Submitted to: International Soil Management Workshop
Publication Type: Abstract Only
Publication Acceptance Date: January 4, 2006
Publication Date: May 1, 2006
Citation: Mamedov, A., Huang, C., Norton, L.D., Smith, D.R. 2006. Effect of surface application of gypsum and dry PAM on nutrient loss. International Soil Meeting. May 22-26, 2006, Sanliurfa, Turkey. 2006 CDROM. Technical Abstract: Soil surface degradation by rainfall, runoff generation and erosion, is one of the main processes regulating the loss of nutrients from the agricultural areas. We studied the effect of applied soil amendments (gypsum and dry polyacrylamide, PAM) on nutrient (N, P) loss from loamy soil. PAM was applied in dry form for ease of application with gypsum. Erosion flumes were packed with <4 mm diameters aggregates and wetted fast with distilled water. Amendments were applied 10 min prior to a rainstorm with high intensity (60 mm h-1). Adding the amendments significantly (i) increased surface aggregate stability and drainable porosity, (ii) decreased runoff and soil loss with the pattern: control < gypsum < gypsum + PAM and (iii) decrease soluble (NH3 and PO4) and total nutrient (TN and TP) concentrations in runoff. Applying gypsum alone was more effective in reducing absorbable nutrient concentration, particularly the PO4, whereas, gypsum +PAM was more effective in lowering TN and TP concentrations. Compared to the control, adding fertilizer increased soluble nutrient loss. Increasing soil surface drainable porosity and prevention of clay dispersion by soil amendments affected the dynamics of runoff generation and nutrient mobilization and significantly decreased the total amount of nutrient loss by runoff and soil loss. The relationships between amendment addition on surface condition and nutrient loading in runoff water are discussed in this paper.