Critical land is a condition of land that is no longer able to carry out its functions properly because it has experienced physical, chemical, and biological damage. One area that has the potential to experience critical land problems is the Cikapundung Sub-watershed, West Java. This research aims to identify the existence of critical land in the Cikapundung Sub-watershed area by integrating the Geographic Information System, Sentinel-2 Imagery, and DEMNAS as well as mapping the distribution of land criticality levels in the Cikapundung Sub-watershed at a detailed scale (1:25,000). The research was carried out from May to August 2023. The research was carried out using spatial analysis methods by overlaying thematic maps of each critical land parameter consisting of maps of land cover, erosion, and slope. The results of overlaying all critical land parameter maps were then analyzed using a scoring method to classify the level of land criticality and create a critical land distribution map in the Cikapundung Sub-watershed area. The results of identifying critical land in the Cikapundung Sub-watershed area produced five classes of land criticality, namely uncritical, potentially critical, rather critical, critical, and very critical. The identification results show that there are 4210.94 ha (13.83%) of land identified as critical land in the Cikapundung Sub-watershed area. The results of mapping the level of land criticality in the Cikapundung Sub-watershed show that the Cikapundung Sub-watershed area which is included in the forest area is dominated by the moderately critical land criticality class, while the Cikapundung Sub-watershed area which is outside the forest area is dominated by the uncritical land criticality class.
Conservation of water and water level regulation is an important key to successful agricultural development in swampland. Several techniques to create embankments, blocks, and sluices are available and their application in the field is determined by hydrological conditions and characteristics of the area. Elbow Water System Application ( TASEL) is a technique to create blocks and sluices for water conservation and regulation in tidal swampland. TASEL uses pipes as culverts and elbows as sluices. This paper discusses the application of the TASEL system in tidal swamp rice fields in Talio Hulu Village, Central Kalimantan Province. The location of this study is in secondary areas (ray) 39, 40, and 41 as a part of tidal rice fields. This area has been abandoned by farmers for 10 years, and the rice fields have been covered by various grasses and long-leaved paperbark ( Melaleuca leucadendra ), frequent floods, and fires. Soil type is dominated by peaty soil. The hydrological survey was carried out to determine the condition of the canals and inundation conditions in the plots of land. Furthermore, the pipe requirements, elbow requirements, and TASEL installation locations are formulated. As a result, 2 pipes and elbows were required for each hectare of land and were installed on the left and right of the rice fields. In addition, the perimeter ditches and micro ditches are made to facilitate the circulation of water in the rice fields. The combination of TASEL, perimeter ditches, and micro ditches can conserve water, regulate water levels, and provide water for plant growth.
<p><em>Information on the spatial distribution of soil organic carbon content is required for sustainable land management. But, creating this map is time consuming and costly. Digital soil mapping methodology make use legacy soil data to create provisional soil organic carbon map. This map helps soil surveyors in allocating next soil observation. This study aimed: (i) to develop predictive statistical soil organic carbon models for Sulawesi, and (ii) to evaluate the best model between the three obtained models. Boalemo Regeny in Gorontalo Province (Sulawesi) was selected as studying area due to abundant legacy soil data. The study covered dataset preparation, model development, and model comparison. Dataset of soil organic carbon at 6 different depths as target was established from 176 soil profiles and 7 terrain parameters were selected as predictors. Soil-landscape models for each soil depth were created using regression tree, conditional inference tree, and multiple linear regression technique. Result showed that model performance differed among 3 modelling techniques and soil depths. The tree models were better than the multiple linear regression model as they have the lowest RMSE index. The best model in the mountanious area seems to be the regression tree model, whereas in the plains it may be the conditional inference tree. In creating provisional map, several model should be developed and the median of predicted value is used as provisional map.</em></p><p><em> </em></p><p><em>Keywords: Digital soil mapping, multiple linear regression, regression tree, soil-landscape model, soil organic carbon map</em></p>
<p>Understanding peatland coverage and characteristics is essential for improved utilization and conservation efforts. Peatlands in Bangka Belitung Islands, Sumatra, are under threat of illegal mining activities. Creating detailed maps is challenging in Indonesia amid low accessibility, yet the physiographic approach provides an alternative strategy in peatland map provision. This research aims to update peat data in the Bangka Belitung Islands Province, create peat soil maps at a scale of 1:50,000, and estimate peat soil carbon stocks. This research started with a base map using a 1:50,000 scale, surveyed and sampled the soil on transects perpendicular to the river, analyzed the samples in the laboratory, and created a peat soil map. Compared with the existing map, the new map improves land unit attributes and peat characteristics as well as improves delineation results. Results show that peat soils cover 24,311 hectares, mostly distributed in Central Bangka and South Bangka Regencies, with depths varying between 50 to < 300 cm. Shallow peats dominate with an area of 13,668 hectares (56.22%). The estimated carbon stock contained in peat is 11.6 million tons C. The peat soils are Organosol Saprik, Organosol Hemik, and Organosol Sulfidik. The soils are acidic with low exchangeable cations and base saturation. The study highlights that deep peat soils under bushes and shrubs should be conserved for forests or reforested. Detailed spatial information on peatlands is useful for policymakers related to local peat soils planning and management.</p>
Black soils store a high amount of soil organic carbon (SOC) and play a crucial role in climate change, food security, and land degradation neutrality. However, data and information regarding black soils in tropical regions, including Indonesia, are limited. This study aimed to characterize and identify the utilization of black soils in Indonesia based on legacy soil survey data. We collated 142 soil pedon samples of Mollisols from articles, technical reports, and existing datasets. The site information (site position, elevation, land use type, parent material) and selected physicochemical properties were stored in a spreadsheet, from which exploratory data analysis was conducted. The result showed that the median SOC content was 1.53%, ranging from 0.6 to 8.2 %; cation exchange capacity was 30 cmol kg<sup>-1</sup>, ranging from 9 to 95 cmol kg<sup>-1</sup>; base saturation was 87%, ranging from 11 to 100 %; and bulk density was 1.21 g cm<sup>-3</sup>, ranging from 1.13 to 1.36 g cm<sup>-3</sup>. Other soil characteristics (particle size distribution, exchangeable bases, pH, pore, and water retention) varied with horizon type and land use/land cover. The black soils have been used for paddy fields, dryland farming, and gardens with low management intensity. Main cultivated crops include rice (<em>Oryza sativa</em>), corn (<em>Zea mays</em>), cassava (<em>Manihot esculenta</em>), sweet potato (<em>Ipomoea batatas</em>), and nutmeg (<em>Myristica fragrans</em>), clove (<em>Syzygium aromaticum</em>), coconut (<em>Cocos nucifera</em>), and cocoa (<em>Theobroma cocoa)</em>. Threats to black soil functions include soil erosion, carbon loss, and nutrient imbalance. Soil and water conservation measures, integrated soil nutrient management, and agroforestry are among the best land management practices for black soils.
Conversion of tropical peat swamp forests to meet the demand for industrial plantations and agricultural production systems has triggered rapid and substantial carbon loss in the Asia‐Pacific region. Various management practices have been designed to reduce carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O) emissions from tropical peat soils after changes in land use. We conducted a meta‐analysis using 506 paired observations on greenhouse‐gas (GHG) emissions from peat soils under different land uses and the effects of management practices on emissions. As compared to peat swamp forest, other land uses had higher emissions of CO 2 (heterotrophic respiration) and N 2 O from soils, whereas soil‐based CH 4 emissions were also increased but not significantly so. Raising the water table decreased CO 2 emissions but increased N 2 O emissions; reducing nitrogen fertilizer inputs led to decreased CO 2 and N 2 O emissions in oil‐palm ( Elaeis spp) plantations and cropping systems; and shading and growing cover crops decreased CO 2 emissions. Practices such as these are needed for careful management of tropical peatlands, and additional measurements at appropriate spatial and temporal scales are required to guide future GHG mitigation strategies in tropical peatlands.
Low soil fertility of acid paddy soils in East Kalimantan becomes the primary constraint in boosting rice yield. Generally, integrated soil management by applying organic matter, lime, humic acids, biofertilizer, and zeolite improves the soil's physical, chemical, and biological quality. To promote rice productivity in acid paddy fields, we tested the effectiveness of local bio-activators in promoting rice growth and flowering. The experiment was carried out from July to November 2020 in Embalut Village, Kutai Kertanegara Regency, East Kalimantan (Indonesia). We used a split-plot design using two factors and three replications, using Cibogo as a standard variety. The first factor was the application of local bio-activators by using four levels (A-0: control, A-1: 100mL/L, A-2: 150mL/L, A-3: 200mL/L). The second factor was spraying frequency during ten days intervals using four levels (F-0: control, F-1: twice, F-2: four times, dan F-3: six times). The results showed that pyrite was on the soil after four days of application on the soil surface. In addition, rice sprayed by local bio-activators was more resistant to leaf blasts. The application of local bio-activators increased soil quality and rice yield. The highest yield was from four-time spraying (128.50g, equivalent to 8.03t unmilled rice per ha) and a dose of 10 L/ha (122.22 g, equivalent to 7.64 t unmilled rice per ha). Bio-activator is prospective material for improving rice production.
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