Colloidal particles in runoff may have an important role in P transfer from soils to waterbodies, but remain poorly understood. We investigated colloidal molybdate-reactive phosphorus (MRP) in surface runoff and water extracts of calcareous arable soils from the semiarid western United States. Colloidal MRP was determined by ultrafiltration and operationally defined as MRP associated with parti...

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...

in calcareous soils of the southern Everglades and of adjacent areas is needed urgently. The understanding of P sorption and desorption by soils is imporThe relationships between P-sorption capacity, P tant for safeguarding water quality and for fertilizer management. availability and soil components in calcareous soils have Little is known about the P-sorption characteristics of the calcareous...

incorporation of plant residue in soils is considered as an important agricultural practice for maintaining soil fertility in sustainable agricultural system. co2 levels, nitrogen fertilization and plant residues are factors which highly affect decomposition of added organic matter to soil. in this research controlled chambers were used to investigate the effects of elevated atmospheric co2 con...

To reduce Cd phytoavailability in calcareous soils, the effects of soil amendments of red mud, rape straw, and corn straw in combination with zinc fertilization on Cd extractability and phytoavailability to spinach, tomato, Chinese cabbage and radish were investigated in a calcareous soil with added Cd at 1.5 mg kg-1. The results showed that water soluble and exchangeable Cd in soils was signif...

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). ...

Ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and other synthetic polycarboxylic acids have been shown to possess substantial capacity as washing agents of heavy metal-polluted soils, but they are environmentally problematic. Therefore, a sample of natural soluble humic substances (HS) was tested as a possible substitute. The efficiency of HS to extract cadmium (Cd), copp...

Abstract Phosphorus (P) reactions in calcareous soils limit the concentration of P soil solution for plant uptake. Calcareous with high calcium carbonate content (CaCO 3 ) and pH have low fertiliser efficiency, leading to crop deficiency limited productivity. The aim this work was test if acidifying amendments could reduce improve solubility nutrition biomass. Three varying CaCO (14–29% w/w) we...

to determine the effects of vinasse on physicochemical properties of a calcareous and an acidic soil experiment was factorial and had a complete randomized design and three replications. factorial combinations of five vinasse levels (0, 5, 10, 20 and 40 t/ha) and three exposure times (10, 20 and 30 days) were considered as the treatments of this experiment. the result of experiment showed that ...