Cover crops do far
more than cover soils. They provide an array of benefits,
such as the ability to reduce soil erosion and increase soil health. They can
help attract pollinators, repel pests, turn into ‘green manure,’ or can be used
as feed for livestock.
A new study shows that
the benefits of cover crops extend even into semi-arid areas. This review
was recently published in
the Soil Science Society of America Journal, a publication of Soil Science
Society of America.
“Much of the research
data we have on cover crops is from regions with high precipitation,” says
Humberto Blanco, lead researcher at the University of Nebraska – Lincoln. “So,
questions remain about ecosystem services provided
by cover crops in drier regions.”
Some skeptics have
argued that growing cover crops in more arid areas could use too much water. In
turn, it could reduce subsequent food crop yields. But the research concludes
that isn’t necessarily the case.
“We found that cover
crops can improve most ecosystem services in water-limited environments,” says
Blanco. “In the majority of cases, these improvements come without negative
effects on food crop yields.”
To determine how well
cover crops work in semi-arid areas, Blanco and colleagues assembled and
analyzed the limited number of studies on cover crops in dry regions. They
emphasized studies focusing on the semi-arid Great Plains in the United States.
The researchers looked at cover crops in connection with several ecosystem services. These included the amount of organic carbon in soils, soil microbial properties, weed management, and food crop yields, among others.
One of the key soil
features the researchers focused on was soil organic carbon.
“Soil organic carbon
is the catalyst for many other changes in soil properties and soil services,”
says Blanco. “Soils in water-limited regions are often low in organic carbon.”
The researchers found
that in dry areas cover crops increased soil organic carbon levels close to 60%
of the time.
“This accumulation of
organic carbon is critical to these soils,” says Blanco. That’s because soil
organic carbon is the food source for many soil organisms, like microbes.
Ultimately, these soil organisms play a vital role in maintaining healthy,
fertile soils.
Cover crops also suppress weeds in
dry areas. This is especially important because several weed species are
resistant to current herbicides. The suppression of weeds by cover crops has a
knock-on effect on increasing water conservation and preventing soil erosion.
“Herbicide-resistant
weeds can lead to tillage of typically no-till systems,” says Blanco. “This can
reduce the water-conservation ability of those agroecosystems.” Tilling can
also make soils more susceptible to erosion. Find more.
|Source: Onlinr/KSU
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