Validation of Evapotranspiration Prediction Model: an Effort to Complete the National Climate Database System

To cope with limited evapotranspiration data, recently, there are many evapotranspiration estimation methods have been developed. Those methods were generally developed in sub tropic region when climate is not similar with Indonesia and the methods may not be applied directly. Validation of several estimation methods including Blaney Criddle, Radiation, Penman, and Pan Evaporation have been done in Cikarawang (Bogor) and Ciledug (Tangerang). The average correction factor andcorrelation coefficient (r) were respectively 1.83 for Blaney Criddle method (r = 0.97); 1.90 for Radiation method (r=0.97); 1.10 for Penman method (r=0.96), and 1.81 for Pan Evaporation method (r=0.98). Penman is the best method with regard on the smallest correction factor especially for station with complete climatic data. Since all methods have correlationcoefficient of more than 0.95, those methods can be used to estimate evapotranspiration based on the available climatic data. The present study used the Penman and Pan Evaporation methods to estimate evapotranspiration in Bogor for period of 1995-2005. The study provides insight into alternative to estimate the evapotranspiration for the area with no lysimeter. The method is selected by considering the available climatic data

Sistem Informasi Kalender Tanam Terpadu: Status Terkini Dan Tantangan Kedepan

. The accuracy in determining time of planting is one of determining factors in securing good harvest and increasing yield of food crop. Local wisdom and other conventional ways applied previously in determining cropping pattern are no longer appropriate because of shifting seasons. As a guideline for extension workers in determining cropping pattern and time of planting, Indonesian Agency for Agricultural Research and Development has published information system of integrated cropping calendar to secure national rice production in coping with climate variability and climate change. This paper aims to describe the development of web-based Information System of Integrated Cropping Calendar at a sub-district level. The system is constructed by integrating three sub-systems, namely sub-system data, model and query and can be accessed through the website address at www.litbang.deptan.go.id. The main information that can be obtained from this system is initial estimate of paddy planting time for the upcoming planting season. In addition, the users can obtain information on disaster prone areas such as droughts, floods and pests attack. Other informations are recommended technology for varieties, seed requirement and fertilizers, that be prepared by users prior to growing season period. Therefore, this system needs to be improved for all sub-districts in Indonesia at least three times a year of the beginning of each growing season. The challenges of developing integrated cropping calendar system for the future are: (1) global warming increases unpredictable weather that impacts on the accuracy of planting time estimate, (2) decreases in productivity and yield production which would require an increasingly technological innovation informations, and (3)land conversion and fragmentation of agricultural land resulting in reduction of paddy field area. Maintenance and development of this system are still needed, to improve the quality of data and information in order to meet the user needs