Adsorption of phosphate by aluminum and iron in soils pdf
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- Hydrolysis of aluminium on weakly acidic organic exchangers: Implications for phosphate adsorption
- Processes and Factors Affecting Phosphorus Sorption in Soils
- Relative Contribution of Iron and Aluminium in Phosphate Sorption by Acid Surface Soils
Assessment of phosphorus status influenced by Al and Fe compounds in volcanic grassland soils. Cartes 1,2 , R. Demanet 1 , G.
Hydrolysis of aluminium on weakly acidic organic exchangers: Implications for phosphate adsorption
Soil phosphorus P adsorption and desorption occur in an important endogenous cycle linked with soil fertility problems and relevant to the environmental risk assessment of P. In our study, the effect of long-term inorganic and organic fertilization on P adsorption and desorption characteristics in relation to changes in soil properties was evaluated by selecting three long-term experimental sites in southern China. The adsorption and desorption characteristics of P were evaluated using Langmuir and Freundlich isotherms. All three treatments fit these equations well. NPKM showed the highest Q m In conclusion, it is suggested that manure addition is crucial to improve P utilization in red paddy soils within the recommended range to avoid the risk of environmental pollution. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
In contrast to its behaviour on soil clays and in aqueous solution, aluminium is more extensively hydrolysed between pH3 and 4. The amount of phosphate adsorbed depended not only on the amount of Al adsorbed but also on the basicity of the adsorbed Al. Once adsorbed, the Al was quite stable and P adsorption on the Al-exchanger was unaffected by a rise in pH from 4. This is a preview of subscription content, access via your institution. Rent this article via DeepDyve. Effects of organic compounds on the adsorption of phosphate.
Processes and Factors Affecting Phosphorus Sorption in Soils
Continuous crop expansion has led to a growing demand for phosphate fertilizers. A sound knowledge of the dynamics of phosphorus, and its interaction with iron oxides and organic matter, can be useful to develop effective strategies for sustainable management, especially in a scenario of increasing shortage of mineral phosphate resources. In this paper, we review the relationship of phosphate to iron oxides and organic matter, and its effect on phosphorus availability. Crops typically obtain phosphate from weathered minerals and dissolved fertilizers. However, the amount of phosphorus present in the soil solution depends on the extent to which it is adsorbed or desorbed by iron oxides, which may be influenced by interactions with organic matter. Therefore, systems for fertilizer recomendation based on methodologies considering interactions between soil components such as oxides and organic matter, and the phosphorus sorption capacity resulting from such interactions e.
Relative Contribution of Iron and Aluminium in Phosphate Sorption by Acid Surface Soils
Principal mechanisms for phosphorus P removal in bioretention are the filtration of particulate-bound P and chemical sorption of dissolved P see Hunt et al. Most stormwater control measures SCMs capture particulate P by settling or filtration, but leave dissolved P typically phosphates untreated. This untreated P accounts on average for 45 percent of total phosphorus in stormwater runoff and can be up to 95 percent of the total phosphorus, depending on the storm event Erickson et al.
We evaluated the effect of 1 N NH 4 OAc and sodium-citrate dithionite extractable forms of soil Fe, Al, and Mn on P-sorption of a flooded acid sulfate soil Sulfic Tropaquepts and a non-acid sulfate soil Typic Tropaquepts under different soil oxidation-reduction and pH conditions. After the incubation period, the soil suspensions in the first treatment control were not washed or pretreated with any extractants. Sorption isotherms were described by the classical Langmuir equation. Significant correlations between the P-sorption parameters and the amount of free iron oxides indicated the primary role of iron oxides in P-sorption of acid sulfate soils.
В нескольких метрах от них лежало тело Хейла. Выли сирены. Как весенний лед на реке, потрескивал корпус ТРАНСТЕКСТА. - Я спущусь вниз и отключу электропитание, - сказал Стратмор, положив руку на плечо Сьюзан и стараясь ее успокоить. - И сразу же вернусь.
Adsorption and Desorption
Червь удвоил скорость! - крикнула Соши. - Штрафная санкция. На центральном экране прямо под извещением об ошибке ВР представила зрителям ужасающую картину. По мере того как рушилась третья защитная стенка, полдюжины черных линий, эти хакеры-мародеры, устремлялись вперед, неуклонно продвигаясь к сердцевине. С каждым мгновением появлялась новая линия, а за ней - следующая. - Они повсюду! - крикнула Соши. - Присоединяются зарубежные налетчики! - крикнул один из техников.
Сьюзан рассеянно кивнула, но тут же вспомнила, как Танкадо отдал им Северную Дакоту.