Other Civil and Environmental Engineering Commons^™

Spatial Patterns Analysis Of Field Measured Soil Nitrate, Farida Shaukat Goderya, Mohamed F. Dahab, Wayne E. Woldt, Istvan Bogardi

Biological Systems Engineering: Papers and Publications

The purpose of this study was to assess the spatial variability of residual soil nitrate, measured in three contiguous 16 ha fields. Available data for residual soil nitrate were examined using conventional statistics. Data tended to be skewed with the mean greater than the median. Geostatistical methods were used to characterize and model the spatial structure. Three dimensional spatial variability was examined using two semivariograms: horizontal-spatial and vertical. Two dimensional horizontal-spatial semivariograms were also computed for each 0.3m (1ft) layer. Semivariogram analysis showed that there were similarities in the patterns of spatial variability for all fields. The results suggest that …

Metering Characteristics Accompanying Rate Changes Necessary For Precision Farming, A. Bahri, K. Von Bargen, Michael F. Kocher, L. L. Bashford

Biological Systems Engineering: Papers and Publications

Agricultural machines used in precision fanning must adjust application rates according to the needs of each cell within a field. Changing from an initial application rate to a new rate while the machine travels from one cell to another in the field is accompanied with some misapplication. The severity of this misapplication depends on the down-the-row delivery characteristics of the metering system and the magnitude of the rate change from cell to cell.

On-the-go rate change tests evaluated the down-the-row performance of an operator controlled metering system when increasing and decreasing wheat seeding rates by 10 and 20 kg/ha steps. …

Variability In Volume Metering Devices, Leonard L. Bashford, Abdeljabar Bahri, K. Von Bargen, Michael F. Kocher

Biological Systems Engineering: Papers and Publications

The inherent variability of seed and fertilizer application from volumetric metering devices is not readily recognized. The Canadian Prairie Agricultural Machinery Institute (P AMI) suggests a maximum coefficient of variation (CV) of 15% among outlets for seeding grain or applying fertilizer. P AMI does not report down-the-row variability of individual outlets. Parameters that influence variability of volumetric measuring external fluted wheels such as rotational speed of the metering wheel, product delivery rate, seed size, and cell collection lengths were examined.

In the first study, external fluted wheel meters on four grain drills were tested for seed delivery variability for wheat …