Long-term effects of harvesting maize stover and tillage on soil quality

Rising concerns about greenhouse gases, increased fuel prices, and the potential for new high value agricultural products have raised interest in the use of maize stover for bioenergy production. However, residue harvest must be weighed against potential negative impacts on soil quality. This study, conducted in Chazy, NY, evaluated the long-term effects of 32 yr of maize (Zea mays L.) stover harvest vs. stover return on soil quality in the surface layer (5-66 mm) under plow till (PT) and no-till (NT) systems on a Raynham silt loam (coarse-silty, mixed, active, nonacid, mesic Aeric Epiaquept) using physical, chemical, and biological soil properties as soil quality indicators. Twenty-five soil properties were measured, including standard chemical soil tests, aggregate stability (WSA), bulk density, (ρ_b) penetration resistance (PR), saturated hydraulic conductivity (K_s), infiltrability (Infilt), several porosity indicators (aeration pores(PO > 1000), soil water potential = Ψ > -0.36 kPa; air-filled pores at field capacity (PO > 30), Ψ > -10kPa; available water capacity (AWC), -1500 < Ψ < -10 kPa), total organic matter (OM), parasitic (Nem _Parasitic) and beneficial nematode (Nem_Beneficial) populations, decomposition rate (Decomp), potentially mineralizable N (PMN) and easily extractable (EEG) and total glomalin (TG). Only eight indicators were adversely affected by stover harvest, and most of these effects were significant only under NT. Almost all indicators affected by stover removal were affected equally or more adversely by tillage. A total of 15 indicators were adversely affected by tillage. Results of this study suggest that, on a silt loam soil in a temperate climate, long-term stover harvest had lower adverse impacts on soil quality than long-term tillage. Stover harvest appears to be sustainable when practiced under NT management.