition of Soil Microbial Communities Differ in Three Land Use Types of the Sanjiang Plain, Northeastern China.

In recent years, the Sanjiang Plain has experienced drastic human activities, which have dramatically changed its ecological environment. Soil microorganisms can sensitively respond to changes in soil quality as well as ecosystem function. In this study, we investigated the changes in soil microbial community diversity and composition of three typical land use types (forest, wetland and cropland) in the Sanjiang Plain using phospholipid fatty acid analysis (PLFA) technology, and 114 different PLFA compounds were identified. The results showed that the soil physicochemical properties changed significantly (p < 0.05) among the different land use types; the microbial diversity and abundance in cropland soil were lower than those of the other two land use types. Soil pH, soil water content, total organic carbon and available nitrogen were the main soil physico-chemical properties driving the composition of the soil microbial community. Our results indicate that the soil microbial community response to the three different habitats is complex, and provide ideas for the mechanism by which land use changes in the Sanjiang Plain affect the structure of soil microbial communities, as well as a theoretical basis for the future management and sustainable use of the Sanjiang plain, in the northeast of China.