The use of Groasis Waterboxx devices to improve mineland reclamation efforts by increasing transplant survival and growth of five native woody species

Abstract

The reclamation of disturbed lands worldwide is a difficult and increasing problem. In the Mountain West region of the United States, mining activities commonly occur in zones dominated by native woody plants. The restoration of woody plants in these areas is challenging, and direct seeding efforts result in poor seedling emergence and establishment. Therefore, seedling transplants are often used, but they frequently experience high mortality during the first year, particularly due to summer stresses. We evaluated if the Groasis Waterboxx device could be used to mitigate drought stress on seedling transplants and improve their establishment on a reclaimed waste rock dump. The Waterboxx device collects precipitation into a polypropylene reservoir and slowly dispenses water onto the soil next to the seedling. To test such a hypothesis, 400 seedlings from five native woody plants (Atriplex canescens, Cercocarpus ledifolius, Pinus edulis, Purshia tridentata, and Rhus glabra) were planted with and without a Waterboxx. The Waterboxx device improved soil water potential, at 40 cm, it took 1 month longer to go below −1 MPa under a Waterboxx. Survival increased 30–65% in four of the five species, and seedling vigor increased for three of the five species. Vigor was higher with all plant species at both planting times and was significantly better in 50% of comparisons. Results support the use of the Waterboxx for improving seedling establishment on mineland overburden sites in the semiarid mountain west. The effectiveness of the Waterboxx device provides merit for future testing where drought challenges seedling establishment.