Enhancing Sustainability and Climate Resilience of Salt‐Affected Table‐Grape Orchards Through Regenerative Management: Soil Biological Function, Localized Sodium Leaching, and Nutrient Dynamics

<p>A pioneering study in Murcia within the framework of the ASSIST (Use of Advanced information technologies for Site-Specific management of Irrigation and SaliniTy with degraded water) research project, seeks to lay the foundations for a new integrated system for the assessment of salinity through combined use of traditional techniques (soil and plant sampling) and new technologies (multispectral aerial videography or satellite observation; and image analysis) to help quantify and map soil salinization / degradation and the effects of soil-plant interactions (salinity-toxicity) on the growth and yield of irrigated crops. In this sense, the initial objective was to evaluate the salinity of the soil and the development of lettuces irrigated with unconventional water resources through thermal and multispectral images. Different soil and plant salinity indices were studied, observing that the temperature (on plant) and salinity index (SI) (on soil), had a moderate correlation with the soil salinity. Although the results obtained have been encouraging, more research is needed to develop specific equations capable to predic soil salinity from the values of these indices taken remotely. In this context, a review of the spectral salinity indices has been prepared to be applied at a regional scale. As an experimental area, El Campo de Cartagena located in the southeast of the Iberian Peninsula has been chosen, since there is intensive irrigated agriculture in a semi-arid environment. Due to this, farmers resort to using non-conventional and saline water sources, consequently the use of saline irrigation water is causing salinization of the soils and damage to the crops. Values from existing salinity records combined with soil salinity data obtained in various plots, provided information that was correlated with time series of Landsat images (1984-2020). Regression models were also applied in which environmental variables provided an improvement in the estimation of soil salinity. The results allowed us to determine the main salinity concentration areas, as well as inputs to establish criteria for improvement in the management of irrigation systems.</p>

By affecting 10% of the world’s total arable land, soil salinity has become a potential threat to feeding the exploding population. As per the current scenario, among 1,125 million hectares of salt-affected land, nearly 76 million hectares are seriously affected due to human-induced salinization. Due to soil salinization, crop productivity is being hampered. In order to enhance productivity, there is an urgent need to shift from traditional methods to advanced 3E (efficient, economic, and environmentally sound) technology for soil salinity reclamation and management to achieve better soil health and sustainable crop production. The detailed mechanism of salt interference with various pathways involved in plant growth and development needs to be understood. This article critically reviews the mechanism of harmful salt interference with nutrient dynamics in soil and various physiological pathways involved in crop growth to apply various soil-oriented (crop residue management, biochar application, and agroforestry system) and plant-oriented [plant growth-promoting microbes (PGPMs), plant growth regulators, and nanotechnology] promising reclamation and rehabilitation approaches to mitigate its hazardous effect on soil salinity. The monitoring and assessment of salt-affected soils through remote sensing (RS) and geographical information systems (GISs) are pivotal in the management and framing of long-term policies to confront alarming threats to crop productivity and sustainability. This study provides an insight into recent developments in soil salinity management and proposes futuristic solutions that could ameliorate soil salinity to attain crop sustainability under adverse environmental conditions.

Soil salinity is a growing threat all over the world due to its toxic effect to reduce soil fertility and water uptake in the crops. An average of 418 million ha soil is saline in nature. Various climatic, geomorphic and rainfall pattern causes which involved in saline soil formation. To reduce the toxic effect proper management of saline soil is required. Irrigation water also a major concern regarding soil salinity management. Saline irrigation water enhances and maintains the severity soil salinity. Crop production aspects root zone salinity provides a strong negative impact on soil fertility. Salinity causes the reduction in nutrient ion, and water uptake has a significant negative effect on crop yields. Soil and water salinity interactions and their influence on crop growth and management of salinity are deliberated in this chapter.

The present study evaluated the physiological and quality responses of eight Sudanese onion (Allium cepa L.) genotypes Abu Sabein, Wad Hamid, Zeidab Red, Shendi White, Texas Grano, Bombay Red, N-53, and Hybrid Super Star under varying levels of soil salinity and water stress to identify tolerant genotypes for sustainable production in semi-arid environments. A split-plot randomized complete block design was employed with three salinity levels (0, 4, and 8 dS m⁻¹) and three irrigation regimes (100%, 75%, and 50% of ETₐ). Physiological parameters such as relative water content (RWC), membrane stability index (MSI), Na⁺/K⁺ ratio, and proline accumulation were measured alongside yield and bulb-quality traits, including total soluble solids (TSS), dry matter, and pyruvate concentration. The results revealed significant main and interaction effects of salinity, water stress, and genotype on onion performance. Yield reduction under combined high salinity and severe water stress ranged from 20% to 38%, with Hybrid Super Star, Abu Sabein, and Texas Grano exhibiting the highest tolerance indices (0.76-0.80). These genotypes maintained superior RWC, higher MSI, and lower Na⁺/K⁺ ratios, demonstrating efficient osmotic adjustment and membrane integrity. Moderate stress induced an increase in TSS by up to 0.9 °Brix, suggesting a potential improvement in bulb sweetness and storage quality. Correlation and regression analyses identified RWC and MSI as the most reliable physiological predictors of yield stability, whereas the Na⁺/K⁺ ratio showed a strong negative association with stress tolerance. The study concludes that the integration of physiological screening with yield-quality assessment provides a robust framework for developing and recommending stress-resilient onion cultivars. Practical interventions such as selective breeding, improved irrigation scheduling, and salinity management can significantly enhance onion productivity and quality in Sudan’s irrigated farming systems facing increasing salinity and water scarcity.

Several environmental factors adversely affect plant growth and development and final yield performance of a crop. Drought, salinity, nutrient imbalances and extremes of temperature are among the major environmental constraints to crop productivity worldwide. Gibberellic acid (GA3)treatment has alleviated the drastic effect of salinity in growth parameters (leaf area, dry weight of grains and photosynthetic pigments) and chemical constituents (carbohydrates, proteins, amino acids and proline content in two wheat cultivars (Sohag 3 and Giza 168). The effect of GA3 on alleviation of damaging effects of different levels of salinity was studied in view of, wheat grains (Triticum aestivum L. Sohag 3 and Giza 168) were screened for germination and growthresponses to different NaCl concentrations (50, 100, 150 and 200 mM). After four weeks, two groups; each of pots were sprayed with GA3 (100 mg L-1 synthetic plant growth regulators). The result in this report reveals that the wheat cv. Sohag 3 was the most sensitive to salinity, while cv. Giza 168 was the most tolerant. Thus salinity stress had no effect on leaf area, photosynthetic pigment and consequently crop yield at mild salinity (100 mM), while in cv. Sohag 3, there was a marked and progressive reduction in these parameters by increasing the salinity stress even at the lowest salinity (50 mM) level used. Carbohydrate and proline content increased significantly by salinity stress in the different organs of the two wheat cultivars except for Giza 168 stem where carbohydrates were significant declined by salinity stress. Soluble protein content varied not only between the two wheat cultivars but also between the different organs. While salinity stress induced a significant increase in the soluble protein content in root and leaf, on the other hand itdeclined the soluble protein in stem of Giza 168. In cv. Sohag 3, the soluble protein content in root and stem decreased slightly by increasing salinity in the soil, this reduction was obvious only at higher salinization. While in leaves the soluble protein content increased markedly by salinity stress. Proline concentration in root, stem and leaf of both cultivars significantly increased with increasing salinity in soil. The accumulation was greater in the salt sensitive cv. Sohag 3 compared to the salt tolerant cv. Giza 168 especially at higher salinity concentration. GA3treatments (100 ppm) improved the growth criteria, photosynthetic pigments and consequently the crop yield of two wheats cultivars. This was injudged with the observable increase in protein content in the different organs of the two wheat cultivars. Key word: Leaf area, carbohydrate, protein, proline, salinity, wheat cultivars, GA3.

In order to explore the effect of fishponds on soil water, salt transport and salinization in cropland wasteland, a study on soil water balance and salt distribution pattern in a cropland–wasteland–fishpond system was carried out in 2022–2023 in a typical study area selected from the Yichang Irrigation Area of the Hetao Irrigation District. A water balance model was established for the cropland–wasteland–fishpond system to analyze the effects of irrigation on soil salinity at the boundaries of the cropland, wasteland, and fishpond. The results showed that the lateral recharge from the cropland to the wasteland during spring irrigation in 2022 was 24 mm, the lateral recharge generated by fishponds to wasteland was 18 mm, and the lateral recharge from fishponds to fishpond boundaries was 34 mm. In the fertility period of 2023, the lateral recharge from cropland to wasteland was 15 mm, the lateral recharge from fishponds to wasteland was 9 mm, and the lateral recharge from fishponds to fishpond boundaries was 21 mm. Due to the low salinity content of fishpond water, it diluted the groundwater of the wasteland, and the soil salinity at the boundary between the wasteland and the fishpond was monitored. The data show that the soil salinity at the boundary of the fishpond was smaller than that of the wasteland, which indicates that the migration of fishpond water to the wasteland will not lead to an increase in the soil salinity of the wasteland, but rather to a decrease in the soil salinity of the wasteland. Fishpond regulation has a significant impact on soil and groundwater, and when the topographic conditions of the Hetao irrigation area allow, the model of cropland–wasteland–fishpond can be appropriately adopted to solve land degradation and increase the economic income of farmers; the results of the study provide a contribution for the improvement of the management of land use and soil salinization in the Hetao irrigation area.

Soil salinity threatens agricultural sustainability globally and is a significant challenge in Oman. Previous studies in Oman focused on examining the causality and spatiotemporal variation of groundwater and soil salinity, neglecting farmers' perceptions and attitudes towards salinity management. Therefore, this study evaluates (i) perceptions and attitudes of landowners and farmers towards soil salinity and its management, and (ii) determinants of willingness to use elemental sulphur to alleviate soil salinity in Oman. A questionnaire survey (122 responses) assessed perceptions, attitudes and knowledge using Likert scales and qualitative questions. Binary Logistic Regression analysed determinants of willingness to use elemental sulphur. Results reveal variations in perceptions, attitudes, knowledge and management practices. Most of the respondents were aware of adequate nutrient and water requirements for crops ( p < .05). Respondents rely on social media (38.5%), fellow farmers (32.1%) and personal experiences (11.5%) for knowledge acquisition about soil salinity management. Half of the respondents did not monitor soil salinity, while the other half relied primarily on visual observation. A substantial number (62.6%) of the respondents did not implement any techniques to alleviate soil salinity, while among those who acted, a majority preferred cultivating date palms (55%) or fodders (29.4%). Awareness of the national salinity management strategy and commercial products is lacking. However, when introduced to elemental sulphur as a soil amendment for salinity, 74.8% of the respondents demonstrated a willingness to utilize it. Most (82.4%) preferred elemental sulphur products within the lowest price range. Being a full‐time farmer, owning a farm, awareness of the national strategy and low‐price preferences were positive determinants, while <1 year of farming experience was a negative determinant of willingness to use elemental sulphur. These findings inform future research on socio‐economic perceptions of salinity in Oman, the Gulf region and similar arid areas facing food production limitations.

Reduced soil ecosystem multifunctionality is associated with altered complexity of the bacterial-fungal interkingdom network under salinization pressure.

Plant water deficit index-based irrigation under conditions of salinity

The application of pyrolyzed organic carbon (C) to soils has been assessed worldwide to play a vital role in improving the physical-chemical characteristics of the soil. However, the effects of co-use of biochar and nitrogen (N) fertilizer on soil biological process in an arid region are not well understood. For this, a 2-year field experiment was conducted in an arid region to assess the co-use of biochar and nitrogen (N) fertilizer on soil microbial biomass and enzyme activity in the rhizosphere of the wheat crop. Sugarcane bagasse was used as biochar feedstock and applied with three levels of biochar (0, 0.5, and 1% C ha−1) on carbon equivalent basis in the presence and absence of N fertilization (46 kg N ha−1). Biochar was incorporated in the soil before sowing of wheat, and the soil samples were taken from each treatment at crop maturity. Findings of the study indicated that biochar amendments enhance the soil organic carbon, DOC, inorganic N, and soil moisture contents, while reducing the bulk density and salinity of soil in both wheat growing season. Microbial biomass carbon and nitrogen increased by 18% and 63% with biochar amended at 1% C ha−1 with nitrogenous fertilizer and the same trend was observed in the following year. Urease and dehydrogenase activities also significantly increased with biochar applied at 1% C ha−1 with N fertilization illustrating 15% and 19%, respectively. During the second year of wheat trial, the enzymatic activity also boosted up as the first year. The results revealed that sugarcane bagasse-derived biochar addition can be utilized in improving the soil health, nutrient status, and soil biological functions in the calcareous soil of the arid region.

<p>Water shortage and soil salinization are main limiting factors in agricultural production in arid and semi-arid regions worldwide. Located in western Inner Mongolia of China, the Hetao Irrigation District (HID) is the largest gravity-fed irrigation district in Asia and one of the top three largest irrigation districts in China. Irrigation water overuse and high level of soil salinity are the main challenges that curb agricultural productivity, adversely affect farmers’ revenues, and threaten long-term sustainability of irrigated farming in the HID. Nevertheless, irrigation water allocation, salt leaching and accumulation, crop productivity and farming decisions are intrinsically connected and thus necessitate taking a holistic approach to investigate into the interactions among all those factors and devising appropriate technological, management and policy interventions. Towards this goal, an integrated hydro-agro--economic optimization model was developed to optimize water allocation among sub-irrigation districts, across stable and cash crops, and in the four irrigation events of a year that are unique for the HID. The model optimizes net revenue of the HID considering water and salt balance, the response of crops to salinity and water stress, land availability, and existing irrigation management practices that have been proved effective. The Positive Mathematical Programming (PMP) approach is used to calibrate the model such that it can reproduce base year observations of crop acreage, water uses and production costs and benefits, making the model suitable for evaluating alternative management and policy scenarios. Sensitivity analysis were conducted for initial groundwater table, initial soil salinity level and leaching coefficient, and the results were moderately sensitive to initial soil salinity and marginally sensitive to groundwater table and leaching coefficient values. Scenario analyses were conducted to analyze the effects of irrigation water supply, winter irrigation (non-growing period) water application, irrigation efficiency and crop commodity market prices. We found that water supply reduction increases land fallow and reduces net revenue. Winter irrigation can store soil moisture to increase summer crop planting areas and increase salt-leaching to lower crop salinity stress. However, irrigation water use efficiency improvement can cause unintended negative consequences, such as exacerbated soil salinization. Higher crop commodity market price increases planting areas and water allocation of the crop but reduce areas and water uses of other crops, leading to a “crowding-out” effects. These results and modeling exercises provide a holistic perspective and useful insights for future water, land and salinity management, irrigation infrastructure investment, and market risk management in the HID.</p>

Soil salinity and groundwater quality degradation increasingly threaten the sustainability of irrigated agriculture in semi-arid regions worldwide, posing significant socio-economic consequences for smallholder farmers and rural communities. This review synthesises current literature on the climatic and anthropogenic drivers of soil and groundwater salinisation, highlighting assessment techniques, management practices, and the socio-economic dimensions of salinity risks. Recent advances in remote sensing and geographic information systems (GIS) are critically evaluated, and the utility of irrigation water quality indices is examined. The review contextualises these themes with primary and secondary data from Oba Dam, southwestern Nigeria. Findings demonstrate spatially and temporally variable salinity trends, compounded by climate variability, sub-optimal irrigation management, land use change, and policy limitations. The authors propose integrated, participatory approaches grounded in climate adaptation, technological innovation, and policy reform, aiming to ensure agricultural resilience and socio-economic sustainability. Optimized irrigation is recommended for integration into farming practices as it maintains healthy soil by preventing the accumulation of excess salt. This work contributes original synthesis and context-specific recommendations for researchers, policymakers, and practitioners involved in salinity management in semi-arid, irrigated environments.

Due to increasing soil and water salinity in arid and semiarid regions around the world, people in these areas suffer from the lack of fresh quality water for drinking, irrigation, production of crops and livestock. This research was thus carried out in Khuzestan province, in the southwest of Iran, with a hot and dry climate, to simulate quinoa (Chenopodium quinoa) yield and soil salinity under salinity and water stress using the SALTMED model. To that end, the field data from a split-plot experiment with a randomized complete block design including treatments with four levels of water salinity (Karun river water, ECW 10, 20 and 30 dS/m) and three levels of irrigation (full irrigation (278 mm), regulated deficit irrigation at 75% (208 mm) and 50% (139 mm)), were used. The results showed that saline water and deficit irrigation negatively affected most investigated parameters of yield and yield components of quinoa; however, quinoa was able to grow even with ECw 20 (dS/m) under deficit irrigation at 50%. According to the results of sensitivity analysis, the irrigation water amount had the most effect on the output parameters of the SALTMED model. Once successfully calibrated and validated, the model proved to be efficient for estimating the quinoa crop yield and soil salinity under different irrigation strategies and water qualities. Besides, the coefficients of determination (R2) obtained for simulating yield response of quinoa crop and soil salinity were 0.922 and 0.992, respectively. The results also showed no significant difference in model performance in simulating quinoa crop yield compared to soil salinity simulation.

Evaluating the impacts of saline water irrigation on soil water-salt and summer maize yield in subsurface drainage condition using coupled HYDRUS and EPIC model

In drylands, poor rains combined with high evaporation rates increase the risks of soil salinization in addition to drought stress. Here, we determined the values of the parameters in the Feddes root water uptake function for sesame (Sesamum indicum L.) under drought and salinity stresses in a pot experiment using “Lebap-55”, which has been bred for the drylands of the Aral Sea Basin but is moderately sensitive to salinity stress. We measured the hourly values of the transpiration, soil moisture, and salinity in the upper and lower soil layers in pots, solar radiation, and root distribution. The values were quantified by two methods. The bulk method uses only daily pot weight data, and the average soil water content and salt concentration are back-calculated from the mass balance. The inverse method uses the monitored values of the soil water content and salinity as well as daily weight data and solar radiation. Both methods could successfully estimate all the parameter values for both stresses. The bulk method performed better under drought stress, even without the measured soil water content or root distribution. It also had satisfactory accuracy in estimating the values under salinity stress. Both methods performed better under drought stress than under salinity stress. The parameter values determined here could be used for irrigation scheduling and salinity management using numerical models for the studied crop.