A Proposed Improvement of Belanti II Tidal Irrigation Scheme, Kalimantan, to Support Leaching of Acid Sulphate Soil Reclamation

The reclamation process of acid sulphate soil of the Belanti II tidal irrigation scheme remains unfinished. During ebb tide, the upstream acidic drainage water retains and settles in the irrigation canals. During high tide, the acidic water flows back into some parts of the agricultural land and reduces rice productivity. The measured pH is about 2.5 ~ 3.5 and the measured electric conductivity is about 0,25 ~ 0,35 mS/cm. Sedimentation in the middle to the end of the primary, secondary, and collector canals and tidal pond at the upstream end of the primary canal, preventing the leaching process of sulfuric acid soil. Primary canal normalization as an alternative solution to increase the capability of acidity leaching is proposed. Leaching the acidic soil of Belanti II irrigated area of 3.976 ha requires 500 m3/ha/day of freshwater, equivalent to 1.998.000 m3/day. The one-dimensional HEC RAS mathematical model is used to evaluate the hydraulics performance to support the leaching process. The hydraulic analysis was carried out using two tidal cycles on the existing channel and the normalized channel. Channel normalization has succeeded in reducing the water supply deficit to support the leaching process from 39% to 9%.

Post reclamation of acid sulphate soil due to extended tidal irrigation area in Palingkau, Central Kalimantan, Indonesia

The Palingkau Swamp Irrigation Scheme SP1 SP2 SP3 extends tidal irrigation between Kapuas Murung River and Kapuas River, which local peoples developed. The development of the new agricultural land behind the old tidal irrigation system creates oxidation of potential acid sulphate (FeS2) soil. The result of the leaching process polluted local’s agricultural area causes the decrease land productivity. The field observation recorded the water pH ranges between 3.9 - 5.3; 3.7 - 4.31 at the handil; 2.5 - 4 at the collector channels; and 2.8 - 3.6 at the primary channels. Good water management is needed to overcome these problems, both at the new irrigation system and handil. The HECRAS mathematical model is used to evaluate water circulation in the system and its reliability. The Efforts to normalize the handil impact increasing the amount of water entering the handil although it is not significant. Moreover, it still cannot meet the water demand for the leaching process in the network system by 2.06 million m3/day. It is necessary to increase the capacity of the channel to allow freshwater flow from the river for the leaching process in the network system.

Effects of cropping system and varieties on the rice growth and yield in acid sulphate soils of tidal swampland

Swampland plays a critical function in agriculture, specifically in growing rice production. The study aimed to determine the effects of cropping systems and varieties on the rice growth and yield in acid sulfate soil of tidal swampland. The experiment was conducted in a potential acid sulphate soils in Kapuas Regency, Central Kalimantan Province. The experiment was arranged in a split plot design with three replications. The main plot consisted of three HYV’s of rice, namely Inpara 8, Inpari 32, and Margasari. The subplot consisted of five cropping systems, namely, Jarwo 2:1A, Jarwo 2:1B, Jarwo 2:1C, Hazton, and Tegel. The plot size was 4 m x 5 m. The variables observed included initial soil properties, plant growth, and yield components. The jajar legowo cropping system in this study was not able to increase rice yields in acid sulphate soil. There was an interaction effect of cropping systems and varieties on the plant height and number of tillers at vegetative phase. At generative and pre-harvest phases, there was significant single effect of variety and cropping system in the planting height and number of tillers, respectively. Both cropping system and variety significantly affected the number of panicles per hill, while panicle length, grain per panicle and grain yield were only affected by variety. There was no significant effect of both factors on the number of filled grains per panicle. Inpara 8 variety achieved the highest grain yield, which was 6.78 ton.ha-1 or equivalent to 4.34 ton.ha-1 of 14 % water content.

Behaviour of Fe, Mg and Ca in acid mine drainage and experimental solutions in the presence of Aspergillus niger species isolated from various environment

This article analyzes the ability of micromycetes to accumulate Fe, Mg and Ca from acid mine drainage (AMD) at the locality Smolník. Four strains of the Aspergillus niger (An) species originating from various types of environment were used in the experiments: the An-G strain (the locality of Gabčíkovo, Eutric Fluvisol), the An-P strain (the locality of Pezinok-Kolársky vrch, mining region with elevated amounts of As and Sb), the An-N strain (the locality of Nováky, mining region with elevated amounts of As and S), the An-Š strain (Banská ŠtiavnicaŠobov, the locality impacted by an acid sulphate weathering and extremely low pH). In the most cases the accumulation of Mg was the highest in comparison to accumulation of Fe. Accumulation of Ca was very low. Among the tested microfungi, the highest accumulation was noted by the strain An-N 55 % of Mg and by the strain An-Š 54 % of Fe from the model solution of the elements (Fe [1.67 mg/L], Mg [2.35 mg/L] and Ca [1.14 mg/L]).

Acid Mine Drainage (AMD) and Acid Sulphate Soil monitoring using mineral and image spectroscopy: hyperspectral and multispectral approaches

<p>Mining generates a number of significant environmental impacts, such as increased acidity of the soil/water environment, called mineral Acid Mine Drainage (AMD) being produced when sulphide-bearing material is exposed to oxygen and water.  Similar problem represent acid sulphate soils which are naturally occurring soils containing iron sulphide minerals (predominantly pyrite) or their oxidation products. Once these soils are drained, excavated or exposed to air by a lowering of the water table, the sulphides react with oxygen to form sulfuric acid. For both AMD and acid sulphate soils, there is a lack of historical and update records and, consequently, there is a need for new monitoring techniques allowing systematic analysis. A systematic study on how to map mineral patterns that characterize these acid environments using proximal remote sensing and imaging spectroscopy is presented. Furthermore, the upscaling to the spectral and spatial resolution of the satellite data such as WorldView2/3 and Sentinel-2 is discussed as well as an issue of transferability of the developed methods between the test sites which are characterized by different geographical conditions and environments.</p>

Hydrothermal alteration and sealing at Turrialba as a mechanism for phreatic eruption triggering

<p>Turrialba is a basaltic to andesitic Holocene stratovolcano that after decades of quiescence re-activated in 1996 and has been highly active ever since. Turrialba is characterized by a highly active magmatic-hydrothermal system, and we propose that hydrothermal sealing and volatile accumulation are the mechanisms responsible for the reactivation and persistent phreatic activity at Turrialba since 2010. Evidence of sealing is found in pyroclastic breccias from phreatic eruptions as high concentrations of hydrothermal minerals coupled with low intrinsic permeability. The suite of volcanic breccias studied erupted from the main vent between 2014 and 2019 and has an alteration mineral assemblage of SiO<sub>2</sub>polymorphs ± gypsum ± natroalunite ± pyrite. The mineral assemblage is indicative of acid sulphate alteration within the advanced-argillic alteration facies characterized by temperatures of approximately 200-350°C as indicated by the presence of gypsum and natroalunite, the high temperature endmember of the alunite series. Acid sulphate alteration is the result of extreme base leaching by acidic fluids (pH<4) with a high sulphate content. Measurements of permeability and porosity yielded variable porosity and very low to non-existent permeability in all hydrothermal breccia samples. Back-scatter electron (BSE) images reveal nano-, micro- and macro-scale fracture networks discontinuously filled with hydrothermal gypsum and pyrite which are responsible for diminished permeability, supporting the conclusion that hydrothermal sealing is active at Turrialba. Diminished permeability associated with the formation of a seal inhibits the escape of gases, causing them to accumulate below the seal and pressurize the system. Eventual seal failure releasing overpressure and possibly dynamic rapid seal formation result in the frequent phreatic eruptions seen at Turrialba.</p>