Coastal acid-sulfate soils are crucial for producing crops and thus, for food security. However, over time, these soil resources experience degradation, leading to higher agro-input, lower yields, and environmental hazards that finally threaten food security. The optimal use of this fragile resource is only attained by implementing vigorous integrated water–soil–crop management technologies amid the climate change impact. This study aimed to review the distribution, properties, use, and management of acid-sulfate soils in Kalimantan, Indonesia. Acid-sulfate soils cover about 3.5 Mha of the coastal area in Kalimantan and have high acidity, high-risk iron and aluminum toxicity, and low fertility, requiring precise water management, amelioration and fertilizer application, crop variety selection, and rice cultivation technologies. Lime, biochar, organic fertilizer, compost, ash, and fly ash are ameliorants that raise pH, reduce iron and aluminum toxicity, and improve crop yield. Rice cultivation has developed from traditional to modern but needs re-designing to fit local conditions. Depending on the soil nutrient status, rice cultivation requires 80–200 kg ha⁻¹ of urea, 50–150 kg ha⁻¹ of SP36, 50–150 kg ha⁻¹ of KCl, and 125–400 kg ha⁻¹ of NPK compound fertilizer, but is affected by CH₄ and CO₂ emissions. Good water management impacts the effective implementation of amelioration and fertilizer application technologies. The remaining challenges and future directions for water management, amelioration, fertilizer application, crop varieties, cultivation techniques, land use optimization, climate change adaptation and mitigation, technology adoption and implementation, and resource conservation are outlined. Acid-sulfate soils remain a resource capital that supports food security regionally and nationally in Indonesia.

Black soils refer to soils with black, thick upper layers containing 0.6% or more soil organic carbon in the tropical region. This high organic carbon content makes these soils essential for climate change control and food production. In Indonesia, black soils are found under forests, shrublands, and grasslands in tropical monsoon and savannah climates. Land clearing for agricultural uses will change black soil properties; however, knowledge of change (level, direction, and sensitivity) is limited. Meanwhile, soil surveying records land-use types and collects soil samples, resulting in voluminous legacy soil data. This study aimed to compare the mean difference in soil properties between two land-cover/use types. We used 142 black soil datasets containing legacy data on particle size distribution (sand, silt, clay), pH, soil organic carbon (SOC), total nitrogen (TN), available P₂O₅ (AP), and exchangeable cations (Ca, Mg, K, Na). We calculated the Hedges’s g-index for effect size assessment and performed a Welch’s t-test for significant differences. The results show that, compared to the forest, the agricultural dryland and monoculture home gardens have a large effect size and trigger changes in many soil properties. In contrast, mixed home gardens and paddy fields have a small effect size. In decreasing order, the black soil properties sensitive to change are TN > SOC = exchangeable K > exchangeable Mg = available phosphorus = pH = exchangeable Na > sand = silt = clay > exchangeable Ca. The results suggest that a combination of home gardens and paddy fields better supports food security and mitigates climate change in black soils. In addition, the legacy soil data can be used to monitor soil property changes.

Iron toxicity is a major problem in increasing rice production in acid-sulfate soils. Humate materials and Silica ions can interact with Fe ions to form chelates so that they can decrease Fe toxicity and increase rice yields. This research aimed to study the effect of humate-silica soil on decreasing Fe toxicity and increasing rice yields in acid-sulfate soils. The research employed a simple randomized block design incorporating treatments F0=100% lime, F1=30% humate manufacturer+30% rice husk ash+40% lime, F2=30% water hyacinth humate+30% rice husk ash+40% lime, F3=30% water hyacinth humate+30% rice husk biochar + 40% lime, F4=30% humate manufacturer+30% rice husk biochar+40% lime, and control=without ameliorant. Each treatment was repeated 4 times. Observations of soil characteristics were carried out at the end vegetative stage including pH and Fe, while at the end of the research, observed including panicle length, 100g weight, and grain weight per pot. The findings indicated that F1 was able to increase pH and decrease Fe2+ concentration and wasn’t significantly different from F3. Ameliorant F3 was able to decrease Fe toxicity and increase rice yields. The application of this formula resulted in a decrease in the usage of agricultural lime while enhancing rice productivity in tidal soil.