About 60% of the rice produced in Indonesia is grown in the fertile soils of the island of Java. Introduction of the high-yielding rice varieties and improvement of cultural technique have increased rice production, and self-sufficiency was attained in 1984. However, increasing population and decreasing land for rice cultivation could threaten the food supply in the country. Rice production is also threatened by interannual climate variability and possible climate change. To provide policymakers and planners with information to formulate a strategy to cope with interannual climate variability and the possible climate change, rice yields of 2 production areas on Java were simulated using the DSSAT (Decision Support System for Agrotechnology Transfer) rice growth simulation model. The crop model predicted lower rice yields for different management options, compared with experiment plots, but predicted yields similar to or slightly higher than the farmers' yield. In general, the predictions relate quite well. The GISS, GFDL, and UKMO climate models predicted higher rainfall, solar radiation, and temperature in both locations. In the higher rainfall and lower temperature of the West Java site, the climate change scenarios reduced rice grain yield in both the first and second crops. During normal years in the relatively warmer and dryer climate of the East Java site, there was no significant yield reduction due to climate change, except under the UKMO scenario in the second crop. Because high temperature and CO 2 concentration favor rice growth, development of more heat-tolerant varieties probably can compensate for the yield losses due to climate change in the future. Except for the GISS and GFDL climate scenarios in the first crop and the baseline climate scenario in the second crop in the West Java site, higher yield losses were predicted because of interannual climate variability. Since the dry spell threat is more imminent and frequent, to improve preparedness a short-term climate prediction for the tropical region is urgently needed.

Indonesian government has promoted the acceleration of local reservoirs development in rural areas. This development shall be integrated in agri-cultural areas to increase its production. Therefore, identification of the potential location and the type of water harvesting infrastructure are crucial to support and optimize the reservoir construction. Here, this research aims to identify the potential location distribution and the type of water harvesting infrastructure in Lampung Province. A Geographic Information System analysis was conducted using several base maps and thematic maps to extract each region characteristics, which include land use, rice field location, river network, slope, area status, buffer zone, groundwater basin, and rainfall pattern. In addition, a survey was conducted to identify potential water availability and land area, including flow discharge in each region. The results showed that the most suitable types of water harvesting infrastructure were channel reservoirs, followed by river water utilization and shallow wells. All infrastructures are highly dependent on rainfall. This means that channel reservoirs have the largest potential area for irrigation services, followed by the river water utilization, shallow wells, and small reservoirs (embung), respectively.