Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/22/1998
Publication Date: N/A
Technical Abstract: Improved synchrony between N supply and N demand will increase N use efficiency and decrease offsite N transport. A major source of N supply in Midwestern agricultural soils is N mineralization. As part of a larger study investigating soil N dynamics under winter cover crops, we conducted a series of experiments to determine the effects of living plants on N mineralization. Polycarbonate cylinders with and without Oat plants were placed in a growth chamber. Net N mineralization was determined by N balance calculations. At 2, 4, and 6 weeks, denitrification N loss, dinitrogen fixation, ammonia volatilization, plant biomass N (root + shoot), and soil inorganic N (nitrite, nitrate, and ammonium) were measured. Net N mineralization in the presence of plants was 50% higher in one experiment, while in another experiment there was no difference in net N mineralization. We suspect that plant effects on net N mineralization may vary seasonally, and may also be related to cropping history.