Corn crop could contain toxic nitrate

With crops drying up and leaving farmers without food for livestock, many farmers around the Heartland are trying to salvage corn stalks destroyed by the drought to use as feed. There is a big problem right now. Damaged corn could contain deadly levels of nitrate.

â??We have had a really hot dry summer in our area and there is lots of concern in the agriculture and livestock sector about drought stressed corn. We are certainly recommending because of the drought situation that producers think really hard about what they are going to do when it comes to utilizing their corn crop this year if they are going to use it for livestock feed. Basically this corn that we have been testing has been higher in nitrates this year then in years past because of the heat and drought,â?? said Livestock Specialist Bruce Lane.

Although the majority of the crops are a total loss, options for farmers havenâ??t dried out completely. Corn is now being salvaged and turned into livestock feed but damaged corn could contain high levels of toxic nitrates that farmers need to be aware of.

â??Basically this corn that we have been testing has been higher in nitrates this year than in years past because of the heat and drought,â?? Lane said.

Across Missouri, there has already been reports of livestock being killed by feed high in nitrate. Corn high in nitrate may look identical to corn lower in nitrate. That is why it is important to have the corn tested.

â??We can use a simple nitrate spot test. If a producer brought in some samples we can split the corn stalks and use our diphenylamine solution and put a few drops on there and determine if there are high nitrate levels. From there we can develop a strategy with producers on what they may want to do with it. Whether they want to green chop, bale, graze, or silage the corn,â?? Lane said.

If the testing solution stays clear on the stalk, nitrate levels are low. A dark color indicates high levels of nitrate which should then be sent off for further testing to determine the exact amount.

â??We can get a pretty good idea with the spot testing. But if it comes back positive, we recommend sending it down for further testing down in Columbia so that farmers can get an exact number on the nitrate levels,â?? Lane said.

Nitrogen is essential for forage and grain-crop production. Nitrates are in the plants all the time, creating normal growth. Nitrogen picked up by plant roots from the soil moves up into the plant. Eventually the plant stores that energy in the seed heads as protein.

Nitrates are converted into amino acids, which are building blocks for plant proteins. Protein is an essential part of animal diets.

Lack of moisture stops the flow of nitrates up the plant and the conversion to protein. The roots continue to bring nitrogen into the plant, where it accumulates first in the stalks. Too much unconverted nitrate is where it becomes toxic.

â??If you feed a load of high-nitrite corn to your cattle in the morning, by noon, you can be out of the cattle business,â?? said Forage Specialist Rob Kallenbach.

Nitrites tie up the oxygen-carrying capacity of blood hemoglobin. Without oxygen, the cow suffocates. Even low amounts of nitrites can cause pregnant cows to lose their calves.

If your corn is too high in nitrate for silage, there are still other options left. You can bale your hay and wrap it tight in plastic wrap. That plastic wrap acts as a barrier to oxygen can not get in and fermentation can start occurring.

â??During the fermentation process, those high nitrate feeds can be lowered in nitrates because during the ensilage process we will get some of the nitrates used up and lower the amount of toxic nitrates for livestock,â?? said Plant Science Specialist Rob Kalleach.

After four to six weeks of sitting the fermentation process can lower the nitrate levels as much as half making the corn safe for livestock.

Now when rain eventually returns to the Heartland, the water wonâ??t clear up problems overnight. it takes the plant at least five days to convert nitrate to safer levels and even longer if there are no ears of corn on the stalk.

All University of Missouri extension offices offer the free nitrate testing. For more information check out their website at

While it will take months to figure out the true costs of the intensifying drought, one thing is clear. There is going to be plenty of pain to go around.