Delineation of Potential and Actual Rice Planting Scheduling in Lampung and West Kalimantan
Deliniasi Kalender Tanam Padi Potensial dan Aktual Propinsi Lampung dan Kalimantan Barat
Rice is the staple food for 95% Indonesian. As the population growth, the demand for rice is expected to increase at a rate of 2.5% per year (BPS, 2006). To meet this increasing demand, Government of Indonesian has planned and conducted intensification and extensification programs. However, inter annual variability of rice production is relatively high due the occurrence of extreme climate events. One approach to minimize the impact of extreme climate events is to determine appropriate cropping pattern and planting time as well as total area planting under different extreme climate condition. This study assessed appropriate cropping pattern, planting time, and optimal planting area for rainfed rice under dry, normal and wet years. The study was conducted in two main rice growing area of Indonesia, i.e. Lampung and West Kalimantan. The two districts contribute to about 3.9% and 2% of national rice production, respectively. Cropping system in lampung and west kalimantan depend on water availability, mainly is rice - rice – fallow. Based on 25 years of rainfall record, these two districts are sensitive to ENSO. The extreme climate events such as drought and flood are commonly associated with ENSO. This study classified the climate condition under three conditions, dry, normal, and wet years. Based on 30 years average rainfall data, wet year is a year when the rainfall is higher than 115% of the average. Normal year is a year when the rainfall is between 85% and 115% of the average, and dry year is a year when the rainfall is below 85% of the average. The classification is shown as isohyet, potential first planting , and cropping index maps. The isohyet map is used to determine the potential paddy plantation period during one year, the potential first planting map is used to determine the first time of paddy planting, and cropping index map is used to determine the crop rotation potential during one year. The first planting of paddy is based on water availability, when the rainfall during three decad is more than 150 mm. The three maps are then overlaid with land use map. The result is a database of potential planting scheduling of wet year, normal year, and dry year. This database is compared by the actual condition based on field research. Based on the potential and actual planting scheduling analysis in Lampung, it is concluded that the planting area in normal and wet years have not met its optimum area. Meanwhile, in dry years it has exceeded its optimum area. The actual annual cropped land is 64023 Ha, in wet years it increases to 130440 Ha, in normal years it 122133 Ha, and dry years is 56377 Ha. Lampung and West Kalimantan’s rainfall are sensitive to climate anomaly. It is concluded from the changing in first planting period and cropped land area potency during wet, normal, or dry years. The planting scheduling can increase agricultural production yield by giving information for first planting period, cropped land width potency, and crop rotation.