Kinetics of phosphorous sorption to biochar-amended soils
1Food Animal Environmental System Research Unit, US Department of Agriculture - Agricultural Research Service, Bowling Green, KY, 42104, United States.
Chemosphere
|October 25, 2023
Summary
Adding iron-coated biochar (BCFe) to soils significantly altered phosphorus (P) sorption kinetics, with effects varying by soil type. Unmodified biochar (BC) showed minimal impact on P sorption dynamics.
Area of Science:
- Soil Science
- Environmental Chemistry
- Biogeochemistry
Background:
- Biochar is a potential soil amendment for enhancing phosphorus (P) sorption.
- Iron (Fe) oxide coating on biochar can increase P sorption, but its kinetic effects in soils are poorly understood.
Purpose of the Study:
- To investigate the kinetics of P sorption in four soils with contrasting properties amended with unmodified biochar (BC) and Fe-coated biochar (BCFe).
- To determine the impact of BC and BCFe on P sorption amounts and kinetic behavior over time.
Main Methods:
- Four soils with different textures and surface properties were amended with 5% (w/w) BC or BCFe.
- Phosphorus sorption was measured at incubation times from 1 to 314 hours.
- Sorption data were fitted using five kinetic models to assess the influence of biochar amendments.
Main Results:
- Unmodified biochar (BC) had minimal effect on P sorption across all soils.
- Fe-coated biochar (BCFe) significantly increased P sorption in low P-sorbing soils but showed less-than-expected increases in high P-sorbing soils.
- Kinetic model parameters were significantly altered by BCFe in all four soils, and by BC in two soils.
Conclusions:
- Fe-coated biochar shows potential for enhancing P sorption, but its effectiveness is soil-dependent.
- The addition of BCFe significantly alters the kinetics of P sorption in amended soils.
- This study provides crucial kinetic data for understanding biochar-soil-P interactions.
Related Concept Videos
01:21The Phosphorus Cycle
37.2K
Unlike carbon, water, and nitrogen, phosphorus is not present in the atmosphere as a gas. Instead, most phosphorus in the ecosystem exists as compounds, such as phosphate ions (PO43-), found in soil, water, sediment and rocks. Phosphorus is often a limiting nutrient (i.e., in short supply). Consequently, phosphorus is added to most agricultural fertilizers, which can cause environmental problems related to runoff in aquatic ecosystems.
37.2K
04:01Factors Affecting Solubility
33.5K
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:
33.5K