Andrew F. Olson

Carbon, ash and organic matter relationships for feedlot manures and composts

Composting is increasingly recognized as a means of handling livestock manure. Using relationships derived from a dataset of >3000 samples representing the decay spectrum from raw manure to mature compost (from unpaved feedlot pens bedded with straw or wood residuals) we propose that measurement of either total carbon or ash content is sufficient to estimate carbon, organic matter and dry matter mass changes during composting of beef feedlot manure. Key words: Compost, carbon, ash content, feedlot manure

Windrow temperatures and chemical properties during active and passive aeration composting of beef cattle feedlot manure

Windrow composting emerged in the mid-1990s as an alternative manure-handling practice in Alberta’s cattle feedlot industry. This study compared two composting methods: active (turning) and passive aeration. Temperatures were monitored over the first 90 d and chemical properties over 188 d of composting. Pre- vs. post-turning sampling of the active treatment was also compared. Mean daily temperature was warmest at the bottom windrow location (53.6oC) and coolest at the top (46.4oC) in the active treatment, but warmest at the top (44.1oC) and coolest at the bottom (33.9oC) in the passive treatment. Final compost from the passive treatment had significantly higher total N (TN), total C (TC), electrical conductivity (EC), Na, and Cl than the active treatment. There were no significant treatment effects on C:N ratio, NH4-N, NO3-N, total P (TP), Kelowna-extractable P (KEP), pH, Ca, Mg or K. Both treatments showed substantial and non-significantly different C (71–80%) and N (44–58%) losses. Pre- versus post-tur...

Dissipation of Three Veterinary Antimicrobials in Beef Cattle Feedlot Manure Stockpiled over Winter.

Dissipation of veterinary antimicrobials is known to occur during aerated windrow composting of beef cattle manure. However, it is unclear if a similar dissipation occurs during stockpiling. Chlortetracycline, tylosin, and sulfamethazine are three of the most commonly used veterinary antimicrobials in beef cattle production in western Canada. Their dissipation in stockpiled manure was investigated over 140 d during winter in Alberta, Canada. Beef cattle housed in pens were administered 44 mg of chlortetracycline kg feed (dry weight), 44 mg of chlortetracycline + 44 mg sulfamethazine kg feed, 11 mg of tylosin kg feed, or feed without antimicrobials (control). Manure samples were extracted using pressurized liquid extraction, and the extracts were analyzed for chlortetracycline, sulfamethazine, and tylosin by LC-MS-MS. Dissipation of all three antimicrobials in the manure was explained by exponential decay kinetics. Times for 50% dissipation (DT) were 1.8 ± 0.1 d for chlortetracycline alone or 6.0 ± 0.8 d when mixed with sulfamethazine, 20.8 ± 3.8 d for sulfamethazine, and 4.7 ± 1.2 d for tylosin. After 77 d, <1% of initial chlortetracycline and <2% of sulfamethazine remained. Tylosin residues were more variable, decreasing to approximately 12% of initial levels after 28 d, with 20% present after 77 d and 13% after 140 d. Temperatures within stockpiles reached maximum values within 6 d of establishment and varied with location (bottom, 62.5°C; middle, 63.8°C; and top, 42.9°C). Antimicrobials in the manure did not inhibit microbial activity, as indicated by temperature and mass losses of carbon (C) and nitrogen (N). The C/N ratio in the manure decreased over the stockpiling period, indicating decomposition of manure to a more stable state. Dissipation of excreted residues with DT values 1.8 to 20.8 d showed that stockpiling can be as effective as windrow composting in mitigating the transfer of these three veterinary antimicrobials into the environment during land application of processed manure.

Dissipation of Antimicrobial Resistance Determinants in Composted and Stockpiled Beef Cattle Manure

Windrow composting or stockpiling reduces the viability of pathogens and antimicrobial residues in manure. However, the impact of these manure management practices on the persistence of genes coding for antimicrobial resistance is less well known. In this study, manure from cattle administered 44 mg of chlortetracycline kg feed (dry wt. basis) (CTC), 44 mg of CTC and 44 mg of sulfamethazine kg feed (CTCSMZ), 11 mg of tylosin kg feed (TYL), and no antimicrobials (control) were composted or stockpiled over 102 d. Temperature remained ≥55°C for 35 d in compost and 2 d in stockpiles. Quantitative PCR was used to measure levels of 16S rRNA genes and tetracycline [(B), (C), (L), (M), (W)], erythromycin [(A), (B), (F), (X)], and sulfamethazine [(1), (2)] resistance determinants. After 102 d, 16S rRNA genes and all resistance determinants declined by 0.5 to 3 log copies per gram dry matter. Copies of 16S rRNA genes were affected ( < 0.05) by antimicrobials with the ranking of control > CTC = TYL > CTCSMZ. Compared with the control, antimicrobials did not increase the abundance of resistance genes in either composted or stockpiled manure, except (M) and (2) in CTCSMZ ( < 0.05). The decline in 16S rRNA genes and resistance determinants was higher ( < 0.05) in composted than in stockpiled manure. We conclude that composting may be more effective than stockpiling in reducing the introduction of antimicrobial resistance genes into the environment before land application of manure.

Transport of three veterinary antimicrobials from feedlot pens via simulated rainfall runoff

Veterinary antimicrobials are introduced to wider environments by manure application to agricultural fields or through leaching or runoff from manure storage areas (feedlots, stockpiles, windrows, lagoons). Detected in manure, manure-treated soils, and surface and ground water near intensive cattle feeding operations, there is a concern that environmental contamination by these chemicals may promote the development of antimicrobial resistance in bacteria. Surface runoff and leaching appear to be major transport pathways by which veterinary antimicrobials eventually contaminate surface and ground water, respectively. A study was conducted to investigate the transport of three veterinary antimicrobials (chlortetracycline, sulfamethazine, tylosin), commonly used in beef cattle production, in simulated rainfall runoff from feedlot pens. Mean concentrations of veterinary antimicrobials were 1.4 to 3.5 times higher in surface material from bedding vs. non-bedding pen areas. Runoff rates and volumetric runoff coefficients were similar across all treatments but both were significantly higher from non-bedding (0.53Lmin(-1); 0.27) than bedding areas (0.40Lmin(-1); 0.19). In keeping with concentrations in pen surface material, mean concentrations of veterinary antimicrobials were 1.4 to 2.5 times higher in runoff generated from bedding vs. non-bedding pen areas. Water solubility and sorption coefficient of antimicrobials played a role in their transport in runoff. Estimated amounts of chlortetracycline, sulfamethazine, and tylosin that could potentially be transported to the feedlot catch basin during a one in 100-year precipitation event were 1.3 to 3.6ghead(-1), 1.9ghead(-1), and 0.2ghead(-1), respectively. This study demonstrates the magnitude of veterinary antimicrobial transport in feedlot pen runoff and supports the necessity of catch basins for runoff containment within feedlots.

Soluble salts, copper, zinc, and solids constituents in surface runoff from cattle manure compost windrows

Larney, F. J., Olson, A. F., Miller, J. J. and Tovell, B. C. 2014. Soluble salts, copper, zinc, and solids constituents in surface runoff from cattle manure compost windrows. Can. J. Soil Sci. 94: 515-527. Composting has become widely adopted by the beef cattle feedlot industry in southern Alberta. Compost windrows subjected to heavy rainfall can lead to runoff whose properties may vary with compost maturity. A rainfall simulator generated runoff on days 18, 26, 40, 54, 81, 109 and 224 of manure composting. Runoff was collected in timed 5-L increments to 30 L, creating the variable “time during runoff event” (TDRE). Calcium, K and S showed significant maturity×TDRE interactions, especially earlier in the composting process, e.g., on day 18, Ca values increased from 34 mg L-1 for the initial 0- to 5-L runoff increment to 43 mg L-1 for the final 25- to 30-L increment. Most significant changes in runoff concentrations occurred between days 26 and 40, e.g., Cu levels fell by 67% and Zn levels by 78%. Even though compost Cu and Zn concentrations were higher during the latter stages of composting, their transport potential in runoff was curtailed due to binding with stable organic matter (OM). The C:N ratio of runoff solids decreased from 10.5 on day 18 to only 4.9 on day 224, suggesting the transport of very stable OM after compost curing. The study showed that runoff quality was influenced by compost maturity, which has implications for the timing of rainfall events relative to the maturity spectrum and the potential risk to surface water quality if runoff is not contained.

Vegetation Response to a One-Time Spent Drilling Mud Application to Semiarid, Mixed-Grass Prairie

Abstract Landspraying while drilling (LWD) is an approved disposal method for water-based drilling mud (WBM) systems in western Canada. The mud is applied either on cultivated land, where it is incorporated by cultivation, or on vegetated land where it is not incorporated. This study examined the effects of summer WBM application (0, 15, 20, 40, and 80 m3 · ha−1) on native vegetation properties. Our results indicated that LWD increased bare ground but decreased lichen cover at the 80 m3 · ha−1 rate relative to the untreated control. Nitrogen (N), sulfur (S), and magnesium (Mg) concentrations in aboveground plant tissue increased with increasing LWD rate in samples taken 45 d after WBM application, but these differences disappeared 1 yr after treatment. Increase in tissue concentration of phosphorus (P) with LWD rate, however, was only detected 3 yr after LWD. Nonetheless, these changes in tissue chemistry were not associated with significant changes in biomass yield or species composition. Overall, our results suggest that single WBM applications at rates (≤ 20 m3 · ha−1) commonly used in western Canada, if properly managed, are unlikely to adversely affect native prairie vegetation.

Residual effects of topsoil replacement depths and one- time application of organic amendments in natural gas wellsite reclamation

Larney, F. J., Olson, A. F. and DeMaere, P. R. 2012. Residual effects of topsoil replacement depths and one-time application of organic amendments in natural gas wellsite reclamation. Can. J. Soil Sci. 92: 883-891. The success of reclamation on abandoned wellsites depends on their capacity to recover and sustain levels of soil quality similar to those existing prior to soil disturbance. A 1997-2000 study looked at four (0, 50, 100 and 150%) topsoil replacement depths (TRD) and five amendments [compost, manure, alfalfa (Medicagosativa L.) hay, wheat (Triticumaestivum L.) straw, check] in the reclamation of three natural gas wellsites in Alberta. In 2007 (10 yr after establishment) the wellsites were re-sampled to examine residual effects of reclamation treatments on soil properties. In 2007, there was no difference in SOC between the 50, 100 and 150% TRD treatments and all three were significantly higher than the 0% TRD by an average of 18%. Therefore adding half the amount of topsoil (50%) 10 yr previously caused long-term improvement in SOC (vs. 0% TRD), but adding more topsoil (100, 150%) did not produce further gains. Soil organic C (0- to 15-cm depth) on the compost and manure treatments (across all sites and TRD treatments) was significantly higher (+8%) than straw, alfalfa and check treatments some 10 yr later. Results show that initial investment in organic amendments for wellsite reclamation can have residual effects on soil quality.

Transport of Three Antimicrobials in Runoff from Windrows of Composting Beef Cattle Manure.

Rain runoff from windrowed or stockpiled manure may contain antimicrobials with the potential to contaminate surface and ground water. To quantify the concentration of antimicrobials transported in runoff from windrowed manure, antimicrobials were administered continuously in feed to beef cattle () as follows: 44 mg of chlortetracycline kg feed (dry weight), a 1:1 mixture of 44 mg of chlortetracycline and 44 mg sulfamethazine kg feed, and 11 mg of tylosin kg feed. Cattle in a fourth treatment group received no antimicrobials (control). Manure from the cattle was used to construct two windrows per treatment. On Days 2 and 21 of composting, a portable Guelph Rainfall Simulator II was used to apply deionized water at an intensity of 127 mm h to each windrow, and the runoff was collected. Manure samples were collected before rain simulations on Days 2 and 21 of composting for antimicrobial analysis. On Day 2, average concentrations of chlortetracycline, sulfamethazine, and tylosin in manure were 2580, 450, and 120 μg kg, respectively, with maximum concentrations in runoff of 2740, 3600, and 4930 μg L, respectively. Concentrations of all three antimicrobials in runoff were higher ( < 0.05) on Day 2 than on Day 21, reflecting the higher concentrations in manure on Day 2. Maximum estimated masses of chlortetracycline, sulfamethazine, and tylosin that could be transported in runoff from a windrow (3 m long, 2.5 m wide, 1.5 m high) were approximately 0.87 to 0.94, 1.57, and 1.23 g, respectively. This study demonstrates the importance of windrow composting in reducing antimicrobial concentrations in manure. The runoff from windrows can be a source of antimicrobials and demonstrates the need for containment of runoff from composting facilities to mitigate antimicrobial contamination of surface and groundwater resources.

Wheat yield and soil properties reveal legacy effects of artificial erosion and amendments on a dryland Dark Brown Chernozem

Abstract: Erosion leads to substantial loss of soil productivity. To abate such decline, amendments such as manure or fertilizer have been successfully employed. However, the longevities of erosion and soil amendment legacy effects are not well quantified. In 1957, a Dark Brown Chernozem soil at Lethbridge, AB, was land-levelled, creating three degrees of topsoil removal or erosion: noneroded, moderate erosion, or severe erosion. Two amendment studies (1980–1985 and 1987–1991) were superimposed on the erosion treatments. Both studies were cropped to spring wheat (Triticum aestivum L.) from 1993–2010 to examine legacy effects of erosion and soil amendments on wheat yield and soil properties. Without amendment, mean wheat yield under moderate erosion was 40% of the noneroded treatment, whereas severe erosion was 34% of the noneroded treatment, 36–42 yr (1993–1999) after erosion. Under moderate or severe erosion, the restorative power of manure diminished substantially in the first 10–15 yr following cessation of addition, but then levelled off resulting in wheat yields up to 35% higher than equivalent nonamended treatments. Legacy effects of erosion (54 yr) and amendment (27–31 yr) on soil organic carbon and total nitrogen were also observed.