Enhancing the Value of Cover Crops through Integration of Row Crop and Cattle Enterprises

Oct 2018


While establishing cover crops following grain production helps protect and enhance Iowa’s water quality and the soil profile, cover crops also provide an additional forage resource. To date, most of the research from a livestock perspective has focused on spring grazing of overwintering cover crops. Yet spring grazing of cover crops can be a challenge due to a narrow window of opportunity based on weather implications hindering spring growth, and the desire to get the cash crop established in a timely manner. Thus, there is growing interest in fall grazing of cover crops.


This project will evaluate nutrient quality and potential yield of an oat-cereal rye cover crop when interseeded into standing cash crop as a forage resource for grazing cattle; determine if cover crops still maintain agronomic benefits when grazed; demonstrate integration of an oat-cereal rye cover crop into row crop systems to enhance fall grazing potential for the beef herd; and further develop decision tools to evaluate weather risk, costs, and grazing potential of cover crops.


This project complements an existing project evaluating stocker cattle performance while grazing cereal rye at three ISU outlying research farms (Allee, McNay, and Western). This project focuses on interseeding an oat-rye mix into an existing corn or soybean stand to focus on fall grazing potential. This interseeding will be done in August before a rainfall. Plant stand, forage biomass yield, and nutritional quality will be measured throughout the fall to benchmark the forage availability. In addition, bulk density measurements will be collected at the same two time points to evaluate any soil compaction due to cattle grazing. Cattle will be individually weighed prior to oat-rye mix turnout and after removal from cover crop to determine average daily gain and weight gain per acre. The research will be conducted in the fall of both 2018 and 2019, allowing data to be collected behind both corn and soybean crops at each of the outlying farms.

Project Updates

May 2021


Cover crop forage quality and quantity varies greatly based on weather patterns, location in the state, seeding dates and competition from the cash crop when interseeded. Table 1 and Figures 1, 2, and 3 demonstrate the variability in nutrient quality of various cover crop samples taken from the outlying farms in the fall of 2018 and 2019 are demonstrated in Table 1 and Figures 1, 2, 3 in the final report (linked, below). The average number of fall grazing days in 2018 was 8 days. Only one field was grazed for 7 days in the fall of 2019. Despite the limited availability of fall grazing days, the cover crops’ nutritional value makes it a high-quality feedstuff and contributes to feed savings for the Iowa beef producer. Thus, the forage availability creates further incentive for cover crops adoption across the state and aids in more efficient use of resources, which can improve both cattle and crop enterprise profitability.

While the amount of fall grazing was limited in this two-year study, fall grazing does not appear to negate the agronomic benefits cover crops are known to provide, such as reducing soil compaction (Table 3) and building soil organic matter (Table 4). However, since many of the agronomic benefits take time to have an impact, a longer assessment is needed to continue to evaluate how grazing can impact the agronomic benefits cover crops can provide.

Final report attached.

Publications created:

*Specific to the project alone: Grazing Fall-Seeded Cover Crops with Fall-Calving Cow-Calf Pairs (RFR-A18120), Grazing Fall-Seeded Cover Crops with Stocker Cattle (RFR-A1953)

*Joint publications that include project data: Best Management Practices for Fall Grazing Cover Crops infographic (ILF), Grazing Cover Crops to Avoid Soil Compaction (ILF), Herbicide Use May Restrict Grazing Options for Cover Crops (CROP 3082), Managing Cattle Health Issues When Grazing Cover Crops (IBC 129), A Field Guide to Winter Cereal Rye Forage Quality (ASL R3309), Nitrate and Sulfur in Fall Grazed Cover Crops (ASL R3312), Farmers Experiences with Fall Grazing Cover Crops (IBC 142; in progress), Cover Crop Integration in Iowa (an extension programming evaluation summary; in progress)

Other activities and accomplishments:

- 11 field days, 14 presentations, 7 workshops

December 2019

Fall weather patterns of 2019 made for a challenging year for fall grazing cover crops. Two of the three ISU outlying research farms (Allee in Buena Vista County and Western in Monona County) were aerial seeded with a cereal rye and oat mix in early August. Lack of an interseeder in the area and wet weather conditions delayed the seeding of the cover crop mix at the McNay Farm in Lucas County into October. With the first killing frost across the state occurring in October, fall cover crop growth was limited, especially in the late planted fields at McNay, which saw no noticeable fall growth. At Western, steers grazed the cover crop for approximately two weeks in the fall. Project investigators decided that grazing would not take place at Allee due to limited growth, although there was some forage present.

The challenges of weather conditions and delayed cover crop planting reflect real-world experiences. This short-term grazing makes it a challenge to accurately depict the stocker cattle growth performance; therefore, it may be more accurate to represent the grazing days as feed cost savings or hay savings. Data collected from the project including forage yield data, soil compaction data and grazing days have been shared at various meetings by both the beef and agronomy specialists.

Outreach during this period included 2 field days, 4 presentations and 2 workshops.

Publications during this period: 

July 2019

angus cattle grazing cover crops
Cattle grazing cover crops. 

Since the project is focused on fall grazing of cover crops, minimal data collection has been collected so far this year. Nutrient analysis and forage yields were finalized earlier this spring. Forage yields in fall of 2019 ranged from approximately 350 -1700 pounds of dry matter per acre. The majority of progress regarding this project was made through outreach efforts. These included several presentations and guest speaking at two field days.


December 2018

A cereal rye and oat cover crop mix was seeded at the Western Farm in Monona County, Allee Farm in Buena Vista County, and the McNay Farm in Lucas County in late August.  Due to an abnormal wet fall and delayed harvest, grazing at the Allee and Western Farms did not take place until mid- to late November. Due to weather and a short grazing period, cattle performance was hard to measure, but ultimately, stocker cattle maintained body weight while grazing.  At the McNay farm, PIs and farm staff were faced with a couple of different new challenges this year including rust in oats, which stunted oat growth in one field, and chickweed pressure, which limited cover crop emergence and growth. Two of the fields at McNay offered short-term grazing for fall-calving cow-calf pairs that did result in some hay-cost savings. While not ideal for collecting research data, these factors are real-world situations facing Iowa’s farmers and offer great talking points when discussing the challenges and successes of integrating cover crops for forage.   

Fall forage yield can be found in Table 1 while grazing days can be found in Table 2. 

Table 1.  Fall forage yield of a cereal rye and oat cover crop mix (lb DM/acre)











1Aerial seeded into corn 8/29/18, 16.3% DM. 
2Intereseeded into corn 8/25/18, 22.2% DM.
3Drilled behind corn silage 8/22/18, 18.7% DM.
4Estimated to be less than 100 lb DM/acre. Arial seeded into corn 8/24/18, 14.6% DM.
5Arial seeded into soybeans 8/24/18, 17.5% DM.

Table 2.  Fall grazing days of a cereal rye and oat cover crop mix



Stocking Rate (hd/acre)

Days Grazed

Cattle Turnout

Cattle Removal































1Cow-calf pairs also had access to adjacent pasture in order to have access to water sources.

September 2018

At this point in the grant, cover crops have been established, but the grazing component is  waiting until after  harvest of cash crops at the outlying farms. At the Western Farm in Monona County, cereal rye and oats were interseeded into standing corn,August 25th. Due to above- normal rainfall and soil conditions at the Allee Farm in Buena Vista County, the seed was flown on via airplane on August 29th.  At the McNay Farm in Lucas County, the cover crop mix was drilled behind corn silage on August 22nd.  The farm crew and grant PIs were unable to identify a highboy in southern Iowa, so the remaining two fields at McNay were aerial seeded that same week.  Grazing is anticipated to begin in late October and November.  Below are pictures from the ISU Western Research Farm taken by farm manager, Chris Beedle, on the day of interseeding, August 25th(Photo 1) and oat and rye growth between corn rows taken on September 5th(Photo 2).