GDD accumulations and probabilities were calculated from PRISM daily tmin and tmax grids at 800-m resolution, time period GDD base temperature was 50F (10C) and the maximum was 30C (86F) Twenty-five planting dates were considered, ranging from 31 March to 29 July, at an interval of five days Twenty probability-of-success categories were considered, ranging from 5 to 100%, at an interval of 5% Four fall freeze thresholds were considered: 26, 28, 30, and 32F Maps used a 32F fall freeze threshold Spring freeze threshold is assumed to be 32F Maps show the latest planting date that meets the given probability of success, at a 5-day and 5% precision Planting Date Methods

The first set of maps shows final planting dates in their native grid form, at 800-m resolution Grey areas labeled as “No date” denote areas for which there was no planting date that met the probability criteria Variations of 25 days or more can be see within individual counties Elevation differences within counties can be up to 500 ft (150 m) or more; this is enough to cause significant variations in GDDs that accumulate over the growing season At the end of this presentation, a close-up of Cloud County highlights how terrain variations can producing varying final planting dates Planting Date Maps – Native Grids Grain Sorghum

Spring Freeze: 32F GDD Base: 50F GDD Max: 86F Time Period: Probability of Success (%) Maturity GDD Fall Freeze Temperature (F) GDD-Based Final Planting Dates Kansas PRISM native 800-m grids Grain Sorghum

Spring Freeze: 32F GDD Base: 50F GDD Max: 86F Time Period: Probability of Success (%) Maturity GDD Fall Freeze Temperature (F) GDD-Based Final Planting Dates Kansas PRISM native 800-m grids Grain Sorghum

Spring Freeze: 32F GDD Base: 50F GDD Max: 86F Time Period: Probability of Success (%) Maturity GDD Fall Freeze Temperature (F) GDD-Based Final Planting Dates Kansas PRISM native 800-m grids Grain Sorghum

County-level maps were created by determining the modal (majority) planting date in each county Areas not in cultivation were excluded from the modal calculations Cultivated areas were derived from the National Agricultural Statistics Service (NASS) Cropland Data Layer (CDL) The native resolution of the CDL is 30 m The CDL was resampled to 800 m resolution by denoting an 800-m pixel as cultivated if it contained one or more 30-m CDL cultivated pixels This resampling process increased the cultivated area substantially, but was necessary to maintain a reasonable number of pixels for the modal calculations in counties with little cultivated land The cultivated land designation is for all crops, and has not been refined to include only grain sorghum, for example County-Level Planting Date Maps Grain Sorghum

Kansas Cultivated Land Areas Source: NASS Cropland Data Layer, 30-m resolution

Kansas Cultivated Land Areas Source: NASS Cropland Data Layer, 30-m, post-processed to 800-m. Any 800-m pixel containing cultivated land was labeled cultivated. Used as mask in county-level calculations.

Spring Freeze: 32F GDD Base: 50F GDD Max: 86F Time Period: Probability of Success (%) Maturity GDD Fall Freeze Temperature (F) GDD-Based Final Planting Dates Kansas Modal date for county Cultivated land only Grain Sorghum

Spring Freeze: 32F GDD Base: 50F GDD Max: 86F Time Period: Probability of Success (%) Maturity GDD Fall Freeze Temperature (F) GDD-Based Final Planting Dates Kansas Modal date for county Cultivated land only Grain Sorghum

Spring Freeze: 32F GDD Base: 50F GDD Max: 86F Time Period: Probability of Success (%) Maturity GDD Fall Freeze Temperature (F) GDD-Based Final Planting Dates Kansas Modal date for county Cultivated land only Grain Sorghum

Charts showing probability of success vs. planting date for a county represent the 800-m grid cell at the center (centroid) of the county, not the entire county We do not yet have the capability to easily create this kind of graph for an entire county at a time The locations of the county centroids are shown on the following slide We switched from a smooth curve to straight connecting lines because the spline line smoother was overshooting and undershooting in areas of rapidly changing slope The Rawlins and Scott county graphs do not always show smoothly increasing probabilities as one moves later in spring; this appears to be caused by occasional relatively late freezes in these areas Probability of Success vs. Planting Date Graphs Grain Sorghum

Locations of County Centroids

This set of maps zooms in on Cloud County, showing in more detail the fine-scale variations in final planting date that can occur due to temperature variations within a county The high-resolution (30-m) CDL shows that much, but not all, of the higher terrain is uncultivated Excluding uncultivated land from the county statistics helps to lessen the influence of unrepresentative areas However, it does raise the risk of failure in areas of higher terrain that are cultivated Planting Date Maps – Cloud County

Spring Freeze: 32F GDD Base: 50F GDD Max: 86F Time Period: Probability of Success (%) Maturity GDD Fall Freeze Temperature (F) GDD-Based Final Planting Dates Cloud County, KS PRISM native 800-m grids Grain Sorghum

Spring Freeze: 32F GDD Base: 50F GDD Max: 86F Time Period: Probability of Success (%) Maturity GDD Fall Freeze Temperature (F) GDD-Based Final Planting Dates PRISM native 800-m grids Cloud County, KS Grain Sorghum

Spring Freeze: 32F GDD Base: 50F GDD Max: 86F Time Period: Probability of Success (%) Maturity GDD Fall Freeze Temperature (F) GDD-Based Final Planting Dates PRISM native 800-m grids Cloud County, KS Grain Sorghum

Cloud County Cultivated Land Areas Source: NASS Cropland Data Layer, 30-m resolution