ARS | Publication request: EFFECT OF RAIN INTENSITY ON NUTRIENT LOSS: LABORATORY STUDY

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2005
Publication Date: November 6, 2005
Citation: Mamedov, A., Huang, C. 2005. Effect of rain intensity on nutrient loss: laboratory study. In: Proceedings of the ASA-CSSA-SSSA Annual Meeting Abstracts, November 6-10, 2005, Salt Lake City, UT. 2005 CDROM.

Technical Abstract: Soil surface structure has a significant influence on percolation and runoff rate. We hypothesized that seal formation on the soil surface will considerably effect "mixing zone" formation and nutrient loss through runoff. Effect of rain intensity 15-100 mm h-1 and surface structural condition (degraded and roughness) on nutrient loss from a loamy soil was studied. Increases in the rain intensity increased runoff rate and sediment concentration, amount of total nutrients and PO4, but decreased NH3 and NO3 concentration in runoff; the total nutrient concentration in the runoff was higher at lower rain intensity. The absorbable nutrient concentration (PO4 and NH3) in runoff and infiltrated water (subsurface water) was comparable, whereas non-adsorbed NO3 in infiltrated water was several times higher than in runoff. The total and available nutrients (P) concentrations in the soil profile after rainstorm were high in the surface seal (<3 mm) and decreased under the seal (3-20 mm). Rain intensity mostly affected nutrient distribution in 0-20 mm depth. Increasing surface roughness significantly decreased runoff volume and nutrient loading. However with an increase in rain depth, surface sealing increased the nutrient loss from degraded flat soil surfaces. Seal formation on the soil surface influenced the runoff and sediment rate and on other hand limited the depth of soil-runoff interaction and thus affected the dynamics of nutrient mobilization. The relationship between rain properties, surface condition, soil, soluble and total nutrients in infiltrated and runoff water are discussed in this paper.