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%.

The Effect of Biochar, Lime, and Compost on The Properties of Acid Sulphate Soil

<p><span style="font-size: small;"><span>Making acid sulphate soils as paddy fields is a wise choice because it can prevent the soil from oxidizing which occurs in acidification of the soil. The use of biochar as an amendment to the land has long been known since the discovery of terra preta since 1870 in the Amazon Basin as the Amazon dark earth. Because biochar soil amendments are rich in C-organics, have a buffering capacity and can increase soil acidity, are able to absorb heavy metals, and are able to retain water and nutrients for soil organisms. Meanwhile, lime has also been known as an acid sulphate soil amendment in Rome 2000 years ago to balance the acidity in agricultural land. This has been practiced for centuries until now. Though compost or organic soil can be traced more than 2000 years ago. Soil organic matter (SOM) is formed from the remains of animals and plants. It contains C and many nutrients such as N, P, and K. Based on the description above, the author wants to combine the three ingredients in the review, especially in relation to acid sulphate soils.</span></span></p>

The role of iron oxidizing bacteria to the quality of leachate on acid sulphate soil

The problem encountered in acid sulphate soil is the presence of pyrite (FeS2) which causes soil to have highly acid reaction when the pyrite is oxidized. The decline in quality not only occurs on the soil but also on the quality of the surrounding waters. One way to improve the quality of the leachate is by draining it through biofilter plants in the form of purun tikus (Eleocharis dulcis) and bulu babi (Eleocharis retroflaxa) which can absorb or neutralize these elements. The purpose of this research was to know the inoculant influence of iron oxidizing bacteria to leachate quality in acid sulphate soil. The research was conducted on a pot scale in greenhouse. The research was in randomized block design (RBD) of 3-factors with 3 replications. The first factor was inoculants, the second factor was water management, and the third one was phytoremediation material (Eleocharis dulcis and Eleocharis retroflaxa). The results showed that the plant height in the inoculant treatment+wood charcoal was in the range of 89.33−95.33 cm, while that in the inoculant treatment+husk charcoal was in the range of 89.50­­­−93.00 cm. Meanwhile, the yield of rice with bacteria oxidizing iron inoculant+wood charcoal was higher, which was at 6.77 ton.ha-1 than inoculant treatment of oxidizing iron+husk charcoal which was only 5.95 ton.ha-1.