Operationalizing the concept of robustness of nitrogen networks in mixed smallholder systems: A pilot study in the mid-hills and lowlands of Nepal

Nitrogen (N) is often the most limiting nutrient to productivity in smallholder mixed crop-livestock systems such as commonly found in the mid-hills and lowland (Terai) of Nepal. Identifying current bottlenecks constraining agroecosystem functioning in terms of N flows and associated improvement options in these systems is paramount. Here, we explore variations in robustness, a concept from ecological network analysis (ENA) which represents the balance of system’s degree of order between organization (order/constraint) and adaptive flexibility (freedom/resilience) of N flows. Robustness can provide a detailed assessment of N flows and assist in evaluation of measures to reduce nutrient losses. In this study, the FarmDESIGN model was employed to quantify nitrogen flows, generate ENA indicators of integration, diversity and robustness, and to explore the impact of crop intensification options on N networks across farm types in the mid-hills and lowland (Terai) of Nepal. Results revealed that the farms in the different agroecosystems recycled only a small portion of the total N inputs (