Cropping systems rsearch: Reconsidering agricultural experimental approaches

Systems approaches to research can be used to study characteristics of agricultural systems that cannot be addressed using conventional factorial experiments. The goal of a factorial experiment is to break down a complex system in order to isolate and study specific components and identify cause-effect relationships. In contrast, systems experiments aim to understand how a complex system functions as a whole and thus requires that intact systems be studied. Two approaches have been successfully applied to agricultural systems research: 1) field station experiments where simulated cropping systems are established in replicated plots and 2) studies of intact agroecosystems using commercial farms as study sites. These two approaches have complementary strengths and limitations and have made significant contributions to our understanding of ecological processes in agricultural systems. The development of sustainable agroecosystems will be best accomplished using an integrated research approach combining systems experiments with appropriately designed factorial experiments.