Organic Carbon Linkage with Soil Colloidal Phosphorus at Regional and Field Scales: Insights from Size Fractionation of Fine Particles

Nano and colloidal particles (1-1000 nm) play important roles in phosphorus (P) migration loss from agricultural soils; however, little is known about their relative distribution arable crop soils under varying geolandscapes at the regional scale. Surface (0-20 cm depth) were collected 15 fields, including two sites with different carbon input strategies, Zhejiang Province, China, water-dispersible nanocolloids (0.6-25 nm), fine colloids (25-160 medium (160-500 separated analyzed using asymmetrical flow field fractionation technique. Three levels of fine-colloidal P content (3583-6142, 859-2612, 514-653 μg kg-1) identified The nanocolloidal fraction correlated organic (Corg) calcium (Ca), Corg, silicon (Si), aluminum (Al), iron (Fe). Significant linear relationships existed between Si, Al, Fe, Ca for Ca. controlled saturation, which turn affected carrier ability colloids. Field-scale inputs did not change overall morphological trends size fractions However, they significantly peak concentration each nano-, fine-, medium-colloidal fractions. Application chemical fertilizer carbon-based solid manure and/or modified biochar reduced soil by 30-40%; however,the application biogas slurry boosted formation. This study provides a deep novel understanding forms composition highlights spatial regulation characteristics inputs.