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Soil Health, A Montana Perspective - Tools for Soil Health, Cover Crop (SWF; 5 minutes, 4 seconds; 109 MB)
This segment in the Soil Health, A Montana Perspective video series discusses one of the tools that agricultural producers can use to improve soil health. This tool is cover crop. Other videos in the series feature additional conservation practices used as tools for soil health and interviews with Montana farmers and ranchers.
This video is also available on DVD. To request a copy, e-mail MT-nrcs-publications@one.usda.gov. Please include the title of the DVD, your name and mailing address.
Transcript of Tools for Soil Health, Cover Crop from the Soil Health, A Montana Perspective video series
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United States Department of Agriculture
Natural Resources Conservation Service
Soil Health, A Montana Perspective
Tools for Soil Health: Cover Crop
NARRATOR:
This segment in the Soil Health, A Montana Perspective video series will discuss one of the tools that agricultural producers can use to improve soil health. This tool is cover crop.
Cover crops have traditionally been used to reduce erosion or add nitrogen to soil. But they do even more.
The relatively new concept of growing “cocktail mixes” to increase diversity and improve soil quality can make cover crops a useful tool for soil health, as well. A cocktail mix of cover crops applies the idea that multiple species and multiple types of cover crops are better than a single species, or even a mix of two species. These cocktail mixes generally include five or more cover crop species from different functional groups. The four functional groups include cool season grasses, cool season broadleaves, warm season grasses, and warm season broadleaves.
KALYN BOHLE, PLEVNA, MONTANA:
“We've got 9 different species in there. Millet, Sudan grass, corn, sunflowers, lentils, ah, crimson clover, radishes, turnips.”
NARRATOR:
So what is the best “cocktail mix” for improving soil quality? Well, that depends on where you farm and what specific goals you have for your operation. Some examples include, cover crops planted to break up soil compaction layers, cover crops planted to provide nitrogen to the next crop, cover crops planted to scavenge excess nitrogen that is too deep in the soil for the normal crop to reach, or cover crops to break up disease and pest cycles.
DIRK O’CONNOR, PLEVNA, MONTANA:
“With the cover crops we've been growing lately, most of them have been trying to put residue back on the soil.”
MARCUS VOGEL, BALLANTINE, MONTANA:
“Oh, I felt that they could help us build up our organic matter and ah, give us some grazing options.”
JULIE TAYLOR, FAIRFIELD, MONTANA:
“Even if that’s all your cover crop did was stand up in the air and catch snow through the winter, it would pay for itself.”
NARRATOR:
In Montana’s semi-arid climate, soil moisture is always in the forefront of our minds. Summer fallow is an inefficient method to store soil moisture; it does not improve soil quality; and it can cause saline seeps. Growing cover crops keeps soil microbes active and can help improve soil organic matter. They provide cover for erosion control, and they help to control weeds. Cover crops do need to be managed so that they don’t become weeds in the rotation, but this can be addressed through good planning.
So, how do cover crops conserve moisture if they are using moisture to grow?
ERIK SUFFRIDGE, NRCS:
In fallow, soil moisture loss occurs primarily through evaporation. Evaporation is due to sunlight hitting the soil, wind, and high surface temperatures.
NARRATOR:
As temperatures increase or are maintained in the top of the soil, moisture continues to be lost through evaporation, so moisture continues to be drawn up from deeper layers of the soil. This cycle will continue until temperatures cool off in the fall, or when the soil moisture has reached a point where it can no longer be drawn up and lost.
Cover crops, however, provide shade to the upper levels of the soil so that the temperatures are much cooler - sometimes 50 degrees Fahrenheit cooler than they would be if left uncovered. Cover crops also protect the topsoil from wind. These effects are significant. This shading and wind protection effect slows the amount of moisture that is lost through evaporation.
It is important to recognize that moisture is lost through plant use, called transpiration, as the cover crops grow. Because of this we must seek out a middle ground to strive for. The key in limited moisture conditions, as found in most of Montana’s dry land crop production, is to find the balance between maximizing cover crop growth for shade and root production while minimizing the loss of soil moisture through cover crop growth and transpiration. One way to accomplish this balance is by timing the killing of the cover crop late enough in the growing season that shade is provided throughout the growing season, but early enough to leave some moisture in the soil.
Another common question from producers is, “Where should I put a cover crop into the rotation?”
ERIK SUFFRIDGE, NRCS:
Cover crops can be used in a rotation in place of fallow if you take soil moisture into consideration. And the important aspect of that is the timing of the termination of the cover crop.
NARRATOR:
In other systems, such as annual cropping systems, cover crops can often be substituted for a cash crop in cases where the benefits of the cover crop outweigh the use of the cash crop. They can also be implemented after harvesting an earlier season crop such as irrigated barley.
For more information about soil health and cover crops visit your local USDA Service Center or go to www.nrcs.usda.gov.
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