2 min read•july 24, 2024
Salt-affected soils can wreak havoc on crops and land. These soils come in three flavors: saline, sodic, and saline-sodic, each with unique characteristics that impact soil structure, water availability, and plant growth.
Managing these tricky soils involves a mix of techniques. From and drainage improvements to chemical amendments and smart crop selection, farmers have tools to combat salt issues. Regular soil testing is key to staying on top of potential problems.
Saline soils accumulate high concentrations of soluble salts with EC > 4 dS/m, pH < 8.5, and SAR < 13 often forming white crust on soil surface (sodium chloride)
Sodic soils contain high levels of exchangeable sodium with EC < 4 dS/m, pH > 8.5, and SAR > 13 appearing dark and greasy due to dispersed organic matter
Saline-sodic soils combine saline and sodic properties with EC > 4 dS/m, pH < 8.5, and SAR > 13
Formation processes involve salt accumulation from inadequate leaching for saline soils, high sodium content relative to calcium and magnesium for sodic soils, and combination of both for saline-sodic soils
Soil structure impacts minimal in saline soils but severe in sodic soils causing clay dispersion, loss of structure, reduced infiltration and hydraulic conductivity
Water availability decreases due to increased osmotic potential in saline soils reducing plant-available water and impairing root water uptake
Plant growth suffers from osmotic stress hindering water absorption, specific ion toxicity (sodium, chloride), nutrient imbalances, and and quality
Salt-tolerant plants (halophytes) thrive in saline environments (saltbush, pickleweed)
Natural sources include weathering of primary minerals, marine sediments, and salt spray in coastal areas
Irrigation water with high salt content leads to salt accumulation as water evaporates
Groundwater causes salinity through capillary rise of saline water especially in arid regions with shallow water tables
Human activities contribute through excessive fertilizer application, road salt use, systems, and land clearing
Leaching flushes salts using high-quality water calculated by leaching requirement formula
Drainage improvement involves installing subsurface systems and enhancing surface drainage to prevent water ponding
Chemical amendments include gypsum for reclamation, sulfur for pH reduction, and calcium chloride as an alternative
Crop selection focuses on salt-tolerant varieties (barley, cotton) with proper irrigation scheduling and to reduce evaporation
Phytoremediation uses halophytic plants to extract salts followed by biomass removal
Monitoring and prevention requires regular soil testing for EC, pH, and SAR, water quality assessment, and implementing best management practices