Assessing the potential yield of tropical crops: role of field experimentation and simulation

Abstract

This review assesses the role of field experimentation and simulation in better quantifying the potential productivity in different environments, and examines how knowledge on potential productivity can improve the efficiency of the production system. Case studies are presented for the tropical crops maize and rice to highlight the importance of temporal and spatial variation in climatic factors on the yield performance of high-input systems. The key role of field experimentation is to quantify the impacts of temperature and solar radiation on resource capture and resource utilization for a given variety. There is a need to collect minimum data sets of key crop, soil, management and climate variables, and to ensure that climatic data, particularly solar radiation, are regularly calibrated. When knowledge from field experimentation is encapsulated into crop growth simulation models, the gap between actual and potential yield for a given environment can be determined and opportunities for yield improvement can be assessed. Simulation can also be used to quantify temporal and spatial variation in productivity, for use in planning future world food supplies. Given that scope for raising maximum yields is limited, the focus of production research should be on narrowing the gap between actual and potential yields and on the maintenance of maximum yields. By characterizing the frequency of occurrence of constraints in different regions, crop simulation can potentially enhance the efficiency of plant breeding. Given the potential negative impacts of high-input agriculture on the environment, simulation can identify best-practice management options to better align resource supply with crop demand. The development of electronic data bases of climate, soil, management and crop growth data is a priority need, so that the synergy between field experimentation and simulation can be maximized.