Determining the impacts of experimental forest plantation on groundwater recharge in the Nebraska Sand Hills (USA) using chloride and sulfate

Adane, Z. A.; Gates, J. B.

Determining the impacts of experimental forest plantation on groundwater recharge in the Nebraska Sand Hills (USA) using chloride and sulfate | Détermination des impacts d’une plantation forestière expérimentale sur la recharge des aquifères dans les Sand Hills du Nebraska (USA) en utilisant des chlorures et du sulfate Determinación de los impactos de plantaciones forestales experimentales sobre la recarga de agua subterránea en las Nebraska Sand Hills (USA) usando cloruro y sulfato 利用氯化物和硫酸盐确定实验性植树造林对(美国)内布拉斯加州沙丘地下水补给的影响 Determinação do impacte de plantações florestais experimentais sobre a recarga de águas subterrâneas, nas Sand Hills, Nebrasca (EUA), através do uso de cloreto e sulfato

2015

Adane, Z. A. | Gates, J. B.

Although impacts of land-use changes on groundwater recharge have been widely demonstrated across diverse environmental settings, most previous research has focused on the role of agriculture. This study investigates recharge impacts of tree plantations in a century-old experimental forest surrounded by mixed-grass prairie in the Northern High Plains (Nebraska National Forest), USA. Recharge was estimated using solute mass balance methods from unsaturated zone cores beneath 10 experimental plots with different vegetation and planting densities. Pine and cedar plantation plots had uniformly lower moisture contents and higher solute concentrations than grasslands. Cumulative solute concentrations were greatest beneath the plots with the highest planting densities (chloride concentrations 225–240 % and sulfate concentrations 175–230 % of the grassland plot). Estimated recharge rates beneath the dense plantations (4–10 mm yr⁻¹) represent reductions of 86–94 % relative to the surrounding native grassland. Relationships between sulfate, chloride, and moisture content in the area’s relatively homogenous sandy soils confirm that the unsaturated zone solute signals reflect partitioning between drainage and evapotranspiration in this setting. This study is among the first to explore afforestation impacts on recharge beneath sandy soils and sulfate as a tracer of deep drainage.

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