Guard against excessive nitrates

Nitrate is the form of nitrogen that plant roots take up from the soil.
It is transported to the leaves, where it eventually is converted into protein.
When plants are stressed or injured, this process is interrupted and excess nitrates accumulate. Drought, hot dry winds, hail, or frost can result in high nitrate levels.
Even cool, cloudy weather can cause the problem.
Large applications of nitrogen fertilizer or manure increase soil nitrate, and thus the nitrate available to the plant.
Herbicides that disrupt or interfere with normal plant function also may result in nitrate accumulation.
Immature plants usually have higher nitrate levels.
In cereal forage crops, nitrate levels can start to decline from the milk stage onward.
However, never assume that a crop will be safe. Oats still can have relatively high nitrate levels even at the milk stage.
Always test to be sure.
Annual forage crops tend to accumulate greater amounts of nitrates than perennial forages. Oats and millet can be particularly troublesome.
Several weedy species also will accumulate nitrate if appropriate conditions exist.
Never assume a particular crop will be safe.
If there has been a stress and soil nitrate is expected to be high, have a nitrate test conducted by a lab.
Nitrates accumulate over time in an injured or damaged crop. Typically, the highest accumulations will occur two-three days after the injury or stress.
It is best to cut or harvest the crop within one day of the damage.
Nitrate levels gradually will decline 10-14 days after the injury as the plant resumes growth and repairs itself.
Plants killed by the injury or stress will not be able to decrease their nitrate levels.
Ensiling may reduce nitrate concentrations under some conditions. However, this cannot be relied upon to always ensure lower nitrate levels.
Crops ensiled with a high soluble sugar content (e.g., cereal grains) have a rapid fermentation process. But this does not promote degradation of nitrate during the ensiling.
Checking silage nitrate levels when the pit is being filled usually provides an accurate indication of what the nitrate level will be later on.
Curing and baling will not reduce nitrate levels. In fact, if round bale greenfeed is baled too moist (18-20 percent moisture) and heats, the problem can become worse.
The nitrate present in the feed may be converted to nitrites by the microbial action that causes heating.
Nitrites in a feed are 10 times more toxic than nitrates.
Nitrate levels may be reported in three different ways depending on the analytical procedure used.
The results may be reported as nitrate (N03), nitrate nitrogen (N03-N), or potassium nitrate (KN03).
Be sure you know which method was used before trying to interpret the results.

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