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

土壤盐碱化是一个全球性问题，影响了大约10％的农业土壤，特别是在干旱干旱地区。这项研究量化了洪水灌溉和土壤肥料/改良剂对大气沉积物的盐分含量，研究了溶质运移和盐分累积的控制方法，并评估了石膏的施用对改善美国西南干旱地区土壤碱度的有效性。研究地点包括得克萨斯州埃尔帕索附近的该地区主要农作物田中的一个自然地点和两个农业地点，一个山核桃果园和一个苜蓿田。农业土壤中的盐分加载速率主要取决于灌溉水的数量和质量，而不是灰尘。估计灌溉水的盐负荷约为306 g Na ⁺ m - ²年^-1 129克Ca ²⁺米^-2年^-1，361克氯^-米^-2年^-1，419克SO ₄ ^2-米^-2年^-1，和284克HCO ₃ ^-米^-2年^{- 1个}，然后进行土壤改良。而在农业土壤中，粉尘和肥料的含量可以忽略不计。土壤质地的变化在物理上控制着水的流动和溶质的运输。灌溉后，较粗的土壤保留的水分明显少于较细的土壤（p <0.005），从而促进了盐的淋洗。低渗透层周围会积聚更多的盐。仅在耕种90年后，一些土壤就达到了盐度阈值。由于科罗拉多州降雪减少，预计将使用里奥格兰德河流量减少，从而导致使用更多盐度更高的地下水。如果将地下水作为唯一的水源，那么盐分的负荷率将几乎翻倍。土壤改良剂暂时降低了高Na ⁺引起的土壤碱度灌溉水中的浓度。每年都需要使用它们来防止土壤分散，提高渗透率并阻止更快的盐分积累。这项研究突出了美国西南部的里奥格兰德河谷和其他灌溉旱地面临的挑战。