It all started with this glorious yet ominous sunrise over the first heavy frost of the year. But the chill of the glittering, icy landscape (and the weather forecast, for that matter) gave no hint of what was to come – three days of rain that have limited us to just two paddocks for the milking herd until the third flood in 30 days releases its grip on the farm.
Normally, a minor flood like this one wouldn’t cause us any angst. We’d still have two-thirds of the farm, after all. The river flats are cut off but we also have undulating paddocks that never see a flood.
Unfortunately, we are halfway through calving and need to have six different groups of cattle in different paddocks: calves, large and small yearlings, dry cows, springing (soon to calve) cows and milkers. We also have nine “high ground” paddocks out of action due to renovation.
On top of this, we have been making up for punishing the high ground during the last two floods with remedial doses of fertiliser, including urea.
Urea is 45 per cent nitrogen, an element that is every bit as essential for plant growth as sunshine and rain. It’s even fed to animals sometimes to boost the protein level of their feed but too much of a good thing can be lethal. Nitrate poisoning brings a sudden, horrific death.
According to University of Melbourne guru Richard Eckard:
“The timing of grazing, relative to nitrogen fertiliser application, may adversely affect cows. Figure 1 shows the pattern of nitrogen uptake, as nitrate-nitrogen or crude protein in the plant, after grazing and subsequent application of nitrogen fertiliser. The following observations, from Figure 5.1, are important:
- depending on condition, it usually takes around 4 to 5 days for the applied nitrogen fertiliser to dissolve into the root zone and to be taken up by the plant;
- nitrate levels in the plant peak around 7 to 14 days post nitrogen application;
- protein levels in the plant peak slightly later, usually around 16 to 18 days;
- usually nitrate levels in the pasture drop off to acceptable levels by 18 to 21 days post nitrogen application.”
In other words, don’t let the cows into the paddock for 18 days after you spread urea. It’s 10 days right now.
Oh bother, oh dear, holy cow. I want to go home! (Hang on, this is home. Damn.)