Research on the Evolution of Organic Farmland Ecosystems under the Intervention of External Factors

The research on the evolution law of organic farmland ecosystems under the intervention of external factors (such as the return of native species, human decisions, and environmental changes, etc.) holds significant theoretical value and practical significance for the transformation of traditional agriculture into green agriculture. To deeply reveal the dynamic evolution mechanism of the ecosystem, this paper first constructs an ecosystem model based on the Lotka-Volterra differential equations on the basis of comprehensively considering agricultural cycles and seasonal factors. This model is used to describe the interaction relationships among producers, primary consumers, secondary consumers, and top consumers. Subsequently, two types of native species, namely the Brazilian tapir and butterflies, are introduced, and a cellular automaton model is applied to simulate the impacts of their return on the ecosystem. Furthermore, an ecosystem stability evaluation model is established, and the particle swarm optimization algorithm is adopted to determine the optimal weights. Then, the impacts of removing herbicides (in traditional agriculture) and introducing bats and earthworms (in organic agriculture) on the ecosystem stability under the intervention of human decisions are explored. The research results show that: on the one hand, within a single growth cycle, the application of chemical pesticides can suppress the number of pests and promote crop growth in the short term; on the other hand, bats and earthworms can serve as ecological alternative solutions, playing key roles in pest control and soil improvement respectively, enhancing biodiversity and the sustainability of the ecosystem.