Time for farmers to think about top-dressing
It is dry, but it is time for Oklahoma farmers to start thinking about top-dressing their wheat crops, according to David Marburger, Oklahoma State University Extension small grains specialist.
"Normally, the alarm for beginning wheat (nitrogen) top-dressing gets sounded right away in early January," Marburger said. "However, it might be understatement to say this year has been dry so far. A significant portion of the Oklahoma wheat crop belt has now gone plus 90 days with less than a quarter of an inch of rain.
"Because it has been dry and no significant rain is in the current forecast, the question is what do we do now about top-dressing? This is a tough question to answer as there is not a really good option at the moment. In the parts of the state where it is dry and dry deeper than the majority of the rooting zone, we should not worry about filling up the nitrogen tank as long as the water tank is empty.'
Marburger said nitrogen should get down in the rooting zone just prior to jointing. Several things, including the number of potential grain sites, are determined just prior to jointing, and it is imperative the plant has the fuel it needs to complete those tasks. Jointing occurs around the end of February in southern Oklahoma and around the second week in March in northern Oklahoma.
Jointing also marks the beginning of rapid nitrogen uptake by the plant, which is used to build new leaves and stems and the developing grain head, he said. The nitrogen stored in those plant arts will be used to fill the grain later in the season, and the plant is dependent on the stored nitrogen to complete grain fill, he said. And while it doesn't seem like it right now, farmers still have the potential to make a decent crop if there is rain before the wheat breaks winter dormancy.