Predicting Runoff of Suspended Solids and Particulate Phosphorus for Selected Louisiana Soils Using Simple Soil Tests
- Theophilus K. Udeigwea,
- Jim J. Wang *a and
- Hailin Zhangb
- a School of Plant, Environmental, and Soil Sciences, Sturgis Hall, Louisiana State Univ. Agricultural Center, Baton Rouge, LA 70803
b Dep. of Plant and Soil Sciences, Oklahoma State Univ., Stillwater, OK 74078. Contribution of Louisiana Agric. Exp. Stn. Journal No. 06-14-0300 and is published with the approval of the Director
This study was conducted to evaluate the relationships among total suspended solids (TSS) and particulate phosphorus (PP) in runoff and selected soil properties. Nine Louisiana soils were subjected to simulated rainfall events, and runoff collected and analyzed for various parameters. A highly significant relationship existed between runoff TSS and runoff turbidity. Both runoff TSS and turbidity were also significantly related to runoff PP, which on average accounted for more than 98% of total P (TP) in the runoff. Runoff TSS was closely and positively related to soil clay content in an exponential fashion (y = 0.10e0.01x, R 2 = 0.91, P < 0.001) while it was inversely related to soil electrical conductivity (EC) (y = 0.02 x −3.95, R 2 = 0.70, P < 0.01). A newly-devised laboratory test, termed “soil suspension turbidity” (SST) which measures turbidity in a 1:200 soil/water suspension, exhibited highly significant linear relationships with runoff TSS (y = 0.06x − 4.38, R 2 = 0.82, P < 0.001) and PP (y = 0.04x + 2.68, R 2 = 0.85, P < 0.001). In addition, SST alone yielded similar R2 value to that of combining soil clay content and EC in a multiple regression, suggesting that SST was able to account for the integrated effect of clay content and electrolytic background on runoff TSS. The SST test could be used for assessment and management of sediment and particulate nutrient losses in surface runoff.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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