Mapping Yield Gaps for Rice and Maize in Indonesia.

Indonesia is respectively the 3^rd and 8^th world largest rice and maize producing country and achieving food self-sufficiency for its 250 million people is important for the country and the world. Hence, assessing food production potential is crucial to design policies aimed to achieve a reasonable level of food self-sufficiency under different climate, land, and socio-economic scenarios. Eleven main rice and maize production areas, distributed in Java, Sumatra, Kalimantan, Sulawesi, and Nusa Tenggara were selected. Measured long-term (15-y) daily weather data, including rainfall, maximum and minimum temperature, and radiation were retrieved from one to four weather stations located within each of these production areas. Soil, management, and actual yield data for dominant maize- and rice-based crop sequences were retrieved from local experts and national database. Crop model ORYZA for rice and Hybrid-Maize for maize were calibrated using data from well-managed experiments conducted in Indonesia. These models were subsequently used to estimate average yield potential (and its variability) for each of the rice and maize production areas. The yield gap was estimated as the difference between the simulated yield potential and the actual average on-farm yield in each region. Results of these modeling will be essential as a solid foundation to estimate potential food production increase on existing cropland area and to identify regions with greatest potential for crop intensification.