Final Report for GNC10-136

Project Type: Graduate Student
Funds awarded in 2010: $9,979.42
Projected End Date: 12/31/2012
Grant Recipient: Iowa State University
Region: North Central
State: Iowa
Graduate Student:
Faculty Advisor:
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Project Information


Grazing cattle on reconstructed prairies is a solution proposed by land managers and graziers in Iowa, as an opportunity to balance the conservation goals of incorporating perennial, native plants into the Iowa landscape while maintaining the productivity and profitability of the state’s agricultural lands. Though grazing native plants is common to much of the Western United States, the limited amount of grazing lands in Iowa are dominated by exotic, cool-season grasses and legumes. In a case study at Whiterock Conservancy in Coon Rapids, Iowa we explored the nutritional quality and yields of reconstructed native plant grassland and prairie through clip sampling. Results from sampling found that all of the nutritional requirements of cattle would not be met with the harvested samples, although some aspects of nutrition may be achieved during the season. We created an economic budget model based on this case study, which suggests that grazing prairie is most profitable for graziers when a reduced rental rate is offered by land owners to provide a service of disturbance to the prairie.  A review of the ecological literature suggests that grazing has the potential to maintain or increase plant biodiversity, though native plant abundance was not well studied.  This review also concluded that water quality and wildlife populations could be maintained under strategic grazing management.  Communication should be a priority in designing management strategies for conservation lands that involve multiple stakeholders. Grazing prairies presents a balanced approach to both agricultural production and natural resource conservation. 


Perennial native plants, which in Iowa are dominantly warm-season grasses with smaller amounts of forbs, cool-season grasses, and legumes, are often utilized in the landscape for conservation purposes – whether to improve water quality, decrease soil erosion, or create habitat for wild game and non-game species.  These conservation purposes are often defined as ecosystem services, or processes and resources derived from the ecosystem that provides services on which society depends.  Two divergent approaches to conservation are 1) land is set aside with prohibited disturbance and 2) working agricultural lands are managed in order to enhance conservation.  Planting of native perennials is encouraged by various governmental programs (i.e. Conservation Reserve Program, CRP) and private organizations (i.e. Pheasants Forever), however this land is typically set aside, not a part of the agricultural production land. 

In many cases, landowners or managers receive cost-share or payment in order to establish or maintain areas of native perennial vegetation in order to preserve or enhance specific or general ecosystem services.  However, these payments are often not always enough to keep landowners or managers invested in conservation, when crop production is more profitable. In an era of an increasing need to preserve and enhance ecosystem services, we must seek to reconcile the goal of conservation with the need to maintain economic feasibility. 

One possibility, which is pioneering the balancing act of conservation and profitability, is the concept of grazing livestock in native or reconstructed ecosystems. In theory, by grazing livestock in conservation areas, the land is able to generate profit while still maintaining the ecosystem services of conservation. Not only does grazing native plants improve conservation efforts, but can benefit grazing operations by providing dominantly warm-season grass forage during summer months when cool-season pastures are less productive.  Grazing native lands has the potential to meet the needs of conservation and economic feasibility, but there is little data about putting the idea into practice in Iowa.

In order for grazing native plants to fully meet the goals of producers, conservationists, and land managers, three questions need to be answered: 1) how are producers in Iowa currently utilizing native plants in grazing operations; 2) what in-field tools can be used to determine when to graze native plants to optimize productivity and quality; and 3) can the incorporation of grazing native plants into a grazing operation be economically feasible in Iowa. 

Project Objectives:

I. Farmer survey of current practices and barriers to implementation: This portion of the study aims to identify agricultural producers in Iowa who are grazing livestock on native plants in order to document the varying approaches to grazing native plants, and the positive and negative aspects of each approach. Participants were interviewed regarding the inclusion of native plants into their operation, including specific details on forage production, animal production, timing, and specific plants utilized.  Data was analyzed qualitatively, creating a baseline report, or directory, of strategies for grazing native plants in Iowa.

II. Evaluating Management Tools for Grazing Native Plants: objective was not completed.

III. GIS-based prairie productivity calculator and economic analysis: Three prairie locations will be randomly selected, and samples will be harvested, then dried and weighed to determine dry-matter yield. Forage quality data was converted into relevant animal nutrition components in order to compare the forage quality available with the animal nutrition needs Based on the results from the study of prairie productivity, an economic analysis of the use of prairies for grazing.


Click linked name(s) to expand
  • Rachael Cox Ohde


Materials and methods:

The first step in the design process was to survey the agronomic potential of the land on a biomass yield and forage quality basis. After agronomic information was assessed, it was compared with animal nutrition data and livestock scenarios. Agronomic, livestock nutrition, ecological and economic data was shared with stakeholders in the Whiterock Conservancy project to develop a management plan.

Agronomic Data Collection:

Weather data was used from a weather station at Guthrie Center, approximately 24 kilometers from Whiterock Conservancy. Monthly mean temperatures and monthly total precipitation was calculated from the Iowa Environmental Mesonet at the closest available weather station. 

Two areas at Whiterock Conservancy were identified as target areas for research on grazing. The first area, the warm season grassland (WSG) site (30.9 ac, 12.5 ha) is located on Marshall soils, which are loess derived and well-drained, formed under tallgrass prairie, but converted to row-cropland during the last two centuries. This area was planted to a low-diversity warm-season grass mixture in 2002, including species Andropogon gerardii, Panicum virgatum, and Sorghastrum nutans. This area was mowed on a monthly basis to ~45 cm height for the first three growing seasons to reduce competition by annual weeds, and has since been managed with prescribed fire during the time period 20 April – 7 May in 2008 and 2009. This area is currently under a Conservation Reserve Program contract and sample areas were “bought back”.

The second area, the reconstructed prairie (RP) plot (43.5 ac, 17.6 ha) is also located on Marshall soils. In 2004, this area was planted to high diversity warm-season grassland species: Andropogon gerardii, Schizachyrium scoparium, Sorghastrum nutans, Bouteloua curtipendula, Elymus virginiana, Baptisia lactea, Eryngium yuccifolium, Astragalus canadensis, Artemisia ludiviciana, Lespedeza capitata, Zizia aurea, Asclepias tuberosa, Rudbeckia hirta, Heliopsis helianthoides, Silphium lacianatum, Ratibida pinnata, Chamaecrista fasciculata, Solidago rigida, Tradescantia ohiensis, Amorpha canescens, Echinacea pallida, Dalea purpurea, Monarda fistulosa, Liatris pycnostachya, Symphyotrichum novaeangliae. The area was mowed to 45 cm for the first three years to reduce competition by annual weeds, and has since been managed with prescribed fire during the time period April 20-May 7 in the years 2008 and 2009 (burned twice due to lack of burn coverage during the first burn).

In 2010, forage nutrition and total available forage was sampled at the two ecosystem reconstruction areas with 1.08 ft2 (0.1 m2) quadrats located every 16.4 ft (5 m) along a 82.0 ft (25 m) transect (five quadrats per transect).  Samples from each transect were combined for analysis.  One transect was laid for every three hectares within each grassland type, i.e. eight transects at both the RP and WSG. Transect locations at the RP and WSG were determined by randomly selecting GPS coordinates in the area.

In the WSG and RP at each transect, forage was sampled on a bi-monthly basis for available forage located 5.9 inches (15 cm) above the soil surface.  Each sample represented cumulative forage growth for the season, with no re-growth sampling.  Samples were dried and weighed prior to forage analysis in order to determine the available forage on a dry matter basis.  Once per month, prior to drying, samples were sorted into plant functional group: warm-season grass, cool-season grass, forb, legume, sedge, and non-herbaceous material.

In 2011, in lieu of transects, four samples were collected at each sampling date in the WSG and RP.  Each sample consisted of four 1.08 ft2 (0.1 m2) quadrats.  The sample locations were selected using randomized GPS coordinates, different with each sampling date, and different from the area sample in 2010.  Once per month samples were sorted into functional groups, this time sorting into warm season grass, cool season grass, forb, and other (sedges, woody material, and legumes), as the ‘other’ categories did not provide sufficient biomass in 2010 to complete forage quality lab analyses.  All other methods were followed as in 2010. 

The following forage quality parameters were measured in the lab: neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), crude protein (CP), ash, and dry matter content (DM).  Fiber procedures, including NDF, ADF, and ADL were conducted following the methods of Vogel et al. with a modification of 4 ml of heat stable α-amylase to the NDF solution before extraction. The Iowa State University Soil and Plant Analysis Lab in the Agronomy Department completed nitrogen and carbon analysis by automated combustion.

 Forage quality data was converted into relevant animal nutrition components in order to compare the forage quality available with the animal nutrition needs using the following equations:

1)    Crude Protein (CP) = 6.25 * Nitrogen

2)    Dry Matter Intake (DMI) = 120 / % NDF

3)    Total Digestible Nutrients (TDN) = A – B x % ADF, for mixed prairie and forbs A=102.56, B=1.069; for warm season grassland, cool season grasses, and warm season grasses  A = 102.33, B=1.14

Animal Nutrition Scenarios: 

Animal nutrition calendars for crude protein and total digestible nutrients are based on a nutritional calendar developed at Iowa State University based on the National Research Council Nutrient Requirements of Beef Cattle.  In this nutritional calendar, we assume a cow calf pair with calving in March. The nutritional calendar for dry matter intake is based on an adaption from the National Research Council Nutrient Requirements of Beef Cattle.  Dry matter intake values are also reported for a beef cow, assuming calving in March. 

Economic Budgets:

Many approaches to include grazing prairie in a grazing system in Iowa are possible.  The three scenarios presented in this paper were developed based on discussions with the research team and on the limited examples of producers grazing animals on native plants in Iowa.  From these discussions, we determined that the most likely scenarios do not include season-long grazing of prairies, but instead targeted grazing when cool season pastures are in the summer slump but warm season grasses are highly productive. The three scenarios included are 1) a typical practice in Iowa of purchasing hay during the summer slump, 2) grazing private CRP land for four weeks in late July or early August; 3) grazing public land for four weeks in late July or early August and paying a typical rental rate (not discounted for lower quality prairie forage); and 4) grazing public land for four weeks in late July or early August and paying a reduced rental rate (discounted for lower quality prairie forage).

The economic models are based on an expected 2.0 ton/ac (734.3 kg/ha) available forage for late July or early August grazing, above the 5.9 in. (15 cm) clipping height.   Typical rangeland management recommends harvesting 50% of forage with grazing. As the yield does not include the biomass below 5.9 inches (15 cm), we approximated 1.4 tons/ac (503.0 kg/ha) targeted for biomass harvest by grazing or haying. 

With this harvest objective, approximately 4 cow/calf pairs can be stocked per acre (0.4 ha) of land, with an estimated daily intake of 24.3 pounds (11.0 kg) dry matter for an estimated 28 days on pasture. We assume a herd of 100 cows, thus 25 ac (10.1 ha) of land is needed.  This is a high stocking rate compared to typical stocking rates on cool season grass pastures in Iowa, however, the livestock will only remain on the land for a small amount of the grazing season, thus avoiding overgrazing. Total forage requirements for duration of the 100 cow/calf pair system is 34.0 ton (30,800.0 kg, 67,902.4 lb).

Hay costs were based on Whiterock Conservancy sale prices in 2011. Hay is typically sold on a quality basis, and the prices used in the economic budgets represent low quality hay, of which CRP hay would be considered.  Land rental rates are the average income from pasture rental at Whiterock Conservancy in 2011.  CRP government payment rates were averaged from CRP contracts at Whiterock Conservancy between older contracts with lower rates and new contracts with higher rates. Grazing CRP land is not a typical management strategy; Farm Service Agency (FSA) regulations allow disturbance to occur only once per three years or one third of land every year. However, in many years an emergency haying and grazing exception is made by the FSA.  In an emergency use declaration year, if a producer chooses to graze or hay CRP land, the producer is required to pay in return 25% of the original payment.  Fencing rates are based on the Iowa State Ag Decision Maker Budgets, assuming the 25 acres being fenced is a square area, and the fencing cost is spread over 10 years.  All economic data considered can be viewed in Table 1. 


Research results and discussion:

Live forage yields of a reconstructed prairie increase through early September peaking above 2.5 tons per acre and decrease sharply in late September. The majority of live biomass is comprised of warm season grasses, followed by forbs as the second largest biomass category (see Figure 1).  Forage quality is represented by percent crude protein (a), dry matter intake as a percentage of body weight (b), and total digestible nutrients as a percent of biomass (c) (see Figure. 2). In the reconstructed prairie, crude protein and total digestible nutrients of composite samples were below animal nutrition requirements for most of the season, whereas dry matter intake was comparable to animal requirements (see Figure 2).

Economic considerations are very important in deciding whether to and how to incorporate prairie into a grazing operation, for either a land manager or a livestock farmer.  Expected costs and income are hard to predict and should be calculated for your individual scenario. A case study in Guthrie County, Iowa, found that multiple grazing scenarios were less costly than feeding hay. The case study compared feeding hay with three grazing scenarios: grazing your own CRP land, grazing at a conservation area paying a full rental rate, and grazing at a conservation area paying a reduced rental rate. All three grazing scenarios had lower costs than feeding hay (see Table 1).






Table 1:  Financial data for grazing scenario economic budgets for a case study using Whiterock Conservancy, Guthrie County, Iowa. 




Fencing   ($/25 acres)


Assumption: for a 25 acre square area, the perimeter fencing required is 4,174 feet.  Non-electric high tensile fence is $1.24 per foot, for a total of $5,176.  We assume fencing will last approximately 10 years, making yearly fencing costs $517.60

Land Rental Rates ($/acre)


$53 was average pasture rental rate at Whiterock Conservancy, average in Guthrie County, 2011

Grazing public land fee ($/acre)


Public land managers may provide land free of costs, or may charge a fee or rental rate.  Likely to charge a small fee, not whole rental rate.  Assumption: fee of $35/acre

Purchased Hay ($/ton)


High quality hay in 2011 sold at $78/ton, whereas low quality hay and CRP hay sold at $45/ton.  To represent similar hay quality as grazing scenarios, the low quality hay cost is used in the budget. 

CRP Payment ($/acre)


Average between older and newer contract rates at Whiterock Conservancy.  Older contracts are about $110/acre, new contracts about $155/acre.

CRP Emergency Penalty ($/acre)


CRP lands can be grazed or hayed when emergency use programs are declared.  Cost of grazing or haying can be up to 25%.  We assume 25% of $132.50 will be paid as a penalty, $33.13/acre

 Table 2. Economic budget for grazing scenarios in Iowa. Each scenario assumes 100 cow calf pairs are grazing or eating hay for 4 weeks. 


Scenario 1: Feeding hay

Scenario 2: grazing CRP

Scenario 3: grazing Public land, full rental rate

Scenario 4: grazing Public land, reduced rental rate

Purchased Hay


Fencing Costs


CRP penalty (25%)


Land Rental



Total Costs






Participation Summary

Educational & Outreach Activities

Participation Summary

Education/outreach description:

Cox, Rachael and Mary Wiedenhoeft. 2014. Grazing native plants in Iowa: Processes and experiences.  Iowa State University Extension.  PMR 1011.

This project was part of Ms Cox thesis, The use of reconstructed prairies in Iowa’s agricultural landscape to increase ecosystem services and move towards multifunctionality. 2012

Project Outcomes

Project outcomes:

Cox, Rachael and Mary Wiedenhoeft. 2014. Grazing native plants in Iowa: Processes and experiences.  Iowa State University Extension.  PMR 1011.

This project was part of Ms Cox thesis, The use of reconstructed prairies in Iowa’s agricultural landscape to increase ecosystem services and move towards multifunctionality. 2012

Economic Analysis

see results

Farmer Adoption

The Extension publication,  Grazing native plants in Iowa: Processes and experiences, will be made available as an online resource for farmers.  In Iowa, the number of grazing lands continues to decline.  Our hope is that conservation lands that have restored prairies will be managed by grazing.  This information will help farmers and managers effectively graze animals without compromising animal growth.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.