Capillary barriers improve reclamation in drastically disturbed semiarid shrubland
2018
Cude, Seth M. | Ankeny, Mark D. | Norton, Jay B. | Kelleners, Thijs J. | Strom, Calvin F.
Soils in arid climates affected by drastic disturbance do not recover without reclamation efforts, and saline-sodic conditions caused by development activities are especially problematic. To improve reclamation success, we created seeded depressions that held three types of sand capillary barriers in October 2013. Sand was placed above (mulch), below (capillary barrier), and encompassing (dual barrier) seeded native soil at ridge and depression sites near Wamsutter, WY, representative of natural gas extraction areas. We compared grass growth, salinity, and moisture among the treatments and under depressions without sand amendments (pit) and plots seeded by standard procedures (control). At the ridge site, the mulch treatment supported 249 stems m⁻² in the seeded patches surviving to August 2014, compared with 110 and 89 stems m⁻² in the pit and lower barrier treatments, respectively, less than 50 stems m⁻² in the dual barrier treatments, and none in the control. The dual barrier and mulch treatments performed best at the depression site, with 40–50 stems m⁻² in August compared with none in the other three treatments. Changes in soil moisture and salinity were variable, but indicate positive effects of capillary barriers. Capillary barriers led to reductions or smaller increases in salinity than in treatments without a capillary barrier. While mulch treatments effectively increased grass growth at both sites, the dual barriers only showed positive impact at the depression site, possibly due to adequate moisture. Sand is readily available in many regions, and scaling up from test plots may be achieved with existing equipment.
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