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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #240473
Title: Nutrient losses in runoff from feedlot surfaces as affected by unconsolidated surface materials

Author
item Gilley, John
item Eigenberg, Roger
item MARX, DAVID - University Of Nebraska
item Woodbury, Bryan

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2011
Publication Date: 5/18/2012
Citation: Gilley, J.E., Eigenberg, R.A., Marx, D.B., Woodbury, B.L. 2012. Nutrient losses in runoff from feedlot surfaces as affected by unconsolidated surface materials. Journal of Soil and Water Conservation. 67(3): 211-217.

Interpretive Summary: Beef cattle feedlots contain unconsolidated surface materials (USM) (loose manure pack) that accumulate within feedlot pens during a feeding cycle. The effects of varying amounts of USM on feedlot runoff water quality are not well defined. The objectives of this field investigation were to: a) compare nutrient transport in runoff from feedlot surfaces containing varying amounts of USM, and b) identify the effects of varying runoff rate on nutrient transport from feedlot surfaces containing different amounts of USM. Simulated rainfall was applied to experimental plots located within feedlot pens. No significant differences in runoff water quality characteristics were found among the four treatments containing varying amounts of USM. The presence of varying amounts of USM did not significantly affect any of the measured water quality parameters under varying flow rates. In contrast, each of the measured water quality parameters was significantly influenced by runoff rate. Thus, runoff rate and not the amount of USM on the feedlot surface is a critical variable influencing runoff water quality. Therefore, runoff nutrient load from feedlot surfaces can be expected to increase significantly with down slope distance.

Technical Abstract: Beef cattle feedlots contain unconsolidated surface materials (USM) (loose manure pack) that accumulate within feedlot pens during a feeding cycle. The effects of varying amounts of USM on feedlot runoff water quality are not well defined. The objectives of this field investigation were to: a) compare nutrient transport in runoff from feedlot surfaces containing varying amounts of USM, b) determine if runoff nutrient transport is correlated to feedlot soil characteristics, and c) identify the effects of varying runoff rate on nutrient transport from feedlot surfaces containing different amounts of USM. Simulated rainfall was applied to 0.75-m wide by 2-m long plots during three 30-min events. No significant (P < 0.05) differences in runoff water quality characteristics were found among the four treatments containing varying amounts of USM. Runoff measurements of particulate phosphorus (PP), NH4-N, NO3-N and electrical conductivity (EC) were each significantly correlated to six or more feedlot soil parameters. The NH4-N, total nitrogen (TN), and NO3-N loads were all correlated to easily obtained soil electrical conductivity (EC) measurements. The presence of USM at amounts varying from 0 to 26.9 kg m-2 did not significantly affect any of the measured water quality parameters under varying flow rates. In contrast, each of the measured water quality parameters was significantly influenced by runoff rate. Thus, runoff rate and not the amount of USM on the feedlot surface is a critical variable influencing runoff water quality. Thus, runoff nutrient load from feedlot surfaces can be expected to increase significantly with down slope distance.