introduction: iron cycle is one of the most important biogeochemical processes which affect the availability of iron in soils. ferric iron oxides are the most abundant forms of iron in soils and sediments. ferric iron is highly insoluble at circumneutral ph. present investigations have shown that the structural ferric iron bound in clay minerals is reduced by some microorganisms. anaerobic bact...

organic acids exuded by plant roots increase solubility of soil micronutrient complexes. this study was carried out to evaluate adsorption isotherms of 4 acidic and 4 calcareous soils at presence of organic acids (citric, malic and oxalic acids). iron sorption and desorption isotherms are defined in to two systems including; system 1; soil-water-metal, system 2; soil-water-organic acid-metal). ...

[1] It is commonly believed that fine-textured soils developed on carbonate parent material are well buffered from possible acidification. There are no data, however, that document resistance of such soils to acidic deposition exposure on a timescale longer than 30–40 years. In this paper, we report on directly testing the long-term buffering capacity of nineteenth century forest soils develope...

Golden Camellia species are highly specific to certain soil environments. Most only native calcareous soils in karst regions, except for a few that grow acidic soils. Our aim is elucidate the adaptation mechanisms of calcareous-soil golden (CSC) and acidic-soil (ASC) habitat through plant–soil nutrient characteristics their relationships. We investigated 30 indices plants. Compared with ASC, CS...

Carbon-rich biochar derived from the pyrolysis of biomass can sequester atmospheric CO, mitigate climate change, and potentially increase crop productivity. However, research is needed to confirm the suitability and sustainability of biochar application to different soils. To an irrigated calcareous soil, we applied stockpiled dairy manure (42 Mg ha dry wt) and hardwood-derived biochar (22.4 Mg...

Phosphorus is the second most important macro nutrient required by the plants for its optimum growth and yield. But it is considered to be a most limiting factor of many crop production systems, due to its unavailability of soluble forms in the soils. About 80% of applied P fertilizers are immobilized due to the formation of complex with Al or Fe in acidic soils or Ca in calcareous soils. An al...

Cadmium (Cd) concentration in soil solution and its bioavailability is controlled by sorption-desorption reactions. The objective of this research was to compare Cd adsorption behavior in six calcareous and four acid soils. Soil samples were equilibrated with 0.01 M Ca(NO3)2 containing 25 to 3200 mg Cd L−1. Results showed that the tendency for adsorption was high at low Cd concentrations (0-400...

In a proof-of-concept study, an acidic (pH 5.8) biochar was created using a low pyrolysis temperature (350 °C) and steam activation (800 °C) to potentially improve the soil physicochemical status of an eroded calcareous soil. Biochar was added at 0%, 1%, 2%, and 10% (by wt.) and soils were destructively sampled at 1, 2, 3, 4, 5, and 6 month intervals. Soil was analyzed for gravimetric water con...