Phosphorus Use and Management Strategies: Exploring Scenarios of Smallholder’s Soil Fertility, Food Production and Livelihood with a Multi-Agent System Model

Phosphorus (P) is a key nutrient for food production. However, excess P use, e.g. in form of inorganic fertilizer application, can lead to environmental pollution, biodiversity losses and low profitability. Continuous cultivation with underuse of P fertilizer results in low food productivity and soil degradation due to soil nutrient mining or soil erosion. The concern is most serious for smallholder farmers in developing countries whose food production and livelihood is tied directly to their access to and efficient use of P as key nutrient for plant growth. This paper introduces a multi-agent system modeling framework for assessing long-term impacts of integrated P nutrient management options on soil fertility, food productivity and profitability of smallholder agro-ecosystems in different geographic regions. We consider Vietnam’s smallholder systems in the Red River Delta (P overuse, market-oriented) and in the Northwest Mountain Region (P underuse, subsistence) as case examples for the two contrasting P use regimes. The model is planned to be used for informing trade-offs between long-term benefits and costs driven by different P management strategies and policies in a multi-stakeholder discourse.