2012 Annual Report
The effects of tilled and no-tilled cropping systems on soil diseases and soybean cyst nematode incidence and severity are continuing to be evaluated. Research is underway on a long term soybean experiment comparing single, to double-cropped soybeans and winter wheat. The six main plot treatments include tillage (disc only, chisel plow, and moldboard plow) compared to no-tillage (single crop in winter wheat cover, single crop in previous crop residue, and no-tillage after wheat harvest in a double crop system). Each of the six treatments were split in 2002 with one half being no-tillage soybeans and the other half being tilled. Sampling was done on all plots to determine nematode populations, and soil bacterial and fungal levels in addition to effects on soybean cyst nematode reproduction. Charcoal rot incidence and severity was also monitored. The split plot design is being discontinued in 2012 with plots being restored to the original design because carbon data collected in the plots for 6 years indicated that carbon levels no longer reflected the changes in tillage. Similar data will be collected but will now include bacterial community structure analysis. This new research will involve more precise bacterial population determinations and measure the ratio of gram negative to gram positive bacteria. Undescribed bacteria parasitizing soybean cyst nematode have been found in this plot area. Research by others suggests that the ratio of bacteria may help determine bacterial predation potential.
New work is also being planned on the effects of rotation crop, cover crop and spatial distribution of charcoal rot. This will be conducted at the Milan Experiment Station on a long term study where soybeans are rotated with cotton and corn both grass and legume cover crops established in each rotation each year. Presently the plots are in their second three year cycle of rotations.