Corn (Zea mays L.) Yield Response to Nitrogen Fertilizer in Conventional and Alternative Rotations

Nitrogen (N) fertilization recommendations are not available for corn in rotation with small grains or forages despite the possibility that the N response may differ from that of more conventional corn-soybean rotations. Rotations of corn with soybean (CS), corn with soybean and oat (CSO) and corn with soybean and an oat/berseem clover intercrop (CSOB) were established in 1991 and studied from 1993 through 1998 to determine the optimal N fertilization level for corn produced in each rotation. Corn in each rotation received NH4N03 applied at the rates of 0, 56, 112, or 168 kg N ha-1. Significant differences in corn grain yield occurred between rotations in three years, but no rotation was consistently superior. Corn grain yield increased with N fertilizer in each year, but in 3 of 6 years there was no advantage to applying Nat a rate greater than 112 kg ha-1. No difference in N response between rotations was observed

Demonstration of an annual forage crop integrated with crop and livestock enterprises

Using a more diverse cropping system, such as strip intercropping, to produce forages for feeding livestock can create a more sustainable, environmentally friendly farming system. Strip intercropping of corn, soybeans, and oats underseeded with berseem clover was used to demonstrate agronomic and environmental benefits of a more varied cropping system. This system produces oat/ berseem clover soilage (green-chop) that can be utilized to feed beef cattle

Tillage Effect on Soil Water Content and Soybean (Glycine max) Yield in a Strip Intercropping System

Soybean [Glycine max (L.) Merr.] response to strip-intercropping with corn (Zea may L.) and oat (Avena Jativa L.) interseeded with nondormant alfalfa (Medicago Jativa L.) may be affected by soil moisture. A three-crop strip-intercropping system of corn, soybean and oat interseeded with nondormant alfalfa was established to determine the effect of tillage system and row position on soil water content and grain yield in the soybean strip. The experiment was a split-plot design with three tillage treatments (conventional, CT; reduced, RT; and minimum tillage, MT) as main plot effects and three row positions (both edge rows and the center row) as subplot effects. In 1989 (a dry year), MT resulted in greater soil water content and soybean yield than other tillage treatments. The row bordering the oat-alfalfa strip had a lower soil water content and soybean yield than did the other two positions. Tillage did not have a significant effect in 1990 (a wet year) on soil water content or soybean yield. The 1990 soybean yield was lower in the soybean row bordering corn, but water availability did not differ significantly between row positions. MT was the most suitable tillage system for soybean production with the three-crop strip intercropping on this soil for both the wet and dry year in which this study was conducted

Evaluation of interactions within a shelterbelt agroecosystem

A tree shelterbeit comprised of four rows of hybrid poplars was established near Ogden, Iowa in 1992 to evaluate shelterbeit characteristics and impacts on soil water content and crop growth andyieid. Major emphasis was on testing crops of corn and soybeans. The first three years saw little effects from the shelterbeit, and data from these years will be used to develop a baseline for future measurements. In the fourth and fifth years, corn yield patterns suggested that the shelterbeit increases yields in the zone leeward from the shelterbeit. Soybeans have not shown a response to the presence of the shelterbeit

Forage-Based Beef Production Research at the Armstrong Outlying Research Farm

Fifty-five yearling crossbred steers and 3C cow-calf pairs were used in a forage-based beef production system demonstration project at the Armstrong Outlying Research Farm. From May 11 to June 13, steers rotationally grazed a 41-acre grass pasture that was divided into eight paddocks. From June 13 to August 24, steers were placed in a drylot and fed berseem clover/oat soilage from a strip-intercropping system. Beginning June 5, 36 cow-calf pairs were allowed to rotationally graze the 41-acre pasture until September 18. Calf weight gains for the 110 days were 1.57 pounds per day, and total production from the pasture was 151 pounds per acre. No cow weight change or condition score change was measured. Total steer production was 29 and 580 pounds per acre or average daily gains were .67 and 2.23 pounds while grazing pasture and being fed in a drylot

Planting Method and Fertilization Timing Effects on Ridge-Till Corn

Fertilizer application technology has improved fertilizer use efficiency in ridge-till systems, but little work on planting methods and application timing within these systems has been done. A study was conducted to evaluate corn (Zea mays 1.) response to injected nitrogen (N) fertilizer applied to different planting methods at common application times. The performance of the late spring soil nitrate and the basal stalk nitrate tests was examined within these systems. A continuous corn and a corn-soybean [Glycine max (1) Merr.] rotation were used in 1989-1991 at two Iowa locations on Nicolett and Monona series soils, line-loamy, mixed, mesic Typic Hapludolls and line-silty, mixed, mesic Typic Hapludolls, respectively. Whole plot treatments were: 1) till planting with fertilizer N applied at layby; 2) slot planting with fertilizer N applied at planting; and 3) slot planting with fertilizer N applied at layby. Subplot treatments (0, 22, 45, 90, 157, and 224 kg N ha-1) were imposed on the whole-plots. The late spring soil nitrate test had consistently low values relative to the scale used for N fertilizer recommendations. The basal stalk nitrate test identified optima nitrate concentrations relating to N fertilizer rates which produced maximum yields. Whole plot treatments generally did not differ significantly in grain yield. Alternative methods of fertilizing corn, such as the use of point injection application equipment, provide opportunities in fertilizer N management that current recommendation tools may enhance