Although crop-fallow systems stabilize production in the semiarid northern Great Plains, fallow often wastes water, minimally controls water and wind erosion, and contributes to the saline-seep problem. Developing alternate cropping systems which rely less on fallow requires additional crop residue and more specific soil fertility management guidelines. To optimize the potential of a spring wheat-winter wheat-fallow rotation for the northern Great Plains, we examined the effects of spring wheat (Triticum aestivum L. ‘Norana’) stubble management (conventional-till vs. no-till stubble at heights of 15, 28, and 38 cm) and N fertilization (rate, timing, and source) on winter wheat yields. Grain yields were significantly higher for ammonium nitrate (NH₄NO₃) than for urea applied at 67 kg N/ha early (1 May) or late (23 May). Maximum grain yields were 2,620 and 2,540 kg/ha for winter wheat seeded directly (no-tillage) into 15- and 28-cm stubble heights, respectively, with 67 kg/ha of N applied in early May as NH₄NO₃. With 22 or 45 kg/ha of N applied early (1 May), grain yield increases for NH₄NO₃ and urea were similar. With a later application at the same rates, NH₄NO₃ was significantly superior. Nitrogen topdressing of winter wheat in a recropping system must be completed early, either before or soon after spring growth begins and definitely before the end of tillering.

Experiments to determine the effects of snowmobile traffic on plant species, frequently grown in heavy snow-belt regions, were conducted over 3 years in northern Wisconsin. Plant species tested during the trials were: alfalfa (Medicago sativa L.); birdsfoot trefoil (Lotus corniculatus L.); red clover (Trifolium pratense L.); bromegrass (Bromus inermis Leyss.); orchardgrass (Dactylis glomerata L.); and winter wheat (Triticum aestivum L,). The soil is classified as a Typic Eutroboralf, very fine Illitic (mixed). Designated areas of each crop species received varying amounts of snowmobile traffic when snow depths were > 7.5 cm. Soil temperatures, snow compaction, and frost depths were measured. Forage dry matter or grain yields were taken during the following summer. Soil bulk density was determined during two growing seasons as a measure of soil compaction. Stands of alfalfa, birdsfoot trefoil, and alfalfa/bromegrass treated for two winters with snowmobile traffic showed no detrimental effects on forage yield. Grain yields from winter wheat stands exposed to snowmobile traffic were not reduced below that of check areas. Red clover and birdsfoot trefoil/orchardgrass yields were decreased during 1 year of the trials but were unaffected by snowmobile traffic during 1 other year. Snow was found to be compacted by snowmobile traffic and soil temperatures colder and more erratic under these areas. Frost penetrated deeper under areas subjected to snowmobile traffic. Soil compaction was not found to be increased by snowmobile traffic.