Effectiveness of Organic Materials as Media in Sulfate Reducing Bacteria Inoculum to Changes on Acid Sulfate Soils

Acid sulphate soils (ASS) had low pH, low nutrients availability and also soluble aluminium and iron were high. Inoculum of sulphate reducing bacteria (SRB) which organic matter as media could increased the soil pH, nutrient content and decrease sulfur-total of acid sulfate soils. The research was conducted in a randomized block design with two replications. This study used a randomized block design with two factors and two replications. The first factor was compost inoculum (C) was taken ten treatments from without any inoculum SRB and 9 treatment with different types and dosages of organic matter as media. The second factor was the water content condition (K) namely of K1: 100% field capacity and K2: 110% field capacity. Different types and dosages of organic matter appear to influence the changes in soil properties (tends to decrease soil sulfate and increase soil pH, and nutrient content levels in soil and plant). Inoculum SRB of palm oil empty bunches and weed gave a higher sulfate reduction compared to C0 (without inoculums) or inoculums with carrier media that used rice straw in water content 100% or 110% field capacity (FC).

Biochar Capacity to Mitigate Acidity and Adsorb Metals—Laboratory Tests for Acid Sulfate Soil Drainage Water

A 96-h laboratory experiment was conducted to assess the potential of biochar as a water protection tool for acid sulfate soil runoff. Acid sulfate soils pose a risk to water bodies due to acid, metal-rich runoff, especially in drained peatland forests. New water protection methods, such as adsorption with biochar, are needed. We investigated the capability of spruce and birch biochar to adsorb metals and reduce acidity in the water. Water from an acid sulfate site was stirred with biochar, biochar with lime, and biochar with ash. We determined water Al, S, Fe, Cu, Co, Cd, Ni, and Zn concentrations periodically, as well as pH and total organic carbon at the beginning and the end of the experiment. The studied substances are considered the most abundant and environmentally harmful elements in the acid sulfate soils in Finland. Biochar surface characteristics were analyzed with FTIR spectroscopy. Concentration changes were used to parametrize adsorption kinetics models. Biochar adsorbed metals and increased pH, but lime and ash additives did not always improve the adsorption. Spruce biochar and ash addition had generally higher adsorption than birch biochar and lime addition. The adsorption was dominated by Al and Fe at lower pH, while increasing pH improved the adsorption of Cd and Zn. The results show that biochar can increase the water pH, as well as adsorb Al, Fe, Co, Cd, Ni, and Zn. Further work could include an actual-scale biochar reactor in a laboratory and field conditions.

Influence of two phosphate-potassium solubilizing bacterial species on biomass and nitrate concentration on mustard greens (Brassica juncea (L.) Czernjaew) cultivated on acid sulfate soils

Two field trials were conducted to determine the effect of P-K solubilizing bacteria and nitrogen chemical fertilizer on growth, yield and nitrate in leaf of mustard greens Brassica juncea L.) cultivated on acid sulfate soils. Eight P-K solubilizing bacterial strains composed of 3 strains of Acinetobacter calcoaceticus and 5 strains of Rhizobium sp., bacterial liquid were directly watered into plant at 3 stages [6, 12 and 21 days after planting] during vegetable cultivation, chemical fertilizer (60N – 40 P2O5 – 20 K2O) and control (no-inoculation). The study revealed that eight P-K solubilizing bacterial strains have good characteristics as nitrogen fixation, phosphate and potassium solubilisation. Application of nitrogen chemical concentration, increasing nitrate concentration of leaf of mustard greens. Application of bacterial liquid with Acinetobacter calcoaceticus strain NT4 and Acinetobacter calcoaceticus strain NT30 strain, Rhizobium tropici strain N18 and Rhizobium leguminosarum strain K35 on mustard greens cultivated on acid sulfate soils (basal fertilizer: 40 P2O5 – 20 K2O) was the best cultural practice because the this model not only supported the highest biomass, but also decreased nitrate concentration in leaf of mustard greens.

Effect of Treating Acid Sulfate Soils with Phosphate Solubilizing Bacteria on Germination and Growth of Tomato (Lycopersicon esculentum L.)

Acid sulfate soils contain sulfide minerals that have adverse environmental effects because they can lead to acidic drainage and prevent the establishment of vegetation. The current study examined the effect of a novel method for the restoration of these soils and the promotion of germination and plant growth. Thus, we isolated two strains of phosphate solubilizing bacteria, Methylobacterium sp. PS and Caballeronia sp. EK, characterized their properties, and examined their effects in promoting the growth of tomato plants (Lycopersicon esculentum L.) in acid sulfate soil. Compared with untreated control soil, treatment of acid sulfate soils with these bacterial strains led to increased seed germination, growth of plants with more leaves, and plants with greater levels of total-adenosine tri-phosphate (tATP). Relative to the untreated control soil, the addition of Caballeronia sp. EK led to a 60% increase in seed germination after 52 days, growth of plants with more than 3 times as many leaves, and a 45.2% increase in tATP after 50 days. This strain has potential for use as a plant biofertilizer that promotes vegetation growth in acid sulfate soils by improving the absorption of phosphorous.

Bacillus Cyclic Lipopeptides Iturin and Fengycin Control Rice Blast Caused by Pyricularia oryzae in Potting and Acid Sulfate Soils by Direct Antagonism and Induced Systemic Resistance

Rice monoculture in acid sulfate soils (ASSs) is affected by a wide range of abiotic and biotic constraints, including rice blast caused by Pyricularia oryzae. To progress towards a more sustainable agriculture, our research aimed to screen the biocontrol potential of indigenous Bacillus spp. against blast disease by triggering induced systemic resistance (ISR) via root application and direct antagonism. Strains belonging to the B. altitudinis and B. velezensis group could protect rice against blast disease by ISR. UPLC–MS and marker gene replacement methods were used to detect cyclic lipopeptide (CLiP) production and construct CLiPs deficient mutants of B. velezensis, respectively. Here we show that the CLiPs fengycin and iturin are both needed to elicit ISR against rice blast in potting soil and ASS conditions. The CLiPs surfactin, iturin and fengycin completely suppressed P. oryzae spore germination resulting in disease severity reduction when co-applied on rice leaves. In vitro microscopic assays revealed that iturin and fengycin inhibited the mycelial growth of the fungus P. oryzae, while surfactin had no effect. The capacity of indigenous Bacillus spp. to reduce rice blast by direct and indirect antagonism in ASS conditions provides an opportunity to explore their usage for rice blast control in the field.