The 2023 Iowa Forage and Grassland Council Annual Conference was held on February 28 at Reiman Gardens in Ames, Iowa. Fifty-eight members from over 20 counties across the state joined to learn about recent research and hot topics in the forage industry.

To kick the day off, Dr. Garland Dahlke, Research Scientist with Iowa Beef Center at Iowa State University, discussed ongoing research he is leading utilizing swath grazing. While the winter grazing strategy “saves time and money”, it comes with challenges too including machine accessibility, fences, and water. To learn more about the research, check out this article from the Iowa Beef Center.

Iowa NRCS staff Hillary Olson, State Soil Health Specialist, Kayla Creek, Livestock Specialist, and Stacy Prassas, Grassland Specialist, teamed up to tackle a presentation on the compound effects of integrating livestock to improve soil health.

Dr. Gene Takle, Emeritus Distinguished Professor in Agronomy, Iowa State University spoke about ongoing research that he is a part of studying climate changes over the past three decades and impacts it may have on agriculture moving forward. 

To wrap up the day, Dr. Bob Hartzler, Retired Extension Weed Specialist and Emeritus Professor of Agronomy, Iowa State University spoke on management tips for new weed threats creeping into Iowa forages including sericea lespedeza, teasel, deer-tongue, and more. Dr. Hartzler encouraged attendees to take a step back and consider the factors that often lead to weeds invading pastures. 

Good cultural practices, including maintaining good soil fertility, are the foundation of a productive pasture. Recent research (2015-17) from the University of Missouri documented the importance of soil fertility in suppressing weeds in pastures^a. Researchers established a 200 ft² sampling area in 63 pastures across the state; tall fescue was the predominant forage species in the pastures. Within the sampling area soil cores were pulled to determine soil fertility and weed populations and forage density were recorded throughout the growing season. Relationships between fertility levels, forage cover, and weeds were examined.

Over 25 weed species were identified in the pastures; 12 species were present in at least 50% of the surveyed pastures. Horse nettle and common ragweed were the most common weeds, found in 100 and 97% of the pastures, respectively. To simplify relationships between weeds, forage cover, and soil fertility, weeds are grouped by life cycle (Table 1). The factor most consistently linked with the presence of weeds was % groundcover provided by the forage species. Each 1% increase in forage ground cover reduced annual broadleaf weeds by 41 weeds per acre, whereas biennials and annual grasses per acre were reduced by 57 plants per acre with each percentage increase in forage ground cover. These results document the importance of promoting vigorous forage growth in reducing the establishment of weeds in pastures.

Soil pH and concentrations of P and K had variable effects on the presence of weeds. Annual broadleaves, brush species and perennial grasses decreased with increases in pH, whereas biennial and perennial broadleaves increased with increases in soil pH (Table 1). While biennial broadleaf species as a group increased with each unit increase in soil pH (e.g. increase in pH from 6 to 7), one specific biennial broadleaf, poison hemlock, decreased by more than 1000 weeds per acre with increases in soil pH (data not presented). Populations of the annual broadleaves common ragweed and spiny amaranth decreased by more than 1000 weeds per acre with each unit increase in soil pH. The lack of consistent responses to soil fertility characteristics among weed species isn’t surprising since each plant species, whether forage or weed, has unique nutritional needs. Some weed species might respond more to increases in a nutrient than the forage species, thus giving the weed an advantage.

This research shows that enhancing the competitiveness of the forage crop is an essential component of pasture weed management. In addition to stocking rates, maintaining proper soil fertility and soil pH are critical to promoting vigorous growth of the forage species. Current recommendations for managing soil fertility of Iowa pastures are available in the ISUEO bulletin Pm 869 - Fertilizing Pasture. For additional information on pasture management contact your local Iowa State University Extension and Outreach field agronomist or beef specialist. 

^aBunton, G., Z. Trower and K.W. Bradley. 2019. Relationships between soil, forage, and grazing parameter effects on weed incidence in Missouri pastures. Weed Tech. 34:408-415.

Iowa farmers with grazing operations are encouraged to visit their local USDA-Natural Resources Conservation Service (NRCS) office if they are interested in implementing conservation practices that treat natural resource concerns. NRCS offers financial assistance to implement practices such as prescribed grazing, watering facilities, watering pipelines, fencing, and heavy use area protection.

Iowa NRCS State Grassland Specialist Jeff Matthias encourages farmers to work with the local NRCS field office to develop a grazing management plan, which can be implemented over time. The development of a grazing management plan takes time and can be intensive. When NRCS staff can see the livestock grazing the land, it helps determine where and what resource concerns can be treated and to recommend alternatives to the livestock producer. “Grazing management plans help farmers manage the soil, water, air, plant, and animal resources, along with helping to design a system that will provide the adequate forage for grazing animals during the grazing season,” he said.

Many grazing practices not only treat a resource concern, but also help improve an operation’s overall profit and efficiency, says Matthias. “The distribution of water is the most limiting resource for developing a grazing management plan,” he said. “After installing well-planned watering systems, benefits of forage management and seeding improvements with prescribed are an excellent long-term investment for a farmer.”

Managing for Soil Health

Similar to managing for cropland soil health, Matthias says grazing operators can benefit from managing pastures with soil health in mind. “As soil health improves, forage production will increase and fertility needs will decrease, leading to increased profits,” he said.

NRCS offers a lengthy list of practices that treat resource concerns and improve pasture soil health, which are eligible for financial assistance through USDA’s Environmental Quality Incentives Program (EQIP). Pasture management practices such as prescribed grazing, forage and biomass planting, and stream/pond access control offer producers a higher payment rate in Iowa.

Go to the Next Level with CSP

For grazers who want to build on existing conservation efforts, the Conservation Stewardship Program (CSP) may be a good option. Local NRCS offices will design a custom CSP plan to help you meet your conservation and operational goals. CSP offers annual contract payments based on maintaining your existing level of conservation and implementing additional conservation practices and activities. Supplemental payments may be offered to producers to implement advanced grazing management.

For more information about conservation practices and programs, visit your local NRCS office or go online to Iowa | Natural Resources Conservation Service (usda.gov)

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Iowa Beef Center’s 2023 Fencing & Grazing Clinic is May 16

The daylong event will be held at the ISU Armstrong Research Farm near Lewis, with topics including building your paddocks, new tools in fencing and planning a grazing calendar. A great group of sponsors means no charge to attend. Registration is required by May 12. See details in this IBC news release.

Agronomy in the Field Events Planned across Iowa

Four Agronomy in the Field cohorts for women will focus on developing agronomic decision-making skills that can be used on one’s personal farm or family cropping operation, including topics focused on forage and crop production. To learn more about the hands-on learning opportunities, check out the details for each of the cohorts including location, dates, time and registration information.

Education Funds Available

Planning a forage-related meeting and looking for sponsorship dollars to offset meeting expenses? The Iowa Forage & Grassland Council provides Education Grants Program which is designed to assist with funding forage education activities in Iowa including forage field days, informational meetings, and pasture walks. Learn more about the grant on the IFGC website.