Grass establishment on natural gas drill pads in wyoming as impacted by reclamation techniques

Abstract

In the semiarid West, establishing perennial vegetation is often difficult on newly constructed natural gas drill pads because of harsh site conditions. Southern Wyoming is characterized by low precipitation and sites can have saline and/or sodic soil and steep slopes. Twenty-five combinations of reclamation techniques were evaluated on six Devon Energy Corporation natural gas drill pads in the Washakie Basin near Baggs, Wyoming. Treatments included combinations of soil ripping, fertilizer applications, gypsum or sulfur application, chopped straw or woodchip amendments, imprinting, pitting, mulch, irrigation, fencing and site-specific seed mixes. Grass density was measured ten months after treatment implementation on five drill pads and six weeks after implementation on one drill pad. Irrigation during plant establishment was beneficial on all sites, increasing grass density 92 % on average compared to areas not irrigated. Wood chips, gypsum and fertilizer; and chopped straw, sulfur and fertilizer treatments, both with and without irrigation significantly increased grass establishment on saline-sodic soils. Irrigation and fertilizer, and fertilizer alone produced little to no grass establishment on saline-sodic soils, suggesting some treatment for the saline-sodic condition was necessary for grass establishment. Imprinting significantly increased grass densities on both saline and non-saline soils and on sloped sites by providing protected microclimates for seedling growth. Pitting produced lower grass density than imprinting, and most likely cut through the topsoil and exposed lower quality subsoil material. Straw mulch increased grass density when used in combination with irrigation, but did not increase density when used with other treatments on a site with low salinity and sodicity. On the same site, grass density was 89 % higher on average when treatments did not include fertilizer. At least one reclamation treatment on each site produced grass density of at least 80 % of that found in the adjacent native range. These reclamation techniques can significantly decrease the time required to reach plant re-vegetation requirements.