Establishing the relationship of soil nitrogen immobilization to cereal rye residues in a mulched system

• DOI: 10.1007/s11104-018-3566-0
• Publication Date: 2018-03-12T00:01:39Z
• Authors: Alwyn Williams; M. Scott Wells; David A. Dickey; Shuijin Hu; Jude Maul; Daniel T. Raskin; S. Chris Reberg-H...; Steven B. Mirsky
• Keywords: Secale; Vicia villosa

Soil nitrogen (N) immobilization from cover crop residues may help suppress weeds. We established a gradient of cereal rye shoot biomass to determine the extent that soil N can be immobilized and its effect on redroot pigweed (Amaranthus retroflexus L.). A microplot study was conducted in no-till (Secale cereale L.)—soybean (Glycine max L. (Merr.)) systems at two sites eastern USA. Microplots received 0, 2000, 5000, 8000, 12,000 or 15,000 kg ha−1 biomass, were injected with mg 15N kg−1 5 cm below surface. Pigweeds sown allowed germinate. Maximum rates decomposition observed ≥5000 ha−1. Although declined, shoots became enriched 15N, indicating fungal transfer shoots. inorganic declined by an average Pigweed tissue reduced presence rye. The magnitude reduction similar across all application rates. found weak evidence for shoot-based mechanism weed suppression. Our results indicate primarily due root residues.