AMARILLO -- Area corn producers are starting to look for ways to salvage what's left of their corn in the aftermath of the current drought. To help farmers consider their options, specialists with the Texas Agricultural Extension Service are offering timely information on drought-stressed grain crops and nitrate management.
"In times like these, there are no easy answers," said Dr. Brent Bean, Extension agronomist in Amarillo. According to Bean, some farmers with irrigated operations are beginning to abandon some of their corn acres in order to concentrate their available water on less acres.
"The portion of the crop that is deprived of water will wither under the heat and produce very little grain," Bean said.
"One of the options some farmers are thinking about is feeding the abandoned corn to livestock; however, they need to approach this alternative with care and planning," said Dr. F. T. "Ted" McCollum, Extension beef cattle specialist of Amarillo.
McCollum is cautioning producers about the high concentration of nitrates in corn at this stage in the plant's growth. Corn doesn't even have to be drought-stressed to be high in nitrates when it is at the tasseling and silking stage of development.
An Extension Service publication (L-5146), available to producers through their local county agents offers information on preventing nitrate problems in drought-damaged corn.
The specialist said nitrate and aflatoxin poisoning are two problems encountered with attempts to use drought-damaged corn. Under drought conditions,the uptake of nitrates may exceed the rate the plant can convert the protein. The demand for nitrates increases as grain fill begins.
Plants that often accumulate nitrates under drought conditions include field crops, weeds, and vegetables, especially corn, forage sorghums, and grain sorghums, according to Bean.
Bean said producers will want to test plants to determine if nitrate is at a level that may pose a risk to livestock.
"It's called the diphenylamine drop test. The test kit is now available through local countyExtension offices in the Panhandle," said Bean. This is used only for an initial screening and only shows if high concentration is present, not the level of nitrates. More indepth analyses areperformed by trained toxicologists in facilities such as the Texas Veterinary Medical Diagnostic Laboratory.
McCollum said producers should start considering a plan to either harvest the corn as greenchop or silage as soon as possible. If the corn is to be grazed, there will be fewer problems with nitrates because the leaf material has a lower concentration.
"Do not let the cattle graze down to the stalks since nitrates are higher in the lower portion of the stalk," he advised.
Greenchop and silage may be safe because the entire plant will be harvested and the nitrate in the stalk will be diluted out by the leaf material. Some nitrate problems can be reduced by raising the cutter bar and leave more residue in the field.
The nutritional value of immature corn forage will contain a little less than 10 percent protein and from 58 to 64 percent TDN. This compares well with forage sorghum hay, said McCollum.
Both specialists agree that it may be possible to hay the corn vbut there will probably be some difficulty drying the forage enough to bale and avoid spoilage.
"Green chop is another alternative, and a good option if the producer has equipment available day in and day out to chop feed, but not so good if the forage cannot be harvested on a daily basis," McCollum said.
"Given the nutritive value, green chop would be a good feed for dry cows and growing cattle that are not expected to gain rapidly," he added. A small quantity of protein supplement may be required for lactating cows, young calves, and other growing cattle where rapid gain is expected.
Silage can be another alternative for putting up the forage rapidly, storing it for future use, and reducing nitrate problems.
"There are two main concerns with this option," said Bean. In failed corn, there is a lack of grain (carbohydrates) necessary for adequate fermentation to make good silage. The second concern is moisture content of the forage.
Ensiling will reduce the nitrate levels by about 50 percent. So a relatively toxic forage can become useful after this process.
"If this option is chosen, then a farmer might consider adding some cracked corn to the forage as it is ensiled. This will provide carbohydrates for the fermentation process," said Bean.
In a mature corn plant, about 45 percent of the dry matter is grain, so adding about 30 percent corn on a dry basis to silage would produce a good product.
"Anything less than 30 percent dry matter can lead to poor fermentation and bleeding of the silage. It may be necessary to wilt the corn forage prior to ensiling to bring the moisture content down to 65 or 70 percent," said Bean.
"Right now, most corn in the Panhandle has reached the tasseling growth stage," Bean said. The forage yield will probably be about 30 to 35 percent of the expected yield for full-season silage.
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