Large gullies in dryland landscapes are often indicators of land degradation by surface runoff. However, under conditions where gully systems are hydrologically arrested by restoration interventions that increase water residence time-most notably check dams and ponds-they may also function as hydrologically active zones of groundwater recharge and subsurface connectivity. In China's Loess Plateau, we assess these functions in the Nianzhuang Catchment using a multi-indicator, process-based approach that integrates stable isotopes (delta H-2, delta O-18), chloride concentrations, and groundwater level fluctuations. Our results show that precipitation is the dominant source of recharge for shallow pore water within engineered gully zones, while deeper fissure water is replenished more slowly through percolation. Hydrological arrest through ecological engineering interventions acts as focal points for groundwater infiltration, enhancing recharge in otherwise limited dryland systems. Estimated annual recharge in the monitored gully-zone pore aquifer (238-241 mm) is equivalent to about 43 % of the mean annual precipitation at the site, a site-specific recharge magnitude that far exceeds reported catchment-wide recharge rates observed in nearby tableland and hilly areas. Our results indicate that engineered gully systems can act as focused recharge zones rather than solely degraded landforms. By linking runoff convergence and ponding to measurable recharge responses, the study provides a process-based framework for assessing groundwater dynamics in managed semi-arid landscapes.

By contrasting water sources and diverging in leaf economic spectrum (LES) traits, plants regulate and balance their use of water, carbon and nutrient resources, thereby potentially promoting species coexistence. However, how these strategies affect species coexistence is unclear. We quantified the relative contributions of different water sources (topsoil water, 0-20 cm; subsoil water, 20-200 cm), intrinsic water use efficiency (WUEi), key LES traits and the importance value index (a proxy for species dominance) across the 10 coexisting plant species in a natural secondary forest at Ziwuling Mountains of the Loess Plateau (LP), Northwest China. Our results showed the large variability in water source utilisation, WUEi, leaf N, P contents and specific leaf area (SLA) among species, indicating diverse resource use strategies. Differences in water sources resulted in varying degrees of water competition between species, ranging from 47% to 81%. The water source utilised by plants was coordinated with the LES. Species that relied on topsoil water, characterised by nutrient-rich but variable water supply, adopted acquisitive strategies, exhibiting high leaf N, P contents and SLA. In contrast, species relying on subsoil water, which provides relatively low-nutrient availability but a stable water supply, adopted conservative strategies, displaying opposite traits. Notably, species with conservative strategies dominated in the community. Synthesis. Our findings highlight a tight coupling between plant water sources and the LES, which jointly influence species coexistence and dominance. Our study evaluated the persistence and coexistence strategies of the 10 species in a natural secondary forest, which serves as a reference for the tree species selection of afforestation in the LP, or similar regions. (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) 10 (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)((sic)(sic)(sic)(sic)(sic), 0-20 cm;(sic)(sic)(sic)(sic)(sic), 20-200 cm),(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)((sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)). (sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic) 47%-81%. (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)((sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic))(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)"(sic)(sic)(sic)"(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic);(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)((sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic))(sic)(sic)(sic)(sic)(sic)"(sic)(sic)(sic)"(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic), (sic)(sic)"(sic)(sic)(sic)"(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic):(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) 10 (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).

Check dams are known to support sediment retention and erosion control for water and soil conservation; however, their hydrological role in perched groundwater recharge remains mechanistically unresolved. To address this gap, we integrated water level monitoring, iodide-bromide tracer tests, water table fluctuation (WTF) calculations, and cumulative sum (CUSUM) analysis to investigate perched groundwater dynamics associated with check dams in the Yangjuangou Catchment of the Loess Plateau in China. We find that the perched groundwater levels exhibit distinct spatiotemporal variability, with recharge-dominated areas located in the middle and tail sections above check dams and discharge-dominated zones occurring near the check dam head. Iodide-bromide tracer tests identified both vertical and lateral subsurface water movement, with rates of 6.4 cm & sdot;day-1 and 7.1 m & sdot;day-1, respectively. Recharge totaled 207.3 mm, representing 48.4% of the annual rainfall, and included contributions from both infiltrating precipitation and lateral water inflow. Recharge response lagged rainfall by approximately 9 days and followed a nonlinear relationship. Collectively, these findings support development of a new conceptual model focused on the "precipitation-driven-perched groundwater" relationship, challenging the traditional view of check dams as static storage. They reveal the formation, migration, and precipitation response mechanisms of perched groundwater, establishing its role as "dynamic hydrological regulators". This process-based framework enhances assessment of groundwater recharge, lateral connectivity, and hydrological regulation within check-dam systems in semi-arid environments.

Under global warming and water resource constraints, winter wheat yield in the Haihe Plain has continued to increase despite decreased agricultural water use, reflecting enhanced adaptation of newer cultivars to water limitation. However, the mechanisms through which roots adapt to water limitation and enhance water productivity (WPc) remain unclear. This study, based on 25 major cultivars since 1950s, analyzed root characteristics and their relationship with WPc over three years of field and tube experiments. Results showed that with cultivar replacement, the number of tillers and secondary roots significantly decreased by 0.66% and 0.55% y- 1, respectively, while primary roots increased by 0.56% yr- 1. In the field, root mass in the 0-0.4 m soil layer decreased significantly, with root mass density (RMD) and root length density (RLD) decreasing by 0.0011 mg cm- 3 yr- 1 and 0.014 cm cm-3 yr- 1, respectively, while root activity (RA) increased by 0.237 mu g g- 1 h- 1 yr- 1. Tube experiments showed a shift towards deeper roots, particularly in the 1.2-1.6 m soil layer. Yield increased by 57.35 kg hm- 2 yr- 1 due to higher grain weight, while yield stability and water productivity (improved by 0.66% yr- 1) also enhanced during cultivar replacement. Field shallow RLD and RMD were negatively correlated with yield and WPc, whereas tube post-anthesis deep RLD, RMD, and RA were positively correlated with grain weight, yield, and WPc. Overall, cultivar replacement reduces shallow-root investment while enhancing RA, whereas deep-root may improve WPc by sustaining grain-filling water uptake, delaying senescence, and increasing grain weight, though deep-root trends require field validation.

BACKGROUND:Extensive wheat cultivation areas in China are crucial for national food security and the global food supply. Identifying potentially suitable planting areas is essential for agricultural planning. The aim of this study was to develop a high-stable index (HSI) - a measure of yield level and yield stability reflecting historical production outcomes rather than intrinsic agro-ecological suitability - to quantify potential suitable planting areas for winter wheat at the national scale. This index was applied to evaluate current planting limits and the effects of land-use change on potential planting areas. RESULTS:The HSI-based approach characterized the spatial distribution of potential winter wheat suitability in China. Within the traditional winter wheat planting region, highly suitable areas accounted for 21.8% of the land, moderately suitable areas for 37.6%, poorly suitable areas for 28.7%, and unsuitable areas for 11.9%. During 1999-2019, about 81.7 × 106 ha of land nationwide was identified as highly or moderately suitable for winter wheat cultivation but remained unused for planting. Strategic planning of urban land can promote the development of the winter wheat planting area, given that 77.2% of newly added urban land in China between 2000 and 2020 was located in areas potentially suitable for winter wheat cultivation. CONCLUSION:The HSI is an indicator of actual land suitability, reflecting observed agricultural performance under actual management and environmental conditions rather than purely intrinsic agro-ecological potential. This framework provides valuable support for strategic crop structure adjustment and food security planning. © 2026 Society of Chemical Industry.

Global climate change is exacerbating the degradation of plantations in China's Northern Shelterbelt regions. While replanting seedlings is essential for stand regeneration and ecosystem recovery, the mechanisms governing seedling survival remain poorly understood, hindering effective restoration efforts. This study investigates the survival strategies of three critical species-P. tabuliformis (Pt), P. orientalis (Po), and P. simonii (Ps)-in the water-wind erosion region of the Loess Plateau, based on two years of field observations and multi-model analyses. Key findings include: (1) Pt achieved a 93.7 % survival rate under drought conditions, significantly exceeding the survival rates of Ps and Po, which trailed by 16.5 % and 16.9 %, respectively. This success is attributed to its deep root system, with 68.6 % of fine roots located at depths of 40-60 cm, and stable leaf stoichiometry, evidenced by minimal variation in C:N ratios (less than 2 %). (2) Soil water content emerged as the primary influence on survival (path coefficient = 0.945), while neighboring vegetation intensified resource competition and limited seedling establishment. (3) Leaf economics spectrum analysis indicated that Pt adopts a conservative strategies, Ps exhibited acquisitive traits, and Po optimizes metabolism within the acquisitive framework, enhancing resource utilization under stress through efficient nutrient allocation. These insights support afforestation strategies: utilizing Pt as a pioneer in arid regions, interplanting Ps with shrubs for improved shading and moisture retention, and prioritizing Po in phosphorus-rich areas. This research lays a scientific foundation for species selection and functional restoration in arid regions, emphasizing the critical role of seedling replanting in plantation regeneration.

Check dams are widely used across the Loess Plateau to control erosion and retain water, yet their effects on groundwater recharge remain poorly quantified. Using stable isotopes, residence-time analysis, and mixing models, we investigated groundwater recharge pathways in a check-dam catchment. Check-dam construction created two new recharge reservoirs-pond water and perched groundwater. These engineered water bodies became dominant recharge intermediaries for both pore and fissure groundwater. Together, they contributed approximately 81% of pore-groundwater recharge and about 50% of fissure-groundwater recharge. Mean residence times increased from pore groundwater (307 days) to fissure groundwater (591 days), indicating slower renewal and greater hydrological buffering in the fractured system. Seasonal isotope analyses further showed that pore groundwater receives substantial dry-season recharge, consistent with delayed infiltration from stored water behind check dams. Fissure groundwater is recharged primarily during the rainy season. These results demonstrate that check dams establish a dominant focused recharge pathway mediated by engineered surface-water storage. Meanwhile, diffuse precipitation recharge remains an important wetting component of the groundwater recharge system. The findings highlight an important but often overlooked role of check dams in groundwater regulation and hydrological-cycle modification in semi-arid landscapes.

Under global warming and increasingly frequent droughts, understanding how root cultivar replacement optimizes crop water-use period in water-limited conditions is crucial for improving water productivity (WPc) and grain yield. A three-year field experiment was combined with a two-year root simulation study to evaluate 25 winter wheat cultivars released from the 1950s to the 2020s, focusing on root traits, grain yield, WPc, actual evapotranspiration (ETc act), and soil water depletion (SWD). Cultivar replacement significantly increased grain yield and WPc by 43.87% and 55.25%, respectively (p < 0.01). SWD gradually increased after anthesis and shifted progressively to deeper soil layers without a corresponding increase in ETc act. These changes were closely associated with root adjustments. Compared with 1950s cultivars, modern cultivars showed lower root length density (RLD) and root mass density (RMD) at jointing, followed by increases from booting to anthesis driven mainly by a greater proportion of deep roots. After anthesis, roots in the 0-0.4 m layer decline sharply; RLD and root activity (RA) in the 1.2-1.6 m layer increase by 86.14% and 56.48%, respectively, with a slower post-anthesis decline. Mantel tests and redundancy analysis (RDA) indicated that SWD during the vegetative stage had limited influence on yield and WPc, whereas post-anthesis deep SWD and roots were significantly positively correlated with kernel weight, yield, and WPc (p < 0.05). Modern cultivars reduce vegetative stage root redundancy and enhance deep-root function during reproduction, improving deep soil water use, and ultimately improving WPc and yield under water-limited conditions.

Precipitation extremes and ecological restoration projects significantly influenced hydrological processes by mitigating or aggravating groundwater depletion within the Earth's critical zone. However, scientific evidence remains limited due to the strong dependence of deep recharge on both unsaturated zone thickness and precipitation event magnitude. Here, we analyzed seven-year field datasets encompassing precipitation, soil water content (SWC), surface water (reservoir water), and groundwater from an ecological restoration catchment on the Chinese Loess Plateau. Precipitation extremes triggered deep hydraulic connectivity between the unsaturated and saturated zones mainly through preferential flow pathways, as evidenced by depleted of delta 18O, increased of SWC profiles, and rising water table. Temporal-spatial patterns of SWC (0-4000 cm profile) revealed preferential flow pathways on a sunny slope with recharge efficiency regulated by precipitation patterns and topography. In the gully, water tables showed a positive correlation with precipitation amount, duration, and initial SWC. These hydrological drivers induced significant differences in water table changes among precipitation years. In contrast, the slope (0-500 cm profile) maintained persistent water deficits with limited recharge response, despite precipitation inputs (except for a 167.7-mm event). Furthermore, precipitation variability coupled with plant root uptake altered the vertical soil water gradient, with the 200-300 cm layer functioning as a hydraulic buffer. However, prolonged drought triggered an accelerated water table recession at 60.8 mm/year, while creating carry-over soil water deficits that extended beyond dry years, sustaining 15.4 mm/year depletion even in the following normal year. When considering the saturated zone contribution, total recharge rates demonstrated the positive hydrological feedback of ecological restoration projects to annual precipitation, accounting for 45 % of precipitation (327.8 mm/year) during a wet year. Therefore, it can be inferred that event-and annual-scale precipitation extremes enhance groundwater recharge at the ecological restoration catchment. These findings provide critical scientific support for maintaining groundwater sustainability in such systems.

The Changbaishan volcanic field ranks as one of China's largest active volcanic fields. Numerous peatlands developed in this area, serving as crucial carbon sink within the country. In this well-known volcanic field, climatic changes and volcanic eruptions are likely to have exerted a notable impact on the carbon accumulation processes of peatlands. That said, the specific carbon dynamics in these peatlands and the possible driving mechanisms remain insufficiently understood. To address these unresolved questions, this study chose the Dongfanghongnan peatland as research subject. Findings from the investigations indicate that this particular peatland began to store carbon during the Late Holocene epoch. From 4344 to 1000 cal. yr BP, temperature and precipitation functioned as major factors that regulating carbon dynamics of the Dongfanghongnan peatland. Nevertheless, since 1000 cal. yr BP up to now, tephra deposition has been the major affecting factor for the carbon dynamics of peatlands. Furthermore, two distinct types of high-efficiency carbon sequestration patterns can be distinguished in the Dongfanghongnan peatland. The first pattern is named the climate-nutrient type. In an environment with increased rainfall and intense solar radiation, higher temperature may boost the productivity of Carex. At the same time, moist conditions are beneficial for the conservation of peat, which in turn helps trap carbon. In addition, nutrient phosphorus was transported into peatland with a phosphorus accumulation rate (PAR) of 0.058 g P m-2 yr-1, raising the net primary productivity of plants growing in the peatland. These combined effects led to a high-efficiency apparent carbon accumulation rate (aCAR), reaching 21.88 g C m-2 yr-1. The second pattern is referred to as the tephra fertilization type. Tephra released a large amount of phosphorus (with a PAR of 0.071 g P m-2 yr-1). Abundant phosphorus supply promoted the net primary productivity of both Carex and mosses. This promotion eventually resulted in a high-efficiency aCAR, which was measured at 24.90 g C m-2 yr-1. These findings deepen understanding of the relationship between climate variations, volcanic activities, and carbon sequestration of peatlands. They also establish important basis for making forecasts about the future carbon dynamics of peatlands in Northeast Asia.

Sustainable agricultural management is one of the important factors for ensuring food security. In recent years, many wheat and maize fields on the Loess Plateau of China have been transformed into apple orchards for better economic returns. However, the evapotranspiration of apple orchards is far greater than the precipitation supply, resulting in a reduction in water resources that are available for apple trees. In this study, an experiment was conducted from 2012–2015 on apple orchards of different ages and maize and wheat fields. The field experiment and the Root Zone Water Quality Model (RZWQM2) were combined (1) to explore the feasibility of RZWQM2 in simulating soil water conditions under the three cropping systems and (2) to simulate long-term soil water dynamics and plant water use in different cropping systems from 1981–2019. The results showed that RZWQM2 was able to simulate the growth of wheat and maize and the water use of the three land use patterns (R2>0.70, −3.86 %0.89). Under the long-term continuous cropping system, the water consumption in the apple orchard was the highest, followed by that in the maize and wheat fields. The turning point of evapotranspiration in the apple orchard occurred at the 22nd year, but it decreased with increasing years of cultivation in the maize and wheat fields. Therefore, the planting of winter wheat after 22 years of apple planting should be considered to restore the soil water in the apple orchard to ensure the sustainable development of agriculture in this area.

Ridge-furrow planting with plastic film (RP) is rarely used as an efficient precipitation harvesting tillage practice in humid and subhumid areas, and its effect on precipitation infiltration remains poorly understood. Given the growing demand for water-saving agriculture under climate change, exploring RP's potential to optimize precipitation use efficiency is critical for advancing sustainable cropping systems in these regions. Therefore, we investigated the infiltration processes of 10 typical precipitation events in wheat fields under flat planting (FP) and RP from 2022 to 2024 in the Guanzhong Plain, China. Hydrogen and oxygen stable isotope technology was used to quantify precipitation loss and contribution proportion (f) of precipitation to soil water in different soil layers. The f values were then applied to determine the infiltration depth (ID) and effective contribution time (ECT) of precipitation. Ridge regression analysis was employed to further reveal the sensitivity of ID, f, and precipitation loss to precipitation amount (Pr). This study suggests that compared to FP, RP reduced the average precipitation loss by 56.9% on the first day after precipitation. The depth-weighted average f values of precipitation to 0-120 cm soil layer under RP significantly increased by 12.0%-20.7% versus FP within 5 days after precipitation. Furthermore, RP extended the ID by 10-20 cm and maintained an ECT of 1-3 days in soil layers where no infiltration occurred under FP. In response to a 100 mm increase in Pr, RP demonstrated a clear advantage over FP, with a 60.9% and 59.9% reduction in precipitation loss, a 24.6% and 27.0% increase in f, and a 22.6% and 18.7% increase in ID, respectively, in wet and normal years. As a result, the 2-year average grain yield and water use efficiency of winter wheat under RP increased significantly by 19.1% and 21.6% in comparison to FP, respectively. This study fills the knowledge gap on the infiltration process of precipitation under RP, and provides empirical support for adopting it as a water-saving practice for wheat cultivation over FP in subhumid regions.

As an efficient water and soil conservation tillage practice, ridge-furrow planting with plastic film (RP) is rarely used in humid and sub-humid areas. It is hypothesized that RP could break the bottleneck of flat planting (FP) in sub-humid areas that makes it difficult to improve wheat yield. Before recommending RP, it should be clarified how RP promotes the efficient utilization of water in fields. Therefore, we conducted a 2-year field experiment following a randomized block design with winter wheat under FP and RP in the Guanzhong Plain. Stable isotopes of delta 2H and delta 18O were used to quantify precipitation infiltration, root water uptake (RWU), and evaporation (E) and transpiration (T). The results showed that the average contribution proportion of precipitation to 0-100 cm soil layer under RP significantly increased by 10.4-22.9 % versus FP within five days after precipitation. RP also increased the average RWU proportion by 8.6 % in the 0-60 cm layer and decreased it by 28.1 % in the 60-200 cm layer compared to FP. Furthermore, RP significantly decreased E by 36.9 % and increased T by 8.9 % versus FP from greening to harvest stage, resulting in significantly depleted delta 2H and delta 18O values in soil water. Ultimately, the two-year average grain yield and water use efficiency (WUE) of winter wheat under RP increased significantly by 19.1 % and 21.6 % in comparison to FP, respectively. Overall, RP can conserve soil water by promoting precipitation infiltration and inhibiting E, thereby increasing T and improving grain yield and WUE. This study bridges the gap between theoretical research and practical dissemination of RP in the sub-humid region, and provides an empirical support for soil and water conservation and yield enhancement.

The soil organic carbon (SOC) content of cropland affects global food production and is crucial for agricultural carbon reduction. The SOC response to long-term changes in main grain land (MGL) likely differs from non-MGL cropland. We constructed a quantitative indicator system for the MGL planting pattern to reveal the relationship between MGL use change and SOC. We produced an MGL dataset for China from 1985 to 2020 based on the existing MGL distribution data and available Landsat images and analyzed the heterogeneity of SOC under different MGLs using two SOC datasets. Time series change detection explained the interaction between planting patterns and SOC. Different MGLs exhibited considerable heterogeneity in SOC. The single rice area with the highest SOC was twice (31.62 g/kg) that of the wheat and maize areas. SOC showed an opposite trend in MGL and non-MGL with increased planting intensity. Soil SOC content affected the expansion decisions of farmers in cropland and MGL. Areas with a high SOC were developed into MGL by farmers early. MGL consumed more SOC and had a stronger urgency for fallow cultivation than non-MGL. The planting intensity of MGL more than the inflection threshold (about 15 years) decreased shallow SOC (0-15 cm), decreasing below the initial value after more than 30 years. Currently, 62.08 % of MGL in China causes a decrease in SOC, with an urgent need for a fallow MGL of 27.38 Mha. Theoretical guidance for optimizing crop planting patterns to ensure food security and reduce agricultural carbon emissions was provided.

Air pollution in Punjab, Pakistan, is an escalating environmental crisis driven by uncontrolled urban expansion and inadequate political and social will to manage pollutants. This situation severely threatens agricultural productivity, ecosystem health, and human well-being, reflecting the consequences of unchecked development in a region h eavily dependent on its fertile agricultural land. The interplay between key air pollutants Nitrogen Dioxide (NO2), Sulphur Dioxide (SO2), and Formaldehyde (HCHO) and vegetation dynamics necessitates urgent investigation, as these pollutants can disrupt plant growth and agricultural yield, impacting the local economy and food security. This study utilizes satellite data from Sentinel-5P and MODIS, spanning 2019 to 2023, to analyze correlations between key air pollutants (NO2, SO2, HCHO) and vegetation indices (NDVI and EVI), alongside Land Surface Temperature (LST). Our analysis reveals a significant negative correlation between NO2 levels and both NDVI (r = -0.45, p < 0.001) and EVI (r = -0.40, p < 0.01), indicating detrimental effects on vegetation health. Conversely, SO2 positively correlates with LST (r = 0.30, p < 0.01), which may suggest a role in local warming, potentially influenced by factors such as reduced vegetation cover, traffic, and industrial activity. The relationship between HCHO and vegetation indices remains inconclusive, suggesting that further research is needed to understand these interactions fully. These findings highlight the urgent need for comprehensive air quality management strategies in Punjab to address both environmental and climatic impacts. To address the challenges identified, it is crucial to implement targeted emission reduction strategies for industrial and vehicular sources and to promote sustainable practices. Future research should prioritize integrating sustainable development practices aligned with the Sustainable Development Goals (SDGs) to enhance environmental health and ensure long-term sustainability for the region.

The vertical soil moisture heterogeneity in the rhizosphere affects the way vegetation absorbs water, resulting in hydraulic lift (HL). However, quantifying and resolving HL is difficult due to the unpredictability of subsurface components and complex plant-soil interactions. In this study, we investigated the HL occurrence in tree species (Acer truncatum Bunge and Pinus tabuliformis Carrie`re) in the mountainous areas of Beijing by pot experiments through the addition of heavy water (2H2O) to create a soil moisture gradient. The results indicated that soil moisture differences (0.107-0.204 cm3 cm- 3 for A. truncatum, 0.048-0.145 cm3 cm-3 for P. tabuliformis, respectively) led to a significant occurrence of HL in both broadleaf (A. truncatum) and conifer species (P. tabuliformis). The total HL was up to 4767 and 2735 cm3, with daily fluxes of 64-1,49 and 84-1133 cm3 d- 1 for A. truncatum and P. tabuliformis, respectively. The flux of HL in P. tabuliformis was lower and appeared later than that of A. truncatum. This is because P. tabuliformis will respond to drought by preferentially decreasing stomatal conductance (Gs) and transpiration rate (Tr) compared to A. truncatum. As the Tr of A. truncatum and P. tabuliformis decreased, the probability of HL occurring increased, but the fluxes gradually declined. The occurrence of HL increased the likelihood of plant water uptake from deep soils, helping to alleviate drought stress in shallow soils. This study will help to understand the water acquisition and allocation strategies of plants under drought stress.

Rainfall partitioning by canopies into canopy interception (Ic), throughfall (TF), and stemflow (SF) alters hydrological fluxes reaching the ground. Although biotic and abiotic factors significantly influence the fluxes, their contributions remain unclear due to complex interactions among collinear factors. A five-year study was conducted in a rain-fed apple orchard to quantify the contributions of factor groups and each factor to Ic, TF, and SF through variation partitioning and hierarchical partitioning. Results indicated that rainfall was redistributed 83.1% as TF, 15.5% as Ic, and 1.4% as SF. The rainfall event factors group contributed the most to explaining the variance in rainfall partitioning components. Rainfall amount was the primary driver, explaining 47.5% of TF, 41.9% of SF, and 29.6% of Ic, while rainfall duration had the greatest individual importance on Ic percentage (25.9%) and TF percentage (25.4%). High amount (>19.0 mm) and long duration (>10 h) events showed a higher TF%, enhancing water availability.

Estimating the actual evapotranspiration (ETc act) of cropland in arid areas, exploring the time trend, and analyzing periodic variation are the key to long-term assessment of water resource availability and regional drought. The Penman formula has a strong ability to characterize reference crop evapotranspiration (ETo). However, the application of this formula may be limited in the absence of a complete set of climate data. While previous studies have investigated Kc act in China, few have employed localized Kc values to systematically analyze long-term periodic fluctuations in ETc act under climate variability conditions. Therefore, this study aimed to evaluate the applicability of nine ETo estimation models in the Loess Plateau of China, calculate actual crop coefficients (Kc act) for spring maize and winter wheat, and examine the temporal trend and periodicity of ETc act for long-term (1961–2018) continuous cropping of spring maize and winter wheat in the study area. The Mann–Kendall test and continuous wavelet transform (CWT) were used to obtain the temporal trend and periodicity of ETc act. The results were as follows: (1) Priestley–Taylor (Prs–Tylr), based on radiation, and the 1985 Hargreaves–Samani (Harg), based on temperature, can be used when meteorological data are limited. It should be noted that among the models evaluated in this study, except for FAO56-PM, only the Harg equation is compatible with Kc-ETo due to established conversion factors. (2) The Kc act of spring maize at the seeding–jointing stage and the earning–filling stage was 12% and 10% lower than the value recommended by FAO, respectively. For Kc act of winter wheat, it was 65% higher, 31% lower, and 85% higher than the FAO experience values in the rejuvenation–jointing stage, heading–grouting stage, and grouting–harvest stage. (3) Winter wheat, through its ETc act cycle synchronized with precipitation and excellent water balance, can effectively alleviate regional drought. It is recommended to be included in the promotion of drought resistance policies.

In arid and semi-arid regions, vadose zone thickness strongly influences precipitation infiltration and groundwater recharge, both increasingly affected by climate-driven shifts in rainfall patterns. However, its influence on soil water dynamics and groundwater recharge in plantation ecosystems remains inadequately understood. This study, conducted in the Mu Us Sandy Land of China, monitored stable isotopes, soil water, and groundwater levels over two years across three Mongolian pine plantations. These sites had different initial groundwater depths: 4 m (downland), 9 m (midland), and 13 m (upland). Key findings include: (1) Downland exhibited significantly greater mean soil water content (SWC) in the middle and deep soil layers than in the midland and upland (p < 0.05). (2) The soil desiccation index was higher in the midland and upland than in the downland. SWC increased in the upper and middle layers from the dry to the rainy season, but deep SWC decreased in the upland. (3) Rainfall events >= 20 mm day(-1) replenish deep SWC in the downland, whereas >= 30 mm day(-1) was required in the midland and upland. (4) In 2022, precipitation was more concentrated in >= 10 mmday(-1) events, totaling 311 mm (74.5 % of the annual total), and produced greater groundwater recharge than in 2023, when such events accounted for only 190 mm (56.5 %). These findings demonstrate that vadose zone thickness and rainfall intensity thresholds critically control groundwater recharge-a process further modulated by Mongolian pine plantations. Therefore, integrating these factors into management strategies is essential for sustainable groundwater conservation in arid regions.