Pitch × Loblolly Pine Growth in Organically Amended Mine Soils

Abstract

AbstractSoils on the mountainous terrain of southwestern Virginia are difficult to recover and replace before and after surface mining for coal. For this reason, combinations of soil, weathered rock, and blasted, unweathered rock are authorized as topsoil substitutes. If treated and amended properly, topsoil substitutes might be made even more productive for tree growth than the original soil disturbed by mining. Accordingly, the benefits of added municipal sewage sludge, sawdust, and inorganic fertilizer were assessed. Seven surface treatments were applied to 2:1 sandstone/siltstone overburden on a reclaimed coal surface mine in Wise County Virginia: fertilizer (168, 147, and 139 kg/ha of N, P, and K, respectively); limed (7.8 Mg/ha), and fertilized topsoil (30 cm deep); fertilized sawdust (112 Mg/ha) + 336 kg/ha slow‐release N (SRN); and lime‐treated municipal sewage sludge at rates of 22, 56, 112, and 224 Mg/ha. Stem volumes of 3‐yr‐old pitch × loblolly pines (Pinus rigida Mill. × P. taeda L.) were five times larger in soils amended with sawdust + SRN and nearly three times larger in soils amended with 22 and 56 Mg/ha sludge than fertilized‐only seedlings. Soil moisture retention was two times higher in sawdust‐amended soils than in all other treatments and contributed to increased seedling growth. Increased seedling mortality and decreased growth due to severe Mn deficiencies and/or high soluble salt levels was observed in the 112 and 224 Mg/ha sludge treatments.