Assistant Professor California State University, Los Angeles, California, United States
Abstract: Efficiently growing food crops requires that we know how the environment influences the growth of plants and how the plants grown in an agricultural context influence each other. Densely planted crop species will often be resource-limited and require artificial fertilizers to ensure maximum growth. However, positive interactions between neighboring crops are also common, and often overlooked in an agricultural context. We must understand the ways in which plants affect their neighbors in both positive and negative ways if we want to efficiently grow crops. To address these issues, I manipulated planted crop diversity (monoculture vs polyculture) using the Three Sisters (squash, bean, corn) and measured microclimate temperature, microclimate humidity, soil moisture, and crop yield in an urban farm at California State University Los Angeles. I found no overall effect of planting scheme (monoculture vs. polyculture) on microclimate temperature or yield, but squash grew more in high diversity mixtures during some weeks, whereas bean and corn did not (P=0.027). Additionally, complementarity effects were stronger in drier soils (P=0.008) and selection effects were stronger in areas that received more light over the course of the day (P=0.02). These results can assist in designing more efficient urban farms for maximum productivity and yield in an increasingly stressed food system.
