Contour Strip Intercropping and Rotations to Reduce Soil Erosion and Energy Costs in Production Systems
1. To compare Diversified strip intercropped and crop rotation landscapes with monoculture (continuous) corn and corn-soybean rotations on highly erodible lands in eastern Nebraska,
2. To calculate biological, ecological, economic and water quality impacts of these systems on single fields, whole farms, and watersheds in terms of yields, net returns, energy use and savings, soil erosion control, and water quality,
3. To simulate new combinations of component technologies and other rotations from these trials to provide a data base to develop innovative systems for future field testing, and
4. To conduct demonstrations and field days at the experiment station and on fields of cooperating farmers, using SCS, ASCS, Cooperative Extension, Nebraska Sustainable Agriculture society, and industry meetings and other channels where this information is needed.
Three large fields were designated to include the contour strip intercrop rotation experiments at eh Agricultural Research and Development Center near Mead, NE. Strip widths of 20 and 80 feet were included in each experiment for comparisons of erosion control.
Plots were planted in four different rotations: 1) corn-soybeans, 2) grain sorghum-soybeans, 3) corn-alfalfa-alfalfa-alfalfa, and 4) corn-wheat/soybean/cover crop. Rotations 1, 2, and 4 are two year rotations; rotations 3 is a four year rotation.
Use of Strip patterns on the contour reduced soil erosion by over 50% with the wide strips and by 75% when using the narrow strips. This is the L factor in the Universal Soil Loss Equation. Full residue on the soil surface reduced soil loss by 50-75% as compared to the conventional fall tillage on these soils. This represents the C factor in the USLE. Soil erosion can be reduced by 50% by planting on the contour strips (P factor in USLE).
While yields from the strip intercropping system were similar to those on monoculture fields elsewhere on the ARDC station, economic analysis was not accomplished due to several changes in the project set-up.