Crops, Soils and Nutrient Management


Wisconsin Custom Rate Guide (.pdf)

Nutrient Management Resources

Bedding Use AU/day (1000 lb animal) Chopped Straw Shavings Sand cubic ft / day
Freestall 2.7 lb 3.1 lb 20-30 lb .3 cu ft sand or .2 cu ft straw
Tie Stall 12 lb
1.4 cu ft
Bedded Pack 11.0 lb
.8 cu ft chopped 1.9 long stra


Soils Information & Farm Maps

Area Climate Information for Crops and Pest Management

What are Growing Degree Days (GDD) and how are they calculated?

Growing degree-days are a temperature-derived index representative of the amount of heat that the plants are exposed to, which in turn is directly related to the rate of growth and development of the plant. GDD are calculated several ways, so it is important to make sure GDD are calculated using the same formula that was used to establish the relationship you will use to harvest alfalfa. For instance, different base temperatures are used for different crops, and corn uses a different method of calculation entirely. Alfalfa GDD used for recommendations in this article are calculated by averaging the maximum and minimum temperature (° F) for a given day (24-h period) then subtracting the base temperature of 41°F to get the number of GDDs for that day. Daily GDD for days with an average temperature less than 41°F are set equal to 0. Finally, a seasonal total is then obtained by summing the daily growing degrees from March 1st through the current day.

40°F wheat, barley, rye, oats, flaxseed, lettuce, asparagus
45°F sunflower, potato
50°F sweet corn, corn, sorghum, rice, soybeans, tomato
44°F Corn Rootworm
48°F Alfalfa Weevil
50°F Black Cutworm, European Corn Borer
52°F Green Cloverworm
Modified Growing Degree DaysModified Growing Degree Days are similar to Growing Degree Days with several temperature adjustments. If the high temperature is above 86°F, it is reset to 86°F. If the low is below 50°F, it is reset to 50°F. Once the high / low temperatures have been modified (if needed), the average temperature for the day is computed and compared with a base temperature, which is usually 50°F. Modified Growing Degree Days are typically used to monitor the development of corn, the assumption being that development is limited once the temperature exceeds 86°F or falls below 50°F. For example, if the high for the day was 92°F and the low 68°F, the average for use in the modified GDD calculation would be 86 + 68 = 154 / 2 = 77.


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