Search Results (226)

Ammonia injection into soils is used both to supply N to field crops and to reduce soil-borne pests and weeds. Ammonia efficacy depends on its persistence in the soil environment following application. Hence, the extent of ammonia binding in six thermic, xeric Mediterranean soils, varying widely in texture, was evaluated at three moisture contents. Fitting the experimental retention data for each of the six oven-dry soils to the Langmuir isotherm yielded apparent maximum retention capacities (S_MAX) ranging from 440 to 1730 mg NH₃-N kg⁻¹, and Langmuir binding coefficients (k) ranging from 0.08 to 4.31 L mg⁻¹. The S_MAX correlated strongly and linearly with clay content (r² = 0.946, p < 0.01). The S_MAX of the six soils increased with moisture content, likely due to ammonia dissolution in the liquid phase and the adsorption of its cationic derivative. The expected reduction in ammonia binding to the solid phase upon wetting, due to competition with water, was reflected in a sharp, unanimous decrease in the Langmuir model coefficients. A reduction in ammonia retention (but not in S_MAX) due to moistening occurred only in the very-fine clayey montmorillonitic soil. While anhydrous ammonia may act as an effective slow-release N source in heavier-textured soils, its tendency to remain in the gas phase in sandy soils is advantageous for pest control. Full article

The Upper Minjiang River Basin is a critical ecological barrier in the upper Yangtze River, where forest ecosystems play a vital role in carbon sequestration, water conservation, and soil retention. Given that different forest types exhibit significant variations in community structure, species composition, and ecological processes, their ecosystem service (ES) supplies and trade-off/synergy relationships are also expected to show distinct heterogeneity. However, systematic research on the trade-offs and synergies of ESs across different forest types remains limited, constraining the development of precision forest management and differentiated management strategies. To deal with this, we used the InVEST model and calculated five key services across the basin: carbon stock (CS), water yield (WY), soil conservation (SC), habitat quality (HQ), and forest stock volume (FSV). We then applied Spearman’s correlation, root mean square deviation (RMSD), and the GeoDetector model to analyze trade-offs and uncover driving mechanisms. Finally, we used spatially constrained K-means clustering to map different management zones. The results indicate that the Upper Minjiang River Basin stored 1.78 × 10⁸ t of carbon, retained 2.98 × 10⁸ t of soil, produced 6.48 × 10⁹ m³ of water yield, maintained a mean habitat quality of 0.78, and supported a forest stock volume of 1.20 × 10⁸ m³. Coniferous forests exhibited the highest CS (181.07 t ha⁻¹) and FSV (176.37 m³ ha⁻¹), whereas shrublands contributed the largest share (52.17%) of regional water yield. At the regional scale, CS and FSV showed the strongest synergy (r = 0.71, p < 0.01), while WY displayed significant trade-offs with most other services. GeoDetector analysis revealed that forest type acts as the primary driver shaping the relationships among services, while elevation and precipitation play supporting roles. Based on the ES bundles identified via spatially constrained K-means clustering, the Upper Minjiang River Basin was divided into four distinct management zones: a carbon sequestration core zone, an ecological balance zone, an ecologically fragile zone, and a multifunctional conservation zone. Therefore, findings from the Upper Minjiang River Basin may provide insights applicable to other mountain forest ecosystems facing similar environmental and management challenges. Full article

The scarcity of resources has constrained the supply of conventional feedstuffs for livestock production. Consequently, mulberry (Morus spp.), known for its high protein content and bioactive compounds, has been developed as a promising alternative feed. However, the optimal water–fertilizer ratio for cultivating feed mulberry and the underlying physiological and agronomic mechanisms remain poorly understood. To address this, a two-year field experiment (2023–2024) was conducted to investigate the effects of water–fertilizer coupling on feed mulberry yield, water use efficiency (WUE), and soil quality. This experiment employed a split-plot design with three irrigation levels (I1 = 45, I2 = 90, and I3 = 135 mm) and four fertilizer rates (F1 = 0, F2 = 150, F3 = 225, and F4 = 300 kg·ha⁻¹). The results demonstrated the following: (1) The variation trends in SWC were consistent with those of soil available N, P, and K contents. Under water–fertilizer coupling, the total water consumption peaked in the I3F3 treatment, with values of 639.9 mm and 703.5 mm in the two years, respectively. (2) The I3F3 treatment produced both the highest yield (37.19 and 41.66 t·ha⁻¹) and the highest leaf N, P, and K contents among all treatments. (3) Water and fertilizer use efficiencies exhibited parabolic trends in response to increasing irrigation and fertilizer inputs. The highest agronomic nitrogen efficiency (AEN) was observed in I2F2. (4) The AMOS 26 model further revealed that soil nutrient content had the strongest direct positive effect on yield (standardized coefficient = 0.68), followed by total water consumption (0.33). And irrigation significantly enhanced soil nutrient availability (standardized coefficient = 0.29). In summary, the I3F3 combination achieved the highest yield and water use efficiency, whereas the I2F2 treatment exhibited the highest AEN. This trade-off suggests that the optimal strategy depends on management objectives (yield maximization vs. resource conservation) in the North China Plain. Full article

Soil acidification and base cation depletion constrain sustainable pomelo production in subtropical orchards. We hypothesized that the co-application of organic fertilizer and dolomite powder would alleviate soil acidification, improve Ca and Mg supply, and enhance pomelo yield and fruit quality more effectively than either amendment alone. A two-year field experiment was conducted in a pomelo orchard in southern Fujian Province, China. Four treatments were established: optimized fertilization alone (CK, 200 N-0 P₂O₅-200 K₂O kg ha⁻¹), optimized fertilization plus organic fertilizer (OF, 200 N-0 P₂O₅-200 K₂O kg ha⁻¹ + 7500 kg ha⁻¹ organic fertilizer), optimized fertilization plus dolomite powder (DP, 200 N-0 P₂O₅-200 K₂O kg ha⁻¹ + 2145 kg ha⁻¹ dolomite powder), and optimized fertilization plus organic fertilizer and dolomite powder (OF + DP, 200 N-0 P₂O₅-200 K₂O kg ha⁻¹ + 7500 kg ha⁻¹ organic fertilizer + 2145 kg ha⁻¹ dolomite powder). Pomelo yield, economic benefits, fruit quality, fruit mineral nutrients, and soil physicochemical properties were determined using standard procedures. Soil analysis showed that OF + DP most consistently increased soil pH and exchangeable Ca and Mg, while organic fertilizer improved soil organic matter. Compared with CK, OF + DP increased yield by 34.27% and 30.13% in 2023 and 2024, respectively, mainly by increasing fruit number per tree. OF + DP also produced the highest net profit, improved total soluble solids and TSS/TA, and increased fruit K, Ca, and Mg concentrations. These results indicate that combining organic fertilizer with dolomite powder is an effective amendment strategy for improving acidified pomelo orchard soils and productivity. Full article

Deep stormwater drainage tunnels are increasingly being used to mitigate urban flooding, but in-tunnel sediment deposition reduces their discharge capacity and complicates their maintenance. With direct field observation constrained, numerical simulation is essential, and river-based total sediment load formulas require reassessment for use in deep tunnels. The three-phase (air–water–sediment) CFD solver SedInterFoam is first validated against a benchmark open-channel suspended sediment experiment, and is then applied to a horseshoe tunnel under a fixed design discharge for multiple inlet sediment concentrations spanning urban stormwater conditions. Four classical formulas (Yang, Shen–Hung, Ackers–White, Engelund–Hansen) are evaluated at the CFD-resolved hydraulic state; Toffaleti is omitted because its zone-based formulation is incompatible with the partially filled horseshoe geometry. The CFD consistently shows persistent retention of a substantial fraction of the inlet sediment load, whereas the transport capacity-limited interpretation of the classical formulas predicts near-complete sediment throughput—indicating structural inadequacy for the dilute, supply-limited regime typical of urban stormwater. A Universal Soil Loss Equation (USLE)-style dimensionless deposition formula is therefore proposed, with inlet sediment loading as the explicit independent variable and a tunnel correction factor $K_{tunnel}$ absorbing the geometric, hydraulic, and sediment variations. Its regression yields an almost linear scaling and a nearly constant deposition ratio, while analysis of the internal flow and concentration fields shows that the retained sediment is strongly concentrated near the bed and that near-bed turbulent mixing weakens moderately with a rising inlet concentration. While calibrated for a single non-cohesive settleable sand fraction, the framework provides a transferable basis for inlet-loading-dependent deposition prediction in deep stormwater drainage tunnels, and subsequent extension of $K_{tunnel}$ to broader sediment conditions with field-based validation is expected to enable maintenance planning, dredging volume estimation, and sediment retention risk assessment. Full article

Excessive chemical fertilization in maize production has reduced fertilizer-use efficiency and increased pressure on soil quality, whereas reducing fertilizer input without yield loss remains challenging. This challenge has shifted attention toward strategies that improve crop nutrient acquisition and utilization under lower fertilizer supply. Harpin protein-based enzyme complexes may provide a regulatory approach, but their field performance under reduced fertilization remains unclear. A two-year field experiment was conducted from 2023 to 2024 using two maize cultivars, Heyu236 and Fuyuan2. In 2023, the harpin protein-based enzyme complex was applied at 200-fold and 300-fold dilutions under conventional fertilization to identify effective spraying concentrations. In 2024, the same two concentrations were evaluated under conventional fertilization and 15%, 30%, and 45% fertilizer reductions. In the 2023 concentration screening trial under conventional fertilization, the enzyme complex increased kernels per ear by 5.6–9.7% and tended to increase the yield by 0.4–17.2% (not significant). In 2024, under reduced fertilization, enzyme application combined with 30% fertilizer reduction produced a stable yield response. In particular, the 300-fold dilution combined with 30% fertilizer reduction increased kernels per ear by 18.1% and 13.2% and grain yield by 16.9% and 9.5% in Fuyuan2 and Heyu 236, respectively. Soil analyses showed that the enzyme treatment mainly improved nutrient availability, as reflected by higher available P, available K, alkali-hydrolyzable N, organic matter, and available Cu, Zn, Fe, and Mn in the soil. These findings suggest that the harpin protein-based enzyme complex helped maintain maize yield under moderate fertilizer reduction by improving kernel formation and soil nutrient availability. Among the tested treatments, foliar application at 300-fold dilution combined with 30% fertilizer reduction showed the greatest potential for reducing fertilizer input while sustaining maize productivity. Full article

Traditional inter-station crude oil heating processes rely heavily on fossil fuels, leading to high energy consumption and environmental pollution. To address this issue, this paper develops a dynamic thermal simulation model for a novel pipeline heating system that couples geothermal and solar energy. The model synergistically utilizes abundant solar energy and abandoned geothermal well resources in the Jilin region, and is applied to analyze the thermal performance of the Xinmiao Station on the Qingtie Fourth Line pipeline. The results show that the system achieves approximate thermal stabilization during long-term operation: the produced water temperature stabilizes at approximately 30.85 °C, and the average coefficient of performance (COP) of the heat pump remains above 4.79, demonstrating good stability. Solar energy contributes about 23.5% of the total annual heat supply (7.0 × 10⁶ kWh) over 1600 effective hours, significantly reducing the annual electricity consumption of the heat pump and water pumps. The integration of solar energy effectively mitigates the decline in the average soil temperature; after 25 years, the soil temperature remains at approximately 54.43 °C. Through optimized configuration, the system reduces its life-cycle cost and levelized cost of heat (annual cost reduced by about 4.35%), showing excellent economic performance. Comprehensive analysis indicates that the coupled system exhibits outstanding energy efficiency and sustainability, providing technical support for the optimized design and engineering application of clean heating systems for crude oil pipelines. This paper contributes four novelties: first application of a coupled geothermal–solar system to a crude oil pipeline (Xinmiao Station, Qingtie Fourth Line); reuse of abandoned deep oil wells as geothermal boreholes to cut drilling costs; a 25-year dynamic simulation quantifying long-term soil temperature evolution and proving sustainability gains over a standalone geothermal system; and multi-scenario economic optimization identifying the optimal collector area under site land constraints. Based on these, a dynamic thermal simulation model is developed and its synergistic operation strategy is investigated, aiming to provide theoretical and technical support for clean-energy-driven crude oil heating. Full article

Efficient nutrient management through fertigation is essential for sustaining table grape production under water-limited Mediterranean environments. This study evaluated the effects of graded potassium (K) fertigation rates on yield and berry quality of grapevines under semi-arid conditions in northern Jordan. Field experiments were conducted over three consecutive seasons at three locations using four potassium application rates (0, 100, 200, and 300 kg K₂O ha⁻¹) applied through drip fertigation and synchronized with key vine phenological stages. Yield and fruit-quality parameters were analyzed using linear mixed-effects models accounting for treatment, year, location, and their interactions. Potassium fertigation significantly increased total yield, cluster weight, and berry physical attributes, including firmness, volume, weight, and diameter, whereas total soluble solids (TSS) and juice pH were largely unaffected. Relative to the control, potassium fertigation progressively increased total yield per vine by approximately 21%, 47%, and 72% under the 100, 200, and 300 kg K₂O ha⁻¹ treatments, respectively, although the magnitude of response differed among locations and growing seasons. Significant treatment × location interactions indicated that site-specific soil conditions influenced potassium response. These results demonstrate that synchronizing potassium supply with vine phenological demand through fertigation enhances productivity and berry physical quality without compromising fruit chemical composition. The observed improvements are consistent with the established physiological roles of potassium in osmotic regulation, assimilate transport, and berry development, supporting optimized potassium fertigation as a key component of precision nutrient management for sustainable viticulture in semi-arid Mediterranean regions. Full article

The application of manure to field corn has the potential to sustain corn yields and reduce nutrient leaching in the soil profile. A field trial with a randomized complete block design was conducted on Adkins fine sandy loam soil to evaluate the impact of application of manure and synthetic fertilizer on nutrient concentrations (N, P, K and S) in plant and soil as well as field corn yield. Experimental treatments included application of synthetic fertilizer (NPK: T1) and dairy manure application at 12.4-(T2), 24.7-(T3) and 37.1-(T4) tons ha⁻¹ in addition to a non-fertilized control (CK). All manure was applied before planting. Corn was manually harvested, and plants were separated into leaves, stems and cobs to determine dry weights. Post-harvest soil sampling was performed at 0–30, 30–60 and 60–90 cm soil depths. The results indicated that in-season leaf nutrient concentration was significantly different among applied treatments. The application of synthetic fertilizer (T1) resulted in the highest plant height (295 cm) and produced a higher corn yield (112.3 Mg ha⁻¹) compared to CK and application of dairy manure. Application of manure at 12.4 tons ha⁻¹ produced higher corn yield (87.8 Mg ha⁻¹) compared to manure application at 24.7 (64.0 Mg ha⁻¹) and 37.1 tons ha⁻¹ (64.5 Mg ha⁻¹). A similar trend was observed for leaf, stem and cob fresh and dry weights. Nutrient recovery was higher under application of synthetic fertilizer, followed by application of manure at 12.4 tons ha⁻¹. Soil nutrient analysis indicated no significant impact on N, P, K and S concentration among treatments except for NH₄⁺–N. However, nutrient concentration significantly varied under different soil depths. These results suggest that a combination of synthetic fertilizer application and manure might be a practical approach for a balanced nutrient supply for field corn. Further investigations are necessary to explore the potential of manure application to ensure balanced nutrient supply, improved yields and reduced nutrient losses in field corn. Full article

Ground source heat pump (GSHP) systems, while energy-efficient, often face persistent soil thermal imbalance in heating-dominated severe cold regions, which undermines their long-term performance and sustainability. This study proposes a TRNSYS-GenOpt framework for the life-cycle cost optimization of hybrid GSHP systems integrating electric boilers and geothermal regulation towers. A transient model for a 5650 m² fire station in Changchun was developed, employing the Hooke–Jeeves algorithm to co-optimize boiler capacity, borehole depth, and geothermal regulation tower airflow under constraints on heating supply temperature and soil thermal balance. Time-of-use electricity pricing was incorporated for realistic operational economics. The optimized configuration (148 m, 864.8 kW, 290,400 m³/h) achieved a minimum 20-year life-cycle cost of CNY 1.13 million. Sensitivity analysis revealed “rigid design, flexible cost” characteristics: optimal parameters remained invariant across discount rate variations (3.5–7.5%) and equipment costs (±20%), while life-cycle cost showed the highest sensitivity to electricity pricing and discount rates. The long-term simulation confirmed compliance with all physical constraints. This methodology demonstrates that thermodynamic constraints supersede economic trade-offs in severe cold climates, providing engineers with a reliable tool for sustainable hybrid geothermal system design. Full article

Wheat productivity and grain quality are strongly influenced by nutrient management and soil moisture availability. Nitrogen (N) and potassium (K) regulate biomass production, physiological stability and grain protein development. However, their efficiency varies under water-limited conditions. This study aimed to evaluate how soil moisture modulates nitrogen–potassium efficiency, nutrient partitioning, physiological responses and grain quality development in wheat. The current experiment was planned to assess the impact of varying but combined levels of N and K fertilizers on wheat crop growth and yield components as well as nutrient uptake and grain quality under different irrigation levels (i.e., normal irrigation Field Capacity (FC) 100%, partial water deficit FC75%, moderate water deficit FC50%, severe water deficit FC25%). The results of the study showed that increasing N-K supply enhanced biomass, chlorophyll contents, nutrient accumulation and grain quality under full irrigation, with N2K2 showing the highest growth, yield and quality traits. Under moderate deficit, N2K1 maintained a relatively stable yield and physiological performance, whereas severe moisture limitation markedly reduced nutrient uptake, grain development and fertilizer efficiency despite a higher NK application. Progressive reductions in irrigation also altered nutrient distribution among leaves, straw and grain, indicating moisture-regulated remobilization during grain filling. Maximum increments in values for plant height (27%), total biomass (108%), grain yield (183%), grain NPK content (38%, 6.3%, 26%), grain protein (38%) and wet gluten (38%) were noted in the N2K2 treatment at FC100%, but these parameters showed up to 80% reduction under the same treatment of N-K at FC25%. It is concluded that wheat response to N–K fertilization was moisture dependent and fertilizer rate alone did not ensure productivity under severe water deficit. Therefore, integrating nutrient supply with irrigation management is essential to sustain productivity and grain quality. Full article

Brazilian soils are prone to a gradual decline in fertility due to intensive agricultural activity combined with natural weathering, which increases the demand for chemical fertilizers. Among potential alternatives, soil remineralization using crushed rock is a promising strategy. Silicate agrominerals (SAs) applied as soil remineralizers have attracted attention due to their ability to supply plant-available nutrients while reducing dependence on conventional mineral fertilizers. This study evaluated the potential of residues from six quarries in Brazil as soil remineralizers as a regulatory screening assessment. Samples were subjected to mineralogical, petrological, and chemical characterization using an integrated approach, including X-ray diffraction (XRD), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), and leaching experiments. XRD analysis revealed that anorthite and augite were the major minerals present in the mining waste. These minerals are less resistant to weathering, which enhances the release of macro- and micronutrients, essential for the development of various crops. Chemically, the samples were dominated by SiO₂, Fe₂O₃, and Al₂O₃, with the sum of bases (K₂O + CaO + MgO) ranging from 11.92% to 16.85%, meeting Brazilian standards for use as a soil remineralizer. Leaching results revealed that pH responses varied significantly among the studied samples for the filler particles, with an alkaline shift reaching values above 9.0 after 72 h. In contrast, the powder particle size samples showed no significant variation between the different materials tested, maintaining nearly constant pH levels throughout the period. This preliminary evaluation demonstrates that mining tailings from Brazilian quarries have potential as a sustainable soil remineralizer. This approach not only offers an alternative for soil fertilization but also promotes waste management and circular economy practices, although further studies are needed to assess long-term effectiveness and safety. Full article

Nitrogen (N) and phosphorus (P) are essential nutrients that play critical roles in plant physiological processes and the accumulation of N and P in broccoli head was significantly correlated with yield. Therefore, there is a need for a rapid, non-destructive diagnosis of crop status by detecting deficiencies in essential nutrients. This study evaluated the effects of N and P deficiency on field grown broccoli (Brassica oleracea L. var. italica Plenk) using a plant-induced electrical signal (PIES) sensor, in which needle electrodes are inserted into the stem to measure electrical conductivity reflecting plant water and ion status. Four treatments were established, including the control (N100P100) with sufficient N and P supply, N deficiency (N0P100), P deficiency (N100P0), and combined N–P deficiency (N0P0). For sufficient supply, urea and fused phosphate (FP) were applied at rates of 122 kg N ha⁻¹ and 71 kg P ha⁻¹, respectively. Soil, stem, and leaf nutrient contents, growth parameters, and stress related indicators were analyzed and their relationship with PIES values were evaluated. PIES was highest in control (N100P100) and lowest under N–P deficiency (N0P0). Higher PIES values were observed during the vegetative stage, whereas values declined during the reproductive stage, reflecting changes in physiological activity. Growth parameters such as shoot and root weight and stem diameter were generally superior in the control (N100P100) treatment, while leaf calcium (Ca), magnesium (Mg), and potassium (K) concentrations showed no significant differences among treatments. Total N content in leaves was higher in N fertilized treatments (control and P deficiency). Photosynthesis-related parameters, including soil plant analysis development (SPAD), Fv/Fm, and chlorophyll content, were lowest under N–P deficiency, which was reflected in the PIES. Principal component analysis (PCA) showed that the PIES was closely associated with growth and photosynthetic parameters and clearly distinguished N sufficient treatments (control and P deficiency) from N deficient treatments (N0P100, N0P0). Overall, these findings suggest that PIES monitoring can serve as a sensitive physiological indicator of nutrient stress and may be applied as an early diagnostic tool before visible growth inhibition occurs in broccoli cultivation. Full article

The adoption of photovoltaic (PV) energy in irrigation is rapidly increasing, supported by a range of available technologies. However, an agronomic perspective that could help overcome inherent limitations of PV systems remains absent. In fact, current irrigation design methods do not explicitly take into account the dynamic nature of PV power generation. While irrigation engineering conceptualises soil as a reservoir for plant-available water, it can also function as an energy reservoir, storing solar-derived energy in the form of soil moisture for subsequent crop use. Building on this concept, this study proposes an integrated framework for designing off-grid PV irrigation systems based on asymmetric irrigation sectors. The framework couples hydrological, agronomic, and energy components to synchronise solar energy generation with crop water requirements, thereby eliminating the need for intermediate energy storage. The methodology was applied to two case studies: a hedgerow olive orchard and an almond orchard in southern Portugal, both with drip irrigation. Results demonstrate that the asymmetric-sector design provides a technically feasible and low-complexity solution for integrating photovoltaic energy into irrigation systems. The conventional irrigation system required 1.42 kW of minimum pumping power for olive orchards and 1.32 kW for almond orchards. The dimensions of the main lines ranged from 97.8 mm for olive and 75 mm for almond orchards, while the flow rate of the emitter was 2.3 L h⁻¹ for olive and 3 L h⁻¹ for almond orchards. Although PV-compatible operation required hydraulic adjustments including increases in design flow rate (226–255%), pump power demand (87.5–241%), and pipe diameters (up to 120% in olive and 75% in almond), these adaptations enable irrigation systems to operate under the variability inherent to solar-based energy supply. This hydraulic oversizing leads to higher initial investment costs; however, this can be mitigated to a certain extent by diminished operating costs and complete energy autonomy from the electricity grid. Full article

The pronounced heterogeneity of high-Andean soils constitutes a critical constraint to the sustainable productivity of quinoa in southern Peru, where current yields (1.6 t ha⁻¹) remain well below potential (>5 t ha⁻¹). This study aimed to develop a spatially predictive model of a weighted soil quality index (SQIw), the edaphic supply of nitrogen (N), phosphorus (P) and potassium (K), and the agricultural gypsum requirement by integrating edaphoclimatic covariates through regression–kriging. A total of 198 quinoa-cultivated soil samples were analysed; a minimum data set (MDS) was defined using correlation and principal component analyses, and regression–kriging was applied to map SQIw and the variables of interest. The MDS comprised electrical conductivity (EC), organic matter (OM), available P, exchangeable Na, sand, clay, and effective cation exchange capacity (ECEC); exchangeable Na (Wi = 0.160) and available P (Wi = 0.158) received the largest weights in the SQIw. SQIw values ranged from 0.22 to 0.84 and supported a five-class soil quality taxonomy; spatial modelling revealed a dominance of moderate-quality soils across the territory (85.21% of the agricultural area, 13,461.19 ha). The model achieved R² = 0.56, RMSE = 0.05, and MAE = 0.04 for SQIw. Most of the area (12,175.65 ha; 77%) exhibited an intermediate gypsum requirement (9.73–14.33 t ha⁻¹). Nitrogen and phosphorus showed the greatest territorial limitations, whereas potassium was largely non-limiting (84.82–570.17 kg ha⁻¹). These results indicate that sodicity and N–P deficiencies are the primary functional constraints; the generated maps enable prioritisation of gypsum amendments and targeted variable-rate fertilisation strategies to optimise the sustainability of quinoa production in the Altiplano. Full article