|Dugas, W - TEXAS AG. EXP. STATION|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 2, 1995
Publication Date: N/A
Technical Abstract: Information is needed on the magnitude of CO2 flux and nitrogen transformation caused by tillage in different cropping systems. The objective of this work was to measure the effects of tillage on short-term CO2 flux and nitrogen transformation from three cropping systems on a Houston Black clay. The cropping systems included a four-year no-till sorghum, a 30-year Coastal bermudagrass sod, and a 30-year conventional tilled sorghum. The two primary tillage methods were moldboard and chisel plow, each followed five hours later with two passes of a disk harrow. The CO2 flux was measured using a soil chamber (10**-3 m**3) and a canopy chamber (3.2 m**3) for 24 hours. The largest flux (12.5 mg CO2 m**-2 s**-1) occurred immediately after chisel plow on the bermudagrass. Cumulative CO2 fluxes after tillage with the canopy chamber were highest on bermudagrass and lowest on conventional-tilled sorghum. The soil chamber and canopy chamber showed similar qualitative temporal and treatment trends. There wa no clear relationship between N transformations and CO2 flux, suggesting initial high CO2 fluxes are not microbially controlled.