The decomposition of leaf litter regulates nutrient cycling, carbon turnover, and soil fertility, in resource-limited semi-arid ecosystems, where resource-limited conditions intensify ecological responses. In this study, we estimated the decomposition patterns and nutrient release scheme of leaf litter from five woody species (Cassia fistula, Pongamia pinnata, Azadirachta indica, Acacia leucophloea, and Leucaena leucocephala) and the invasive Prosopis juliflora in the Delhi Ridge using litterbags (5 g air-dried litter per bag). Decomposition was enhanced under the P. juliflora canopy, with a lower mean residual litter weight (2.16 g) than that of the native canopies (2.69 g). Percent mass loss, decay constants, and decomposition rates were significantly higher in the presence of P. juliflora, with the maximum decomposition rate observed for P. juliflora litter (16.11%/month, decay constant (k) = 0.59), and the lowest for C. fistula (8.91%/month, k = 0.29). Nutrient release followed the order K > P > N, with more rapid nitrogen and phosphorus mineralization under the P. juliflora canopy. The decomposition rate was positively correlated with the initial litter N and P content (R2 = 0.90) and negatively correlated with the C/N and C/P ratios.
A long-term field study (2015-16 to 2019-20) was conducted at Punjab Agricultural University, Regional Research Station, Bathinda, Punjab, India, to evaluate the effects of cyclic and alternate irrigation with canal and saline water on fodder productivity, soil health, and forage quality in berseem-sorghum and ryegrass-sorghum rotations. Six various combinations of good quality and saline water were tested: W-C, 1 W-C - 1 W-S, 1 W-C - 2 W-S, 2 W-S - 1Wc,1W(C) - W-SS and W-S. Continuous saline irrigation significantly reduced green fodder yield, crude protein concentration, and soil quality, while accelerating soil salinity buildup. In contrast, cyclic irrigation regimes, particularly alternate canal and saline water (1 W-C - 1 W-S), consistently restricted salt accumulation within root zone and stabilized crop performance. Forage quality improvements were evidenced by higher crude protein and moderated fiber fractions, indicating superior digestibility and feed value. Soil electrical conductivity and sodium adsorption ratio of surface soil (0-15) were substantially lower under cyclic irrigation, confirming improved soil chemical functioning. Inclusion of berseem in rotation further strengthened system resilience by enhancing subsequent sorghum productivity and farm profitability. Overall, the 1 W-C-1 W-S strategy sustained fodder yield and quality relative to saline water while markedly reducing freshwater dependence. Thus, cyclic irrigation integrated with legume-based fodder rotation represents a practical scalable solution.
Landscape changes in northern China's arid and semi-arid regions significantly affect ecological security and sustainable development. Understanding vegetation, lakes, and sandy area interactions is essential for landscape management. Using remote sensing data spanning 1980-2024 across 5.6 million km(2), we integrated object-based classification, landscape metrics, Grey Relational Analysis (GRA), and Geodetector to quantify landscape dynamics and driving forces. Four key findings emerged. (1) Landscape evolution comprised three human-dominated phases: agricultural expansion (1980-2024) increased cropland by 7.59% (1980 baseline) while vegetation cover decreased by 2.66%; urbanization (2010-2024) expanded built-up land by 57.65%; a spatial pattern of western desertification and eastern urbanization emerged. (2) Fragmentation increased: patch density (PD) rose 18.70%, Shannon's diversity index (SHDI) declined 9.2%; lakes experienced severe connectivity loss, with PD nearly doubling (+94%). (3) High vegetation cover stabilized sandy areas (r = 0.57, GRA = 0.74) and lakes (r = 0.58, GRA = 0.50); low cover correlated with degradation (r = -0.88 with sandy areas). Over the study period, 42% of small lakes (<1 km(2)) disappeared, and high-cover vegetation declined 34.70%. (4) Human activities - population (q = 0.54) and GDP (q = 0.49) - were the dominant driving forces, with precipitation secondary (q = 0.32). These findings reveal a cascade of agricultural expansion, urbanization, and subsequent ecological constraints under intensifying human-environment interactions, providing a scientific basis for ecological management. The methodology is transferable, and quantified thresholds offer targets for global desertification control.
Soil salinization severely threatens agricultural productivity in arid regions. This study comprehensively evaluates carboxymethyl cellulose (CMC) as an eco-friendly soil amendment through laboratory and a two-year field experiment. Laboratory results showed that CMC's swelling capacity was inhibited by high salinity but slightly enhanced at a low salt concentration (1 g & centerdot;kg-1 NaCl). CMC exhibited excellent biodegradability, which was moderately slowed in saline soil. A distinct dose-dependent effect on maize was observed: low concentration (0.1 g & centerdot;kg-1) promoted seedling growth (root length increased by 77%; stem length by 29%) and boosted nitrate reductase (NR) activity. In contrast, high concentrations (>= 0.5 g & centerdot;kg-1) induced severe stress, evidenced by elevated malondialdehyde (MDA) and proline levels. Crucially, CMC application reduced the soil water infiltration rate. The field trial confirmed this mechanism, showing that CMC retained irrigation water within the 0-40 cm root zone by impeding deep percolation. Consequently, compared with the control, the 300 and 450 kg & centerdot;ha-1 CMC treatments increased maize grain yield by up to 23.41% and enhanced water use efficiency (WUE) by up to 22.38%. Under the conditions of this study, CMC functioned primarily as a root-zone water regulator rather than solely as a water reservoir. By slowing water infiltration and reducing nonproductive water losses (evaporation and deep percolation), it optimizes the soil water balance for crop use. This study indicates that appropriate CMC application can improve water retention, crop performance, and water use efficiency under saline conditions.
Soil salinity and sodicity severely degrade soil structure and hydraulic properties in arid regions, limiting agricultural productivity. This study investigated the effects of reduced fertilizer combined with humic acid (HA) and biochar (BC) on the physical properties of sodic soil. A three-year field experiment included five treatments: an untreated control (CK), full fertilizer application (F, 700 kg/ha compound fertilizer with 1:1:1 NPK ratio), reduced fertilizer combined with HA (FA, 350 kg/ha fertilizer + 3000 kg/ha HA), reduced fertilizer combined with BC (FB, 350 kg/ha fertilizer + 3000 kg/ha BC), and reduced fertilizer combined with both HA and BC (FAB, same rates). Results demonstrated that the FAB treatment synergistically enhanced soil aggregation, increasing the content of >2 mm macroaggregates by 7.10-fold in the surface layer and improving aggregate stability (mean weight diameter increased by 2.62-fold) compared to CK. It also reduced soil bulk density by 17% and increased saturated water-holding capacity by 47%. Strong correlations indicated that aggregate stability governed improvements in porosity and water retention. These findings provide a mechanistic basis for using combined organic amendments with reduced fertilizer to rehabilitate sodic soils in terms of soil structure and hydraulic properties.
Groundwater recharge in the Modder River Catchment is spatially heterogeneous and episodic, controlled by fractured Karoo formations, intrusive dolerite, relief, and soil texture. To map recharge potential, a 107-band composite integrating monthly NDVI, NDWI, rainfall, soil moisture, soil properties, and terrain data was constructed. Compact spatial features were encoded into a 96-dimensional latent vector using a residual denoising convolutional autoencoder with three stride-2 residual blocks (64 -> 128 -> 256 channels), Group Normalization, and Squeeze-and-Excitation modules. Temporal dynamics were extracted using a pre-trained time series encoder. Features were fused, reduced using Uniform Manifold Approximation and Projection (UMAP), and clustered with Hierarchical Density-Based Spatial Clustering of Applications with Noise (HDBSCAN) to delineate hydrogeomorphic groups based on slope, soil texture, and rainfall-vegetation. This yielded 153 clusters of gentle slopes, sandy surface soils over moderately clayey subsoils, and short rainfall-NDVI response lags, consistent with diffuse recharge on interfluves and footslopes. Cluster labels were transformed into a continuous recharge-potential surface using a weighted linear scoring function combining terrain slope (0.35), soil sand fraction (0.30), soil clay fraction (0.20), and maximum rainfall-NDVI lag correlation (0.15) over a 0 to 2-month interval. HDBSCAN membership probabilities propagated uncertainty. An upper-decile threshold identified 23,776 recharge hotspots covering 1,633.67 km(2) (10.02% of the study area), refined by the Topographic Wetness Index (TWI) to 1,392.80 km(2) (8.94%) concentrated in localized mid-slope and interfluve zones. Repeatability tests confirmed robustness of these spatial patterns. The workflow is reproducible, auditable, supporting recharge mapping, groundwater protection, and managed aquifer recharge planning in data-scarce environments.
Arid and semi-arid regions occupy a substantial proportion of the global land surface and are highly susceptible to soil degradation driven by climatic stress and human disturbance. Biological soil crusts, composed of cyanobacteria, algae, lichens, mosses, and associated microorganisms, are fundamental regulators of soil stability, hydrological processes, and biogeochemical cycling in these ecosystems. This review synthesizes current understanding of the composition, development, and ecological functions of biological soil crusts, with a particular focus on their role in dryland restoration. We examine how crust structure and successional stage control key ecosystem processes, including erosion resistance, water redistribution, carbon sequestration, and nitrogen transformations, while also addressing emerging controversies related to functional redundancy and reactive nitrogen emissions. The review further evaluates restoration strategies based on biological soil crust inoculation, comparing field-sourced and laboratory-cultured approaches, and assessing how inoculum selection, application techniques, and habitat amelioration influence establishment success. Special attention is given to the challenges of translating plot-scale successes to field-scale applications, where environmental heterogeneity, disturbance regimes, and economic constraints strongly affect outcomes. By integrating evidence from long-term field studies, experimental manipulations, and recent meta-analyses, this review highlights the context-dependent nature of biological soil crust restoration and emphasizes the need for site-specific, function-oriented assessment frameworks. The synthesis provides guidance for researchers, land managers, and policymakers seeking to design effective and sustainable restoration strategies for degraded dryland soils.
The Weibei Upland, a major apple-producing region in China, is transitioning toward sustainable management and high-density orchards. To support sustainable apple production, it was essential to understand the relative importance of the factors associated with orchard performance. We evaluated 16 indicators of tree growth, leaf nutrients, and fruit quality, along with yield (17 parameters in total) across 27 orchards in Chinese Weibei Upland, The effects of geographical location, management type (organic, green, and conventional), and rootstock type (dwarfing vs. standard) were assessed using fixed-effects ANOVA restricted to main effects, together with partial correlation and Random Forest analyses. Geographical location showed the strongest association with the measured variables. Random Forest modeling was consistent with this pattern, accurately classifying orchard locations (14.81% OOB error) but failing to distinguish management types (66.67% OOB error). ANOVA indicated that geographical factors-expressed through altitude, climate, and soil properties-significantly influenced 11 of the 17 parameters. In contrast, management types had minimal effects, with a significant difference only in hundred-leaf weight, possibly related to widespread nutrient input saturation, which may have obscured theoretical agronomic distinctions. Rootstock type had no significant direct effect on any measured physiological, quality, or yield trait. These findings suggest that in this semi-arid region, orchard performance is more strongly associated with geographical context than with management certification or rootstock type. The findings support geographically informed precision management and suggest that reducing excessive fertilizer inputs, especially in conventional orchards, may improve sustainability while maintaining yield.
In arid and semi-arid ecosystems, dominant tree species create mosaics of tree-islands and barren plant interspaces that exert pressure on ecosystem processes and offer an opportunity to explore the impact of bacterial communities. We evaluated potential links between soil respiration, N mineralization, and community co-occurrence networks and predicted gene function across three tree island microsites (beneath tree canopies, at the canopy edge, and in interspaces) in a replicated field experiment in thirty-eight woodland sites in the Great Basin Desert in UT, USA. We measured a suite of characteristics relating to the metabolic functional state of communities to improve our interpretation of potential links between function and structure. We found that tree islands were the predominant driver, creating highly complex and connected assemblies of bacterial populations and easily discernible differences in abundance and composition of predicted functional genes. Specifically, communities directly beneath Juniperus and Pinus canopies were comprised of at least 5.2-times more connections between bacterial taxa than present in networks from interspace and edge. Tree island communities included 236 predicted genes with many related to the degradation of polyaromatic or polycyclic compounds, while interspace communities included only 66 predicted genes associated with the decomposition of more labile C substrates. Our results identify that tree islands exert enough pressure to create distinct interactions between bacteria and alter gene expression resulting in changes to ecosystem function.
Soil degradation in Northwest Ethiopia, driven by acidity and nutrient depletion, severely limits maize productivity. This study evaluated the integrated use of biochar (BC), vermicompost (VC; applied on a nitrogen-equivalent basis), and inorganic nitrogen-phosphorus (N-P) nutrients to rehabilitate acidic soils over two growing seasons (2023/24-2024/25). Treatments markedly improved key soil physical properties: bulk density decreased by up to 10.8%, while gravimetric moisture content increased substantially. These improvements directly enhanced maize growth, increasing leaf area index by 26% and harvest index to over 50%. The highest grain yield (12.13 t ha-1) was achieved with high amendment rates (8 t BC + 10.04 t VC + 120-30.2 kg N-P ha-1), representing a 176% increase over the control. However, economic analysis revealed that moderate integrated application (4 t BC + 5.02 t VC + 120-30.2 kg N-P ha-1) delivered near-optimal yield (12.09 t ha-1) with superior economic returns, optimizing the cost-benefit ratio. A strong predictive model coefficient of determination (R2 = 0.906) confirmed soil and crop parameters as reliable yield indicators. We recommend this moderate, integrated package as a suitable agronomic and economically viable strategy for sustainable maize intensification in acidic and drought-prone agroecosystems.
The middle Heihe River Basin is located in the arid-semiarid transitional zone of Gansu Province, northwestern China, where severe wind erosion has resulted in a fragile ecological environment. This study analyzed spatiotemporal patterns and driving factors of soil wind erosion from 2003 to 2023 using the Revised Wind Erosion Equation (RWEQ) and Geodetector. The findings reveal that the multi-year average wind erosion rate was 23.93 kg m(-2) a(-1), while the reduction in soil loss exhibited a significant increasing trend, rising by 152% over 20 years. Spatially, the severity of soil wind erosion increased gradually from the southeastern to the northwestern parts of the study area, with high-intensity zones concentrated in barren lands and the Gobi desert. High sand stabilization zones were primarily distributed in croplands and grasslands within oases. Vegetation coverage (q = 0.91, p < 0.05) was the key natural driver, and the intensity of ecological restoration (q = 0.68, p < 0.05) was the key anthropogenic driver. Their interaction effect (q = 0.95, p < 0.05) was the most prominent, facilitating regional ecological restoration. Future efforts should enhance synergies between vegetation restoration and engineering measures in high-risk zones.
Drought stress limits forage production in semi-arid grasslands, threatening the sustainability of grazing systems. This study evaluated whether native perennial grasses from the semi-arid Pampas of Argentina exhibit drought-tolerant germination traits comparable to commercial forages. Germination experiments were conducted using diaspores of eight native and two commercial grass species (cool- and warm-season functional groups) exposed to six water potential levels (0 to -1.5 MPa). Germination responses were analyzed using the hydrotime model to estimate the hydrotime constant (theta H) and the base water potential for 50% germination (Psi b(50)). Warm-season species showed more negative Psi b(50) values (-0.96 to -1.21 MPa) and lower theta H (1.90-2.69 MPa.day), indicating greater tolerance to water stress than cool-season species, which exhibited broader variation (Psi b(50): -0.55 to -1.27 MPa; theta H: 3.48-9.24 MPa.day). Within the cool-season group, the commercial Thinopyrum ponticum showed the highest tolerance, being the only species able to germinate at -1.5 MPa. Among native species, Jarava plumosa, Pappophorum vaginatum, and Digitaria californica displayed drought-tolerant germination traits comparable to or exceeding those of commercial species. These results demonstrate that native grasses possess diverse and effective germination strategies under water limitation, supporting their integration into forage systems and restoration efforts aimed at increasing resilience in semi-arid rangelands.
Drylands play a crucial role in global biogeochemical cycles, yet how increasing aridity affects elemental stoichiometry in biocrusts and soils remains unclear. This study investigated carbon (C), nitrogen (N), and phosphorus (P) stoichiometry in cyanobacterial crusts and underlying soil along a precipitation gradient in northwestern China. Cyanobacterial crusts exhibited significantly higher average contents of C (1608.81 mmol kg(-1)), N (97.10 mmol kg(-1)), and higher molar C:P (114.5) and N:P (7.1) ratios, but lower C:N (16.7) than the underlying soil (C:P = 74.5; N:P = 2.8; C:N = 29.0). Scaling analysis revealed isometric C-N coupling in cyanobacterial crusts (slope = 1.03), but allometric scaling in soil (C > N = P). Our results confirmed that cyanobacterial crusts were primarily P-limited, as evidenced by their significantly higher C:P and N:P combined with low P content, whereas underlying soil was co-limited by N and P, indicated by its elevated C:N ratio, low N and P contents, and low N:P ratio. Aridity explained over 70% of variance in crusts C, N, P, C:P, and N:P, whereas soil stoichiometry was primarily driven by crusts P content (explaining >45% variance). These findings highlight the distinct stoichiometric roles of cyanobacterial crusts in drylands and underscore their importance in stabilizing surface substrates and modulating soil nutrient balance under increasing aridity.
Grassland degradation has impacted the Qinghai-Tibet Plateau over recent decades, with bare patches and Ligularia virgaurea-degraded grasslands serving as typical examples. The effects of grassland degradation on soil nutrients, microbial communities, seed banks, and vegetation restoration potential were investigated to identify restoration techniques for degraded grasslands. The contents of total nitrogen, phosphorus, potassium, water, and organic carbon in degraded grasslands decreased significantly, whereas pH and nitrate nitrogen content increased. CaCO3 content was highest in bare patches, followed by L. virgaurea-degraded grasslands, which were higher than that in non-degraded grasslands by 76.46% and 54.09%, respectively (P < 0.05). Water content in the two types of degraded grasslands was significantly lower than that in non-degraded grasslands, by 18.4-22.85%. Brassinosteroid content in bare patches and L. virgaurea-degraded grasslands decreased by 44.18% and 80.66%, respectively. The soil seed bank composition in degraded areas changed significantly, shifting toward higher forb abundance, while Poaceae decreased by 55.21-78.13%. The germination rate of Elymus nutans seeds treated with soil extracts from degraded grasslands did not change significantly. Bacteria in non-degraded grasslands were significantly enriched for brassinosteroid biosynthesis pathway function. Bacteria associated with brassinosteroid biosynthesis were classified as Beggiatoa Trevisan 1842 (Approved Lists 1980) and members of the class Deltaproteobacteria Kuever et al. 2006 and order Chromatiales Imhoff 2005. Compared with non-degraded grasslands, soil microorganisms in degraded grasslands were unfavorable to seed germination. Therefore, artificial restoration of the grassland soil seed bank, optimization of the soil microbial community, and maintenance of soil moisture are crucial to the restoration of the aboveground plant community.
Water erosion causes soil fertility loss and land degradation, posing serious threats to agricultural production, soil and water conservation, and environmental protection. Accurately assessing the spatiotemporal dynamics and driving mechanisms of water erosion is essential for mitigating regional erosion risks. In this study, the Revised Universal Soil Loss Equation (RUSLE) was coupled with the Transport Limited Sediment Delivery (TLSD) to simulate water erosion in the Shiyang River Basin from 2001 to 2020. Additionally, the Random Forest (RF) algorithm was employed to quantify the contributions of different driving factors to net soil erosion. The results showed that the RUSLE-TLSD model reliably simulated soil erosion processes in the basin (NSE = 0.70). The annual mean net soil erosion rate varied between 2.28 and 9.68 tha-1a-1, with an overall decline, and the most intense water erosion occurred during the summer (June-August). Areas of intense water erosion were primarily concentrated in the southern Qilian Mountains, characterized by steep relief, abundant rainfall, and strong sediment transport capacity. The RF model explained approximately 85% of the variance, indicating that LUCC, NDVI and slope had the most significant impact on the spatial pattern of water erosion in the basin, and the area with sparse vegetation and large topographic relief had a high risk of water erosion. It is hoped that the findings of this study will provide a reference for water erosion risk assessment and management planning in arid zone basins.
One of the challenges associated with microbial inoculants is selecting the appropriate carrier material that ensures reliable and consistent performance in field conditions. This performance is critical in arid environments, which have extreme temperatures and low humidity. Pyroclastic material has been explored as a potential alternative due to its beneficial physical and chemical properties that promote the growth of microorganisms and plants. Our research focuses on evaluating a new fungal carrier that utilizes volcanic particles impregnated with spent grain for its potential incorporation into seed coating technology. We assessed the ability of native fungal strains (Trichoderma aff. virens, Beauveria bassiana, and Zopfiella aff. erostrata) to thrive in this pyroclastic material, monitoring their viability over a six-month period. To evaluate the infective capability of the arbuscular mycorrhizal strain Rizophagus clarus, we used the most probable number method. We also tested seed coating with formulated ashes as a practical method for incorporating these bioinoculants into traditional crops. Our results indicated that this pyroclastic material serves as an effective carrier, maintaining viability above 55% for B. bassiana and 72% for T. virens conidia after six months. For the mycorrhizal strain R. clarus, the volcanic ash contained 39 infective propagules (per g-1 of soil) after three months. Moreover, the seed coating demonstrated a high effectiveness rate of over 90% for the treatments involving T. virens and B. bassiana. The development of bioformulations using this novel, highly available and easy-to-handle carrier material of volcanic origin provides a feasible product with potential worldwide application.
