Author
Gilley, John | |
Berry, Elaine | |
Eigenberg, Roger | |
MARX, D - STATS PROF,UNLEC LNK NE | |
Woodbury, Bryan |
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/1/2008 Publication Date: 5/9/2008 Citation: Gilley, J.E., Berry, E.D., Eigenberg, R.A., Marx, D.B., Woodbury, B.L. 2008. Spatial variations in nutrient and microbial transport from feedlot surfaces. Transactions of the ASABE. 51(2):675-684. Interpretive Summary: Nutrient and microbial transport by runoff may vary at different locations within a beef cattle feedlot. If the areas making the greatest contributions to nutrient and microbial transport can be identified, it may be possible to institute precision management practices to reduce nutrient and microbial transport by runoff. The objectives of this study were to: a) measure selected feedlot soil properties, and nutrient and microbial transport in runoff from locations within a feedlot selected on the basis of apparent soil electrical conductivity b) compare the effects of unconsolidated surface materials (USM) and consolidated subsurface materials (CSM) on nutrient and microbial transport, and c) correlate nutrient and microbial transport in runoff to selected feedlot soil characteristics. Simulated rainfall events were applied to the experimental plots. No significant differences in feedlot soil characteristics or nutrient and microbial transport in runoff were found between USM and CSM. However, concentrations of E. coli in USM and CSM were significantly different. Pen location was found to significantly influence selected feedlot soil measurements. Runoff measurements of selected nutrient constituents were significantly influenced by pen location. Experimental results indicate that it may be possible to estimate runoff nutrient concentrations from selected feedlot soil characteristics. Technical Abstract: Nutrient and microbial transport by runoff may vary at different locations within a beef cattle feedlot. If the areas making the greatest contributions to nutrient and microbial transport can be identified, it may be possible to institute precision management practices to reduce nutrient and microbial transport by runoff. The objectives of this study were to: a) measure selected feedlot soil properties, and nutrient and microbial transport in runoff from locations within a feedlot selected on the basis of apparent soil electrical conductivity (Eca), b) compare the effects of unconsolidated surface materials (USM) and consolidated subsurface materials (CSM) on nutrient and microbial transport, and c) correlate nutrient and microbial transport in runoff to selected feedlot soil characteristics. Simulated rainfall events were applied to 0.75-m wide by 2-m long plots. No significant differences in feedlot soil characteristics or nutrient and microbial transport in runoff were found between USM and CSM. However, concentrations of E. coli in USM and CSM were significantly different. Pen location was found to significantly influence feedlot soil measurements of Bray 1-P, calcium, chloride, copper, electrical conductivity (EC), loss on ignition, organic-N, phosphorus, potassium, sodium, sulfur, total N (TN), water soluble P, and zinc. Runoff measurements of dissolved phosphorus (DP), NH4-N, and EC were significantly influenced by pen location. Concentrations of DP and NH4-N in runoff were significantly correlated to several feedlot soil characteristics. Thus, it may be possible to estimate runoff concentrations of DP and NH4-N from selected feedlot soil characteristics including measurements of ECa. |