Chemical and hydrological controls on salt accumulation in irrigated soils of southwestern U.S

Soil salinization is a global problem affecting approximately 10% of agricultural soils, particularly in irrigated aridlands. This study quantified salt-loading by flood irrigation and soil fertilizers/amendments versus atmospheric deposition, studied controls solute transport salt buildup, evaluated the effectiveness gypsum application improving sodicity arid southwestern United States. Study sites include one natural site two fields dominant crops region, pecan orchard an alfalfa field near El Paso, Texas. The rate soils was dominated quantity quality waters rather than dust. Salt loadings were estimated ~ 306 g Na+ m?2 yr?1, 129 Ca2+ 361 Cl? 419 SO42? 284 HCO3? followed amendments. Whereas dust fertilizer negligible soils. texture variability physically governs water movement transport; coarser retained significantly less finer upon (p < 0.005) facilitating leaching. More salts accumulated around low-permeability layers. Some have approached salinity thresholds after only 90 years cultivation. Rio Grande river flow projected to decrease due reduced snowfall Colorado, leading more groundwater higher salinity, be used. If ground sole source, loading would almost double. amendments temporarily reduce induced high concentrations water. Their needed annually prevent dispersion, improve infiltration, stop even faster accumulation. highlighted challenges that valley States other drylands are facing.