Was your yard once a farm? It matters! Check out our recent paper here.
This farm will affect the yards soon to replace it long after it is gone (Photo: Central Arizona-Phoenix LTER).
The natural world today bears marks of the past. These legacies may seem obvious—clearly coastlines remain affected by hurricanes and oil spills long after these disturbances have ended. However, conclusively linking a particular bit of history to specific conditions today turns out to be tricky. In our recent paper with Ann Kinzig at Arizona State and Jason Kaye at Penn State, we investigated whether the amount of carbon and nitrogen stored in soil was different in lawns that had been farms a century ago than in lawns carved out of previously undisturbed Sonoran Desert ecosystem. It did matter! It also mattered how old the lawn was. Thus two ecosystems (for example, two lawns) that look similar on the surface may function quite differently because they have different histories. (So don’t judge a book by its cover!) Globally, explosive urban growth gobbles up both farmland and natural ecosystems alike. So the habitat for billions of urban people will depend on what their neighborhood used to be. Moreover, carbon and nitrogen are two chemical elements that dramatically alter the energy balance of the atmosphere and the water quality of lakes, streams, and bays. So, the sequestration, or storage, or carbon and nitrogen in soil is of widespread interest. (This work was funded by a McDonnell Foundation grant to Ann Kinzig, and a NSF grant to the CAP-LTER.)
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Tagged agroecosystem, carbon, David Lewis, desert ecology, ecological legacies, Ecology, ecosystem ecology, nitrogen, Soil, soils research, Urban ecology
Study lead Meagan Schipanski and co-author Jason Kaye.
In the environment, everything affects everything else, prompting someone to once say, “ecology isn’t rocket science, it’s much harder.” This complexity is especially true in agricultural systems. Farmers make many management decisions: go organic or not, use full or reduced plowing, decide what mixture of crops to rotate. These decisions then affect soil quality and weed and insect abundance, which in turn affect crop production. This complexity makes it difficult to determine which management strategies really work, and why. To help resolve this challenge, the Lewis Lab collaborated in a recent study that compared soil, weed, insect, and crop responses to different cropping system strategies. The study was conducted at Penn State, led by Meagan Schipanski at Colorado State University. It was set in Pennsylvania at experimental farmland undergoing a three-year transition from conventional to organic production. Farm plots were plowed using either full or reduced tillage, and either included perennial sod-forming or annual cover crops prior to cultivating soy and corn. We used statistical approaches that are relatively new to agroecology in order to determine how these management strategies impacted interactions among soils, weeds, and insects, and how those factors in turn influenced crop yields. We found that managing weed populations through full tillage in organic farm systems can improve crop yields. However, these short-term profits come at the expense of a loss in soil quality and beneficial insect conservation when soils are heavily plowed. Check out the paper here!