By Victor Cabrera: Ag Sense
Dairy producers, farmers, consultants and government personnel now have access to some new computer applications that could help them in their daily work and assessments.
All the applications (Alfalfa Yield Predictor, Grazing-N, NM-Manure and DyNoFlo) at the New Mexico Dairy Extension Program are Excel spreadsheet files containing macros.
These applications are free and publicly available at dairy.nmsu.edu
Users need only to download an Excel file, input their information, and analyze their results displayed in the same spreadsheet.
Also, all the New Mexico Dairy Extension Program applications have documents that explain in detail the procedures and data used in their creation as well as a user guide with contact information for support.
I would like to focus this article on the Grazing-N application.
Grazing-N is an application that calculates nitrogen removal by intensively managed grazing dairy heifers and grazing dry cows according to user-defined parameters of:
weight of animals
daily weight gain
dry matter consumption
protein content of forage
dry matter yield of forage
estimated nitrogen volatilized in pasture after excretion
Grazing-N uses mass balances to estimate nitrogen inputs and outputs from the grazing systems. Grazing animals remove nitrogen from the soil through the forage they consume and return part of the nitrogen through their excretions to the field. Because part of the nitrogen consumed is used for live activities and a portion of the nitrogen excreted is volatilized before plants can use it, the net balance of plant nitrogen uptake from excretions and the consumed nitrogen is negative, indicating a need and an opportunity to apply extra nitrogen to grazed fields.
Users need to define, by animal category:
number of animals
time of the grazing activity
size of the grazing field
quantity of supplemented feed, if any
The application will calculate the status of the grazing operation regarding carrying capacity and the net balance of nitrogen.
The estimates of net balance of nitrogen guide users on the amount required of nitrogen replenishment to grazed fields either with chemical fertilizers or manure in order to maintain a healthy, sustainable production system.
Baseline numbers and functions used in the Grazing-N come from well-known sources including the National Research Council and the U.S. Department of Agriculture’s Waste Management Field Handbook.
Victor Cabrera is an extension dairy specialist at New Mexico State University’s Agricultural Science Center at Clovis. He can be contacted at 985-2292 Ext. 107, firstname.lastname@example.org