AGROECOSYSTEM RESPONSES TO ORGANIC AND CONVENTIONAL MANAGEMENT-PRACTICES

The stability and resilience of two very similar soil ecosystems were challenged over an extended time by organic and conventional managemen t systems. The responses were compared against a native soil ecosystem by following carbon, nitrogen and phosphorus balances through the bio logical, geological, and chemical sub-systems. The types and amounts o f carbon inputs did not predict the resulting system contents or prope rties. Nitrogen and phosphorus retained in the systems were related to , but not proportional to, inputs. Carbon, nitrogen and phosphorus mov ed through the agroecosystems and excesses were exported to maintain s tasis in the component sub-systems. A flow diagram was proposed to des cribe the stabilizing responses in these systems. The unique propertie s of each agroecosystem must be considered when developing sustainable management practices. (C) 1998 Elsevier Science Ltd. All rights reser ved.