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The rice yield gap (YG) is a global concern, requiring more detailed studies spatially and temporally. As a staple food in Indonesia, rice was produced from 7.4 Mha paddy fields in 2019. Better insight into the YG helps assess measures to boost rice production. However, the information on YG variation among regions scale is limited. This study aimed to identify the rice YG based on 295 historical trial datasets from 23 provinces in Indonesia. We surveyed published trial results from 2012 to 2022 and analyzed YGs, expressed as the percentage of farmer yield (FY). The potential yield (PY) was estimated from field trial results using introduced rice cultivation technology package, whereas FY from results using existing farmer practices. Our study showed that the average YG was 62% in rainfed, 54% in tidal, and 32% in irrigated paddy fields. The YG was significantly high in the paddy fields of Kalimantan (74%) and Maluku-Papua (49%), while the lowest was in Sulawesi (27%) and Java (31%). The YG varied significantly with geo-regions, rice varieties, and cultivation technology packages. Closing the YG and ensuring sustainable rice production requires the implementation of sustainable intensification through applying site-specific technology packages, reallocation of agricultural interventions to a higher YG region, and rice variety improvement to increase PY.

Oil palm cultivation on peatlands is of great importance for improving the wellbeing of farmers. Managing peatlands is challenged by poor nutrient availability and low nutrient retention. Applying ameliorants and fertilizers is required to enhance peat soil properties. This study aimed to assess the effect of biochar and ash from oil palm empty fruit bunches (OPEFBs), dolomite, and mineral fertilizers on peat soil quality and fertility. The field experiment was conducted on young oil palm cultivation in the peatland of Palalawan regency, Riau province, Indonesia, by using a randomized block design with two treatment factors. The first factor was the ameliorant: dolomite, dolomite + ash from OPEFB, and dolomite + biochar from OPEFB. The second factor was the dose of NPK compound fertilizer: NPK with standard recommendation dose, NPK with site‐specific recommended dose, and NPK with farmer's dose. The observed parameters included soil properties, leaf nutrient status, and midrib characteristics. Assessing the treatment effect used an analysis of variation and treatment mean comparison using the Tukey test. The results showed that ash and biochar from OPEFB improved peat soil pH, electrical conductivity, available phosphorus (P) and potassium (K), and the growth of oil palm plants. Applying NPK fertilizer using the site‐specific recommendations dose improved soil properties, leaf nutrient status (N, P, and K), and the growth of one‐year‐old oil palms. The utilization of ash and biochar from OPEFB may reduce agricultural lime on peatlands. [ABSTRACT FROM AUTHOR]

The application of remote sensing data has been significant in modeling soil erosion. However, previous studies have fallen short in elucidating and lacked an understanding of the multifactor influencing erosion. This study addresses these limitations by employing the InVEST and the Geodetector models. Specifically, it aims (1) to delineate both spatial and temporal variations in soil erosion within the Citarum watershed from 2010 to 2020, (2) to identify the key drivers of soil erosion and unravel the underlying mechanisms, and (3) to identify the high-risk zones for soil erosion. Both models consider a range of natural predictors, including topography (slope factor), climate (precipitation factor), and vegetation cover (vegetation factor). In addition, they incorporate social parameters such as income per capita and population density, which interact with the watershed's position in the downstream, middle, and upper streams. The results reveal that, over a decade, the average soil erosion increased by 15.50 × 106 tons, marking a 16.65% surge. The impact of factors varies significantly across different subwatershed areas. For example, fraction vegetation cover interactions influence upper- and middle-stream regions, while the downstream area is notably affected by precipitation interactions. The high-risk erosion areas in the watershed are primarily influenced by slope, precipitation, and fractional vegetation cover. In these areas, factors causing high erosion risks include slope, precipitation, and other environmental variables categorized into strata. The study highlights the varying influential factors in different watershed areas. [ABSTRACT FROM AUTHOR]

Exploring the drivers of changes in ecosystem services is crucial to maintain ecosystem functionality, especially in the diverse Central Citarum watershed. This study utilises the integrated valuation of ecosystem service and trade-offs (InVEST) model and multiscale geographically weighted regression (MGWR) model to examine ecosystem services patterns from 2006 to 2018. The InVEST is a hydrological model to calculate water availability and evaluate benefits provided by nature through simulating alterations in the amount of water yields driven by land use/cover changes. Economic, topographic, climate, and vegetation factors are considered, with an emphasis on their essential components. The presence of a geographical link between dependent and explanatory variables was investigated using a multiscale geographic weighted regression model. The MGWR model is employed to analyse spatial impacts. The integration of both models simplified the process and enhanced its understanding. The findings reveal the following patterns: 1) decreasing land cover and increasing ecosystem services demand in the watershed, along with a decline in water yield, e.g. certain sub-districts encounter water scarcity, while others have abundant water resources; 2) the impact of natural factors on water yield shifts along vegetation > climate > topography (2006) changes to climate > vegetation > topography (2018). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]