Dynamic System Modelling and Land Suitability to Define Priority Areas of Soybean Plantation in Paddy Fields in Karawang, West Java

One of the agricultural public commodities in Indonesia which still cannot fulfill its domestic consumption needs is soybean. The objectives of the research, which was conducted in Karawang Regency, West Java, Indonesia, were to: (i) identify the suitable area for soybean plantations in paddy fields, (ii) assess the development of soybeans in land use and socio-economic context, and (iii) plan the spatially soybean plantation. A soil survey and land evaluation for soybean was completed. IKONOS imagery was applied to delineate paddy fields while a dynamic system modelling was developed using Powersim 8.0 software. The results of the research showed that the suitability class for soybean plantation in the paddy fields of Karawang Regency ranges from unsuitable (N) to suitable (S2), with limiting factors being temperature, fertility, nutrients retention, slope, erosion, rooting media and toxicity. Very limited arable land has been used so far for soybeans plantations due to low economic returns. The model predicts that, should the development of soybean continues in its business as usual path, a deficit of soybean will occur in 2030. The model provides alternative scenarios to reduce the deficit. Prioritization was done spatially using the suitable land gradually, corresponding to the government budget availability

Spatial-temporal heterogeneity and driving factors of water yield services in Citarum river basin unit, West Java, Indonesia

Many countries, including Indonesia, face severe water scarcity and groundwater depletion. Monitoring and evaluation of water resources need to be done. In addition, it is also necessary to improve the method of calculating water, which was initially based on a biophysical approach, replaced by a socio-ecological approach. Water yields were estimated using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model. The Ordinary Least Square (OLS) and geographic weighted regression (GWR) methods were used to identify and analyze socio-ecological variables for changes in water yields. The purpose of this study was: (1) to analyze the spatial and temporal changes in water yield from 2000 to 2018 in the Citarum River Basin Unit (Citarum RBU) using the InVEST model, and (2) to identify socio-ecological variables as driving factors for changes in water yields using the OLS and GWR methods. The findings revealed the overall annual water yield decreased from 16.64 billion m3 year-1 in the year 2000 to 12.16 billion m3 year-1 in 2018; it was about 4.48 billion m3 (26.91%). The socio-ecological variables in water yields in the Citarum RBU show that climate and socio-economic characteristics contributed 6% and 44%, respectively. Land use/Land cover (LU/LC) and land configuration contribution fell by 20% and 40%, respectively.The main factors underlying the recent changes in water yields include average rainfall, pure dry agriculture, and bare land at 28.53%, 27.73%, and 15.08% for the biophysical model, while 30.28%, 23.77%, and 10.24% for the socio-ecological model, respectively. However, the social-ecological model demonstrated an increase in the contribution rate of climate and socio-economic factors and vice versa for the land use and landscape contribution rate. This circumstance demonstrates that the socio-ecological model is more comprehensive than the biophysical one for evaluating water scarcity

Spatial-Temporal Changes in Water Supply and Demand in the Citarum Watershed, West Java, Indonesia Using a Geospatial Approach

Balancing water supply demand is vital for sustaining livelihoods. Spatial mapping and calculating water yield dynamics due to land use changes over decades are needed to manage land resources and formulate ecological protection policies. This study mapped the supply, demand, and matching status of water product service using the Integrated Valuation of Ecosystem Service and Tradeoff (InVEST) biophysical models in the Citarum Watershed (CW) in 2000, 2010, and 2020. Moreover, this study used Exploratory Spatial Data Analysis (ESDA) and Geographic Information System (GIS) techniques to study the agglomeration characteristics and evolutionary trajectories of supply–demand over two decades. The results showed that between 2000–2010 and 2010–2020, the water supply decreased by 19.01 × 108 m3 (18.28%) and 12.97 × 108 m3 (15.27%), respectively. However, the water demand in the same period increased by 6.17 × 108 m3 (23%) and 15.74 × 108 m3 (47%), respectively. Over the decades, the contribution of land use land cover (LULC) changes to variations in water supply has yielded values ranging from 2.87% to 6.37%. The analysis of the water supply–demand imbalance indicated that the entire CW experienced water shortage, and the type of spatial matching for supply and demand is dominated by a high supply and high demand class (16.09% of the total area). Based on the level of water deficit calculation, the upstream and downstream areas were identified as zones that require ecological conservation, while the middle CW area requires ecological restoration or ecological improvement.</jats:p

Spatial-Temporal Changes in Water Supply and Demand in the Citarum Watershed, West Java, Indonesia Using a Geospatial Approach

Balancing water supply demand is vital for sustaining livelihoods. Spatial mapping and calculating water yield dynamics due to land use changes over decades are needed to manage land resources and formulate ecological protection policies. This study mapped the supply, demand, and matching status of water product service using the Integrated Valuation of Ecosystem Service and Tradeoff (InVEST) biophysical models in the Citarum Watershed (CW) in 2000, 2010, and 2020. Moreover, this study used Exploratory Spatial Data Analysis (ESDA) and Geographic Information System (GIS) techniques to study the agglomeration characteristics and evolutionary trajectories of supply&ndash;demand over two decades. The results showed that between 2000&ndash;2010 and 2010&ndash;2020, the water supply decreased by 19.01 &times; 108 m3 (18.28%) and 12.97 &times; 108 m3 (15.27%), respectively. However, the water demand in the same period increased by 6.17 &times; 108 m3 (23%) and 15.74 &times; 108 m3 (47%), respectively. Over the decades, the contribution of land use land cover (LULC) changes to variations in water supply has yielded values ranging from 2.87% to 6.37%. The analysis of the water supply&ndash;demand imbalance indicated that the entire CW experienced water shortage, and the type of spatial matching for supply and demand is dominated by a high supply and high demand class (16.09% of the total area). Based on the level of water deficit calculation, the upstream and downstream areas were identified as zones that require ecological conservation, while the middle CW area requires ecological restoration or ecological improvement