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

Date: 
Oct 2018

Issue

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.

Objective

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.

Approach

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

August 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)

Allee1

Western2

McNay-A3

McNay-B4

McNay-C5

342

343

1,675

-

728

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

 

Sex

Stocking Rate (hd/acre)

Days Grazed

Cattle Turnout

Cattle Removal

Allee

Heifers

1.4

13

11/13/18

11/26/18

Western

Steers

1.5

12

11/16/18

11/28/18

McNay-A

Cow-calf

1.81

7

10/29/18

11/5/18

McNay-B

Heifers

-

-

-

-

McNay-C

Cow-calf

1.31

8

11/8/18

11/16/18

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).  

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