CROP SWITCHING

[PAPER] Mapping the mechanics of agroecological change

My research centers on how plant biogeography responds to global environmental change. While I focus primarily on biodiversity in natural ecosystems, it turns out that people actually grow plants too, and that these agroecosystems are also highly dynamic in response to changing environmental and economic pressures. It’s been fun to work on the agricultural side of climate adaptation as part of our research collaborative at UVM, and this week I have a new paper out in PNAS in which we present a high-resolution portrait of crop switching patterns across the US. Crop switching is a key mechanism through which farms adapt to climate change, but we’ve lacked a basic understanding of the frequency, context, and geography in which it occurs. This paper helps to fill that gap, using an analysis of remote-sensing based data over the past couple decades.

Here’s the abstract:

Crop switching, in which farmers grow a crop that is novel to a given field, can help agricultural systems adapt to changing environmental, cultural, and market forces. Yet while regional crop production trends receive significant attention, relatively little is known about the local-scale crop switching that underlies these macrotrends. We characterized local crop-switching patterns across the United States using the US Department of Agriculture (USDA) Cropland Data Layer, an annual time series of high resolution (30 m pixel size) remote-sensed cropland data from 2008 to 2022. We found that at multiple spatial scales, crop switching was most common in sparsely cultivated landscapes and in landscapes with high crop diversity, whereas it was low in homogeneous, highly agricultural areas such as the Midwestern corn belt, suggesting a number of potential social and economic mechanisms influencing farmers’ crop choices. Crop-switching rates were high overall, occurring on more than 6% of all US cropland in the average year. Applying a framework that classified crop switches based on their temporal novelty (crop introduction versus discontinuation), spatial novelty (locally divergent versus convergent switching), and categorical novelty (transformative versus incremental switching), we found distinct spatial patterns for these three novelty dimensions, indicating a dynamic and multifaceted set of cropping changes across US farms. Collectively, these results suggest that innovation through crop switching is playing out very differently in various parts of the country, with potentially significant implications for the resilience of agricultural systems to changes in climate and other systemic trends.