SWROC Research: Finding Solutions to Agriculture's Threats

As part of CFANS, we take on the problems that threaten prosperity and ask how we can find solutions. Research at SWROC focuses on southwest Minnesota’s current and emerging production constraints, and we challenge ourselves to provide insight and discover practical solutions that improve agriculture both locally and globally.

With that goal in mind, our faculty led a variety of research projects throughout the 2016 growing season. Our studies are tackling a wide range of problems and questions relating to integrated pest and weed management, soil fertility, water quality, and organic and alternative agriculture. The following is a brief overview of four of these projects and the questions they’re answering.

Could supplemental irrigation be a viable risk management and production tool in humid regions?

Our climate is changing. Average temperatures are rising, average precipitation is increasing in humid regions, and extreme weather events are increasingly common. Severe thunderstorms deliver substantial portions of seasonal precipitation at one time, creating water distribution issues for growers. These current and anticipated climate changes present new challenges to established water and nutrient management practices in the region, so soil scientist Dr. Jeff Strock initiated a four-year study examining whether irrigation could benefit area growers.


Irrigation equipment in corn and soybean plots at SWROC.

Irrigation, while a necessary component of agricultural production in many parts of the country, is uncommon in southwest Minnesota. Historically, the Corn Belt’s humid regions provide excellent natural growing conditions for the corn-soybean rotation. Despite this, previous studies have shown that even with adequate precipitation, supplemental irrigation can mitigate the risks of production by lowering yield fluctuations caused by water distribution issues. Irrigation represents another tool, in addition to crop insurance, to manage the risks that accompany irregular rainfall, flooding, and drought.

The study examines interactions between nitrogen applications and four water management treatments for corn and soybean plots, including rain fed, limited irrigation, full irrigation, and excess irrigation. The agronomic, environmental, and economic aspects will all be examined to determine if supplemental irrigation is practical for the corn-soybean rotation in our region.

Strock hypothesizes that supplemental water and nitrogen applications will increase crop yield, lower environment impact and are economically viable. The study just began in 2016, so it’s too early to make any preliminary conclusions. But, if his hypothesis is correct and water distribution anomalies prevail in the future, irrigation may become a practical tool for corn and soybean producers throughout southwest Minnesota. 

What are the effects of integrating new cover crops into the traditional corn-soybean rotation?

The use of cover crops in the corn-soybean rotation is on the rise throughout Minnesota. Despite the establishment challenges presented by our short growing season, cover crops can provide both environmental and economical benefits to producers through reduced erosion, improved water quality and nutrient management, and enhanced soil fertility.


Axel Garcia, Mark Coulter & Jeff Irlbeck discuss planting soybean into no-til corn as part of the cover crop study.

Cropping systems scientist Dr. Axel Garcia y Garcia is leading multiple research projects focused on integrating cover crops into the corn-soybean cropping system. A three-year project, initiated in 2015 and sponsored by the Minnesota Soybean Research & Promotion Council, is investigating the water and nitrogen use of corn-soybean cropping systems and how cover crops of winter rye, field pennycress, and winter camelina impact the cropping systems.

Preliminary results show potential in which cover crops are most efficient. Thus far, the study found that winter rye uses more water than winter camelina, which in turn uses more water than field pennycress. More than 75% of the water used is used during the spring. The capacity of the cover crops to reduce N leaching is also being studied; preliminary results show winter rye and winter camelina have potential to reduce leaching.

As research continues and cover crop use increases, Garcia’s data will help growers make decisions about what cover crops will help them reach production and conservation goals in the most efficient and environmental manner.

Can the timing of nitrogen applications make them more efficient?

Nitrogen is the nutrient most often deficient for crop production in Minnesota, so nitrogen applications are common and typically result in substantial economic return for growers. However, if N inputs exceed crop needs, excessive amounts of nitrate may end up in water sources and growers waste money and resources on inputs that are not fully utilized by the crop.


Lee Klossner and Paulo Pagliari and two student plot technicians side-dress corn with nitrogen fertilizer.

Soil scientist Dr. Paulo Pagliari studies the role fertilizer and soil microbes play on nutrient availability. His goal is to develop improved nutrient management strategies to help growers maximize the efficiency of their nutrient applications. One of his current studies investigates how the addition of nitrogen fertilizer, applied multiple times throughout the growing season, impacts soil microbial activity, nutrient availability, and the resulting corn grain yield and plant development.

With the data thus far, Pagliari has identified specific physiological stages when corn plants need the most nitrogen fertilizer. The results have also shown that by changing how nitrogen is managed the nitrogen use efficiency of the corn crop can be improved by more than 20%. Ultimately, this research will help growers be even more precise with their N applications to improve efficiency and positively impact yields as well as the bottom line.

Do volunteer soybeans in corn impact yields and soybean pest populations?

Many growers understand that volunteer corn plants within soybean fields should be controlled to protect soybean yields from competition by corn and to prevent future yield loss from corn pests. For the past three years, a project led by IPM Specialist Bruce Potter studied the contrasting relationship – the influence of volunteer soybeans on corn yields and soybean pests.

Minnesota’s early onset, cold winters make it, and a few neighboring states, unique with respect to soybeans lost to shatter or combine losses. In many soybean-growing areas of the U.S., a long, warm fall and early winter provides an environment conducive to soybean germination in the fall and death during winter. However, soybean seeds lying on the ground in Minnesota typically do not accumulate sufficient moisture or degree-days to germinate before winter sets in, so some survive to germinate the following spring.


Volunteer soybean in a Nicollet County cornfield.

With funding from the Minnesota Soybean Research & Promotion Council, Potter’s research studied if volunteer soybeans are competitive enough to reduce corn yields, how volunteer soybeans affect soybean pests like soybean aphid (SBA) and soybean cyst nematode (SCN), and if certain weed control programs are more effective at reducing volunteer soybeans. 

Preliminary findings show SBA colonize volunteer soybeans very early in the season and reproduce well and persist on soybeans, even after the corn canopy develops. In at least one of three years, removal of volunteer soybeans at the V3 stage reduced end-of-year SCN egg populations. In only one of three years, high volunteer soybean populations significantly reduced corn yields.

With further analysis of the data and distribution of the results, Potter will help growers determine what, if any, action is necessary to manage threats posed by volunteer soybeans.