Organic agriculture outperforms conventional agriculture across several sustainability metrics due, in part, to more widespread use of agroecological practices. However, increased entry of large-scale farms into the organic sector has prompted concerns about ‘conventionalization’ through input substitution, agroecosystem simplification and other changes. We examined this shift in organic agriculture by estimating the use of agroecological practices across farm size and comparing indicators of conventionalization. Results from our national survey of 542 organic fruit and vegetable farmers show that fewer agroecological practices were used on large farms, which also exhibited the greatest degree of conventionalization. Intercropping, insectary plantings and border plantings were at least 1.4 times more likely to be used on small (0.4–39 cropland ha) compared with large (≥405 cropland ha) farms, whereas reduced tillage was less likely and riparian buffers were more likely on small compared with medium (40–404 cropland ha) farms. Because decisions about management practices can drive environmental sustainability outcomes, policy should support small and medium farms that already use agroecological practices while encouraging increased use of agroecological practices on larger farms.

有机农业在几个可持续性指标上都优于传统农业，部分原因在于更广泛地使用了农业生态实践。然而，越来越多的大型农场进入有机部门，引发了人们对通过投入替代、农业生态系统简化和其他变化进行“常规化”的担忧。我们通过评估整个农场规模的农业生态实践的使用并比较常规化指标来检验有机农业的这种转变。我们对 542 名有机果蔬农民的全国调查结果表明，大型农场使用的农业生态实践较少，这也表现出最大程度的常规化。间作、昆虫种植和边境种植在小型（0. 4-39 耕地公顷）与大型（≥405 耕地公顷）农场相比，而与中型（40-404 耕地公顷）农场相比，小型农场减少耕作的可能性较小，河岸缓冲区的可能性更大。由于有关管理实践的决策可以推动环境可持续性成果，因此政策应支持已经使用农业生态实践的中小型农场，同时鼓励在大型农场更多地使用农业生态实践。