First of August, and we’re hauling water in pastures, feeding hay, chopping up would be corn fields to salvage some feed.  It’s not what you’d want to be doing!

We get a lot of questions how to value standing forage for silage or haying.  It comes down to a negotiation between two people.  There are rules of thumbs, some may apply some others won’t.  Usually you consider that the corn silage would have some grain in it.  This year some doesn’t    However, the rule of thumb is:  6 times the price of a bushel of corn.  So if corn is trading at $3.00 a bushel, then a ton of silage would be $18.  It may yield 10 to 15 tons per acre, that would mean $180 to $270 an acre.  It’s all really a negotiation.

We’ve done some nitrate testing on corn silage and forage sorghum.  It is coming in all over the board, some very safe, to some very toxic.  If you are considering feeding green chopped forage, test it beforehand. 

In particular, growers should be very cautious about salvaging corn as ‘green chop,’ or silage feed immediately after it is cut. Ensiling corn that is suspected of having high nitrate levels is preferred to green chopping because the fermentation process will decrease nitrate levels by about 50 percent.

When in doubt, have the forage analyzed before feeding.  Even forage with levels in excess of nitrate-N can be fed if diluted with other feedstuffs, but it is important to know what you have before you feed it.

Laboratory analysis can be performed on suspected plants, but samples need to be representative of the field or bales in question. Samples should be packaged in a clean plastic bag and shipped to a laboratory for analysis.

Our KSU Soils lab, tests for nitrates in feeds, at a very minimal cost.

Ways to reduce nitrates in corn silage include:

• Do not feed the silage until the fermentation process is complete. Fermentation will reduce nitrate levels by 30 to 50 percent.

• Avoid situations in which manure and/or fertilizer results in very high rates of nitrogen applied on a droughty soil.

• Minimize plant stresses due to nutrient deficiencies.

• Harvest on bright, sunny days.

• Do not harvest for at least three days following a soaking rain that comes after a period of dry weather.

• Raise the cutter to leave at least 6 inches of stubble.

• Dilute high-nitrate corn silage with feed grains or hay.

It is difficult to predict where nitrates may be a problem, but the potential certainly exists. Now is the time to be aware of that risk and manage accordingly.