Effects of N and P Fertilizer Placement on Establishment of Seeded Species on Redistributed Mine Topsoil

Abstract

The effects of fertilizer on the establishment of seeded grass and legume stands when reclaiming coal strip mines have not been evaluated in northwest Colorado. Nitrogen (0, 28, 56, and 112 kgN/ha) and phosphorus (0 and 56 kgP/ha) were applied in all combinations to the spoils before topsoiling or to the surface after topsoiling. In the greenhouse, herbage yield and yield of roots in the 28 cm of topsoil replaced over the spoil increased as rate of N increased; phosphorus did not increase yield. Nitrogen content of the herbage increased from 1.02% to 1.33% as rate of N increased from 0 to 112 kgN/ha. In a field study in northwest Colorado, neither N nor P fertilizer improved stand establishment ratings. Both the amount and placement of N at time of seeding affected herbage yield during the third growing season. Alfalfa yields were increased 20% by buried P and 44% by surface P in the third growing season. Applying N fertilizer at time of seeding is not recommended.