Recent research at St. Olaf, conducted during the 2003 growing season, compared soil characteristics, runoff water quantity and nutrient fluxes, energy use, and overall productivity of three farm types. The farming systems examined were:
Conventional (C) -- Continuously cropped with corn (C) with heavy tillage (moldboard plow)
Conventional Soybean (CS) -- Field cropped with a corn-corn-soybean (C-C-S) rotation and cultivated with a chisel plow and disk ripper each year
Rotational -- Perenial legume based with a 5-year crop rotation of corn-soybean-oats/alfalfa-alfalfa-alfalfa (C-S-O/A-A-A). Rotation fields were mulch-tilled before planting of corn and soybeans, but were not tilled during the three years alfalfa was grown
No-till -- Used a corn-soybean (C-S) rotation and a seed drill to plant directly into the soil. Residue from the previous year's crop was left undisturbed following harvest
Information from the figures above modified from:
Gregory, M.M., K.L. Shea, and E.B. Bakko. 2005. Comparing agroecosystems: effects of croping and tillage patterns on soil, water, energy use and productivity. Renewable Agriculture and Food Systems 20:81-90.