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“Maintaining soil fertility levels is
paramount, however it does not guarantee high levels of future production."
Greg Schwab
UK College of Agriculture Extension Soil Management Specialist
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By Aimee D. Heald
LEXINGTON, Ky. (Sept. 5, 2003) – During the winter months, many Kentucky
cattle producers rely on corn silage to meet nutritional needs of their herds.
“Kentucky farmers raise nearly 100,000 acres of silage each year, with an
average yield of just under 20 tons per acre,” said Greg Schwab, Extension soil
management specialist at the University of Kentucky College of Agriculture.
“There is no other forage crop that can produce that much high quality feed per
acre.”
Although the early growing season was dominated by cool, wet weather, most areas
received timely rains which will result in higher-than-average corn silage
yields this year. Schwab said he’s already gotten reports of 30 tons per acre
being harvested in some parts of southern Kentucky.
Schwab said soil management is very important to insure future production,
especially after high-yielding years. Three practices will help farmers do this
– maintaining soil fertility, maintaining adequate soil cover and crop rotation.
“The first issue is soil fertility,” he said. “Do you know that 30 tons of
silage removes approximately 100 pounds of phosphate and 240 pounds of potash
from the soil per acre?”
Nutrient removal is much higher in silage production compared to grain
production because the entire plant is harvested. Schwab believes yearly soil
testing is vital to maintaining soil fertility in a silage production system. A
local county Extension office can help farmers understand how to take a soil
sample and then tell them where to send it and even discuss fertilizer
recommendations when the sample results are returned.
The high nutrient removal also makes silage fields ideal places to spread
manure. Schwab said manure will replace some of the nutrients that were removed
and also add organic matter to the soil.
“Maintaining soil fertility levels is paramount, however it does not guarantee
high levels of future production,” he said. “In addition to this, farmers must
maintain adequate soil cover.”
Since the entire plant is harvested, there is no residue left to protect the
soil surface from erosion during the winter months. By planting a cover crop
like wheat or rye in the fall, Schwab said those fields can be protected from
erosion.
“Cover crops also add organic matter to the soil which is important to maintain
soil structure, drainage and workability,” he continued. “Cover crops are well
worth the time required to establish them and can be used for early spring
grazing if weather permits.”
Thirdly, crop rotation can help insure future production. Because silage has a
very high nutrient removal and very low residue, high production cannot be
maintained by continuously producing silage on the same ground.
Schwab said crop rotation helps break weed, disease and insect cycles as well.
Good rotational crops are legumes like soybeans, clover or alfalfa because they
have the ability to fix atmospheric nitrogen which increases soil organic
matter, and they have a strong taproot that can alleviate soil compaction.
“By maintaining soil fertility, planting a cover crop and using crop rotations,
high levels of silage production can be achieved for many years to come,” he
said.
Writer: Aimee
D. Heald 859-257-4736, ext. 267
Contact:
Greg Schwab 859-257-9780
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