COMPARISON OF TWO SEEDING METHODS FOR RECLAMATION OF A SEMI-ARID OIL FIELD NEAR ROSWELL, NEW MEXICO

Southeastern New Mexico is dotted with oil fields. Upon well plugging, these well pads must be reclaimed through equipment removal, surfacing material (caliche) removal, reconstruction of topography and drainage, topsoil redistribution, and then revegetation. Revegetation is the hardest part. Due to the challenging climate with intense heat and minimal precipitation (12.9 inches annually), vegetation often takes several growth seasons to fully mimic undisturbed areas near the well pad. Timing of seeding is of the utmost importance, balancing extreme heat and monsoons from June to September. Seeding at the wrong time causes seeds to die, forcing operators to spend more money to reseed the next year. Oil companies choose one of two seeding methods: no till drill seeding and hydroseeding. Drill seeding is the most common, where a mechanical seed drill pushes seeds into the ground. Seeding rows are often visible multiple growing seasons later. Hydroseeding is a costly form of broadcast seeding, involving trucks that spray carefully concocted pressurized mixtures of fertilizer, seed, synthetic dirt, and water over the well pad. No study has been done in this area to compare seeding methods.

In the Bureau of Land Management’s (BLM) Roswell Field Office, there are two oil well pads that are 432 meters apart. These wells were plugged in 2023, but no earthwork was completed until early 2024. Recontouring occurred immediately prior to seeding on both pads. The topography, soil (sandy loam), precipitation, and time of year is the same, but one well pad was hydroseeded in early April while the other one was drill seeded in late March. The hydroseeded pad was fenced in by the operator to exclude cattle (preventing grazing and destruction of new vegetation). The drill seeded pad was fenced in by BLM employees. Over the course of spring and summer, the two pads were monitored. Speed of germination, percent ground cover, and species composition and diversity were assessed. Preliminary results show greater ground cover and species composition on the hydroseeded well pad. Both well pads germinated in the same week. In mid-June, the hydroseeded pad had encroaching low-lying sprouting vegetation. The drill-seeded pad had considerably less vegetation. Monitoring will continue through summer.