Views
1 year ago

SUMMARY

60158pYvc

eturn to table of

eturn to table of contents Aligned with University Fertility Recommendations Many state universities have developed soil fertility recommendations specifically designed for use in their region. These recommendations are based on calculations established through years of field research. State recommendations vary from one another in numerous ways, including soil test methods, soil test level ranges, crop removal rates, and recommended application rates. Growers using the Encirca Fertility service can select their preferred state calculator or set-up a custom calculator to use as the basis for their soil fertility program. Built on Encirca Decision Zones The Encirca Fertility service defines field productivity targets using Encirca Decision Zones, which are a composite of up to three spatial data layers (Figure 3A). All Decision Zones start with the improved soil maps from DuPont Pioneer, known as Environmental Response Units (ERUs) (Figure 3B). Environmental response units reclassify the spatial distribution of soil properties expressed in public soil maps using high-resolution digital elevation data. Because they more precisely account for topography, ERUs describe soilderived differences in field productivity better than public soil maps (Bobryk et al., 2016). Powered by Encirca SM Services Analytics The Encirca SM Fertility service uses a model to determine nutrient needs based on the productivity targets for each Decision Zone in a field and the corresponding interpolated soil test level (Figure 4). Calculated nutrient needs will be highest for field areas with low soil test levels as these field areas offer the greatest financial return on applied fertilizer. In the optimum soil test range, nutrient needs will vary according to productivity targets, which indicate expected crop nutrient removal rates. Specific nutrient quantities will align with the state or custom fertility calculator selected by the user. Yield Targets Soil Test Levels A B C D Nutrient Needs Figure 3. Encirca Decision Zones (A) combine Environmental Response Units (B), multi-year yield analysis (C), and an optional management layer (D) to define field productivity targets. Where historical yield data are available, multi-year yield analysis is also used as a Decision Zone input (Figure 3C). Multi-year yield analysis combines three or more years of historical data to create a field map of relative productivity potential. A third layer can also be incorporated into Decision Zones, when necessary, to define field areas, such as irrigation pivot corners, that are managed for a different yield level than the remainder of a field (Figure 3D). Figure 4. The Encirca Fertility service combines productivity targets represented by Encirca Decision Zones with interpolated soil test levels to determine optimum nutrient needs across fields. Flexible Fertility Prescriptions Once nutrient needs are calculated by the Encirca Fertility service, users can generate variable rate fertilizer or lime prescription files using one of two approaches. If the user’s objective is to optimize return on fertility investment with no budget constraints, they simply select a fertilizer or lime product from their custom list and apply it to the nutrient needs for a specified field (Figure 5A). In this case, the application prescription will match exactly with the field’s nutrient needs but expressed in units of the specified fertilizer or lime product (Figure 5B). 70

5 7 6 5 5 2 5 2 8 5 0 4 4 8 0 4 5 6 4 3 2 4 0 8 3 8 4 3 6 0 3 3 6 3 1 2 2 8 8 2 6 4 2 4 0 2 1 6 1 9 2 1 6 8 1 4 4 1 2 0 9 6 7 2 4 8 2 4 5 5 2 5 2 9 5 0 6 4 8 3 4 6 0 4 3 7 4 1 4 3 9 1 3 6 8 3 4 5 3 2 2 2 9 9 2 7 6 2 5 3 2 3 0 2 07 1 8 4 1 6 1 1 3 8 1 1 5 9 2 6 9 4 6 2 3 5 2 8 5 06 4 8 4 4 6 2 4 4 0 4 1 8 3 9 6 3 7 4 3 5 2 3 3 0 3 0 8 2 8 6 2 6 4 2 4 2 2 2 0 1 9 8 1 7 6 1 5 4 1 3 2 1 1 0 8 8 6 6 4 4 2 2 5 0 4 4 8 3 4 6 2 4 4 1 4 2 0 3 9 9 3 7 8 3 5 7 3 3 6 3 1 5 2 9 4 2 7 3 2 5 2 2 3 1 2 1 0 1 8 9 1 6 8 1 4 7 1 2 6 1 0 5 8 4 6 3 4 2 2 1 4 8 0 4 6 0 4 4 0 4 2 0 4 0 0 3 8 0 3 6 0 3 4 0 3 2 0 3 00 2 8 0 2 6 0 2 4 0 2 2 0 2 00 1 8 0 1 6 0 1 4 0 1 2 0 1 0 0 8 0 6 0 4 0 2 0 4 5 6 4 3 7 4 1 8 3 9 9 3 8 0 3 6 1 3 4 2 3 2 3 3 0 4 2 8 5 2 6 6 2 4 7 2 2 8 2 0 9 1 9 0 1 7 1 1 5 2 1 3 3 1 1 4 9 5 7 6 5 7 3 8 1 9 4 3 2 4 1 4 3 9 6 3 7 8 3 6 0 3 4 2 3 2 4 3 06 2 8 8 2 7 0 2 5 2 2 3 4 2 1 6 1 9 8 1 8 0 1 6 2 1 4 4 1 2 6 1 08 9 0 7 2 5 4 3 6 1 8 4 0 8 3 9 1 3 7 4 3 5 7 3 4 0 3 2 3 3 0 6 2 8 9 2 7 2 2 5 5 2 3 8 2 2 1 2 0 4 1 8 7 1 7 0 1 5 3 1 3 6 1 1 9 1 02 8 5 6 8 5 1 3 4 1 7 3 8 4 3 6 8 3 5 2 3 3 6 3 2 0 3 0 4 2 8 8 2 7 2 2 5 6 2 4 0 2 2 4 2 08 1 9 2 1 7 6 1 6 0 1 4 4 1 2 8 1 1 2 9 6 8 0 6 4 4 8 3 2 1 6 3 6 0 3 4 5 3 3 0 3 1 5 3 0 0 2 8 5 2 7 0 2 5 5 2 4 0 2 2 5 2 1 0 1 9 5 1 8 0 1 6 5 1 5 0 1 3 5 1 2 0 1 0 5 9 0 7 5 6 0 4 5 3 0 1 5 3 3 6 3 2 2 3 0 8 2 9 4 2 8 0 2 6 6 2 5 2 2 3 8 2 2 4 2 1 0 1 9 6 1 8 2 1 6 8 1 5 4 1 4 0 1 2 6 1 1 2 9 8 8 4 7 0 5 6 4 2 2 8 1 4 3 1 2 2 9 9 2 8 6 2 7 3 2 6 0 2 4 7 2 3 4 2 2 1 2 0 8 1 9 5 1 8 2 1 6 9 1 5 6 1 4 3 1 3 0 1 1 7 1 0 4 9 1 7 8 6 5 5 2 3 9 2 6 1 3 2 8 8 2 7 6 2 6 4 2 5 2 2 4 0 2 2 8 2 1 6 2 04 1 9 2 1 8 0 1 6 8 1 5 6 1 4 4 1 3 2 1 2 0 1 0 8 9 6 8 4 7 2 6 0 4 8 3 6 2 4 1 2 2 6 4 2 5 3 2 4 2 2 3 1 2 2 0 2 0 9 1 9 8 1 8 7 1 7 6 1 6 5 1 5 4 1 4 3 1 3 2 1 2 1 1 1 0 9 9 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 2 5 2 2 4 1 .5 2 3 1 2 2 0.5 2 1 0 1 9 9 .5 1 8 9 1 7 8 .5 1 6 8 1 5 7 .5 1 4 7 1 3 6 .5 1 2 6 1 1 5 .5 1 05 9 4 .5 8 4 7 3 .5 6 3 5 2 .5 4 2 3 1 .5 2 1 1 0.5 2 4 0 2 3 0 2 2 0 2 1 0 2 0 0 1 9 0 1 8 0 1 7 0 1 6 0 1 5 0 1 4 0 1 3 0 1 2 0 1 1 0 1 00 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 0 1 0 2 1 6 2 0 7 1 9 8 1 8 9 1 8 0 1 7 1 1 6 2 1 5 3 1 4 4 1 3 5 1 2 6 1 1 7 1 08 9 9 9 0 8 1 7 2 6 3 5 4 4 5 3 6 2 7 1 8 9 2 0 4 1 9 5 .5 1 8 7 1 7 8 .5 1 7 0 1 6 1 .5 1 5 3 1 4 4 .5 1 3 6 1 2 7 .5 1 1 9 1 1 0 .5 1 02 9 3 .5 8 5 7 6 .5 6 8 5 9 .5 5 1 4 2 .5 3 4 2 5 .5 1 7 8 .5 1 9 2 1 8 4 1 7 6 1 6 8 1 6 0 1 5 2 1 4 4 1 3 6 1 2 8 1 2 0 1 1 2 1 0 4 9 6 8 8 8 0 7 2 6 4 5 6 4 8 4 0 3 2 2 4 1 6 8 1 8 0 1 7 2 .5 1 6 5 1 5 7 .5 1 5 0 1 4 2 .5 1 3 5 1 2 7 .5 1 2 0 1 1 2 .5 1 05 9 7 .5 9 0 8 2 .5 7 5 6 7 .5 6 0 5 2 .5 4 5 3 7 .5 3 0 2 2 .5 1 5 7 .5 1 6 8 1 6 1 1 5 4 1 4 7 1 4 0 1 3 3 1 2 6 1 1 9 1 1 2 1 05 9 8 9 1 8 4 7 7 7 0 6 3 5 6 4 9 4 2 3 5 2 8 2 1 1 4 7 1 5 6 1 4 9 .5 1 4 3 1 3 6 .5 1 3 0 1 2 3 .5 1 1 7 1 1 0 .5 1 04 9 7 .5 9 1 8 4 .5 7 8 7 1 .5 6 5 5 8 .5 5 2 4 5 .5 3 9 3 2 .5 2 6 1 9 .5 1 3 6 .5 1 4 4 1 3 8 1 3 2 1 2 6 1 2 0 1 1 4 1 0 8 1 02 9 6 9 0 8 4 7 8 7 2 6 6 6 0 5 4 4 8 4 2 3 6 3 0 2 4 1 8 1 2 6 1 3 2 1 2 6 .5 1 2 1 1 1 5 .5 1 1 0 1 0 4 .5 9 9 9 3 .5 8 8 8 2 .5 7 7 7 1 .5 6 6 6 0.5 5 5 4 9 .5 4 4 3 8 .5 3 3 2 7 .5 2 2 1 6 .5 1 1 5 .5 2 4 2 3 2 2 2 1 2 0 1 9 1 8 1 7 1 6 1 5 1 4 1 3 1 2 1 1 1 0 9 8 7 6 5 4 3 2 1 return to table of contents For users making fertility investment decisions on a defined budget, the Encirca Yield Fertility service offers a unique feature called Opti-Allocate. To create fertilizer prescriptions that maximize return on investment for a specific but limited fertilizer expenditure, users enter their desired budget level, and the best recommendation for that budget will be automatically generated (Figure 5C). A) Calculated Nutrient Needs Phosphorus Potassium Relative Yield Target High Avg. Fertilizer ROI High B) Optimum Rx Costs $52.00/acre DAP ($25.00/acre) Potash ($27.00/acre) C) Best Rx if Limited to $40.00/acre DAP ($20.00/acre) Potash ($20.00/acre) Low Low Optimum High Soil Test Level Low Figure 6. Diagrammatic representation of the fertility return on investment (ROI) model used by the Encirca℠ Fertility service to prioritize nutrient inputs based on productivity targets and soil test levels. Balanced Data Interpolation All variable rate fertility recommendations that use soil sample data incorporate some process to interpolate between sampled field positions. Many variable rate recommendations linearly extrapolate between sampled points, which results in inaccurate interpolation and large changes in application rates across small distances. The Encirca Fertility service employs an optimal smoothing model that maximizes overall accuracy and better matches application capabilities (Figure 7). Minimal Smoothing Figure 5. Calculated P and K needs (A), optimum fertilizer recommendation (B), and best fertilizer recommendation if fertility budget is limited (C) for a field enrolled in the Encirca Fertility service. Sample Accuracy Interpolation Accuracy Total Accuracy Unlike other variable rate fertility programs, the Opti-Allocate feature does not cut application rates evenly across the field when the available fertilizer budget is less than the optimum recommendation. Rather, Opti-Allocate iteratively assigns fertilizer inputs to the field area with the greatest potential return on fertilizer investment until the available fertility budget is exhausted (Figure 6). Optimal Smoothing Too Much Smoothing Figure 7. Comparison of sample, interpolation, and total accuracy for three soil sample interpolation models. The Encirca Fertility service employs an optimal smoothing model that maximizes overall accuracy. 71