Organic Broadcaster

Research looks at integrating crops, livestock to enhance organic farm resilience

By Brad Heins, Kathleen Delate, and Hannah Phillips

Steers graze the rye cover crop at the University of Minnesota’s West Central Research and Outreach Center. Photo submitted.

Steers graze the rye cover crop at the University of Minnesota’s West Central Research and Outreach Center.
Photo submitted.

Currently, organic production in the U.S. is dominated by cash grain crops, with the majority of organic farmers in the Midwest and Northeast using off-farm purchases to feed their organic animal herds. Integrating crops and livestock on a multi-function operation could have multiple benefits and the potential to improve the profitability of these kinds of operations.

Researchers at Iowa State University, the University of Minnesota, and Rodale Institute are in the second year of a four-year project, funded by the USDA Organic Research and Extension Initiative, to evaluate the production, environmental, and economic benefits of growing cash crops with forage crops for grazing, including small grains and hay crops for livestock feed. They are comparing two crop rotations—pasture-winter wheat-soybean-pasture and pasture-winter rye/hairy vetch-corn-pasture—and grazing dairy steers on the cover crops as a method of integrating livestock and organic cropping systems.

Pasture, Animal Productivity
At the University of Minnesota West Central Research and Outreach Center’s organic dairy in Morris, Minn., the dairy bull calves are: Holsteins; crossbreeds, including combinations of Holstein, Montbéliarde, and Swedish Red (HMS); and, crossbreeds, including combinations of Normande, Jersey, and Swedish Red (NJS).

These steers are grazing on a pasture divided in half for the two crop sequences (S1: Pasture-wheat-soybean, and S2: Pasture-rye/vetch-corn). These pastures are separated into 15 paddocks, with a non-grazed enclosure in each paddock.

Winter wheat and winter rye forages were planted on Sept. 11, 2015, for grazing during spring 2016. During this spring, calves were randomly assigned to replicated groups (winter wheat or winter rye), but balanced by breed group to reduce potential breed bias. Twelve-month old dairy steers started grazing the wheat and rye pastures on April 25, 2016. Forage samples were collected when steers moved to new paddocks which was about every three days.

Crude protein (Figure 1) was very high in both the winter wheat and winter rye across the grazing season, which lasted until June 14, 2016 for these grasses. From early May through the end of the grazing season, the crude protein was lower than at the start of grazing; however, the steers were probably more efficient at utilizing the protein when it was lower compared to high protein levels observed during late April.

Figure 1.

Figure 1

Digestibility of the winter wheat and rye also was very high (Figure 2). As the wheat and rye matured, the digestibility was lower; however, the dairy steers grazed each paddock and wheat and rye four times in a two-month period.

Figure 2

Figure 2

At the Rodale Institute in Pennsylvania, dairy steers grazed an eight–acre pasture in 2015, subdivided into four rotationally grazed strips that were each one acre. The steers were allowed to graze each one-acre paddock for about 14 days. Over the 150 grazing days, the steers gained an average of 1.68 lbs/day. There was no difference in the rate of gain on the two pastures.

Grazing enhanced pasture production, as biomass in the enclosures was only 1.85 kg m-2 compared to 12.16 kg m-2 in grazed areas. Rye and wheat were planted in fall 2015 and mob grazed for 14 days in early spring 2016 with plots designed for moving the steers daily. Preliminary data showed higher steer weights after grazing on rye compared to wheat plots. For rye, grazing had a positive effect on plant biomass and grain yield, which averaged 1.2 tons/hectare. By comparison, grazing in wheat plots reduced biomass and grain yield, which averaged 2.6 tons/hectare.

In Iowa, organic steers brought from the Minnesota organic dairy were raised on an organic pasture and rotationally grazed throughout the year on an average rotation of eight days.

Pasture biomass production, in general, was greater in the grazed areas of the paddocks, with one of the higher-producing paddocks averaging 2,372 lbs/acre biomass in mid-season, compared to 1,677 lbs/acre in the non-grazed enclosure.

Soil Quality
Six surface soil samples (0-15 cm) from each sample plot and enclosures were collected for nutrient availability and biological activity among the sites in spring 2016. Microbial biomass carbon, and enzyme activity for acid and alkaline phosphatase, beta glucosidase, and arylsulfatase were found to be highest in Minnesota, intermediate in Iowa, and lowest in Pennsylvania. These three enzymes are directly related to the phosphorus, carbon and sulfur turnover in soil. Pennsylvania soils had the highest levels of available phosphate, nitrate, and ammonium. The higher nutrient availability could have provided soil microbes with readily available nutrients and therefore required less effort from the microbial community to obtain nutrients. In contrast, the lower nutrient availability in Minnesota and Iowa led to greater enzyme levels to facilitate nutrient turnover during the season.

Social Aspects

Steers graze wheat at the University of Minnesota's West Central Research and Outreach Center.  Photo submitted

Steers graze wheat at the University of Minnesota’s West Central Research and Outreach Center.
Photo submitted

Three farmer focus groups were conducted in summer 2016 to understand farmers’ experience and interest in livestock-crop integration. Groups were convened in Kutztown, Penn., Greenfield, Iowa, and Morris, Minn. Recruitment prioritized livestock farmers who were currently growing, or interested in introducing, small grains for grazing. The farmers in these groups expressed concerns about: economic risk of transitioning to a new system; potential food safety risks associated with livestock proximity to crops; demands on time and labor; physical demands of livestock/complex management; federal subsidies for conventional mono-cropping systems disincentivize integration; and, lack of local markets/educated consumers to fully support alternative systems. Researchers plan to address these concerns through this study.

The integration of livestock in organic cropping systems is a prerequisite for long-term agricultural stability. We are studying methods to integrate crops and livestock to determine this model’s effect on animal performance, crop productivity (including small grains for grazing), soil quality, food safety and social acceptance. During the third year of the project, we will harvest organic row crops, and produce crop/livestock budgets.

Brad Heins is an assistant professor of organic dairy management at the University of Minnesota’s West Central Research Center in Morris, Minn. Kathleen Delate is a professor of organic agriculture at Iowa State University, and directs the Organic Agriculture Program there. Hannah Phillips is a graduate student in animal science at the University of Minnesota.

From the November | December 2016 Issue

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