Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 8, 1996
Publication Date: N/A
Technical Abstract: Agricultural systems are notoriously leaky with regard to nitrogen, due in part to the lack of synchrony between N availability and N uptake by the crop. Use of small grain cover crops have the potential of increasing N use efficiency by immobilizing N released in the late fall and early spring. This study reports on N transformations and N partitioning as influenced by fall seeded oat, rye, and an oat + rye mixture. Cover crops were seeded in a standing soybean canopy in August, and nitrogen transformations and pools monitored over the period of September (soybean harvest) to May (corn planting). Control plots (no cover crop) had higher net N mineralization (72 kg-N/ha) and higher nitrate leaching loss (50 kg-N/ha) than any of the cover crop treatments. N leaching losses from the oat, rye, and oat + rye mixture were 15.9, 19.9, and 0 kg-N/ha, respectively. It appears that oats effectively reduce N leaching in the fall, and rye reduces N leaching in the spring, thus the oat + rye mixture was most effective in retaining N in the rooting zone.