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Using Simulated Rainfall to Evaluate Field and Indoor Surface Runoff Phosphorus Relationships
- Guidry, A. R., Schindler, F. V., German, D. R., Gelderman, R. H., Gerwing, J. R.
- Journal of environmental quality 2006 v.35 no.6 pp. 2236-2243
- rainfall simulation, agricultural soils, phosphorus, chemical concentration, prediction, agricultural runoff, Mollisols, regression analysis, equations, South Dakota
- While numerous studies have evaluated the efficacy of outdoor rainfall simulations to predict P concentrations in surface runoff, few studies have linked indoor rainfall simulations to P concentrations in surface runoff from agricultural fields. The objective of this study was to evaluate the capacity of indoor rainfall simulation to predict total dissolved P concentrations [TP(<0.45)] in field runoff for four dominant agricultural soils in South Dakota. Surface runoff from 10 residue-free field plots (2 m wide by 2 m long, 2–3% slope) and packed soil boxes (1 m long by 20 cm wide by 7.5 cm high, 2–3% slope) was compared. Surface runoff was generated via rainfall simulation at an intensity of 65 mm h⁻¹ and was collected for 30 min. Packed boxes produced approximately 24% more runoff (range = 2.8–3.4 cm) than field plots (range = 2.3–2.7 cm) among all soils. No statistical differences in either TP(<0.45) concentration or TP(<0.45) loss was observed in runoff from packed boxes and field plots among soil series (0.17 < P < 0.83). Three of four soils showed significantly more total P lost from packed boxes than field plots. The TP(<0.45) concentration in surface runoff from field plots can be predicted from TP(<0.45) concentration in surface runoff from the packed boxes (0.68 < r ² < 0.94). A single relationship was derived to predict field TP(<0.45) concentration in surface runoff using surface runoff TP(<0.45) concentration from packed boxes. Evidence is provided that indoor runoff can adequately predict TP(<0.45) concentration in field surface runoff for select soils.