NUANCES-FARMSIM (Nutrient Use in Animal and Cropping systems – Efficiencies and Scales FARM SIMulator)

NUANCES–FARMSIM (Nutrient Use in Animal and Cropping systems – Efficiencies and Scales FARM SIMulator Tittonell et al., 2008a; van Wijk et al., 2009) is a farming systems model with a special focus on organic matter flows within the farm. The model looks at interactions between the crop and livestock components, and assesses how nutrient management strategies work out on estimated productivity and profit of the farming system. To look at the interactions between crops, soil and livestock, component subsystem models are used that are as simple as possible to avoid being overwhelmed by detail, but to include all major activities to allow scenario analysis. Agricultural fields are represented by the FIELD model that contains linked crop and soil models (Tittonell et al., 2010), livestock production (milk, meat and manure) and reproduction are represented by LIVSIM (Rufino et al., 2009), an individual based model, and manure and organic residue management by HEAPSIM (Rufino et al., 2007). Each of the component models can have multiple instances depending on the configuration of the farm studied and have been tested in detail individually. NUANCES–FARMSIM and the component models are used together with secondary data, expert knowledge and empirical agronomic experiments or feeding experiments to generate understanding of the key processes that control farm performance. Farmers’ decisions on resource allocation are represented in the model based on farmers’ responses during the detailed system characterization and observations in the field. Discussions with key informants and farmers are conducted, both individually and in groups, to understand farmers’ objectives and aspirations and the major constraints faced (Misiko, 2007; Misiko et al., 2008). These discussions feed into the choice of future scenarios to be explored. The model has been applied to study farming systems in West, East and Southern Africa, and to study how individual farms differing in the amount production resources (e.g. amount of land, number of livestock) available respond differently to specific intervention options.

Summary of uses: • Implementing a scenario analysis to evaluate decisions on resource and labour allocation at farm scale, considering a number of different fields