The continued dry weather has affected pasture quality and increased the calls from producers feeding livestock who are trying to determine whether it would be more profitable to feed their corn as silage rather than harvest stressed fields for grain. Drought stressed corn is more likely to have higher nitrate levels which can harm pregnant livestock and cause serious animal health issues. However, it can be a good forage option when handled carefully because stalks and leaves tend to have more carbohydrate and protein levels may also be greater than normal silage. Some things to consider when deciding how to handle a stressed corn field are listed below:
- Determine the grain yield potential of a field before making a decision to cut for silage. Grain yields should be better where corn pollinated okay but moisture is lacking to fill the ears out completely. In fields with a higher percentage of barren stalks or delayed ears that won’t develop, grain yield will suffer more. Use the formula provided in “Estimating Corn Yields in a Dry Year” posted on 7/3/12 to help determine grain potential.
- Obtain a Summary of Coverage from your crop insurance agent and determine if there are any regulations or restrictions involved in switching an insured field from grain to silage. Make sure the field is not tied to other fields under a blanket type policy and it is okay to handle it differently.
- P and K that would be recycled back into the soil will be taken off the field when stalks are cut for silage or baling.
- Ensiling drought stressed corn will actually reduce nitrate levels by up to 50% and is preferred over feeding it as green chop if the facilities are available to ferment silage.
- If green chop is to be used, test nitrate levels before feeding by submitting a sample to the Plant and Soil Lab in Nashville. Blending high nitrate green chop with other feedstuffs can reduce the liklihood of harming livestock.
- If the decision is made to chop for silage, make sure crop is at the proper moisture level— the right amount of moisture is critical for fermentation and good quality silage. If corn is burned up and already too dry, it may be best to leave it in the field. For bunkers, silage should contain between 30 to 35% dry matter (65 to 70% moisture). Upright silos and bags can be a little drier at 35 to 40% dry matter (60 to 65% moisture).
- Moisture content can be determined less accurately but quicker by gathering a small amount of chopped corn forage and squeezing it hard in your fist. If water drips out of the sample it is too wet to chop for silage. A more accurate estimate can be made by drying a known quantity in a microwave oven . http://www.agry.purdue.edu/ext/forages/publications/ID-172.htm
- Nitrate levels tend to be higher in the lower stalk portions so cut corn higher on the stalk to reduce the nitrate content in the chopped corn.
- Test for nitrates after the silage has fermented for 3-4 weeks and before feeding.
