Roger A Eigenberg

Long Term Effects of Annual Additions of Animal Manure on Soil Chemical, Physical, and Biological Properties in the Great Plains

The objective of this study was to determine the effects of long-term annual beef manure amendments and wheat and rye cover crops on selected chemical, physical and biological properties of a typical Midwest U.S. soil under corn silage production. The treatments included: manure application/cover crop, manure application/no cover crop, no manure/cover crop, and no manure/no cover crop each sampled at three depths (0 to 7.5, 7.5 to 15, and 15 to 30 cm). Using beef manure significantly increased the total, organic, and microbial biomass carbon by over 60%, 40%, and 125%, respectively, when compared with commercial fertilizer. Planting a cover crop also significantly increased soil concentrations of total, organic, and biomass carbon; however the level of increase was not as dramatic as the fertilizer treatment. Using beef manure as a fertilizer significantly increased total, organic, and microbial biomass nitrogen and nitrate-nitrogen in the upper 30 cm profile by 78%, 75%, 130% and 130%, respectively. Annual applications of beef manure applied to meet the entire nitrogen needs of a corn silage crop resulted in excessively high Bray-phosphorus concentrations for the surface horizons particularly for the 0-7.5 cm depth. High water soluble P (WSP) concentrations were measured in the upper 0-15 cm depth of the treatment receiving annual beef manure applications. Use of a cover crop on the beef manure treatments increased the surface concentration of plant nutrients such as Bray-phosphorus and WSP. This indicates the importance of a cover crop for retaining mobile plant nutrients near the surface.

Comparing Soil and Pond Ash Feedlot Pen Surfaces for Environmental Management

Removing manure and replacing soil to maintain pen surfaces is expensive. Pond ash (PA), a coal-fired electrical generation by-product, has good support qualities. A study was conducted comparing the performance of pond ash (PA) surfaced pens with soil surface (SS) pens. Four pens of an eight pen series with dimensions of 7.3 m by 20.7 m were excavated to a depth of 0.5 m and resurfaced with PA. Eight heifers were housed in each pen (19 m2/head) for four feeding cycles that ranged from 73 days to 172 days. Following the feeding cycles, animals were removed, pens were cleaned and filled soil was brought in to restore pens to grade. A 1 kg sub-sample was removed from each pen to analyze for total mass (TM), total solids (TS), volatile solids (VS), percent volatile solids (VS%), moisture and ash content. Higher heating value (HHV) was estimated using the VS% and moisture. Surfacing pens with PA reduced the TM by 35%, TS by 34%, and ash content by 46%. The PA increased VS% by 70% and HHV by 75%. Also, the PA pens needed only ¼ the amount of fill material as the soil surface pens (SS). However, there were no differences measured in the total amount of VS removed. Harvested feedlot surface material (FSM) from the PA pens was much more nutrient and energy dense. This increased density, improved the economics of transport and handling, and allowed for energy recovery. Also, the PA pens were less erodible and required much less fill-material to maintain pen surfaces.

Effect of feeding wet distillers grains with solubles (WDGS) to growing-finishing cattle on ammonia concentration in air and manure nutrient composition

Air quality is a difficult and pressing problem for feedlot producers. This is compounded by feeding practices that influence the excretion of starch, fiber, crude protein, and sulfur (S) by cattle that significantly affect the production of odorous compounds. Wet distillers grains with solubles (WDGS) are a common and economical ingredient in feedlot diets. WDGS are high in protein, fiber, and S but low in starch. The objective of this study was to compare ammonia (NH3) concentration in the air and nutrients and volatile organic compounds (VOC) concentration in manure between two dietary treatments fed to feedlot cattle. Five pens of feedlot cattle were fed diets containing 14-35% WDGS and five pens were fed a corn-based diet with no ethanol byproducts (Control). Each pen had twelve sampling locations (N = 120) where air and manure samples were collected from the feedlot surface. Air samples were analyzed for NH3 concentration. Manure samples were analyzed for dry matter, pH, volatile solids, VOC, and nutrient composition (N, P, and S). Concentrations of P and S in manure and NH3 in the air were higher in pens fed WDGS compared to pens fed the control diet. Concentrations of VOC were similar across both treatments.

Application of an Automated Early-Warning Leak Detector for Earthen Wastewater Holding Structures Using Non-invasive Geophysical Instrumentation

Abstract. Wastewater generated during animal production contains contaminants that can degrade soil and groundwater quality as well as impact human health. Typically, wastewater is stored in earthen-holding ponds until it can be properly disposed. Monitoring wells are the principal tool used for detecting subsurface leakage. There are implicit difficulties when using monitoring wells for detecting wastewater pond leakage. An alternative to monitoring wells based on resistivity array (RA) technology was developed to improve early detection and mitigate soil and groundwater contamination. The objectives of this paper are to explain the development of the technology sensitivity, discuss the advantages compared to monitoring wells and then illustrate the application of the technology based on the advantages. To improve early detection, monitor multiple sides of a pond using one array and eliminate many physical site limitations, correction geometric factors (GF) were developed. These GF were generated using georeferenced probe locations and applied to non-collinear arrays to correct for angular discontinuities. Next, a near-surface data analysis protocol was developed that had user-set thresholds to allow scaling of instrument sensitivity. The protocol used a statistically-based process for calibrating the reference data for a wide range of geological and geographical settings. This protocol allowed the RA technology to be automated to continuously monitor for leakage and when thresholds are exceeded, send an alert message to managers of potential problems. These advantages provide substantial improvements for protecting soil and groundwater quality from wastewater pond leakage.

Using Electromagnetic Induction Methods to Determine Environmental Sustainability of Vegetative Treatment Beef Feedlot Runoff Control Systems in Iowa and Nebraska

Cattle feeding operators are interested in alternative runoff control and treatmentnsystems that eliminate the need for long-term liquid storage; however, thenfeasibility and sustainability of these alternative systems is yet to be determined.nSeveral demonstration sites were constructed in Iowa and Nebraska utilizingnvegetative treatment areas (VTAs) to determine their sustainability for feedlotnrunoff control. These sites represent varying climate, site considerations (i.e.nmanagement, soil texture, topography etc.), and designs.

Use of a Resistance Meter to Locate Manure Suitable for Energy Recovery in Beef Cattle Feedyards

Mineral constituents, i.e., salts, contained in beef feedlot manure alter inherent soil conductivity. Researchers at USMARC have adapted tools such as electromagnetic soil conductivity meters and mapping/modeling software to identify areas where by manure accumulates on beef cattle feedlots. These tools combine to identify the spatial distribution of the manure for selective harvesting, creating a product of value for energy or nutrient recovery. However, electromagnetic soil conductivity meters poorly define soil profile conductivities. Thus, a question arises regarding the well-defined depth of manure within feedlot pens. Traditional methods of soil coring can be laborious, time-consuming, and costly as well as risky in areas containing buried water and electrical lines. Preliminary shallow soundings using a 4-probe resistivity meter have been conducted at a cattle feedlot. Associations of the shallow soundings with soil electrical conductivity (EC) values as well as profile plots are presented in this paper. This is an introductory report and examines the potential for future development and use of resistivity meters for cattle feedlot waste management research.

Flow Characteristics of the Dynamic “EPA Flux Chamber”

A dynamic flux chamber, commonly referred as the “EPA chamber”, is one method that has been adapted to investigate spatial gas emission on feedlot surfaces. However, the flow characteristics within the chamber have not been evaluated to determine if it can be effectively used outside of its original design specifications. Understanding the chamber flow characteristics will improve the proper application for determining the spatial distribution of emissions from feedlot surfaces. A series of pulse tracer studies at flow rates of 2.5, 5 and 7.5 L min-1 with and without an internal mixing fan were performed to determine tracer break-through curve (BTC) characteristics. Tracer BTCs indicated ideally mixed conditions in the chamber at the evaluated flow rates. However, deviations in the actual retention times from the calculated retention times were greater at the 2.5 and 5.0 L min-1 flow rate when the mixing fan was not used. It appears the deviation was driven by the “tailing” of the BTCs. The tailing was not a problem when the flow rate was increased to 7.5 L min-1 or when the mixing fan was used. This tailing is not expected to limit the effectiveness of the chamber for evaluating treatment effects on spatial gas emission from feedlot surfaces, but others have shown that low flow rates inhibit the overall emission rate from flux chambers.

Energy and Nutrient Recovery from Cattle Feedlots

Selective harvesting of manure can benefit cattle producers by creating a product of value. A tool that identifies locations of manure accumulation has been developed and demonstrated. A dual geometry sub-surface sensor (Dualem-1S, Milton, ON, Canada) was used with software designed for salt mapping (ESAP, Riverside, CA). The combination allowed the development of models to estimate a higher heating value (HHV) of feedlot manure across a feedlot pen. Soil sample data from cattle feedlots in Texas and Nebraska were analyzed for volatile solids (VS) and then combined with the Dualem-1S apparent soil electrical conductivity (ECa) data to produce models having correlations between ECa and associated VS (r2=0.869). A corresponding model is under development to estimate the moisture content of the collectable solids. The combined models allow real-time spatial estimates of HHV within a feedlot pen. These methods will allow direct harvesting of VS for use as a recoverable energy source through direct combustion or co-combustion.

Coal-Ash as a Surfacing Material for Feedlots to Improve Energy and Nutrient Value of Manure

Hauling soil/manure out and fill-soil in to maintain adequate feedlot pen surfaces is time consuming and expensive. Pond ash (PA), a by-product from coal-fired electrical generation, has very good support qualities even when wet. Four pens of an eight pen series, each with dimensions of 7.3 m by 20.7 m, were excavated to a depth of 0.5 m and returned to grade with PA. The remaining four pens were not altered. Eight heifers were housed in each pen (19 m2/head) for approximately 85 days. Following the feeding cycle, animals were removed and the pens cleaned to approximately the same surface condition. Collected feedlot surface materials (FSM) were piled in the center of each pen. Samples were taken from each pile and mixed in a plastic tub. A 1 kg sample was removed for proximate analysis which included moisture, total solids (TS), volatile solids (VS,) and total ash. Total mass (TM) of material removed from each pen was determined gravimetrically using a truck scale. Analysis indicates PA pens had a 70% reduction in TM when compared to the soil surface (SS) pens. Though the mass of VS removed was similar between the two surface materials, the PA pen percent VS was nearly twice that of the SS pens. The difference between the two FSM is the amount of ash (i.e. soil) contained in the SS pens. The FSM from the SS pens contained nearly four times more ash than PA pens. Additionally, SS pens required an average 11,000 kg of fill to return the surface to original grade, while the PA pens did not require any fill. The data set is limited and additional evaluations are required before more definitive conclusions can be drawn; however, analysis indicates nearly 14 times more material handled for SS pens when compared to PA pens.