About the APPA model 

APPA is an integrated model for long term and geographically detailed planning of agricultural activities. Physical production potentials of land are incorporated in the model together with demographic and socio-economic variables and behavioral drivers to reflect spatial distribution of demands and production intensification levels. The model permits to  study in a systemic way robust pathways increasing resource use efficiency in national, subnational and regional agricultural systems to fulfill food security goals, reduce pollution (e.g., non-point source pollution) and stress on natural non-renewable resources (e.g., water, soil), which may significantly depend on the climatic conditions and weather variability.

How the model works

FAST FACTS

• APPA model has been applied for the analysis of agricultural developments in China in the context of EU FP7 project CATSEI and INMIC
• APPA model serves as a basis for the analysis of food, water, energy security issues in Ukraine within a collaborative IIASA – Ukrainian NMO (NASU) project
• In Ukrainian, the model has been revised and applied for the analysis of recent agricultural development trends
• Ukrainian resource data base is being harmonized and compiled to support the APPA-based research

The model incorporates economic growth scenarios and population projections to simulate alternative pathways of agricultural demand increases. In some locations, the indicators characterizing status of the environment and socio-economic conditions may exceed acceptable thresholds, signaling that further production growth in these locations should not take place. The question then becomes how and where to plan expansion of production facilities to meet demand without exacerbating problems. For this, the model uses indicators defined by various interdependent factors including the spatial distribution of people and incomes; the current levels and costs of crop and livestock production and intensification; the availability, conditions and current use of land resources. These indicators are used to discount production locations by the degree of their diverse risks and production suitability. The risk-based preference structure is then used in production allocation algorithms to derive solutions regarding sustainable and robust production expansion, allocation and intensification.

Background

Industrialization of agriculture has a number of comparative advantages, however adverse implications such as weather and market risks, environmental impacts, decrease of rural welfare, rural-urban migration, health hazards, GHG emissions establish the need to identify pathways to sustainable agriculture. APPA model assists in planning geographically detailed agricultural production expansion and allocation coherently with food security goals, social targets, resource and ambient constraints.

Challenges

There exist different approaches to the analyses of optimal production structure and resources allocation in agriculture. APPA model follows general ideas of economic modeling outlined in Nobel Memorial Lecture by Tjalling C. Koopmans (Koopmans 1975).

APPA is a dynamic model with embedded stochastic optimization algorithms enabling to plan production expansion and resource use under natural and anthropogenic uncertainties before the information on uncertainties reveals. 

In the presence of uncertainties and resource (financial, land, water) constraints, the employed stochastic optimization algorithms allow for planning production expansion and allocation in a multi-producers environment using environmental safety and food security constraints in the form of multidimensional risk measures similar to Value-at-Risk (VaR) and Conditional Value-at-Risk (CVaR or expected shortfalls) type indicators.

Last edited: 23 April 2013