Farm consolidation and turnover dynamics linked to increased crop diversity and higher agricultural input use

Abstract

ContextCrop-type composition and configuration at field and landscape scales are known to impact ecological functions in agricultural landscapes. However, links between regional farmland structures (e.g., variable farm size, ownership, configuration, etc.), which are important determinants of farm-level management decisions, and subsequent changes in agroecosystem impacts, remain understudied.Objective:To investigate these dynamics, we examined relationships between changing farm structures, as indicated by farm consolidation and persistence, and concurrent changes in crop diversity and agricultural resource use between 2002 and 2018 in Kern County, California.Methods:We integrated parcel-level datasets documenting farm size, operatorship, crop cover, pesticide usage and evapotranspiration rates for 2002 and 2018. We then applied seemingly unrelated regression analyses to quantify potential relationships between these key variables.Results and conclusions:In our study area we observed low (28%) persistence of farm operators from 2002 to 2018 and farm consolidation, as evidenced by a 43% increase in farm midpoint size in the studied time period. We further found significant associations between farm structures and agro-environmental outcomes. A doubling in farm size was associated with an 8% increase in crop diversity, but also with an 18% increase in pesticide-use and a 7% increase in water use at the farm level, raising concerns about the impact of large farms on landscape-scale resource use. Both crop diversity and water use were higher in persistent farms (8% and 11%, respectively) than in replaced or emergent farms. Our findings illustrate how regional shifts in farm size and operatorship may link to changes in crop diversity and resource use. SignificanceGiven continued concerns about the impacts that landscape simplification, pesticide use, and water shortages may have on agroecosystems both in our study region and beyond, our study highlights regional farm structure dynamics as a key element to investigate further and to consider in policies aiming to increase the sustainability of future agricultural landscapes.