Water availability reverses edge effects on crop yields across the United States

Ensuring food security under climate change is a critical challenge for humanity. Maximizing food security requires an understanding of the drivers of within-field crop yield variation. Edge effects are expected to play an important role in determining total farm yields, as agricultural edges differ in their microenvironmental conditions and ecological processes, impacting crop productivity. However, the magnitude and variation of such effects remains largely unclear. Here, we used the normalized difference vegetation index (NDVI) as a proxy of crop yields to estimate the edge effects on two major US crops (corn and soybeans). We found that crop yields tend to be higher near field edges in the eastern US, an effect that was entirely reversed in the western US. This spatial variation may be driven by environmental conditions, as moist conditions in the Eastern US support natural vegetation and pollinators that promote crop growth near field edges, while dry conditions in the western US make field edges harsher than the interiors. Based on these edge effects, we simulate that optimizing edge effects to maximize their benefits on productivity leads to an annual economic gain of nearly 900 million dollars for corn and 500 million dollars for soybeans. These findings highlight the importance of strategic field-boundary management to enhance yields and economic returns.