Forward and reverse successions of karst rocky desertification (KRD) occur simultaneously, and are linked to human activity, thus presenting a mutual feedback loop. Previous studies have focused on the unilateral human-driven mechanism of KRD or the impact of KRD on social-economic activities. These lack quantitative measurement and in-depth understanding of interactions involved. Therefore, this study builds and applies a novel model for measuring the coupling relationship and degree between KRD and social-economic activity in the Guizhou karst region of China. Results show an overall improvement but local deteriorations in KRD from 2000 to 2011; conversely, social-economic activity intensities increased during that time period. With their spatio-temporal variations, positive and negative human–desertification coupling relationships with an increased coupling degree are found. Different coupling relationship types between KRD and social-economic development, including urbanization, economic development and household income, are shown. KRD is found to be high positively coupled with specific human behavior intensities such as population movement, steep slope cultivation and ecological restoration. An inverted U-shaped curve is observed in the coupling index of KRD and urbanization within different development levels. Negative coupling at a low urbanization level indicates the limitation of the karst physical environment on social-economic development. Positive coupling with increasing urbanization implies a conflict between environment protection and social-economic development. A return to negative coupling in several counties with high urbanization levels indicates a win-win for ecology and economy. The effectiveness of the proposed coupling model is demonstrated, informing differentiated strategies for combating KRD and improving social-economic development.

Sanjiang Plain is the largest area of freshwater wetland in China. Due to agricultural development, a large volume of groundwater in this area has been extracted over the last few decades, resulting in wetland degradation. In order to provide information for the development and protection of wetland ecosystem, investigations examining processes of wetland degradation are important. The aim of this work is to assess the impacts of wetland degradation on the communities of soil microbial community under four different types of degradation wetland including swamp meadow (SW), meadow wetland (MW), paddy farmland (PF), and cropland (CL) in Sanjiang Plain. Using both 16S and ITS rRNA gene amplicon sequencing to evaluate the fungal and bacterial diversity and composition. The dominant fungal phyla and bacterial were Ascomycota and Proteobacteria in this study, respectively. In addition, wetland degradation remarkably augmented the partial affluence of Chloroflexi and Gemmatimonadetes, but the partial affluence of Proteobacteria and Verrucomicrobia significantly diminished. Bacterial Shannon index of SW was lower than those in other sites. While, fungal diversity had no significant differences under different types of degradation wetland. Along with the wetland degradation, such differential reactions of the dominant phyla microbial and diversity were notably coordinated with TP, TK, AK, and SOM, which were the most essential criteria influencing the soil microbial communities. Generally, these outcomes suggested that wetland degradation could result in variations in soil microbial community composition structure. These changes could be used as an early warning signal for the degradation wetland in Sanjiang Plain.

Globally, urban wetlands are facing immense pressure of land use land cover changes (LULCCs) and associated water quality degradation that is severely affecting the trophic status of these pristine ecosystems. This study analyzed water quality degradation resulting due to the land system changes in the vicinity of Khushalsar, an urban wetland, in Srinagar city from 1980-2017. The analysis of satellite data indicated that the wetland has lost ~18.1 ha from 1980-2017. During the same period the urban area within the wetland increased from 0.2% to 16.5%. The land cover changes assessed in the immediate vicinity of wetland indicated an increase of 119% in built-up and 62.8% in roads. The analysis of surface water quality of the wetland showed much greater degradation of Khushalsar wetland. The Trophic State Index (TSI) ranged from 73.4-84.6 thereby indicating the hyper-eutrophic nature of the wetland. A snapshot of comparative water quality data from 2002-2018 revealed that the mean concentration of NO3–N increased from 219-433 µg L-1 and total phosphorus (TP) increased from 135.4-1236 µg L-1 indicative of continuous nutrient enrichment. Hierarchical cluster analysis (HCA) clustered 8 sampling sites into 4 groups based on likeness of water quality characteristics. Similarly, discriminant analysis (DA) showed the formation of similar patterns of clusters, authenticating the outcomes of HCA. Wilk’s λ quotient dispersion highlighted the role of nutrients and ions in the development of clusters. Principal component analysis (PCA) formed three principal components (PC’s) accounting for a cumulative variance of 90.61%.

Long-term application of high nitrogen and phosphorus fertilizer and mono-tillage practices can adversely affect soil health, carbon sequestration and crop growth. A 10-year field experiment was conducted in a wheat-maize cropping system on the Loess Plateau in China to explore fertilization and tillage methods that improve SOC sequestration and crop yields. We evaluated the effects of (1) fertilization (balanced fertilization (BF), low fertilization (LF), and conventional fertilization (CF)) and (2) alternating years of different tillage (no-tillage and subsoiling (NS), subsoiling and ploughing (SP), ploughing and no-tillage (PN)) or continuous ploughing tillage (PP) on input-C, SOC pool, and crop yields. BF and rotational tillage (NS, SP, and PN) increased the amount and stabilization rate of input-C, thereby increased SOC storage, and the highest effect was found in BF+NS treatment. Simultaneously, BF produced higher contents of SOC, readily oxidizable carbon (ROC), particulate organic carbon (POC) and dissolved organic carbon (DOC) and C pool management index (CMI) at 0-10 cm depth. For tillage, rotational tillage increased labile C contents and CMI at 0-10 cm, 20-35 cm and 35-50 cm depths, which improved soil quality. Crop yields showed an increase tendency with the increases of SOC content, labile C fraction contents, and CMI. Therefore, the higher yields of wheat and maize were found in BF and rotational tillage; the highest were in BF+NS treatment. Our finding suggested that NS combined with BF may be the best management to increase SOC storage, improve soil quality and productivity on China’s Loess Plateau.

People’s preferences influence national priorities for economic development and ecological integrity. Often policy makers and development agents base their actions on unclear assumptions about people’s preferences. This paper explores rural citizens’ preferences for economic and ecological development goals and how they differ within and between communities. We collected data from three purposely selected communities representing dominant social-ecological systems in the transboundary Cubango-Okavango River Basin in southern Africa. We used contingent ranking survey experiments, which are a novel methodological advance in policy related research. This included a qualitative experimental design process that provided a broad framing underpinning the research. The contingent ranking itself allowed us to simultaneously assess (i) participants’ ranking priorities for the development goals; and (ii) participants’ preferences for the ordering of those goals. We found relatively strong preference homogeneity within and between communities. Economic development attributes were given high priority across all communities. At the same time, all communities expressed a high preference for a healthy river system providing stable water quality and quantity. This does not mean that our respondents prioritized nature conservation. They showed low preferences for preserving biodiversity and forests which provide less important local benefits than water. This is of high governance relevance. The results point at development domains where policy makers can most likely expect stronger buy-in from citizens. Understanding citizens’ preferences helps to better align national development priorities with what citizens want.

Soil salinity has today become a highly disastrous phenomenon that is responsible for crop failure worldwide and specially in countries with low farmer incomes and food insecurity. Soil salinity is often caused due to water accumulation in fields due to unscientific flood irrigation wherein plants intake the water leaving salts behind. It is, however, the sub-surface soil salinity that affects the plant growth. These salts in sub-surface soil get trapped in root nodules of plants and prevent further water intake. There have been very few studies conducted for sub-surface soil salinity estimation. Hence this study aims to estimate sub-surface soil salinity (at 60 cm depth) for early stage of wheat crop growth in a simplified manner using freely available satellite data, which is a novel feature and prime objective in this study. The study utilizes Sentinel-1 SAR (Synthetic Aperture RADAR) data for backscatter coefficient generation, Sentinel-2 multispectral data for NDSI (Normalised Differential Salinity Index) generation and on ground equipment for direct collection of soil electrical conductivity. The data were collected for two dates in November and December 2019 and one date for January 2020 during the early stage of wheat crop growth. The dates were selected keeping in mind the satellite pass over the study area of Rupnagar on the same day. Ordinary Least Squares regression was used for modelling which gave R2-statistics of 0.99 and 0.958 in training and testing phase and root mean square error of 1.92 in modelling for soil salinity estimation.

As an important soil carbon pool in Qinghai-Tibet Plateau (QTP), alpine peatland are extremely sensitive to global change. Duration of drainage and water table drawdown accelerate peatland degradation due to the soil changed from anaerobic condition to aerobic condition, which may even worsen under climate warming. Hence, the objective of our research was to evaluate the effect of drainage on microbial characteristics, greenhouse gas (GHG) emissions and their influencing factors, and further analyze whether the the variability of GHG emissions increases with warming. The results showed that the influence of water table drawdown on microbial communities were greater than that of duration of drainage. Both the fungal and prokaryotic community compositions varied with water table gradient, and soil microbiota may served as a biomarker to analyze the differences in GHG emissions among three different water table treatments. Intriguingly, the GHG emission decreased with the increase of drainage age, while water table drawdown decreased the emissions of CO2 and CH4, and increased the emission of N2O. In addition, high temperature increased CO2 by 75% and N2O by 42%, but not significantly decreased the CH4 emission rates. Structural equation modeling showed that microbe was the primary factor affecting GHG emissions from drained peatlands, especially prokaryotes. In all, this study indicate water table has a greater effect on GHG emissions than duration of drainage, and the variability of GHG emissions increases with warming.

The Yangtze River basin is distributed across subtropical monsoon climate regions, and has four seasons, including a hot rainy season. These climatic conditions provide favorable conditions for paddy-upland rotation. This paper summarizes the spatiotemporal changes in soil potassium (K) and K cycles in soil-plant systems, as well as environmental impacts on K changes, and provides information for optimal K management. During the past 30 years, soil available K increased by -7.1% to 103.4%. The increase was lower in Hunan, Guizhou, Zhejiang, and Jiangsu provinces (<10%) and higher in Anhui, Jiangxi, Henan, and Chongqing provinces (>30%), demonstrating that soil K pools were enhanced. Farm manure was gradually replaced by synthetic K sources, such as straw and mineral fertilizers, which contributed to an increase in crop yields and soil available K. The meta-analysis results showed that comprehensive K management strategies increased crop yield and soil available K by 11.0% and 44.3%, respectively, on average. Other factors such as balanced fertilization, recycling of straw, increase in atmospheric deposition, decrease in leaching, runoff, and soil K fixation also greatly influenced soil K changes, leading to improvements in crop yields, soil structure, soil fertility, and nutrient availability. Positive K cycles and appropriate K fertilizer use will facilitate proper K management, including cycling of straw, improving machinery and equipment, and estimating the optimal K fertilizer dose after straw. Future studies should focus on tradeoffs between different forms of K under various environmental conditions and accurate estimates of reductions in mineral-K fertilizer requirements following straw return.

This study’s objective was to develop a method by which smallholder forest plantations can be mapped accurately in Andhra Pradesh, India, using multitemporal visible and near-infrared (VNIR) bands from the Sentinel-2 MultiSpectral Instruments (MSIs). Conversion to agriculture, coupled with secondary dependencies on and scarcity of wood products, has driven the deforestation and degradation of natural forests in Southeast Asia. Concomitantly, forest plantations have been established both within and outside of forests, with the latter (as contiguous blocks) being the focus of this study. Accurately mapping smallholder forest plantations in South and Southeast Asia is difficult using remotely sensed data due to the plantations’ small size (average of 2 hectares), short rotation ages (4-7 years for timber species), and spectral similarities to croplands and natural forests. Cloud-free Harmonized Landsat Sentinel-2 (HLS) S10 data was acquired over six dates, from different seasons, over four years (2015-2018). Available in situ data on forest plantations was supplemented with additional training data resulting in 2,230 high-quality samples aggregated into three land use classes: non-forest, natural forest, and forest plantations. Image classification used random forests on a thirty-band stack consisting of the VNIR bands and NDVI images for all six dates. The median classification accuracy from the 5-fold cross-validation was 94.3%. Our results, predicated on high-quality training data, demonstrate that (mostly smallholder) forest plantations can be separated from natural forests even using only the Sentinel-2 VNIR bands when multitemporal data (across both years and seasons) are used.

This study evaluates the effectiveness of remediation treatments in the long-term (twenty years later) in one of the largest mine spills in the world, the Aznalcóllar accident. Soil recovery was carried out through the application of different rates of organic (compost and manure) and inorganic amendments (materials rich in iron oxides and calcium carbonate). The different amendment combinations were grouped in four treatments (T1 to T4) and applied in different sectors depending on the soil properties and the degree of initial pollution. To assess the degree of soil recovery, the physicochemical properties, the total, soluble and bioavailable concentrations of the main pollutants (Pb, As, Zn and Cu) were determined over time. The applied treatments increased the pH, CaCO3 and organic carbon of the soils, reduced the EC and decreased the mobility of the pollutants, indicating that remediation treatments were efficient in the recovery of soils contaminated by potentially harmful elements. However, twenty years after the accident, total concentrations of Pb and As still exceed the intervention levels of the current regulations in certain areas. These areas are located in the sectors closest to the mine and where treatments T1 and T2 were applied; in these cases, the dose of organic amendment, materials rich in iron oxides and calcium carbonate were not effective enough, so the application of new treatments is recommended to complete the full recovery of the area.

Few studies have comprehensively evaluated the effect of changing land use on the soil quality in Ecuadorian amazon region that subject to continued deforestation processes. This study evaluated the influence of different types of land use on soil quality using an integrated soil quality index (SQI) with minimum set of indicators, based on 140 soil samples from 7 land use types, in seven productive distinct landscapes in the Pastaza province, Ecuador. The land use type evaluated were: Chakra_A, Chakra_B, Chakra_C, Cattle_A, Cattle_B, Cattle_C and Forest. Land use type had significant effects on soil properties and thus on soil quality. Soil quality index was developed by using, AP, Zn, TOC, BD and LL; AP and Zn had highest weighting values (0.38), which indicated that these indicators contributed the most to final SQI. In general, the SQI decreased as soil depth increased and for each type of land use, in the surface layer (0-10cm) the uses of Chakra_A (0.46) and forest (0.44) showed the highest SQI, while for the second depth (10-30cm), Chakra_A (0.45) and Chakra_B (0.43) presented significantly higher SQIs than the other land uses. The applied SQI can be used to assess the effect of changes on land use on soil quality in other landscapes of the Ecuadorian Amazon Region.

Rapid urbanization leads to fragmentation of large land patches, islandization of ecological landscape, and destruction of ecological security network. As a basic guarantee of life, a sound ecological security network promotes connectivity between ecological sources, improves ecological security patterns, and mitigates the degradation of an ecological system. The objective of this study was to improve a framework for assessing the ecological security network. We demonstrated the application of the proposed framework through a case study of the urban agglomeration around Hangzhou Bay (UAHB), a rapid urbanization region in Eastern China’s Zhejiang Province. We improved the identification method of ecological sources by integrating the evaluations of ecosystem services value and ecological sensitivity, while we screened ecological sources by using the rank-size rule and the natural breaks method. Based on the screened ecological sources, the ecological corridors were reconstructed and optimized for the UAHB region. Results from this study showed that the structure and function of the ecological security network were strongly influenced by human activities and urban sprawl. The ecological security network has deteriorated locally in eastern coastal areas of UAHB during the past 20 years with strong spatial variability in ecological security patterns. To maintain a well-protected and sustainable ecological quality, we proposed a set of 5 measures to improve the ecological security pattern and the sustainable development of the ecological system in Eastern China.

Violence in Rakhine, Myanmar forcibly displaced nearly one million Rohingya who took refuge in Cox’s Bazar–Teknaf peninsula of Bangladesh. Initially, nearly 2,000 ha of forested lands had to be cleared to accommodate them in an area, that is ecologically very sensitive. Fuelwood collection and illegal logging have become widespread since their arrival, causing severe environmental degradation, including loss of a vast amount of forest cover. To devise conservation strategies of a highly sensitive ecosystem, it is imperative to understand the degree of forest cover deterioration and associated impacts related to Rohingya emigration. This study employed satellite images to monitor and model spatiotemporal pattern of forest cover degradation, and loss of ecosystem function in the peninsula. Supervised classification method was used to derive multidate land use/cover data which was then utilized to monitor spatiotemporal pattern of forest cover change from 2017–2019. Dynamic modelling was performed to predict changes in the forest covers using markov cellular automata. Analysis revealed that 3,130 ha of different forested covers were transformed into either refugee camps or degraded forest cover between 2017 and 2019. Prediction showed that around 5,115 ha of forest may experience loss from 2019–2027. Furthermore, above ground biomass and carbon stock estimation indicated a consistent loss, which is likely to swell if present rate of deforestation continues. The findings of this work have considerable implications in developing conservation decisions, priority interventions and public policies to save an ecologically sensitive area.

This paper examines land use patterns of rural households and the association with food production and income across three different zones of various forest proximity across a landscape gradient (remote, intermediate and on-road) in the Chittagong Hill Tracts region of Bangladesh. We conducted in-depth semi-structured surveys of households (175-300) and farm owners (30) to collect information on people’s perceptions of land use change, present land use patterns and contributions to food production and income. Our research found that more than half of the surveyed households experienced a decline in the land available for food production over the past 30 years. The land use patterns revealed decreasing crop lands (mainly swidden farms) and an increase in areas of planted trees. However, household use of the reduced crop land has not affected food production in the on-road zone, whereas the diversity of food sources has declined. People living in more remote areas used larger areas of crop (swidden farms) and fallow lands, fruit orchard and accessed natural forest lands that provide a diverse reservoir of food sources. The current land uses contribute to variations in annual household income, with remote dwelling people earning less to those living in the intermediate and on-road zones. In summary, this transition of land uses over three decades and changes in income and food availability cannot be generalised across the region because of zone specific differences. We recommend a broader and context-reliant landscape management approach in consideration of the diversity of forest and tree benefits.

In the last two decades, the productivity of Rice-wheat cropping system in the upper Indo-Gangetic Plains of India has stagnated and now in a declining trend. As a result, farmers shifted to a different cropland grown systems so as to achieve a higher net productivity. This study aim to assess as how nutrient index (NI), microbial diversity and soil quality changed after replacement of rice-wheat by vegetable (VGS), pulse (PGS), potato (PoGS) and mustard (MGS) grown system. An analysis of 307 soil samples from various croplands revealed a soil pH range of 6.58-8.87 with 75.3% soils under low category of mineralized N (MN) resulting in its low NI (<1.67). The highest NI, enzymatic activity and microbial biodiversity was recorded under PGS, which restored 34.2, 24.1 and 10.2% greater SOC, carbon substrate oxidation rate and MN than PoGS, respectively. The diversity indices were the highest in PGS followed by VGS, but soil quality index was 0.783 (VGS), 0.771(PGS), 0.695 (WGS), 0.663 MGS), and 0.647 (PoGS). The silt content, SOC, Zn, total N, acid phosphatase activity (ACP), available P and total culturable fungi were the key soil indicators across the cropland grown systems. Among the cropland systems, silt content, SOC, total N and ACP were the main soil indicators for PGS, whereas, silt content, SOC, P and Zn were the ideal indicators for VGS that affected microbial dynamics and soil quality. Overall, it is concluded that PGS maintained higher nutrient index, microbial and functional diversity, but VGS improve greater soil quality.

There is limited understanding about agricultural land dynamic across global drylands and the impacts of different agricultural land transitions on ecosystem productivity changes. This study attempted to fill this gap by examining the agricultural land changes and net primary productivity responses in drylands. A data-driven assessment of the effects on the ecosystem productivity of individual agricultural land displacement was carried out using three methods: the mean difference method, a newly introduced ridge-regression method, and a proposed method based on actual change excluding climate impact. Increases in productivity were accompanied by agricultural land transitions from natural land covers, expected forests. The agriculture expansion mainly replaced sparse vegetation and grassland, and increased the overall productivity of the dryland ecosystem. Mean difference method and ridge-regression method over overestimated the NPP increase caused by agricultural land expansion. Land use change contributed more than 70% to increase in net primary productivity in new agricultural area. But land use change effects less on total productivity in drylands than climate change. Monitoring agricultural land dynamics and distinguishing productivity changes caused by different agricultural land transitions is helpful to the targeted management and sustainable development of agriculture in drylands.

In desert ecosystems, the desertification process is characterized by increasing attenuation of plant productivity and deterioration of soil habitats, leading to enhanced environmental stress gradients for soil microbiomes. Despite the significance of microbial communities for multifunctionality in terrestrial ecosystems, the feedback dynamics of microbiomes and their contributions to maintaining subsurface soil multifunctionality as desertification progresses have yet to be evaluated. Here, we used three sites with different desertification stages and investigated the variation trends of microbiomes in soil profiles (0-100 cm) and their contributions to regulating multifunctionality. We first confirmed that multifunctionality did not exhibit a significant difference between superficial soils (0-20 cm) and deep soils (20-100 cm) and slightly decreased as soil depth increased throughout the entire profile. Desertification progression drove distinct variation trends of microbiomes in vertical soil profiles. Soil bacterial communities received on average more positive and progressive feedback from desertification development than fungal and archaeal communities, characterized by significant variation in bacterial alpha- and beta-diversity and slight variation in fungal and archaeal alpha- and beta-diversity. The most abundant phyla in the microbiomes did not vary between the superficial and deep soils at any desertification stage. Significant declines in microbial clades within Acidobacteria are an important feature as desertification proceeds. Particular microbial taxa rather than total microbial diversity best predict and explain the vertical profile variation in soil multifunctionality in desert ecosystems. Our results highlight the significance of microbial community composition in subsurface soils for regulating multifunctionality in desert ecosystems.

Converting alfalfa (Medicago sativa L.) into cropland (rotation cropland, RC) is a common way of land use to reuse degraded alfalfa pasture. However, it is a big challenge for RC to achieve high productivity and maintain high soil organic carbon (SOC) achieved by previous alfalfa. Here, we conducted a nine-year field experiment, with continuous cropland (CC) under plastic film mulching as reference, to evaluate soil moisture restoration, crop productivity, and SOC in RC also under plastic film mulching, in the case of fertilization and non-fertilization, respectively. SOC and total soil N in the alfalfa pasture before conversion were 12.3% and 7.7% higher, but the available P and inorganic-N were 59.2% and 71.5% lower than in CC, respectively. The crop yield and biomass were not significant between RC and CC following the second year of conversion in both fertilization and without fertilization cases. The SOC and total soil N in RC with fertilization were similar to the previous alfalfa pasture throughout the nine-year experiment, while decreased in RC without fertilization by 8.3% and 7.5% after the nine years. Soil moisture in RC at 0-0.6 m restored to the level of CC only one year after the conversion, and restored from 77.6% and 56.2% of CC to 95.3% and 69.2% at 0.6-2 and 2-5 m through nine-years after conversion. These findings help to dispel the worries about the long-term low production and rapid decline of SOC in RC and support for sustainable high-productivity and high SOC sequestration in dryland farming.