A Dynamic Model to Uphold Rice Self-Sufficiency Efforts, Case Study; Karawang Regency, West Java Province.

Abstract

Paddy fields are Indonesia's most important agricultural land use, supporting national food security. Such lands have experienced a massive change in their dynamics, specifically in rice (Oryza Sativa) production home, West Java. Karawang paddy fields notably become the major victim of land-use change and rapid economic growth, development, and population pressure. This study aimed to I) analyse land use/ land cover change, II) Predict the future land-use change in the Karawang Regency, West Java Province, and III) Design/simulate policy scenarios to uphold future rice self-sufficiency policies. The study employed three different methods to meet its objectives. Remote sensing techniques and satellite images were used for investigation across the Karawang Regency. Three kinds of satellite image datasets of Landsat 5 TM, Landsat 8 OLI, and Sentinel 2 from 2009, 2014, and 2019 were analysed. Based on the Markov model, a land change modeller was used to predict conversion in 2031, and PowerSim was used to develop system dynamics to simulate scenarios. The results revealed that land-use change impacted paddy fields conversion significantly. Karawang Regency lost 16,346.77 ha or 8.54 % of its paddy fields throughout the assessment period. Such farmlands declined by 8,639.84 ha (4.51%), 7,706.93 ha (4.02%), and it's expected to be converted by 12,306.75 ha or 6.40 % between 2009 -2014, 2014 to 2019, 2019-2031, respectively. The conversion of paddy fields to build areas, including road infrastructures, is approximately 14,536.21 ha, representing 57.98% of the total paddy fields converted. As a result of build-up area expansion (2014-219) within RTRW and LP2B areas, paddy fields will be reduced by 5,099.68 ha or 5.40% and 3,385.98 ha or 3.28%, respectively. While between 2019-and 2031, they will be reduced by 7,463.88 ha or 7.90 % and 13,913.28 ha or 13.50%, respectively. The highest and lowest conversions will occur in the sub-districts of Banyu Sari and Tegalwaru. Up 95% of the expanded build area will be a converted irrigated paddy field with an area range of 1-99 ha. Only 5% will be rainfed paddy fields exclusively located in the south eastern part of the Regency. The developed system dynamics indicated that the overall Maximum relative errors, coefficient of determination, and mean absolute per cent error of tested variables were 1.33%, 0.760, and 1.49, respectively. Under the Business-as-usual scenario (BAU#), it was found that the population of Karawang will reach 6.1 million people, and the paddy fields will be reduced to only169 a thousand ha by the end of the century. The scenario will result in a reduction of Karawang rice Availability Per Person (APP), surplus (SPs), and Self-sufficiency (SSL) by 66.20, 50.55, and 359%, respectively. Besides that, the Rice demand scenario (SNO#3) indicated the Regency will be out of rice surplus in 2094 and 2085 when the consumption/ demand of rice increases by 80% (SNO#3.3) and 100%(SNO#3.4), respectively. It's been concluded that paddy fields conversion is the main threat that may undermine the future rice supply for Regency and maintain 1.5 million tons of rice surplus. The study recommended that proposed possible interventions should be considered along with the formulation and implementation of upcoming Regional Short, Medium, and Long-term Development Plans (RPJPD, RPJMD, and RPJPD).