Dairy manure

The performance of continuously mixed anaerobic digesters were experimentally evaluated for treating manure, food waste, and their mixtures at 37±2oC and a hydraulic retention time of 20 days. The first mixture was composed of 32% and 68%, and the second was composed of 48% and 52%, of food waste and dairy manure, respectively. The percentage was based on volatile solids (VS). Digesters treating manure and the two mixtures showed stable performance at an organic loading rate (OLR) of 4 gVS/L. However, the digester treating food waste was not stable even at an OLR of 2 gVS/L, as indicated by high volatile fatty acid concentrations and low pH. The pH adjustment by adding hydrate lime to the food waste increased biogas production rate and yield. The 16S rDNA analysis results showed that the food-waste-derived library contained statistically greater numbers of clones related to the phyla Thermotogae and Actinobacteria; and the manure-derived library contained greater amounts of clones r...

There is minimal information on the nitrogen (N) availability and composition of treated manures. Knowing how N availability differs with manure treatment will result in better N crediting guidelines. Raw dairy manure and anaerobically digested manure were incubated with five typical Wisconsin soils for 112 d. Net N mineralized from the different N sources were compared. Nitrogen mineralization differed by

The effect of manure-screening on the biogas yield of dairy manure was evaluated in batch digesters under mesophilic conditions (35 degrees C). Moreover, the study determined the biogas production potential of different mixtures of unscreened dairy manure and food waste and compared them with the yield from manure or food waste alone. A first-order kinetics model was developed to calculate the methane yield from different mixtures of food waste and unscreened dairy manure. The methane yields of fine and coarse fractions of screened manure and unscreened manure after 30days were 302, 228, and 241L/kgVS, respectively. Approximately 93%, 87%, and 90% of the biogas yields could be obtained, respectively, after 20days of digestion. Average methane content of the biogas was 69%, 57%, and 66%, respectively. Based on mass balance calculations, separation of the coarse fraction of manure would sacrifice about 32% of the energy potential. The methane yield of the food waste was 353L/kgVS after 30days of digestion. Two mixtures of unscreened manure and food waste, 68/32% and 52/48%, produced methane yields of 282 and 311L/kgVS, respectively after 30days of digestion. After 20days, approximately 90% and 95% of the final biogas yield could be obtained, respectively. Therefore, a hydraulic retention time (HRT) of 20days could be recommended for a continuous digester. The average methane content was 62% and 59% for the first and second mixtures, respectively. The predicted results from the model showed that adding the food waste into a manure digester at levels up to 60% of the initial volatile solids significantly increased the methane yield for 20days of digestion.

The effect of cattle manure and slurry application on percolation and survival of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium was investigated for different soil depths after the addition of water. Four treatments were chosen for the first set of experiments: (i) addition of inoculated farmyard manure on the soil surface, (ii) mixing of inoculated farmyard manure with the top 10 cm of soil, (iii) addition of inoculated slurry on the soil surface, and (iv) injection of inoculated slurry into the top 10 cm of the soil. Homogeneity of water distribution in the soil profile was confirmed by a nondestructive nuclear magnetic resonance method. Survival data were fitted to a modified logistic model, and estimated survival times were compared. In the second set of experiments, pathogen-inoculated farmyard manure or slurry was applied to soil columns with 1-month-old lettuce plants. More pathogen cells percolated to greater depths after slurry than after manure appli...

Liquid dairy manure is a major organic input to cultivated soils. Therefore, a method for monitoring the mineralisation of slurries should be a useful tool for managing soil fertilisation. In order to examine whether the biodegradation of cattle sludge can be monitored by near infrared (NIR) spectroscopy, soil samples from a laboratory incubation experiment were analysed using this rapid and inexpensive method. Five different cattle slurries were added to three soils with increasing clay content in such an amount as to give 130 ppm of total nitrogen. The resulting 18 experimental treatments (three control soils and 15 soil-slurry combinations) were incubated for 180 days under optimal temperature and soil water content. Each treatment was sampled at 0, 2, 8, 12, 16, 21, 29, 41, 72, 121 and 180 days: the respired CO2 was captured in alkali traps and mineral N was extracted using 1 M KCl. Three replicates of each sampling were analysed individually. The resulting 648 samples, air drie...

The Texas Panhandle is regarded as the 'Cattle Feeding Capital of the World', producing 42% of the fed beef cattle in the United States within a 200-mile radius of Amarillo generating more than 5 million tons of feedlot manure/year. Apart from feedlots, the Bosque River Region in Erath County, just north of Waco, Texas with about 110,000 dairy cattle in

Theeffects on nitrogen losses and volatilisation of ammonia, methane and nitrousoxide from manure storage were investigated using excreta of dairy cows fed twoforage-based rations, (i) young grass (ad libitum) and hay (2 kgd–1) or (ii) hay (ad libitum) and concentrate (3kg d–1). In two series either grass of low crudeprotein content (112 g kg–1 dry matter, similar tothe hay) or of high crude protein content (229 gkg–1) was used. Emissions from the resulting manureswere investigated in two common storage systems, the liquid manure system andthe slurry/farmyard manure system. Storage was performed under controlledconditions using the chamber technique to quantify trace gas emissions and themass balance method to measure total nitrogen loss. The ration characterised bythe low-protein grass resulted in higher urinary nitrogen and lower faecalnitrogen excretion than the hay ration, thus significantly enhancing totalnitrogen and ammonia emissions from all types of manure. Differences to t...

The effect of starch source and phytic acid (PA) supplementation on phosphorus (P) partitioning and ruminal phytase activity was evaluated in eight midlactation cows (four ruminally cannulated). Cows were randomly assigned to treatments in replicated 4 x 4 Latin squares with four 18-d periods. Diets included dry ground corn (DG) or steam-flaked corn (SF), with no supplemental P (L; 0.33% P) or supplemental purified PA (0.44% P) to provide additional P from a nonmineral source. Total collection of milk, urine, and feces was conducted on d 16 to 18 of each period. Ruminal fluid was sampled and ruminal pH measured every 8 h on d 17 and 18. Milk yield was unaffected by starch source, despite lower DMI by cows fed SF. Cows fed SF had increased DM digestibility compared with those fed DG, and tended to have higher efficiency of milk yield (1.40 vs. 1.35 kg of milk/kg of DMI). Intake and fecal excretion of P was lower in cows fed SF than in cows fed DG. In cows fed SF, milk P as a percenta...

The influence of terrain attributes on response of corn (Zea mays L.) to soil management practices has rarely evaluated, especially on degraded soils. Five management zones (MZ) were delineated in a 9-ha Alabama field (Typic and Aquic Paleudults) using a soil survey, topography and surfaces of soil electrical conductivity (EC), soil organic carbon (SOC) and soil texture. From 2001-2004, a conventional system (chisel plowing/disking with no cover crops) with or without manure (CTmanure or CT), and a conservation system (no-till and cover crops) with and without manure (NTmanure or NT), were established in strips traversing the landscape in a corn-cotton (Gossypium hirsutum L.) rotation, following long-term conventional tillage. Conservation systems had greater yield than conventional systems in all MZ in 2002 (dry season; 8.88 vs. 6.71 Mg ha-1), and in four of five MZ in 2003 (wet season; 13.04 vs. 12.33 Mg ha-1); no differences existed in the initial year, 2001, (9.85 Mg ha-1). In 2...

Construction of new homes and businesses is a continuous process in rapidly growing urban areas such as the Dallas metropolis. Post-construction landscaping is usually approached from only the plant-selection viewpoint and little effort is devoted to the severely disturbed soil. Subsoil and construction debris are often mixed with or completely replace the original top soil. Although ornamental plants and turf grasses planted in these disturbed soils may perform well in the short term due to abundant watering and fertilization, they frequently decline with time when heat and drought stress become prevalent. Dairy manure compost (DMC) is a readily available soil organic matter amendment in many areas due to the presence of large dairy operations. These dairy operations need alternative ways to dispose of their manure because soils surrounding the diary operations are often elevated in soil P. Consequently, dairy farmers and state regulatory agencies are considering urban markets for ...

This study was initiated to investigate the hypothesis that using fluidized bed combustion (FBC) residue to stabilize a dairy feedlot surface (DFS) could enhance element attenuation and minimize the environmental impact on water quality. The laboratory leaching experiment included FBC, dairy manure (DM), and DM/FBC treatments. The leaching process consisted of 10 weekly additions of distilled water, each of 460 mL. Using FBC with DM decreased the concentration of most elements (e.g., P, N, K, Ca, Al, Si, Fe, Mn, Cu, Zn, Pb, Cd, Co, Cr, Ni, As, and Se) in the leachate. A decrease ranging from 5.6 to 100% was obtained. The presence of high concentration of dissolved organic matter (DOM) is believed to enhance element attenuation by FBC minerals. Several mechanisms involved in this process are proposed: (1) formation of insoluble metal-organic complexes; (2) sorption of soluble organic and inorganic species on mineral surfaces; and (3) precipitation of soluble inorganic species. These mechanisms are discussed in relation to each of the measured elements. On the other hand, using FBC with DM appeared to increase the concentration of B, S, and Mg in the leachate. Reactions of DOM with FBC minerals to form soluble organic complexes were suggested to explain B and S increases. The increase in leached Mg could be attributed to the presence of SOâ²⁻. Their results provide evidence that using FBC to stabilize DFS has the advantage of immobilizing a large portion of most elements present in DM leachate.

Conditions in microbial fuel cells (MFCs) differ from those in microbial electrolysis cells (MECs) due to the intrusion of oxygen through the cathode and the release of H2 gas into solution. Based on 16S rRNA gene clone libraries, anode communities in reactors fed acetic acid decreased in species richness and diversity, and increased in numbers of Geobacter sulfurreducens, when reactors

The influence of terrain attributes on response of corn (Zea mays L.) to soil management practices has rarely evaluated, especially on degraded soils. Five management zones (MZ) were delineated in a 9-ha Alabama field (Typic and Aquic Paleudults) using a soil survey, topography and surfaces of soil electrical conductivity (EC), soil organic carbon (SOC) and soil texture. From 2001-2004, a conventional system (chisel plowing/disking with no cover crops) with or without manure (CTmanure or CT), and a conservation system (no-till and cover crops) with and without manure (NTmanure or NT), were established in strips traversing the landscape in a corn-cotton (Gossypium hirsutum L.) rotation, following long-term conventional tillage. Conservation systems had greater yield than conventional systems in all MZ in 2002 (dry season; 8.88 vs. 6.71 Mg ha-1), and in four of five MZ in 2003 (wet season; 13.04 vs. 12.33 Mg ha-1); no differences existed in the initial year, 2001, (9.85 Mg ha-1). In 2...