Using drought stressed field crops as emergency forages
August 11, 2017
The area affected by drought conditions continues to expand with parts of the Dakotas now into the D4 (extreme drought) category on the latest Drought Monitor. With this in mind, I know many of you are considering how to salvage some of the drought stressed field crops, which may be available in your local areas. In my column this week, I will give you a few tips and pointers on making the most out of drought stressed field crops.
Drought stressed small grains can be harvested as hays, silages, or grazed. Crops in this category include wheat, barley, and oats. Nitrate accumulation in small grains is a major issue with each of these crops. Be sure to collect a representative sample and test it for nitrate before grazing or feeding these forages. Obviously, drought conditions negatively affect yield. In many cases, it may be economically advantageous to graze these forages rather than harvesting as a hay or silage. Nitrate accumulation will affect this decision.
Drought stressed corn can be harvested as silage. The NDSU Extension Service has an excellent bulletin to help you calculate the cost and value of drought stressed standing corn. You can access the bulletin at http://www.ag.ndsu.edu/drought/ . Click on 'Forages and Grazing' on the left-hand side of the web page.
Depending on the severity of drought, the corn may not form ears. In this case, grain production will be zero. In well-eared corn silage, the grain makes up about 50 percent of the weight of the silage on a dry matter basis. The lack of grain will affect the yield and reduce the energy content. The protein content, however, may actually be greater than corn silage put up under normal growing conditions, especially if the silage is chopped before the plant has matured. Nitrate accumulation is also an issue with corn raised under drought conditions. Be sure you have it tested before grazing or feeding.
Baling corn is difficult, as the plants do not feed easily into most round balers. Corn may not dry down to a moisture content suitable for storing the material as hay, which makes the bales susceptible to mold, spoilage, and in some cases, spontaneous combustion.
Drought stressed soybeans can be harvested as either silage or hay. The quality of soybean hay is quite good, particularly if it is put up with a minimal amount of leaf loss. Typical crude protein content of this hay ranges from 16 percent to 21 percent and it has about 75 percent to 80 percent the energy content of corn silage when compared on a dry matter basis.
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To harvest soybeans as silage, be sure to test the moisture content and aim for about 65 percent moisture in the silage. As the soybean plant matures and leaf drop starts to occur, forage quality will decline.
Drought stressed sunflowers can be salvaged as silage. Any other means of harvest of this crop is not practical. Even in a drought, sunflower plants do not dry down well enough to make hay out of the crop. To make good quality silage with sunflowers, you need to add a drier feed to the silage pile. If you don't, the effluent losses from seepage of excess moisture will be significant and costly.
Sunflower silage has higher levels of crude protein, but lower levels of energy than corn silage. It can be used as a portion of the diet for beef cows and backgrounding calves.
Historical extension bulletins and field day reports have documented cases where producers have successfully blended corn and sunflowers together in a silage pile. One load of sunflower silage added to 3 to 4 loads of corn silage is a ratio that worked well in these situations. Ideally, you should check the moisture content of both the corn and sunflower crops, and calculate the ratio needed to achieve a 35 percent dry matter (65 percent moisture) blend in the final silage pile.
Adding other dry feeds to sunflower silage can also be an effective means to achieve a 35 percent dry matter final silage blend. Depending on feed availability and nutrient needs of the livestock you intend to feed, consider blending straw, grass hay, grain screenings, or cereal grains with chopped sunflowers to achieve the proper moisture level. As a starting point, 5.5 tons of sunflowers at 25 percent dry matter and one ton of grass hay at 90 percent dry matter would result in a silage dry matter of 35 percent, reducing effluent losses to a manageable point.
Grazing is an option for salvaging all of these crops. Grazing may be a very effective means of capturing some value from a failed crop, but you will have to consider the availability of proper fencing as well as water supply for your livestock in the fields you intend to graze. If you are considering renting fields from someone else, be sure you estimate the amount of standing forage available, and factor in trampling, waste, and grazing selectivity (the cattle are not going to eat everything in the field) into the amount you pay for rent.
Crop Insurance. Be sure you understand the rules associated with your crop insurance policy before grazing or harvesting drought stressed field crops. Policies may have restrictions on how and when the crop may be salvaged that will need to be addressed prior to grazing or harvesting.
Nitrates will be an issue with drought stressed crops, especially small grains, corn, and sunflowers. The ensiling process can reduce the nitrate content by approximately 30 percent through fermentation. Testing these feeds before you use them will help minimize potential nitrate problems and give you an indication of whether not the forage will need to be blended with other low nitrate feeds to achieve a safe nitrate level for feeding.
Information on these and many other drought related topics can be found on the NDSU drought Web page at http://www.ag.ndsu.edu/drought/ . Table 1 details average composition of some of the forages I have discussed in this article. It is important to get silage tested prior to feeding to ensure that you formulate a balanced ration, and provide the proper nutrition for your livestock.