Department of Civil and Environmental Engineering, Colorado State University, 1372 Campus Delivery, Fort Collins, CO 80523-1372, United States.
Sci Total Environ. 2022 Mar 1;810:152293. doi: 10.1016/j.scitotenv.2021.152293. Epub 2021 Dec 9.
Soil salinity can have a significant impact on crop yield, particularly in arid and semi-arid irrigated watersheds wherein irrigation and inadequate drainage often combine to increase salt ion concentrations in soil water. To control salinity, the principal step is to identify the key environmental and hydrologic factors that govern the fate and transport of salts in these irrigated areas. To accomplish this objective, global sensitivity analysis is applied to the newly developed SWAT-Salt model, which simulates the reactive transport of 8 major salt ions (SO, Ca, Mg, Na, K, Cl, CO, and HCO) in major hydrologic pathways in a watershed system. The model is applied to a saline 1118 km irrigated stream-aquifer system located within the Lower Arkansas River Valley in southeastern Colorado, USA. Multiple parameters including plant growth factors, stream channel factors, evaporation factors, surface runoff factors, and the initial mass concentrations of salt minerals MgSO, MgCO, CaSO, CaCO, and NaCl in the soils and in the aquifer are investigated for control on salinity in groundwater, soils, and streams. The Morris screening method is used to identify the most sensitive factors, followed by the Sobol' variance-based method to provide a final ranking and to identify interactions between factors. Results show that salt ion concentration in soils and groundwater is controlled principally by hydrologic factors (evaporation, groundwater discharge and upflux, and surface runoff factors) as well as the initial amounts of salt minerals in soils. Salt concentration in the Arkansas River is governed by similar factors, likely due to salt ion mass in the streams controlled by surface runoff and groundwater discharge from the aquifer. Results can be used in decision making regarding the most impactful land and water management strategies for controlling salinity transport and build-up in soils, both for this watershed and other similar semi-arid salinity-impacted watersheds.
土壤盐度会对作物产量产生重大影响，特别是在干旱和半干旱灌溉流域，灌溉和排水不足常常会导致土壤水中盐离子浓度增加。为了控制盐度，主要步骤是确定控制这些灌溉区盐分归宿和运移的关键环境和水文因素。为了实现这一目标，对新开发的 SWAT-Salt 模型进行了全局敏感性分析，该模型模拟了流域系统中主要水文途径中 8 种主要盐离子（SO、Ca、Mg、Na、K、Cl、CO 和 HCO）的反应性输运。该模型应用于美国科罗拉多州东南部下阿肯色河流域内一个 1118 公里长的盐渍灌溉溪流-含水层系统。对多个参数进行了调查，包括植物生长因素、溪流渠道因素、蒸发因素、地表径流因素以及土壤和含水层中盐类矿物 MgSO、MgCO、CaSO、CaCO 和 NaCl 的初始质量浓度，以控制地下水、土壤和溪流中的盐分。采用 Morris 筛选法识别最敏感因素，然后采用 Sobol'基于方差的方法进行最终排序并确定因素之间的相互作用。结果表明，土壤和地下水中盐离子浓度主要受水文因素（蒸发、地下水排泄和上涌以及地表径流因素）以及土壤中初始盐矿物量的控制。阿肯色河中的盐分浓度受类似因素控制，可能是由于地表径流和含水层地下水排泄控制了溪流中的盐离子质量。结果可用于决策最具影响力的土地和水资源管理策略，以控制盐分在土壤中的运移和积累，无论是对于该流域还是其他类似的半干旱受盐分影响的流域。
