Perennial Ryegrass Growing Degree Days
|MFSA 2012 Interim Report
Kevin GulayB.Sc. (Agric)
MFSA Research Manager
This spring eight fields were selected to participate in the Growing Degree Days (GDD) for Perennial Ryegrass Seed Crops project. Fields were selected from across the entire province in order to get a good province wide representation. The majority of the fields were selected from the areas which have the most perennial ryegrass seed production. Do to the fact that travel to some of these sites was excessive, our best efforts were made to obtain local help in the scouting process. Below is a list of the locations and scouting assistance that MFSA obtained for the project.
|A scouting template was developed to assist in the scouting. It also provided some consistency between all of the participants involved. The primary focus of the project was to collect the crop stage on a weekly to bi-weekly basis. When the crop was growing rapidly fields were scouted on a weekly basis. Three areas in each field were to be flagged and revisited every week so that variability within the field could be avoided. In addition to crop stage, weeds, insects, and diseases were recorded every visit. Information from the producer, including variety and inputs used, was collected.
Having accurate local weather data was important for this project. Fields located relatively close to MAFRI weather stations, used data from those stations. MFSA weather recording devices were used for fields which had no weather stations nearby. Each day that a field was scouted, the GDD for that particular day were also recorded. Adjustments had to be made for the GDD calculation provided on the Manitoba Ag Weather Program website. The formula used to calculate GDD on this site is GDD=((Tmax+Tmin)/2-5). For cool season grass crops it is more accurate to use the formula GDD=Tmax+Tmin)/2.
The majority of the field data has now come in and has been tabulated. Comparing the GDD crop stages after one year of collection in Manitoba, to the model developed in Minnesota, it appears that it takes considerably more GDD to produce a perennial ryegrass seed crop in Manitoba. Over the winter the data will be analyzed further. A final report and presentation will be made on the project.