Submitted to: Scientia Agricola
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2006
Publication Date: 3/1/2007
Citation: Balkcom, K.S., Wood, C.W., Adams, J.F., Meso, B. 2007. Suitability of Peanut Residue as a Nitrogen Source for a Rye Cover Crop. Scientia Agricola. 64(2):181-186. Interpretive Summary: Winter cover crops have been utilized in conservation systems to partially meet nitrogen (N) requirements of succeeding summer cash crops, but the potential of summer legumes to reduce N requirements of a winter annual grass, such as rye used as a cover crop, has not been extensively examined. This study, conducted by researchers from the National Soil Dynamics Laboratory and cooperators from the Department of Agronomy and Soils at Auburn University assessed the N contribution of peanut residue to a rye cover crop in a conservation system on a Dothan sandy loam at Headland, AL during the 2003-2005 growing seasons. Treatments consisted of peanut residue retained or removed from the soil surface, and N fertilizer application rates (0, 30, 60 and 90 lb ac-1) applied in fall soon after planting the rye cover crop. Peanut residue did not affect rye biomass yields, but additional N supplied in the fall significantly increased rye biomass yield. However, the highest N rate did not maximize rye biomass production. Although growers should be encouraged to leave peanut residue in the field, specific N rates recommended for a winter annual grass cover crop should not be reduced. Our results also indicate that growers that want to produce a high-residue cover crop should apply a minimum of 30 lb N ac-1 to the cover crop.
Technical Abstract: Leguminous winter cover crops have been utilized in conservation systems to partially meet nitrogen (N) requirements of succeeding summer cash crops, but the potential of summer legumes to reduce N requirements of a winter annual grass, used as a cover crop, has not been extensively examined. This study assessed the N contribution of peanut (Arachis hypogaea L.) residues to a subsequent rye (Secale cereale L.) cover crop grown in a conservation system on a Dothan sandy loam (fine-loamy, kaolinitic, thermic Plinthic Kandiudults) at Headland, AL USA during the 2003-2005 growing seasons. Treatments were arranged in a split plot design, with main plots of peanut residue retained or removed from the soil surface, and subplots as N application rates (0, 34, 67 and 101 kg ha-1) applied in the fall. Peanut residue did not affect rye biomass yields, N content, carbon (C) /N ratio, or N, P, K, Ca and Zn uptake. Additional N increased rye biomass yield, and N, P, K, Ca, and Zn uptakes, although the highest N rate did not maximize these variables. Our results indicate that peanut residue does not contribute significant amounts of N to a rye cover crop grown as part of a conservation system, but retaining peanut residue on the soil surface could protect the soil from erosion early in the fall and winter before a rye cover crop grows sufficiently to protect the typically degraded southeastern USA soils.