Land Degradation & Development最新文献

Farmland abandonment in Mediterranean mid-mountain areas can lead to the degradation or recovery of soil properties. Typically, after abandonment, fields are covered with shrubs, which hinders livestock grazing and constitutes high wildfire risk. To avoid these negative effects, shrubs are cleared in selected areas. The main objective of this study is to evaluate whether shrub clearing can improve soil quality and enhance carbon sequestration. A case study was conducted in the Leza Valley (La Rioja, Spain), examining five different land uses/management practices in both acid and alkaline soil environments. These included shrubland (control), three shrub clearing sites (managed <5, 15, and 25 years ago), and control pasture (reference). Soil replicates at different depths (0–40 cm) were collected, and physico-chemical properties were analysed. A theoretical map of potential shrub clearing areas was created, and the potential to accumulate carbon was evaluated. Results showed that shrub clearing increases soil organic carbon and nitrogen, specially in 25-year clearings. The increases were greater and significant on alkaline environments. The cartographical analysis reveals that 3388 ha can be still cleared in the Leza Valley, which could increase soil organic carbon accumulation by up to 31.6% in 25-year period. We propose shrub-clearing as a strategy for enhancing carbon sequestration in Mediterranean mountain areas.

To combat land degradation through conserving soil and water resources, Ethiopia has undergone vigorous implementation of soil and water conservation (SWC) measures, predominantly physical structures. To evaluate the effectiveness of these implemented structures, various researches have been conducted through using both measured and simulated approaches. This study was initiated to analyze the reliability of SWAT-based simulated studies results on the effectiveness of SWC measures toward erosion reduction potential against the measured dataset using unpaired t-test statistical analysis. In this study, 123 published papers were downloaded, of which 70 were found to be more related to the objective of the review. After applying four refining criteria, only 43 were found more compatible with the study objective and used for data analysis. Studies conducted by different scholars show up to 98% and 93.50% soil loss reduction effectiveness by SWC measures in measured and simulated approaches, respectively. The simulated SWC measure efficiency output was also evaluated with respect to the ground-measured data of the same structure within the same agroecology class. Finally, the unpaired t-test results indicated that the grass strip in the mid-highland agroecology showed a significant difference from the measured one at a 95% significance level. However, none of the other measures showed significant differences between the measured and simulated datasets. Hence, the SWAT model can effectively simulate the effectiveness of physical SWC measures on soil loss reduction if it is well-calibrated and validated with sediment yield data. Refining model parameters that can be sufficiently captured and represent biological measures (grass strip), incorporating additional field data for calibration and validation coupled with exploring alternative modeling approaches that efficiently simulate biological SWC was set as a recommendation to obtain an effective biological measure simulation.

Check dams are a critical soil and water conservation engineering measure in gullies that significantly influence erosion, transportation, and sediment accumulation. Check dams help reduce erosion in the upstream area, ignoring the off-site erosion reduction capacity due to erosion dynamics, and it also alters the morphology of gullies. The morphology of the gully cross-section from the head to the inlet of the gully is mainly “V” shaped, “V, U,” transitional shaped, “U” shaped and trapezoidal shaped. The construction of check dams can force the geomorphologic evolution of the sub-watershed to accelerate the transition to “old age” and reduce the allocation of sediment initiation during field sub-flooding, thus promoting sediment deposition processes. The percentage of downstream scour hours in watersheds where check dams were constructed was 0.65% and 0.80%, respectively, compared to 19.78% and 19.06% in watersheds where there are no check dams. The results reveal the role check dam constructions play in gully morphology evolution from a hydrodynamic perspective and fill the gaps in off-site erosion reduction, providing theoretical support for assessing the role of check dams in soil and water conservation work.

The rehabilitation of diverse and three-dimensional forest vegetation patterns is crucial for preventing forest degradation and improving soil fertility. However, the relationship between soil microbial community and soil fertility was not clear. To accurately assess the capability of vegetation restoration measures on the real impact on degraded soil ecosystems. We selected three vegetation rehabilitation models of degraded Pinus massoniana forests in typical soil erosion areas in China as the research objects, with untreated bare land as the control. All three vegetation construction patterns increased the abundance and diversity of soil bacteria and fungi, thereby enhancing the stability of the soil ecosystem. Additionally, the vegetation rehabilitation models also altered the community structure of soil bacteria and fungi in the degraded P. massoniana forests. The pH and soil fertility index (IFI) were the main factors leading to variations in the community structure of the soil bacteria and fungi. Among them, the grass-planting model showed a significantly greater improvement in the soil fertility of degraded P. massoniana forests than the shrub-planting and arbor-planting models. Furthermore, Ascomycota, Basidiomycota, and Glomeromycota exhibited the most significant response to IFI, indicating their potential as indicator microorganisms for soil fertility changes. The improvement in soil fertility in degraded P. massoniana forests was influenced primarily by the increase in urease activity (S-UE) according to the vegetation rehabilitation models (84.20%, p = 0.000). In conclusion, the grass-planting system effectively improved the soil ecosystem quality of degraded P. massoniana forests in southern erosion-prone areas of China and was suitable for further application.

Saline-alkali soil degradation is a significant environmental problem with a negative impact on sustainable agroforestry development. Therefore, efficient remediation methods are urgently required. A potential solution to this problem is using biochar produced from bamboo waste and inoculated with plant growth-promoting microbes as cleaner production materials for saline-alkali soil. The present study investigated the potential of combining biochar, microbes, and dwarf bamboo to improve saline-alkali soil. Different application rates (1%, 3%, and 5% of soil mass) of biochar were added to coastal saline soil planted with dwarf bamboo (Pleioblastus argenteastriatus) in pot experiments. Soil physicochemical properties, microbial communities, and plant responses were systematically studied. Bamboo and microbial-modified biochar effectively decreased soil pH and electrical conductivity and increased soil nutrient contents. Compared with untreated soil, the relative abundance of the dominant bacterial phyla Acidobacteria, Actinobacteria, and Chloroflexi, and dominant fungal phyla Basidiomycota increased after applying biochar and modified biochar. With the increase in application concentration, the antioxidant activities of modified biochar decreased, biochar peroxidase and catalase content decreased, and the malondialdehyde content of bamboo biochar and microbial-modified bamboo biochar decreased. The biomass of bamboo with added biochar and modified biochar was significantly higher than that of untreated soil. Comprehensive correlation and redundancy analyses showed that the bacterial and fungal communities were greatly affected by soil factors, especially soil pH, electrical conductivity, total organic carbon, potassium, and sodium ions. The findings of this study suggest that 5% bamboo biochar and 3% modified biochar benefit soil remediation, improve the stress resistance of dwarf bamboo, and enhance plant growth. Therefore, combined biochar–microbe remediation has great potential for the sustainable improvement of saline-alkali soil.

Land degradation and soil contamination have become global problem due to irresponsible anthropogenic activities and the overutilization of natural resources by humans. Land degradation and contamination due to toxic heavy metals have adversely impacted not only crop productivity but also the overall environmental health of our planet. Mitigation and management of polluted land are urgently required to achieve the goal of sustainable development because of the continuous human population explosion. In recent years, the biodiversity under phytoremediation is gaining scientists' attention for utilizing polluted lands and obtaining a bio-based economy aimed at economically valuable and nonedible native plants. In the present review, we have focused on the biodiversity prospecting and phytoremediation potentials of economically important native plants, which may open up new horizons for sustainable development and redevelopment of polluted land sites.

Understanding the characteristics of soil phosphorus (P) sorption and desorption is essential for comprehending P biogeochemical cycling and effectively managing ecosystems in a desert revegetation chronosequence. The present study utilized the Freundlich model and enzymatic activity to characterize the features of P sorption–desorption, and microbial activity, which aims to elucidate the effect of P kinetics and microbial activity on P fractions in the soils of a desert revegetation chronosequence, consisting of 11, 31, 40, 57, and 65 years old revegetated deserts. The findings revealed that the 31 years old soil showed the highest alkaline phosphomonoesterase and phosphodiesterase activities, and the 40 years old displayed the highest inorganic pyrophosphatase activity. In revegetated desert soils, microbial activity changed P sorption–desorption kinetics by decreased or increased the parameters including sorption/desorption energy site, P sorption/desorption ability, and the maximum buffering capacity of P sorption/desorption. And in microbial activity soils of 31–40 years old, P desorption significantly decreased T-P and A-P concentrations (p < 0.05). P sorption process and enzyme activity explained 35.10% and 22.20% of P fraction variation, respectively; and P desorption process and enzyme activity explained 48.3% and 22.3% of P fraction variation, respectively. These findings provide valuable insights into the contribution of P kinetics coupled with microbial activity in desert ecosystems, aiding in the effective management of these fragile ecosystems.

Soil compaction is generally viewed as one of the most serious soil degradation problems and a determining factor in crop productivity worldwide. It is imperative to understand the processes involved in soil compaction to meet the future global challenges of food security. In this work, we used co-occurring keyword analysis to summarize 3491 papers on soil compaction over the past 40 years, elaborating on the main research focuses such as the causes, influencing factors, and effects of soil compaction on crops, and the mitigation and prevention of soil compaction. This review provides a comprehensive discussion of the effects of soil compaction, including altering soil structure, increasing bulk density (BD) and penetration resistance (PR), and reducing porosity and soil hydraulic properties. Notably, based on the 387 data points of 11 papers about BD, our results demonstrated soil compaction on average, increased BD by 7.6%, 6.9%, and 3.2% in the medium-, coarse-, and fine-textured soils, respectively. Based on the 264 data points of 18 papers, in the 0–30 cm soil layer, compaction increased penetration resistance (by 91% in the coarse-textured, 84.2% in the medium-textured, and 8.8% in the fine-textured soils). Compacted soil limits the access of crop roots to water and nutrients, leading to poor root development and reduced crop productivity. There was a difference in soil compaction sensitivity between the different crops, but crop growth and yield showed an overall worsening trend with increasing degrees of compaction. This review collected data points on 142 crop yields and found that wheat, barley, corn, and soybean yields decreased by an average of 4.1%, 15.1%, 37.7%, and 22.7%, respectively, in the BD range of 1.1–1.8 Mg/cm³ after compaction. Additionally, the effectiveness of different compaction mitigation measures, including natural, tillage, and biological, is systematically discussed. Compared with soil compaction mitigation measures, prevention should be the top priority although there is still a lack of practical prevention methods. Soil conditions and agricultural machinery type are the main factors affecting the risk of soil compaction in the process of soil compaction. Therefore, it is particularly important to optimize the soil working conditions in the field and the type of farm machinery used to reduce the risk of soil compaction. This initiative is pivotal for ensuring sustainable systems for food production and recovering crop productivity from compacted soil.

Rapid global urbanization has perturbed ecosystem structures and functions, resulting in ecological risk and threatening sustainable human well-being and socioeconomic development. However, scientific indicators to analyze ecosystem service (ES) risk patterns need to be explored in detail. In addition, studies on ES supply risk are stagnating on historical or status explorations, especially from the view of disturbance from land-use changes. This study seeks to develop a framework for modeling past-future ES supply risk pattern evaluation and probing into ES risk patterns under different future land-use scenarios. To achieve this objective, the framework integrates the Future Land Use Simulation (FLUS) model, the Intelligent Urban Ecosystem Management System (IUEMS) model, and an established indicator system incorporating ES supply trend, hotspots and coldspots, and ES trade-offs, and synergies. The results show that: (1) In 2050, the supply of climate regulation in the Xi'an Metropolitan Area (XMA) will increase, while that of carbon sequestration and recreation will decrease. In 2050, the supply of climate regulation is the highest under ecological protection (EP) scenario, while the supply of carbon sequestration and recreation are the highest under cropland protection (CP) scenario. (2) From 2000 to 2050, the hotspots and coldspots of climate regulation increase in both natural development (ND) scenario and CP scenario. Notably, CP scenario experiences the most significant reduction in extremely significant hotspots and coldspots of carbon sequestration. From 2000 to 2050, at the regional and pixel scales, climate regulation and carbon sequestration mainly show trade-offs, and carbon sequestration and recreation show synergies. (3) ES supply risk in XMA is high in the center and low in the north and south. The ES supply risk from 2000 to 2050 is increasing, with expanding “extremely high risk”, “high risk”, and “extremely safe” areas. ES supply risk management should adhere to more strict land-use policies and guidelines, management zoning for areas with different levels of ES risk, and an accurate understanding of ES trade-offs and synergies for scientific risk management. This study could provide theoretical and technical references for ES risk assessment research and promote scientific ecological risk management.

Phosphorus (P) use in agriculture has witnessed a global increase, leading to significant environmental problems. Nevertheless, the understanding of P kinetics in saline soils amended with nano-water treatment residuals (nWTR) remains limited. This study aimed to (1) Investigate the impact of different nWTR addition rates (0%, 0.10%, 0.20%, and 0.50%) on the adsorption-desorption kinetics of P applied to five soils with different salinity levels (1.47–58.50 dS m⁻¹) using batch adsorption experiments. (2) Using different optimization models via Fit Quadratic Model and principal component analysis to predict the optimal utilization of nWTR. The X-ray diffraction and Fourier transform infrared patterns proposed that the main mechanisms controlling the process are ligand exchange and precipitation. The results revealed that the adsorption level of P in amended soils was rapid, then decreased gradually until reaching equilibrium after 24 h/25°C. The kinetics data were well described by a pseudo-second-order model, suggesting a chemisorption-dependent adsorption process. Increasing soil salinity and nWTR addition led to decline the phosphorus desorption. The application of 0.5% nWTR decreased P-desorption from 33.95% to 16.22% in the non-saline soil and from 18.43% to 10.63% in the highly saline soil. principal component analysis distinguished a positive association between P-adsorbed and nWTR. The optimization models predicted that applying 0.5% nWTR for 965 min maximizes the P-adsorption rate, reaching 1041 mg Kg⁻¹ in highly saline-soils. Therefore, nWTR can serve as a cost-effective and efficient absorbent for mitigating P mobility and reducing its transport in saline soils.