Isolation of Water–Dispersible Colloids from Volcanic and Arid Bulk Soils

Contribution of Biogas Slurry-Derived Colloids to Plant P Uptake and Phosphatase Activities: Spatiotemporal Response

“…The fractions (1–450 nm) of colloids could be further categorized into three size groups: nanosized colloids (NC; 1–20 nm) containing abundant organic carbon (OC)–Ca associations, fine-sized colloids (FC; 20–220 nm) composed mostly of OC, Fe, and Al, and medium-sized colloids (MC; 220–450 nm) with a considerable amount of phyllosilicates. , Research found that colloids belonging to various size fractions demonstrated distinct potential to control the P transport, transformation, and other dynamic behavior in the soil. MC bound P was found to be mostly unreactive P associated to some extent with amorphous forms of Fe and Al, and its concentration correlated negatively with soil maximum P sorption capacity. , Differently, smaller-sized colloids (i.e., NC and FC) bound P in soil solution have been proved to become bioavailable potentially by modulating soil P desorption and stability, as the major P carriers for nutrient transport owning to their larger specific surface area and thus increased reactivity relative to bigger-sized colloids …”

“…MC bound P was found to be mostly unreactive P associated to some extent with amorphous forms of Fe and Al, and its concentration correlated negatively with soil maximum P sorption capacity. 14,15 Differently, smaller-sized colloids (i.e., NC and FC) bound P in soil solution have been proved to become bioavailable potentially by modulating soil P desorption and stability, 16 as the major P carriers for nutrient transport owning to their larger specific surface area and thus increased reactivity relative to bigger-sized colloids. 17 In addition to natural colloids, a considerable amount of P coll in the soil also derives from the application of organic fertilizers, especially manures and slurry.…”