Richard K. Koelsch

Economic Feasibility of No-Tillage and Manure for Soil Carbon Sequestration in Corn Production in Northeastern Kansas

This study examined the economic potential of no-tillage versus conventional tillage to sequester soil carbon by using two rates of commercial N fertilizer or beef cattle manure for continuous corn (Zea mays L.) production. Yields, input rates, field operations, and prices from an experiment were used to simulate a distribution of net returns for eight production systems. Carbon release values from direct, embodied, and feedstock energies were estimated for each system, and were used with soil carbon sequestration rates from soil tests to determine the amount of net carbon sequestered by each system. The values of carbon credits that provide an incentive for managers to adopt production systems that sequester carbon at greater rates were derived. No-till systems had greater annual soil carbon gains, net carbon gains, and net returns than conventional tillage systems. Systems that used beef cattle manure had greater soil carbon gains and net carbon gains, but lower net returns, than systems that used commercial N fertilizer. Carbon credits would be needed to encourage the use of manure-fertilized cropping systems.

Vegetative Treatment Systems for Management of Open Lot Runoff: Review of Literature

Runoff from open lot livestock systems (beef and dairy) defined as Concentrated Animal Feeding Operations (CAFO) must be controlled by systems designed and managed to prevent the release of manure-contaminated runoff for storms equal to or less than a 25-yr, 24-h design storm. This performance standard has been attained for open lot systems with some combination of clean water diversion, settling basins, runoff collection ponds, and irrigation systems (baseline system). An alternative approach is to rely on overland flow and infiltration into cropland with perennial forage or grasses for treatment of open lot runoff. Such vegetative systems have been researched since the late 1960s. This article reviews the research literature on vegetative treatment systems (VTS) for managing open lot runoff summarizing available science on system performance, design, and management. Based upon this review of the literature, the following conclusions are drawn about the application of VTS to manage runoff from open lot livestock production systems: (1) Substantial research (approximately 40 identified field trials and plot studies) provides a basis for understanding the performance of VTS. These performance results suggest that a vegetative system consisting of a settling basin and VTA or Vegetative Infiltration Basin (VIB) has the potential to achieve functional equivalency to conventional technologies. (2) The existing research targeting VTS is confined to non-CAFO applications, likely due to past regulatory limits. Unique challenges exist in adapting these results and recommendations to CAFO applications. (3) The pollutant reduction resulting from a VTS is based upon two primary mechanisms: 1) sedimentation, typically occurring within the first few meters of a VTS, and 2) infiltration of runoff into the soil profile. Systems relying primarily on sedimentation only are unlikely to perform equal to or better than baseline technologies. System design based upon sedimentation and infiltration is necessary to achieve a required performance level for CAFO application. (4) Critical design factors specific to attaining high levels of pollutant reduction within a VTS include pre-treatment, sheet flow, discharge control, siting, and sizing. Critical management factors include maintenance of a dense vegetation stand and sheet flow of runoff across VTA as well as minimization of nutrient accumulation.

CHARACTERISTICS OF MANURE HARVESTED FROM BEEF CATTLE FEEDLOTS

Open lot cattle production systems present unique challenges for nutrient planning processes. Previous estimates of quantities and characteristics of harvested manure from this type of facility are based upon data from the early 1970s. In addition, harvested manure is impacted by weather, feeding program, season, and pen management decisions. The objectives of this study are to characterize under commercial conditions for open lot beef systems: 1) harvested manure quantities and characteristics; 2) impact of factors such as feeding program, season, and management on harvested manure; and 3) mass balance for nitrogen (N) and phosphorus (P). Data from six commercial feedlots (representing 6,366 head of cattle) suggest that 33% of excreted N (65 g/hd/d) and 91% of excreted P (32 g/hd/d) are harvested as manure on average and that current standard estimates published by ASAE (2005) and NRCS (1992a) overestimate harvested manure N and P. Additionally, significant variation was observed among feedlots. This variation is driven by ration nutrient concentration (P only), pen conditions prior to and during manure harvest (N and P), and management choices relative to use of manure in lot maintenance (N and P). The variation would suggest that nutrient planning estimates for open lots would need to be based upon farm specific data as opposed to typical or standard values. Finally, a pen-based mass nutrient balance for a beef cattle feedlot suggests that pen outputs as finished animal, harvested manure, and nutrient losses represent 31%, 23%, and 47%, respectively, of all pen N inputs and 38%, 57%, and 5%, respectively, of all pen P inputs. Inputs include nutrient content of all animals and feed entering a feedlot pen over a grow-out period.

Will Voluntary and Educational Programs Meet Environmental Objectives? Evidence from a Survey of New York Dairy Farms

This paper presents the results from a survey of New York dairy farms that links manure management practices and farmer willingness to participate in voluntary environmental programs, focusing on those operations that are not automatically designated as Concentrated Animal Feeding Operations. A wide divergence is found between actual and recommended manure management practices on individual dairy farms (high), the apparent ability of farms to divert financial resources to environmental practices (mixed), and the willingness to participate in voluntary programs at various annual costs per cow (low). These findings have policy implications for the USDA/USEPA National Strategy for Animal Feeding Operations.

CHARACTERISTICS OF PHOTOTROPHIC AND NON--PHOTOTROPHIC LAGOONS FOR SWINE MANURE

Odors are a major result of inadequately sized and mismanaged anaerobic lagoons. However, purple or pink colored lagoons, indicating the presence of phototrophic purple bacteria, are less likely to be an odor nuisance than are non-purple lagoons. Eight swine lagoons were studied to quantify critical parameters thought to allow purple lagoons to be a more reliable odor control alternative. Bacteriochlorophyll a (Bchl a), which indirectly measures the abundance of phototrophic bacteria, was greater in purple lagoons than in non-purple lagoons (P = 0.01). Oxidation-reduction potential (ORP) was less negative for purple lagoons than for non-purple lagoons in both spring (lagoon temperatures of 6.7C to 8.8C) and during summer (temperatures of 22C to 25C), indicating conditions favoring phototrophism (P = 0.04). Dissolved oxygen levels were near zero and light penetration was minimal in all lagoons. Average sulfide concentrations of all the lagoons were in the range of 1.6 to 6.5 mg/L, which is below the preferred range for purple sulfur bacteria (PSB) growth. Purple lagoons appeared to have lower concentrations of ammonia, alkalinity, chemical oxygen demand, and electrical conductivity among the lagoons studied. Copper and zinc concentrations of all lagoons were not in the range considered to be toxic for anaerobic bacteria. Calculated volatile solids loading rates did not explain differences in Bchl a levels in the lagoons.

TOTAL REDUCED SULFUR CONCENTRATIONS IN THE VICINITY OF BEEF CATTLE FEEDLOTS

A field survey of total reduced sulfur (TRS) concentrations in the vicinity of beef cattle feedlots was conducted to compare field observations against current regulatory thresholds. In addition, environmental factors that may contribute to increased TRS emissions were evaluated. It was observed that TRS levels in the vicinity of beef cattle feedlots are not likely to exceed current regulatory thresholds used by midwestern states. It was further noted that concentration of TRS varies with air temperature and time of day. However, wet feedlot surface conditions and wind speed had almost no impact upon observed concentrations.

DEVELOPMENT OF STANDARD METHODS TO ESTIMATE MANURE PRODUCTION AND NUTRIENT CHARACTERISTICS FROM DAIRY CATTLE

Total collection data from many universities were pooled for statistical analyses to evaluate existing data from dairy animals and determine if one or more modifications were needed for Standard Table D384.1. Many of these studies were carried out to evaluate nutritional characteristics associated with different diets. The data collected were sufficient to evaluate total manure, total and volatile solids, and N excretion values. Some experiments had sufficient number of samples analyzed to evaluate P, K, Ca, Mg, Na, Cl, S, and micro-elements. Statistical analyses were conducted to determine if a single column value was appropriate and define the regression equations necessary to estimate excretions if the assumptions of the column inputs were not met. The results indicate that separate classifications are needed for replacement heifers and mature animals. Final classifications for replacement heifers included: milk fed calves, weaned calves weighing less than 274 kg, heifers weighing between 273 and 613 kg, and veal calves. Additionally, classifications for lactating and dry animals are needed. Previously, the estimates for manure production and nutrient excretion were based on body weight. These findings indicate that a better predictor for lactating cattle is daily milk production instead of body weight. Milk production drives feed intake in the lactating animal. It is most appropriate that estimated manure and nutrient excretion values reflect the relationship between feed intake, milk production (nutrient utilization) and nutrient excretion.

Phototrophic anaerobic lagoons as affected by copper and zinc in swine diets

Odor emissions from anaerobic lagoons containing large populations of phototrophic bacteria are usually minimal. This study was conducted to determine whether copper (123 ppm) and zinc (2,310 ppm) in diets fed to weanling pigs for therapeutic purposes affect phototrophic conditions within lagoons. Column reactors containing 47 L of swine lagoon sludge and supernatant were used to represent lagoons. The reactors were placed in an environmental chamber maintained at 24° C. Copper, zinc, and control manure were added to the reactors at a volatile solids loading rate of 128 g vs m -3 da-1 using a hydraulic retention time of 32.5 days. Bacteriochlorophyll a, copper, reduction-oxidation potential, salinity, sulfate, sulfide, and zinc were then measured for at least 99 days. Sulfide, total copper and total zinc were the only parameters to be significantly impacted. The copper and zinc concentrations in the sludge increased but that of supernatant in the individual reactors changed little during the study period. However, the addition of dietary copper significantly increased the concentrations of sulfides in the supernatant, creating a condition that appeared toxic to phototrophic bacteria. In contrast, a decrease in sulfide concentration resulted from the addition of dietary zinc, resulting in an environment that may have been favorable to phototrophic bacteria. Thus, to minimize potential odor concerns, zinc rather than copper may be the best choice as a dietary supplement for weanling pigs. Keywords. Anaerobic bacteria, Lagoon effluent, Manure management practices, Odor control, Swine lagoon waste.

Managing Phosphorus in Beef Feeding Operations

A commercial feedlot study was conducted to determine manure nutrient flow in six feedlots representing 6,366 cattle. On average, cattle involved in this summary were yearlings (BW = 353 kg) and gained 183 kg over 123 d. It was calculated that 11.5% of the feed nitrogen and 16.9% of the feed phosphorus was retained by the animal with the remaining nutrients excreted. On average, 25.6 kg of N and 4.1 kg of P (DM basis) were excreted per fed beef animal. On average, 887 kg total manure (solids and water) were removed per finished animal (7.2 kg/animal/d) averaging 73% total solids. Approximately 28% of the total solids are volatile solids with a wide range of observed volatile solids levels (9 to 63%). Based upon these data, 30.7% of the excreted nitrogen or (7.8 kg/animal fed) and 90.2% of the excreted phosphorus (or 3.7 kg/animal fed) were removed in manure at cleaning. These data suggest there is variation in the amount of P harvested from beef feedlots, reflecting the variation between feedlots as a result of individual pen conditions, and requirements for use and handling of the manure in the pen prior to harvesting. These data suggest that estimates based on the references (ASAE, 2000; USDA, 1992) of P removed in manure are too high, and indicate that acres required for distribution of manure P in NMPs should be 50% of the acres predicted by those references.

Economics of Manure Phosphorus Distribution from Beef Feeding Operations

An economic model was developed to evaluate cost and value of manure distribution. Feedlots ranging in size from 2,500 head to 25,000 head one-time capacities were used as case studies to calculate excretion amounts from cattle fed diets with a range of phosphorus. Diet P and subsequent costs of distributing the manure were used to analyze the corresponding costs of manure distribution, in addition to determining the required available land needed to be in compliance with a nutrient management plan based on utilization of manure P by the crops grown. The model illustrated when animals are fed diets of increasing P concentration, total distribution cost increased, ranging from