Soil salinity severely affects soil ecosystem quality and crop production in semi-arid and arid regions. A vast quantity of data on soil salinity has been collected by research organizations of the Commonwealth of Independent States (CIS, formerly USSR) and many other countries over the last 70 years, but using them in the current international network (irrigation and reclamation strategy) is complicated. This is because in the CIS countries salinity was expressed by total soluble salts as a percentage on a dry-weight basis (total soluble salts, TSS, %) and eight salinity types (chemistry) determined by the ratios of the anions and cations (Cl⁻, SO₄²⁻, HCO₃⁻, and Na⁺, Ca²⁺, Mg²⁺) in diluted soil water extract (soil/water = 1:5) without assessing electrical conductivity (EC). Measuring the EC (1:5) is more convenient, yet EC is not only affected by the concentration but also characteristics of the ions and the salinity chemistry. The objective of this study was to examine the relationship between EC and TSS of soils in a diluted extract (1:5) for eight classic salinity types. We analyzed extracts (1:5) of 1100 samples of a clayey soil (0–20 cm) collected from cultivated semi-arid and arid regions for EC, TSS, soluble cations (Na⁺, Ca²⁺, Mg²⁺), and anions (HCO₃⁻, Cl⁻, SO₄²⁻). Results revealed that (i) the variation in the proportional relationships (R² ≥ 0.91–0.98) between EC (0.12–5.6 dS m⁻¹) and TSS (0.05–2.5%) could be related to salinity type, and (ii) the proportionality coefficient of the relationships (2.2 2–3.16) decreased in the following order of salinity type: SO₄ < Cl(SO₄)–HCO₃ < Cl(HCO₃)–SO₄ < SO₄ (HCO₃)–Cl < Cl. The findings suggest that once the salinity type of the soil is established, EC (1:5) values can be safely used for the evaluation of the soil salinity degree in the irrigated land in the context of sustainable soil and crop management.

Surface sealing is determined by aggregate disintegration and clay dispersion, which in turn depend on aggregate wetting rate, and soil sodicity and texture. We hypothesised that soil susceptibility to seal formation increases when the aggregate wetting rate (WR) is increased, and that the effect of WR depends on soil texture and soil sodicity. The objective of this study was to investigate the effects of WR on seal formation, by observing infiltration rate (IR) and runoff, in cultivated soils varying in clay content and exchangeable sodium percent (ESP). Effects of 3 wetting rates (2, 8, and 64 mm/h) on IR and runoff from 6 Israeli soils exposed to 60 mm of simulated rain of deionised water were studied in the laboratory. The soils ranged in clay from 8.8 to 68.3% and ESP levels from 0.9 to 20.4. Effects of WR on soil infiltration rate and runoff depended on soil texture and soil ESP. In soils with low clay content (8.8%), the effect of WR on seal formation was negligible, whereas effect of ESP was significant. Conversely, in clay soils (>52.1%), WR had a predominant effect on IR and runoff, while the effect of ESP was notable yet secondary to that of WR. The soils with intermediate clay content (22.5–40.2% clay) were the soils most susceptible to seal formation, with WR and ESP having moderate effects on seal formation. Effects of WR on aggregate disintegration and seal formation increased with increasing clay content and aggregate stability. Conversely, the role of ESP in determining sealing decreased with an increase in clay content and in WR.

Scarcity of freshwater for agriculture has led to increased utilization of treated wastewater (TWW), establishing it as a significant and reliable source of irrigation water. However, years of research indicate that if not managed adequately, TWW may deleteriously affect soil functioning and plant productivity, and pose a hazard to human and environmental health. This review leverages the experience of researchers, stakeholders, and policymakers from Israel, the United-States, and Europe to present a holistic, multidisciplinary perspective on maximizing the benefits from municipal TWW use for irrigation. We specifically draw on the extensive knowledge gained in Israel, a world leader in agricultural TWW implementation. The first two sections of the work set the foundation for understanding current challenges involved with the use of TWW, detailing known and emerging agronomic and environmental issues (such as salinity and phytotoxicity) and public health risks (such as contaminants of emerging concern and pathogens). The work then presents solutions to address these challenges, including technological and agronomic management-based solutions as well as source control policies. The concluding section presents suggestions for the path forward, emphasizing the importance of improving links between research and policy, and better outreach to the public and agricultural practitioners. We use this platform as a call for action, to form a global harmonized data system that will centralize scientific findings on agronomic, environmental and public health effects of TWW irrigation. Insights from such global collaboration will help to mitigate risks, and facilitate more sustainable use of TWW for food production in the future.