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MSU research examines the use of cover crops with maize – Picayune Item

STARKVILLE, Mississippi – Researchers at Mississippi State University looking to successfully use cover crops in corn production systems must develop strategies to overcome the challenges unique to this row crop.
Cover crops are plants grown outside of the normal growing season, primarily for conservation purposes. They often end before the cash crop is sown.
Erick Larson, a grain crop agronomist at Mississippi State University Extension Service, said few growers have adopted the use of cover crops in corn because they produce a nominal cash return and often reduce the profitability of the primary crop.
“Cover crops conserve and protect the soil and improve soil health by adding organic matter, which improves the physical attributes of the soil, the relationships between nutrients and water,” said Larson.
Most of Mississippi’s primary crops (corn, cotton, and soybeans) are planted in the spring, grown throughout the summer, and harvested in the fall.
“Cover crops normally grow well beyond typical planting times for field crops, so the usual practice is to kill cover crops before or at the time of planting to minimize their interference with field crops.” , did he declare.
Corn is the first crop planted in Mississippi each year, often as early as March, in what is typically a very rainy time of year. Vegetation produced by a cover crop can mechanically hinder planting and prevent sunlight from warming and drying the soil. It can also limit seed germination and the establishment of a good corn stand, reducing productivity.
“We are looking at different management options where we can realize the benefits of using cover crops while reducing the risk of yield losses and profitability,” said Larson.
“This research project is important because corn is vulnerable to potential complications from cover crops, as it is the first crop planted in the spring, benefits from early planting and is very sensitive to variability in plant growth.” , Larson said.
Crops such as cotton or soybeans have a better ability to compensate for irregular establishment. They are also normally planted later than corn when the soils tend to be warmer and drier.
“In our high rainfall climate, we already have limited planting opportunities for corn because we receive excess rain during the planting season,” Larson said. “We usually need a full week of sunny weather before it’s dry enough for tractors to plant or prepare the fields for planting. “
The challenge for corn is how to reap the benefits of cover crop soil without reducing harvest income.
Nolan Mullican, a graduate student at MSU in Stanley, Ky., Who studies agronomy, said corn is less tolerant than most other conventional row crops grown in this region.
“Corn is planted at lower populations and typically only produces one true ‘fruit’ or cob,” Mullican said. “This means that the loss of corn stands can be very detrimental to the yields produced. The presence of cover crops can mechanically interfere with maize planting and hinder the establishment and development of maize seedlings.
In 2020, Mullican began a master’s research program under Larson’s direction, with MSU Extension and Mississippi Agricultural and Forestry Experiment Station researchers Jason Krutz, Jason Bond, Justin McCoy, and Rocky Lemus.
The aim is to study how to successfully integrate cover crops into maize production systems in the Midsouth.
“The overall objective of this research is to minimize the interference of cover crops on corn establishment, growth and productivity,” said Mullican.
“Our results will identify the limitations associated with cover crops and lead to the development of practical systems that will maintain soil health benefits and improve yields.”
The first step is to assess the timing of herbicide applications to complete the cover crop. Researchers want to determine how long they can allow the cover crop to continue growing and provide soil benefits while terminating them before it interferes with planting or emergence of corn.
“We are looking at treatments at the time of the end of cover crops ranging from 0 to 6 weeks before planting,” Larson said.
“This means we plant some treatments in green, living cover crops, versus other treatments that allow the cover crop to die before planting. “
Mullican said that, based on early results, the timing of the end of cover crops has a dramatic effect on the vigor, health and results of corn planted afterwards.
The next phase of the study examines the methods of planting and tillage of cover crops, which affect plant distribution and potential interference with corn.
Maize in the southeast is grown on raised beds to improve drainage in a high rainfall environment.
“We manipulate the seed distribution of cover crops or use strip tillage to try to limit the growth and potential interference of cover crops growing in the seedling area for the corn crop,” Larson said. . “We are evaluating methods to encourage the growth of cover crops between the rows to provide benefits while limiting potential interference above the row where the corn is planted. “
The third part of the study examines various plant species cultivated for cover. Typically, a cover crop includes a mixture of winter grains, legumes, and crucifers.
Cereal species develop extensive fibrous root systems that mitigate soil erosion and nutrient runoff. Their significant fall growth helps stabilize the soil and produce biomass and organic matter.
Legumes are broadleaf plants capable of capturing nitrogen from the atmosphere and storing it in the soil for plant use.
Mullican said early results show substantial differences in the suitability of different species of cover crops for maize production systems. These differences include growth habit, ease of establishment, and adaptability to a southern climate.
The Mississippi Corn Promotion Board and a Natural Resources Conservation Service Conservation Innovation Grant are supporting this research. The results will be published through the MSU Extension Service.