Avariable Variety Grain Drill for Wheat Production

A variable variety grain drill, with the ability to plant three different varieties of grain, was constructed andtested. Switching of each variety of grain was controlled by a computer which used the global positioning system (GPS)as a locator. The grain drill was used to ground proof the accuracy of the spatially variable application of fertilizer, alsocontrolled by a computer using GPS as a locator, through the placement of different seeds rather than different liquidnitrogen rates. Lentils, oats, and peas were planted in a grid on a small plot and measurements were taken from thesurveyed grid to determine the accuracy of placement. An average switching accuracy of 5.5 m (18 ft) was found at7.2 km/h (4.5 mph). The maximum error was 20 m (66 ft) which was adequate for large fields of cereal grains. Reducedcomputer sampling times were suggested for reducing the error. The feasibility of varying varieties of wheat based on slope position was also investigated through a field study usingBasin, Eltan, and Madsen cultivars of winter wheat and a blend of the three varieties. These varieties were selectedbecause Basin is lodging resistant, Madsen is a higher yielding cultivar and Eltan is winter hardy. Yields were comparedbased on slope position and aspect and were used along with other studies found in the literature to determine thefeasibility of varying the winter wheat variety based on slope position. From this it was determined that Basin or Madsenshould be used at the toe slope, Madsen or a mix should be selected at the midslope, and any of the varieties could beused at the ridge top position. Therefore, Madsen could have been used alone as effectively as varying the varieties.However, the winter was mild and the value of Eltan in preventing winter kill on the ridge top was not adequately tested.