Rice plantation projection based on scenario representative concentration pathways (RCP) 4.5 in West Java Province

Abstract

Climate change is characterized by the changing of weather and climate elements in the earth, such as temperature and precipitation over a long period. The changing of these climate elements will affect the water balance then affect the agricultural management system, especially in timing and cropping patterns. This study aims to explain the projection of climate change result in the future and its relation with the changing of planting time and crop patterns of rice in West Java Province based on Representative Concentration Pathways (RCP) 4.5 scenario from 2006 until 2040. The data used in this study were observation data of temperature and rainfall in period of 2006-2015 from 39 rainfall posts with the height data of each rainfall post. The analysis conducted in this study was based on Thorntwaite and Matter water balance models by using observation data (2006-2015) as the baseline and future periods (2021-2030 and 2031-2040). Air temperature and rainfall data in period of 2006-2015 were used to correct the model data. Calculation of groundwater availability was calculated for each representative of Oldeman climate type. Furthermore, the rice planting schedule can be known when the condition of the level of groundwater availability reaches field capacity. The results of the analysis show changes in the Oldeman climate type and the level of groundwater availability due to changes in air temperature and rainfall parameters resulting from projections on current conditions. This caused a change in the planting schedule. The planting schedule will start early when the climate type turns wet, so the condition of the level of groundwater availability increases. The planting schedule in September was seen more broadly in the East and West parts of West Java in the period of 2021-2030 compared to the period of 2006-2015 and 2031-2040.