Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/22/1998
Publication Date: N/A
Technical Abstract: Two controlled-environment experiments were conducted to determine the effect of oat and rye root residues on soil C and N cycling. In Experiment 1, oat and rye roots were harvested from plants and then were mixed with soil. In Experiment 2, oat and rye plants were grown in soil and after 42 days, shoots were cut off to begin root decomposition. At 7, 14, 28, 56, 84, and 112 days after the start, denitrification, soil nitrate and ammonia, soil respiration, and root and coarse organic matter dry weights and C:N ratios were measured. In both experiments net mineralized N increased during the first 56 days. After 56 days, net mineralized N in the control remained relatively constant, whereas N continued to increase in the treatments with roots. Roots mixed with soil had high respiration rates immediately. Whereas, roots in situ showed a lag before the peak respiration rates occurred. Oat roots had less dry matter recovered, a lower C:N ratio, and an earlier respiration peak than rye roots in the in situ experiment.