Search Results (842)

Understanding how climatic variability affects growth and water relations of Scots pine (Pinus sylvestris L.) is essential for assessing stand sustainability in hemi-boreal regions. Linear mixed-effects models were used to quantify the effects of climatic variability and tree characteristics on stem volume increment (ZV), sap flow (SF), and water-use efficiency (WUE) of Scots pine growing on highly oligotrophic soils in Curonian Spit National Park. Annual ZV was strongly controlled by tree size and seasonal temperature conditions. Higher temperatures in late winter and mid-summer enhanced growth, whereas elevated temperatures in April–May reduced increment. June moisture availability, expressed by the hydrothermal coefficient, had a positive effect, highlighting the sensitivity of growth to early-summer drought and heat waves. Sap-flow density during May–October was primarily driven by climatic factors, with temperature stimulating and relative humidity reducing SF, while tree size played a minor role. Random-effects analysis showed that unexplained variability in ZV was mainly associated with persistent differences among trees and sites, whereas SF variability occurred largely at the within-tree level. In contrast, WUE was dominated by climatic drivers, with no detectable site- or tree-level random effects. Higher June precipitation increased WUE, while warmer growing-season conditions reduced it. Overall, Scots pine growth and WUE are mainly regulated by intra-annual climatic conditions, particularly summer water availability. Despite rapid climatic change, no critical physiological thresholds or growth collapse were detected during the study period, indicating substantial adaptive capacity of Scots pine even under the observed exceptional conditions. Full article

Biochar is recognized for its ability to improve the chemical, physical, and biological properties of soil, thereby enhancing crop productivity. However, the effects of biochar on photosynthetic and transpiration traits in rice crop–soil systems, particularly through the lens of on-site data subjected to Box–Cox transformation, remain insufficiently explored. To address this, a two-factor randomized block design experiment was conducted using the rice cultivar Nangeng 9108 at the Agricultural Meteorology Experimental Station of Nanjing University of Information Science and Technology over the 2022–2023 principle phenophases. This study investigated changes in leaf stomatal conductance, photosynthetic, transpiration, and water-use efficiency (WUE) parameters under combined applications of biochar (0, 15, and 30 t/ha) and nitrogen fertilizer (0, 180, 225, and 300 kg/ha). Application of the Box–Cox transformation substantially improved data normality and variance homogeneity, enabling the development of a robust predictive model linking net photosynthetic rate to environmental factors. A two-way ANOVA further revealed that both the high nitrogen (300 kg/ha) with high biochar (30 t/ha) treatment and the conventional nitrogen (225 kg/ha) with moderate biochar (15 t/ha) treatment significantly enhanced rice photosynthetic and transpiration performance. Of particular note, the N225B15 treatment, which showed a net photosynthetic rate increase from 9.52% to 19.01%, and transpiration rate increase from 11.49% to 28.43%, is recommended as an optimal fertilization strategy for sustainable rice production. These results underscore the synergistic role of moderate biochar and nitrogen inputs in improving key physiological traits of rice, supporting higher crop yields. Full article

Sustainable nitrogen (N) management is critical for enhancing wheat production in the water-limited environment of China’s Loess Plateau. This study investigated the effects of four N rates (0, 120, 180, and 240 kg N ha⁻¹) and two sowing methods, furrow sowing (FS) and drill sowing (DS), on wheat yield, grain quality, and water-use efficiency (WUE). Results indicated that N application significantly improved all metrics. The optimal N rate for yield was 180 kg N ha⁻¹ (N180), producing yields equivalent to the higher 240 kg N ha⁻¹ rate (N240). Compared to the N0 control, the N240 treatment under FS in 2022–23 increased grain yield by 25.4% and WUE by 11.9%, while under DS it increased yield by 23.6% and WUE by 11.1%. However, in the following year (2023–24), the greatest benefits under FS came from N180, which increased yield by 19.3% and WUE by 11.5% over the control. Higher N rates markedly elevated grain quality: N240 resulted in the highest steamed bread score and concentration of volatile compounds. Nitrogen application also intensified soil water use, particularly before anthesis. In 2022–23, the highest N240 reduced soil water at maturity by 16.6% (FS) and 15.9% (DS) and increased total water consumption by up to 7.8% compared to N0. Yield was strongly correlated with soil water depletion in the 0–200 cm layer during the reproductive period. While N240 optimized quality, the N180 rate combined with improved sowing methods (FS or DS) provided the best balance, drill sowing was crucial agronomic practice for enhancing nitrogen-use efficiency (NUE), achieving high yield, superior WUE, and acceptable quality. We therefore recommend an N rate of 180 kg ha⁻¹ with improved sowing as a sustainable practice for dryland wheat production on the Loess Plateau. Full article

Legume green manure incorporation offers a potential pathway for sustainable cropping in arid irrigated areas. This study aimed to determine whether water and nitrogen inputs could be concurrently reduced without compromising maize productivity under this practice. A two-year field experiment (2024–2025) was conducted using a split-plot design with three irrigation levels (I1: 4045, I2: 3240, I3: 2430 m³·ha⁻¹) and three nitrogen rates (N1: 360, N2: 288, N3: 216 kg·ha⁻¹). Compared with conventional management (I1N1), 20% co-reduction in water and nitrogen (I2N2) maintained stable leaf area index (LAI), net photosynthetic rate (P_n), transpiration rate (T_r), DM, and GY, while significantly increasing water use efficiency (WUE) by 7.6% and nitrogen use efficiency for grain yield (NUtEg) by 11.7%. Excessive water reduction (I3) or nitrogen reduction (N3) significantly inhibited growth and reduced yield (p < 0.05). Soil water content under I2N2 did not differ significantly from I1N1 in the 0–110 cm profile, and soil total nitrogen remained higher at silking.) Structural equation model (SEM) revealed SWC and STN indirectly affected P_n and T_r via regulating LAI and SPAD (path coefficients: 0.48–0.62), which drove DM accumulation and determined GY (R² = 0.81). These short-term results suggest that moderate water-nitrogen reduction with green manure can sustain yield while improving resource efficiency, offering a promising practice for arid irrigated maize systems, though longer-term validation is needed. Full article

Climate change exacerbates soil moisture deficits, necessitating efficient water retention strategies. Superabsorbent polymers (SAPs) offer a potential solution to enhance water availability for crops during dry periods. Faba bean (Vicia faba L.) and pea (Pisum sativum L.) were selected as model legumes due to their high nutritional value, agricultural importance in temperate regions, and sensitivity to drought stress This study evaluated the effects of different SAP application rates on the yield and physiological performance of two legume species: faba bean (cv. Granit) and pea (cv. Batuta). The two-year (2017–2018) field experiments employed a randomized block design with four replicates. Treatments included three SAP doses: 0 (control, SAP0), 20 (SAP20) and 30 (SAP30) kg·ha⁻¹. The study was conducted over two years with contrasting weather: 2017 was wetter but had uneven rainfall distribution, while 2018 was drier and characterized by moisture deficits during critical growth stages. SAP application significantly increased seed yield in faba bean and pea, with the most favorable effect observed at 20 kg ha (average yield increase of 23.6% and 17.3%, respectively). SAP did not affect yield components in faba bean. However, in peas, an increase in pod number and seed number per plant was observed with the SAP30 dose compared to the SAP20 dose. Application of superabsorbent at a dose of 20 kg ha⁻¹ significantly increased photosynthesis rate in faba bean, the Fv/Fm index in the tested species, and the PI in peas compared to the control. However, the superabsorbent did not affect transpiration rate or the WUE coefficient in the tested legume species. Significantly higher yields in faba bean and pea and all tested plant structure parameters in pea were recorded in 2018 compared to 2017. The tested parameters of gas exchange and chlorophyll fluorescence were higher in pea in 2018 (except for transpiration intensity) and in faba bean in 2017. The findings suggest that SAPs can be a useful tool to mitigate water stress effects in legumes, although their effectiveness depends on environmental conditions. Therefore, SAP application may be a promising agronomic strategy in regions prone to irregular rainfall or moderate drought. Full article

This study investigated the combined effects of high air temperature and low light intensity on the growth, quality, yield, and water use efficiency (WUE) of greenhouse tomato. A full factorial design was employed to simulate the dynamic air temperature and light intensity of a greenhouse in the controlled environment chambers. Three air temperature levels (control: 25/15 °C, moderately high: 30/20 °C, and high: 33/23 °C, day/night) and three light levels (low: 400, medium-low: 600, and normal: 800 μmol·m⁻²·s⁻¹) were established. A comprehensive assessment approach that integrated linear weighting, TOPSIS, and GRA was employed. A multiple regression model was developed to quantify the temperature–light combined effect. Elevated air temperatures accelerated the flowering, fruit-setting, and veraison periods, and improved fruit brightness and chroma, but severely reduced yield by 13.9% for each 1 °C increase, while increasing water consumption. Yield and WUE declined by 5.0 and 3.5%, respectively, for every 50 μmol·m⁻²·s⁻¹ decrease in light. Combined effects were observed: moderately high temperature and low light intensity (30/20 °C, 400 μmol·m⁻²·s⁻¹) promoted lycopene accumulation; moderately high temperature and normal light (30/20 °C, 800 μmol·m⁻²·s⁻¹) maximized the sugar–acid ratio and vitamin C (VC) content; and high temperature and low light (33/23 °C, 400 μmol·m⁻²·s⁻¹) optimized fruit brightness and chroma. Furthermore, each simultaneous 1 °C temperature increase and 50 μmol·m⁻²·s⁻¹ light decrease resulted in a 14.4% yield reduction and 15.0% WUE decline. Quantitative analysis results indicate that air temperature exerts the most influence on tomato growth; however, the combined effect of high air temperature and low light intensity is less than the individual effects of each factor. These findings provide a basis for environmental regulation in protected tomato cultivation. Full article

This study assessed six tomato (Solanum lycopersicum L.) cultivars within an integrated solar-powered closed hydroponic system in Al Dhaid, UAE (25°16′11.2″ N, 55°55′52.2″ E). The system combined an insect-proof net house, closed hydroponics, root-zone cooling, ultra-low-energy drip irrigation, and a cost-effective solar-powered reverse osmosis (RO) desalination unit to address salinity constraints. The cultivars, selected for their adaptability to controlled environments in the UAE, were evaluated for yield, water-use efficiency (WUE), and fertilizer-use efficiency (FUE). Among them, Torcida recorded the highest mean yield (0.619 kg/m²/harvest), WUE (27.1 kg/m³), FUE (26.5 kg fruit/kg fertilizer), and marketable fruit ratio (66.3%), followed by Roenza, Eviva, and SV 4129 TH; Lamina was intermediate, while Saley, a bushy type, produced the lowest yield. The top cultivars achieved cumulative yields exceeding 7 kg/m²—surpassing regional open-field benchmarks (4–5 kg/m²; 3–6 kg/m³). Compared with conventional cooled hydroponic greenhouses (3.5 kg/plant; 8 kg/m³), the system demonstrated similar productivity using three times less water. The RO unit produced water at baseline 1.05 USD/m³—58–68% below regional tariffs—while minimizing reliance on grid electricity and mechanical cooling. Overall, the integrated solar-powered hydroponic–RO model proved technically reliable, resource-efficient, and economically viable, offering a scalable solution for sustainable vegetable production in hyper-arid regions. Full article

Desert plants develop unique functional traits and resource utilization strategies under environmental stress, among which, water and nitrogen utilization strategies are the key resource utilization strategies for desert plants. Research on plant water and nitrogen utilization and leaf functional traits has rarely involved high-altitude desert shrubs. The synergistic or trade-off relationship between water and nitrogen utilization in desert shrubs remains unclear, and the variation patterns of leaf functional trait combinations related to water and nitrogen utilization along environmental gradients urgently need to be studied. This study takes the typical desert shrubs in the eastern part of the Qaidam Basin on the Qinghai–Tibet Plateau in China as the research object, selects the stable carbon and nitrogen isotopes (δ¹³C, δ¹⁵N) of plant leaves to characterize the water use efficiency (WUE) and nitrogen use strategy (NUE) of plants, explores the main leaf functional traits related to water and nitrogen utilization, and analyzes the relationship between leaf functional traits and environmental factors. The results show that the resource utilization traits of desert shrubs can be divided into two groups: water and carbon utilization centered on δ¹³C and nutrient utilization centered on δ¹⁵N. There are synergistic or trade-off relationships among plant functional traits. There is a trade-off relationship between water and nitrogen utilization in plants. The leaf functional traits related to water and nitrogen utilization in plants form a “water and nitrogen utilization leaf economic spectrum” along the gradients of temperature, drought, salinity, and nutrients. In conclusion, desert plants adapt to the environment of high cold, drought, high salt content, and limited nutrients by adjusting the relevant leaf functional traits. This study combines the stable carbon and nitrogen isotopes of plant leaves with the combined characteristics of leaf functional traits under different environmental gradients, providing a new perspective for understanding the water and nitrogen utilization strategies of high-altitude desert shrubs and their adaptation mechanisms to arid environments. Full article

Elucidating shrub ecohydrological adaptation is critical for optimizing vegetation-restoration strategies in arid regions and maintaining regional ecological stability. This study examined typical desert shrubs at the northern edge of the Mu Us Sand Land. During the growth peak season (July–September), we measured understory-soil δ¹⁸O, soil water content (SWC), leaf δ¹³C_p, stem δ¹⁸O, and gas-exchange rates, and evaluated shrub drought resistance and water-use efficiency using Mantel tests and principal component analysis (PCA). Based on the VPDB standard, the δ13Cp values of leaves ranked as follows: Caragana microphylla (−27.21‰) > Salix psammophila (−27.80‰) > Artemisia ordosica (−28.48‰). The results indicate that leaf δ¹³C_p and water δ¹⁸O are effective indicators of shrub water-use efficiency, reflecting Cᵢ/Cₐ dynamics and water-transport pathways, respectively. The three shrubs exhibit distinct water-use strategies: Caragana microphylla follows a conservative strategy that relies on deep-water sources and tight stomatal regulation; Salix psammophila shows an opportunistic strategy, responding to precipitation pulses and drawing from multiple soil layers; Artemisia ordosica displays a vulnerable, shallow-water-dependent strategy with high drought susceptibility. SWC was the primary driver of higher Long Water Use Efficiency (WUE), whereas Mean Air Temperature (MMAT) and Mean Relative Humidity (MMRH) exerted short-term regulation by modulating the vapor-pressure deficit (VPD). We conclude that desert-shrub water-use strategies form a complementary functional portfolio at the community scale. Vegetation restoration should prioritize high-WUE conservative species, complement them with opportunistic species, and use vulnerable species cautiously to optimize community water-use efficiency and ecosystem stability. Full article

This study aimed to address the limited infiltration capacity of the double ridge–furrow mulching system (DRFM) under heavy rainfall on the Loess Plateau, which exacerbates surface runoff and mid-summer soil water deficits in semi-arid rainfed areas. By incorporating infiltration holes to optimize the system, we evaluated their effects on soil water storage, maize growth, and water use efficiency (WUE). A two-year field experiment (2021–2022) comprised four treatments: conventional flat planting (CK), the traditional ridge-furrow system (CWC), the double ridge-furrow system (DWC), and the double ridge-furrow system with infiltration holes (DWCR). The experimental periods represented a normal precipitation year (2021, 410 mm) and a dry year (2022, 270 mm). Results indicated that the DWCR treatment established preferential flow pathways, significantly enhancing deep soil water storage and its utilization efficiency during critical phenological stages, particularly under drought. This improved deep water accelerated crop growth and boosted yield. Compared to the CK, CWC, and DWC treatments, the DWCR treatment significantly increased plant height, aboveground dry matter (ADM), yield, and WUE. Specifically, the DWCR treatment improved yield and WUE by 0.24–20.04% and 2.75–26.27%, respectively. In the dry year, the yield of the DWC treatment increased by 12.72% compared to its yield in the normal year, whereas the DWCR treatment achieved a greater increase of 19.18%. Root analysis confirmed that the DWCR treatment significantly increased root weight density in the 20–60 cm soil layer under drought, optimizing root spatial distribution and thereby enhancing deep water uptake and drought resistance. In conclusion, incorporating infiltration holes into the DRFM is an effective strategy for optimizing soil water distribution, improving crop drought tolerance and WUE, and promoting sustainable semi-arid rainfed agriculture. Full article

The resilience of arid ecosystems to climate change hinges on their carbon-water dynamics. This study investigates the spatiotemporal patterns of ecosystem water use efficiency (WUE) and its resilience in the ecologically vulnerable Yili-Balkhash Basin, a critical watershed in Central Asia. Contrary to a basin-wide trend of increasing WUE, we identify a significant decline in the WUE of high-productivity forest ecosystems. We demonstrate that this decline stems from a fundamental decoupling between the drivers of carbon (GPP) and water (ET) cycles during drought periods. While GPP shows a positive response to atmospheric aridity (vapor pressure deficit), likely driven by co-varying high radiation and temperature, ET remains primarily controlled by soil moisture and surface thermal conditions. This driver asynchrony results in ET-dominated control over WUE across 65.8% of the basin, rendering forests particularly vulnerable. Machine learning-based attribution reveals that ecosystem resilience is not determined by long-term drought legacy but by the combined effects of immediate thermal stress and a one-month ecological memory. Our findings highlight an emerging vulnerability of high-productivity forest ecosystems to atmospheric aridity and underscore the necessity of process-based frameworks for assessing ecosystem stability under a changing climate. Full article

Agriculture faces growing pressure to optimize water use, particularly in woody perennial crops where irrigation systems are installed once and seldom redesigned despite changes in canopy structure, soil conditions, or plant mortality. Such static layouts may accumulate inefficiencies over time. This study introduces a decision support system (DSS) that evaluates the hydraulic adequacy of existing irrigation systems using two new concepts: the Resource Overutilization Ratio (ROR) and the Irrigation Ecolabel. The ROR quantifies the deviation between the actual discharge of an installed irrigation network and the theoretical discharge required from crop water needs and user-defined scheduling assumptions, while the ecolabel translates this value into an intuitive A+++–D scale inspired by EU energy labels. Crop water demand was estimated using the FAO-56 Penman–Monteith method and adjusted using canopy cover derived from UAV-based canopy height models. A vineyard case study in Galicia (Spain) serves an example to illustrate the potential of the DSS. Firstly, using a fixed canopy cover, the FAO-based workflow indicated moderate oversizing, whereas secondly, UAV-derived canopy measurements revealed substantially higher oversizing, highlighting the limitations of non-spatial or user-estimated canopy inputs. This contrast (A+ vs. D rating) illustrates the diagnostic value of integrating high-resolution geospatial information when canopy variability is present. The DSS, released as open-source software, provides a transparent and reproducible framework to help farmers, irrigation managers, and policymakers assess whether existing drip systems are hydraulically oversized and to benchmark system performance across fields or management scenarios. Rather than serving as an irrigation scheduler, the DSS functions as a standardized diagnostic tool for identifying oversizing and supporting more efficient use of water, energy, and materials in perennial cropping systems. Full article

Efficient water and nitrogen (N) management is critical for sustainable lettuce production in arid regions. This study evaluated N and water management practices for drip-irrigated desert lettuce over three growing seasons at the University of California Desert Research and Extension Center. Two irrigation levels and three N application rates were tested in 1 m and 2 m wide bed configurations. The CropManage (CM) decision support tool was used to estimate crop water requirements for a 100% evapotranspiration (ET) irrigation treatment and to determine the 100% N rate, with additional treatments at 125% ET and 80–120% of the CM-recommended N rate. CM was also used to verify water and N applications in eight commercial fields. Water levels, N rates, and their interaction had no significant effect on yields, whereas 2 m wide beds produced significantly higher yields than 1 m wide beds (p < 0.05). Higher N rates increased N uptake at harvest and significantly reduced N use efficiency (NUE), while higher water levels reduced water use efficiency (WUE) (p < 0.05). Lettuce N uptake increased linearly from thinning to harvest at an average rate of 2.9 kg ha⁻¹ d⁻¹. Across commercial sites, CM-recommended applications were lower than farmer standard practice, reducing irrigation by 34% (from 364 mm to 239 mm) and N inputs by 29% (from 202 kg ha⁻¹ to 144 kg ha⁻¹). These findings provide refined N-uptake estimates and highlight opportunities to optimize water and N management, positioning CM as a practical decision-support tool for desert lettuce production. Full article

In arid regions characterized by extreme water scarcity, it is important to synergistically optimize both crop yield and water use. Irrigation strategies based on empirical knowledge overlook crops’ dynamic water needs and may cause water waste and yield loss. To address this issue, this paper proposes an intelligent irrigation scheduling method based on a crop growth model and an improved deep reinforcement learning (DRL) agent. We construct a high-fidelity cotton growth environment using the Decision Support System for Agrotechnology Transfer (DSSAT) model. The model was calibrated with local data from the Shihezi region, Xinjiang, to provide a reliable simulation platform for DRL agent training. We developed a temporal state representation module based on a Bidirectional Long Short-Term Memory (BiLSTM) network and an attention mechanism. This module captures dynamic trends in historical environmental information to focus on critical decision factors. The Soft Actor–Critic (SAC) algorithm was improved by integrating a feature attention mechanism to enhance decision-making precision. A dynamic reward function was designed based on the critical growth stages of cotton to incorporate agronomic prior knowledge into the optimization objective. Simulation results demonstrate that our proposed method can improve water use efficiency (WUE) by 39.0% (with an 8.4% increase in yield and a 22.1% reduction in water consumption) compared to fixed-schedule irrigation strategies. An ablation study further confirms that each of our proposed modules—BiLSTM, the attention mechanism, and the dynamic reward—makes a significant contribution to the final performance. Full article

This study evaluated the effects of water–fertilizer coupling on the water and fertilizer use efficiency, yield, and quality of fresh common beans (Phaseolus vulgaris L.) in high-latitude and high-altitude regions. For field water-saving, in 2022, six treatments were established, with irrigation rates of 100% FC (W1), 90% FC (W2), 80% FC (W3), 70% FC (W4), 60% FC (W5), and 50% FC (W6). Based on the experiment in 2022, a two-factor experiment (irrigation and fertilizer application rate) was implemented in 2023, and three fertilizer (N−P₂O₅−K₂O) gradients were established: F1 (260−192−255 kg/ha), F2 (195−144−192 kg/ha), and F3 (131−97−127 kg/ha). Based on 2022, three irrigation rates were established at percentages of FC: W7 (100% FC), W8 (80% FC), and W9 (60% FC). Experiments in both years revealed a quadratic relationship (parabola equation) between yield and the rates of both irrigation and fertilization. Excessive fertilization did not consistently enhance yield, and reduced fertilizer application resulted in higher fertilizer partial factor productivity (PFP). Both years of experiments indicated that maintaining soil moisture at 80%~90% field capacity (FC) significantly improved fresh pod yield and water use efficiency (WUE) compared to other treatments. Under the same fertilizer level, reduced irrigation increased key fresh pod quality indicators, such as single-pod weight and soluble sugar content. In contrast, across varying fertilizer rates, these same indicators showed a positive correlation with the amount of fertilizer applied. Vitamin C (VC), soluble protein (SP), soluble solids content (SSC), and nitrate content (NC) reached their highest levels under high fertilizer treatment (N−P₂O₅−K₂O: 260−192−255 kg/ha). Based on the differential comprehensive evaluation models, the study concluded that maintaining soil moisture at 80%~90% FC and applying fertilizer between N−P₂O₅−K₂O: 195−144−192 kg/ha and N−P₂O₅−K₂O: 260−192−255 kg/ha was the optimal strategy. This approach can alleviate the water scarcity pressure in high-latitude and high-altitude regions, and facilitate the selection of common bean management practices that maintain yield while improving quality and PFP, thereby offering theoretical and practical guidance for adapting water–fertilizer regimes to local climatic conditions. Full article