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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Nutrition, Growth and Physiology » Research » Publications at this Location » Publication #313744

Title: Modeling water movement in beef cattle bedded manure pack

item CORTUS, ERIN - South Dakota State University
item AYADI, FEROUZ - South Dakota State University
item Spiehs, Mindy

Submitted to: Waste to Worth Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/2/2015
Publication Date: 3/1/2015
Citation: Cortus, E.L., Ayadi, F.Y., Spiehs, M.J. 2015. Modeling water movement in beef cattle bedded manure pack. In: Proceedings Waste to Worth:Spreading Science and Solutions, March 31-April 3, 2015, Seattle, WA. Available:

Interpretive Summary: Beef cattle producers that raise cattle under the roof in complete confinement, such as mono-slope or hoop barns, may use bedding material to manage moisture and provide a comfortable environment for the animals. Some producers let the manure and bedding accumulate to a bedded manure pack which is compacted by cattle activity. The bedded manure contains essential nutrients (nitrogen (N), phosphorus (P), and potassium (K)) for crop production and soil sustainability. Previous research has shown that the concentration of water-soluble N, P and K compounds may increase with depth of the bedded pack where water accumulates. Thus, understanding the movement of water within the bedded manure will help predict N-P-K fertilizer value of the bedded manure. Evaporation, percolation, and water and water vapor diffusion were considered as the main processes for vertical liquid and vapor movements in and from the bedded manure pack. This model will contribute to a calculator for predicting the moisture content for different depths in the bedded manure pack with different temperatures, bedding material, and storage time.

Technical Abstract: Bedded manure is a valuable fertilizer source because it contains essential macronutrients (nitrogen (N), phosphorus (P), and potassium (K)) for crop production. Previous research with beef cattle bedded manure packs demonstrated that water-soluble macronutrients accumulated toward the bottom of the packs with water movement. Thus, predicting water movement in bedded manure helps to estimate nutrient composition throughout the bedded pack. This work presents a development of a process-based model of vertical water movement that considers percolation and diffusion as the main processes of water and vapor movements in bedded manure packs. Evaporation from the top zone to the atmosphere was considered a process of convective mass transfer. The model predicts the change in moisture content of the different zones in the bedded manure and assists in estimating nutrient composition.