NDSU Extension - Ramsey County


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October 1, 2012 Agriculture Column


What a fall we have had, the weather has permitted a great harvest run to include the combining of corn in Sept (????) and has also created very dry conditions across the region.  I have been helping my son doing some disking and I saw low areas that I have never seen empty and dry, in my years of life.  I saw my folks on Sunday night and told dad that same story and he said he had only seen one slough dry all of the years he farmed near Edmore and they were able to plant a garden, only because he was not able to plant a crop in the normal growing season.  As I go up and down the field I also can not think of all the CRP that will get burn’t this week and as dry as it is makes me very nervous.  I hope some good decision making thoughts are in place to keep the fires within the confines of the area they are burning.  Lastly today I have included a section about fall applied nutrients published by Dave Franzen (Extension Soil Specialist).  This is not a full script but pieces that do fit our area.

Nearly all soils are suitable for fall application of P and K. For small grains, canola, corn, potato, sugarbeets, starter P with or near the seed is very important, so delaying some P application until spring planting is advisable. For annual legumes and sunflower, where starter is not particularly helpful, any broadcast application any time is just as effective. In general, loam soils and soils with more clay are suitable for fall application of N. Soils to avoid in fall N application are soils that flood or sandy loam/loamy sand/sand coarse textured soils with high leaching potential. Fall applied N should include a nitrification inhibitor, such as nitrapyrin (N-Serve/Instinct), or a product containing the appropriate rate of DCD. The guidelines for the most successful fall N application are:

  • Use anhydrous ammonia or urea
  • Do not apply any fall N before October 1
  • Do not apply fall N after October 1 unless the soil temperature at 4 inch depth falls to 50 degrees
  • Once the date is after October 1 and soil temps fall to 50 degrees, it is practical to apply anhydrous ammonia in North Dakota
  • For banded urea, wait one more week after the practical date for anhydrous ammonia
  • For broadcast urea, wait two weeks after the practical date for anhydrous ammonia

    Monitor nitrates in cattle rations during drought conditiosn

    The incidence of prussic acid, nitrate, mycotoxin and other problems may be increased when crops are grown or harvested under extreme weather conditions. These may be kept to a minimum if good judgment is used. Several general procedures may be used to minimize risk:

  • Introduce suspected forages or feeds gradually over a period of one to two weeks.
  • Don't feed suspected items to hungry animals. Make certain that other forages and concentrates are fed prior to the suspected material.
  • Test suspected items for nitrate or myco-toxins, if appropriate. Often materials may be used as part of the ration, depending on levels found.
  • Feed a well-balanced ration with proper nutrient content, proportion of forage dry matter and particle size.
  • Discontinue or severely restrict intake of suspected materials when possibly related problems are encountered.
  • Some of the more common problems:

    Nitrate Poisoning. Recent research indicates that many problems previously ascribed to nitrates may have resulted from other factors. Extremely dry or cool, wet growing conditions may prevent plants from converting nitrate to true protein, so nitrate may accumulate in stressed forages, particularly whole-plant corn silage, sorghum, sundangrass and sorghum-sudan crosses. Heavy or excessive nitrogen fertilization may aggravate the problem, especially if phosphorus and potassium needs are not met. Some weeds, including pigweed and lambsquarter, may accumulate nitrate.

    Nitrate levels generally decrease somewhat during ensiling, as dangerous nitrogen oxide gas is formed. However, nitrate levels may increase in hay if it undergoes heating and molding in the bale. Under normal conditions hays and haylages may contain higher levels of nitrate than corn silage.

    Risk of nitrate poisoning may be reduced by the following:

  • Do not harvest suspected crops for three to five days after an appreciable rain or long cloudy spell.
  • Harvest as close to usual maturities as possible.
  • Cut the crop somewhat higher above the ground than usual as nitrate often accumulates in stems.
  • Gradually introduce suspected forage into the ration over a period of one to two weeks and don't feed it to hungry animals.
  • Utilize suspected material for silage rather than green-crop.
  • Test all forages and water in the ration for nitrates if one forage contains over 1.0 percent nitrate on a dry matter basis.
  • Feed at least 3-5 pounds of concentrate per head per day when suspected forages are fed.
  • Nitrate toxicity may result when animals suddenly consume large amounts of forage con-taining 2-3 percent or more nitrate ion on a dry matter basis. Even forage with lower levels may adversely affect reproduction or become toxic if animals are nutritionally stressed or metabolically abnormal and suddenly eat a large amount of such forage. Cattle may develop blue mucous membranes from lack of oxygen in the blood. Rumen paralysis may occur. Labored or difficult breathing may be observed. Animals may go down and die rather suddenly.

    Subacute or chronic nitrate poisoning may result in more of the usual reproductive problems, including abortions. Milk production and appetite generally are not affected by subacute nitrate intake. Reproductive problems generally may be prevented if feeds are gradually introduced and the nitrate level in the total ration dry matter is kept below 0.40 percent. Because of differences in rate of dry matter intake, grazed forage is about 50 percent less toxic than stored forages.

    Recommended uses for forages containing various levels of nitrate are found in Table 1. A high level of nitrate or nitrite in the water may make it necessary to further reduce intakes of nitrate-containing forage. A total intake of 30-45 grams of nitrate ion per 100 pounds of bodyweight is considered acutely toxic in normal animals. Intakes of 8-22 grams per 100 lbs may be toxic when animals are in abnormal condition or are undergoing an abrupt change in ration.


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