| Popis: |
A variable variety grain drill, with the ability to plant three different varieties of grain, was constructed and tested. 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, also controlled by a computer using GPS as a locator, through the placement of different seeds rather than different liquid nitrogen rates. Lentils, oats, and peas were planted in a grid on a small plot and measurements were taken from the surveyed grid to determine the accuracy of placement. An average switching accuracy of 5.5 m (18 ft) was found at 7.2 km/h (4.5 mph). The maximum error was 20 m (66 ft) which was adequate for large fields of cereal grains. Reduced computer 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 using Basin, Eltan, and Madsen cultivars of winter wheat and a blend of the three varieties. These varieties were selected because Basin is lodging resistant, Madsen is a higher yielding cultivar and Eltan is winter hardy. Yields were compared based on slope position and aspect and were used along with other studies found in the literature to determine the feasibility of varying the winter wheat variety based on slope position. From this it was determined that Basin or Madsen should be used at the toe slope, Madsen or a mix should be selected at the midslope, and any of the varieties could be used 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. |
