Center for Sustainable Agricultural Systems Newsletter

September-October 1997

Linking Ecology and Agriculture to Increase Sustainability

Natural ecosystems supply many valuable services and products to humans, for example, clean air, clean water, and biodiversity as well as a place to grow crops and livestock. As natural systems, they do not provide agricultural commodities of the types and amounts needed by humans, so we have changed many of them into agroecosystems to maximize production of food and fiber.

What is it about an ecosystem that lets it run year after year using only solar energy without degrading the resource base, while farms and ranches require high fossil energy inputs and suffer from soil erosion and water contamination? This question was explored at three workshops co-sponsored by the North Central Sustainable Agriculture Training Program (NCSATP). Linking People, Purpose, and Place: An Ecological Approach to Agriculturewas held in Wooster, Ohio; Manhattan, Kansas; and Morris, Minnesota. The purpose was to demonstrate how an understanding of ecological principles can help us design farms that continue to provide commodities while retaining some of the beneficial processes of natural systems. Because agroecosystems include people, another goal was to explore the economy, infrastructure, and social organization in each place.

The first step toward identifying useful ecological principles is to describe the structure and function of pre-settlement ecosystems within a particular region. Introductions at the workshops gave an overview of the natural ecosystems in Ohio, Kansas, and Minnesota and of the agroecosystems that have taken their place.

In Kansas, Bonnie Lynn-Sherow, an environmental historian, emphasized the importance of human's role in nature by explaining the five roles the Konza Prairie Research Natural Area (KPRNA) has played for Native Americans, farmers, ranchers, scientists, and recreationists. KPRNA was established to provide an outdoor laboratory for the study of ecological processes in a tallgrass prairie. We saw firsthand the differences in vegetation caused by cattle or bison grazing and fire sequences. The next day we compared the native ecosystem with a cattle ranch agroecosystem. The Hubbard family runs almost 2,000 head of steers and cow-calf pairs on 6,000 acres. As with KPRNA, they also use rotational grazing and fire as management tools.

Agroecology was another central topic. Richard Harwood and Richard Olson described how understanding the ecology of a place can lead to practices that are more profitable, more energy and nutrient efficient, and less environmentally disruptive. To effectively manage the biology of agricultural systems, we must understand:

the relationship between the physical environment and key ecosystem processes, such asnutrient cycling, water use, and soil biology;
which processes can be directly managed and which cannot, such as carbon turnover versus photosynthesis, and how managing the processes affects productivity;
the importance of plant diversity and the amount and duration of plant rooting;
the concepts of habitat, both within the landscape and in the soil.

Evaluating soil quality was one popular activity at the workshops. Using a mini version of the USDA-ARS soil test kit, participants measured infiltration rates, soil nitrate-nitrogen, organic matter, and depth to compact soil strata. In Minnesota, they sampled soils in CRP plots and tilled plots of corn or soybeans. Many embraced the hands-on approach as a way to quickly learn how cultivation practices affect soil structure.

Indoor sessions, with topics on weed management and ecological principles of grazing, complemented the extensive farm visits. Farmers and ranchers described how they matched their production systems with weather patterns, soil, vegetation, and markets. For example, the Hartzler family owns and operates five dairy farms that produce milk for the family-owned processing plant and retail store. Joe and Jean Hartzler farm 125 acres with intensive grazing on 35 acres. Their new retail dairy was the first one built in Ohio in 30 years. After the field tour, we visited the processing plant where milk is pasteurized, but not homogenized, and bottled in glass containers. Participants sampled 18 of the 30 available flavors of ice cream!

One of the guiding principles of NCSATP is that training must be inclusive, both in terms of trainers and learners. This year our audience background expanded to include instructors from private colleges, college students, a scientist with a large argochemical company, and representatives from the National Agroforestry Center.

According to the evaluations, participants indicated they would use ecological principles in helping clients design farming systems and consider the social implications. One Extension educator wrote, "I always felt a connection to natural resources, but my path seemed to put me in ag and crops. Now, I see that it is feasible to combine them without losing respect and profitability. It will be a goal to try and bring this information to my county."

Submitted by Heidi Carter, Richard Olson, Charles Francis

Source: http://www.ianr.unl.edu/ianr/csas/newsletr/sepoct97.htm