Farm Progress

Can no-till farming prevent weeds?

A 49-year-old field plot offers look at long-term weed growth.

November 30, 2018

3 Min Read
SEARCHING THE SOIL: Southern Illinois University Carbondale senior Sarah Dintelmann is attempting to grow weeds in a greenhouse. She is seeing if weed seed is suppressed by tillage, depth and time. Photo credit Southern Illinois University Carbondale.Southern Illinois University Carbondale

Weeds are a continual challenge for farmers. They compete with crops for valuable nutrients, space, sunlight and water, and often result in smaller crop yields.

Multiple weed control techniques are used to manage this problem, but teams of researchers at Southern Illinois University Carbondale are looking at a unique way to address the complex struggle. And it all starts with a weed seedbank of 49 years.

Using no-till practices to reduce weeds
A plot at the SIU Belleville Research Center reflects how no-till practices affects weed persistence in the seedbank for close to 50 years.

Sarah Dintelmann, a senior with a double major in crop, soil and environmental management and agribusiness economics, joined the study last year and gathered soil samples from the plot. Working under Karla Gage, assistant professor in the departments of plant, soil and agricultural systems and plant biology, Dintelmann transferred the test soil back to SIU’s Carbondale campus, where half was sent for detailed testing and the rest was kept in a greenhouse.

This fall, Dintelmann has kept a careful watch on the greenhouse soil to monitor the weed growth and report on the various species that survive in the soil.

Evaluating soil depth, long-term impact
SIU research began in the late 1960’s and extended throughout the career of weed scientist George Kapusta before his retirement in 1998. During his time, Kapusta was looking at the long-term interactions of tillage and fertilizer treatments on production. However, weeds in the system were never the focus. They are now.

When gathering soil samples, the team distinguished between the various depths of the soil to determine if tillage actually placed weeds in the right soil depth to allow access to necessary nutrients and sunlight to encourage unwanted growth. The samples were taken at multiple inch variables, 2-, 4-, 6- and 8-inch depths, to evaluate the growth.

The team wants to learn more about the weed distribution in the soil to improve the understanding of tillage as a management practice.

"We wanted to see if tillage actually threw seeds down into the 6 to 8-inch depths," Dintelmann says.

If weed seeds are deposited deep in the soil by tillage, they may remain dormant for long periods, even decades, before eventually losing the ability to germinate and grow. That is why the team is analyzing the effects of this long-term, no-till practice that may have prevented weeds from becoming part of the soil seedbank.

"The best way to keep weeds out of your seedbank is to prevent them from getting there originally," Dintelmann says.

Study to be completed next year
While the soil comes from a long-managed plot, the actual study of the treatment effects on the weeds began more recently. The team examined the in-field growth and development of weeds last year, and then ran the study again this year to replicate their findings.

Researchers will compare the results from the soil seedbank study with the in-field weed emergence data from the experimental plots, to see how accurately the seedbank represents the weeds emerging in the field and vice-versa.

A Belleville, Ill., native, Dintelmann sees the research as another important factor for farmers and those in the agriculture industry to consider when it comes to weed control topics.

"There are some other research stations that have almost 50 years of no-till trials going on, but this is the first time anyone has really looked at the weed seedbank composition over that time," Dintelmann says.

Source: Southern Illinois University Carbondale

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