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1.
Boxwood (Buxus spp.) blight is a devastating disease caused by the Ascomycete fungus Calonectria pseudonaviculata in the U.S. and Europe. A second Calonectria species, C. henricotiae, is also pathogenic on boxwood in Europe, but is not present in the U.S. where it is classified as a quarantine pathogen. Composting can eradicate various plant pathogens and high temperature is likely the most important factor influencing pathogen eradication. We previously reported that C. pseudonaviculata microsclerotia survived exposure to 40?°C in an incubator without compost, whereas exposure to the same temperature and time, but with compost added, greatly decreased survival. That is, the decrease in Calonectria growth and survival in compost was greater than could be accounted for by high temperature alone. We hypothesized that the enhanced decrease in Calonectria growth and survival might be due to ammonia, a fungitoxic gas produced during composting. In this laboratory study, we determined that ammonia within agar in Petri plates reduced radial growth of both C. pseudonaviculata and C. henricotiae. In studies with C. pseudonaviculata, gaseous ammonia reduced microsclerotia survival. Our findings suggest that composting dead or dying blighted boxwoods in the presence of ammonia could reduce dissemination of both Calonectria species from blighted to healthy boxwoods.  相似文献   

2.
Contamination of food and water by microorganisms from animal manure has become an important issue in public health. Escherichia coli O157:H7 is one of several emerging pathogens of concern. In this research, we studied how the self-heating, thermophilic phase of composting influenced laboratory-grown vs. bovine-derived E. coli O157:H7 mortality, specifically the relationship between temperature, time at temperature, and pathogen survival. Composting experiments were conducted in laboratory-scale bioreactors operated in three temperature ranges: 40°C to 50°C, 50°C to 60°C, and greater than 60°C. We measured the effects of temperature and composting time on E. coli O157:H7 mortality. Laboratory-grown E. coli O157:H7, inoculated into the initial compost material, were not detected after approximately 300 degree days of heating. In several experiments where compost temperatures did not rise above 50°C, an initial decline of E. coli O157:H7 with subsequent regrowth was observed. E. coli O157:H7 in compost materials from infected cattle were not detected after approximately 180 degree days of heating. Numbers of total coliform bacteria declined with temperature similarly to those of E. coli O157: H7. The results of this research provide information for reducing or eliminating E. coli O157:H7 in animal wastes.  相似文献   

3.
Abstract

Loss‐on‐ignition (LOI) is a simple method for determining ash content, and by reciprocation, organic matter content of compost and manure. However, reported ignition temperatures and heating times for LOI measurements vary widely, and this brings into question the accuracy of one specific combination of ignition temperature and heating time over another. This study examined the effect of 42 temperature‐heating time combinations (six ignition temperatures from 400 to 650°C in 50°C increments by seven heating times of 1, 2, 8, 12, 16, 20, and 24‐h) on the ash content of a finished compost and a fresh manure. The experiment included the 550°C for 2‐h method recommended in Test Methods for Evaluation of Compost and Composting. The magnitude of the decrease in ash content due to increase in temperature was not consistent across all heating times. For example, after a 1‐h heating time for compost, ash content was 75.7% at 400°C and 67.5% at 650°C, compared to 69.6% at 400°C and 66.8% at 650°C after 24‐h. Irrespective of heating time, an ignition temperature of 400°C overestimated ash content for both compost and manure compared to the TMECC method. The TMECC method with its moderate temperature and short heating time requirement could reduce energy costs without affecting ash content results.  相似文献   

4.
Effects of composting manure on viability of Giardia cysts (GC) and Cryptosporidium cysts (CO) were determined in a two-year study with manure from feedlot cattle bedded on barley straw or woodchips. Each year, manure was deposited in 8 m × 2.5 m × 2 m windrows (one per bedding type) on a sheltered concrete pad. On day 0, porous bags containing 100 g of feces from confirmed Giardia- and Cryptosporidium-positive cattle (9 bags per retrieval day in Year 1; 3 per day in Year 2) were implanted in the windrows. Replicate bags were placed on the concrete pads as uncomposted controls. Windrow temperature and water content were measured and compost was turned mechanically twice each week. Fecal bags were retrieved and subsampled for enumerations of total and viable cysts and cysts after 1, 2, 3, 7, 10, 17, 24 and 31 days in 1998 and after 1, 2, 3, 7, 9, 16, 23, 30, 42, 56, 70 and 98 days in 1999. Windrow temperatures (TEMP) exceeded 55°C during the fourth week of composting, and remained above 50°C for 4 wk thereafter in 1999. Bedding material did not affect overall mean temperature in either year, but TEMP was higher with straw than with woodchip from day 10 to day 17 in 1998 (P < 0.05) and on day 16 and day 42 in 1999 (P < 0.10). In 1998, moisture content decreased from 62.2 to 43.2% during composting of woodchip manure and from 67.3 to 39.3% during composting of straw manure. In 1999, moisture content decreased from 61.0 to 31.8% for woodchip and from 64.5 to 28.6% for straw compost. Percentage of viable CO declined gradually over the 31 days in 1998. The following year revealed a rapid decline in viability of GC and CO once compost temperature exceeded 55°C and viabilities of GC and CO were reduced to zero after 42 days (straw compost) and after 56 days (woodchip compost). Exposure of CO and GC to temperatures > 55°C for a period of 15 days appears to be an effective method of inactivating Giardia cysts and Cryptosporidium cysts in feedlot manure.  相似文献   

5.
Conventional composting for mushroom cultivation involves a largely uncontrolled phase in which there are wide variations in temperature and oxygen level, resulting in the production of odor pollutants. The experiments reported in this paper investigated environmental conditions for compost preparation in an attempt to minimize odor production. Substrates for mushroom culture were prepared in flasks under controlled temperature and aeration. The temperature (48 to 72°C), O2 concentration (0.6 to 8.7 percent v/v) and duration (6 or 20 h) of an initial pasteurization phase were varied before all the substrates were given a standard aerated conditioning period at 47°C. Compost decomposition, initial mineralization rates of 14C labelled glutamic acid (a measure of microbial activity) and actinomycete and fungal populations all decreased as the pasteurization temperature increased from 48°C to 72°C. The duration and O2 concentration of the pasteurization treatment did not affect the overall decomposition of the substrate, mineralization of 14C labelled glutamic acid and subsequent mushroom mycelial extension rate and yield from the substrate. Under the controlled temperature conditions, the optimum pasteurization temperature for mushroom mycelial extension rate and sporophore yield was 60°C but possible benefits of higher temperature zones in a large stack situation were identified: 1) a higher concentration of ammonia which may assist substrate degradation over a prolonged period; 2) the development of high populations of intercellular bacteria following pasteurization at 72°C, 0.6 percent O2; 3) the recovery of low rates of mineralization of 14C labelled glutamic acid following the pasteurization of substrate at 72°C to rates above those of the 48°C and 60°C pasteurization treatments.  相似文献   

6.
As interest in food waste composting grows, so does the need for proven composting methods. Stability testing has been proposed as a compost quality assurance tool. We conducted this study to: (i) to evaluate the efficacy of simple outdoor composting methods in producing a compost with a low, stable decomposition rate, and (ii) to determine the reliability of simple, 4-h compost stability evaluation methods. Composting was conducted outdoors in winter and spring in Eugene, Oregon without moisture addition. Mixed food waste was combined with screened dairy solids and ground yard trimmings. Sawdust was used to cover windrows for the first 27 d of composting. Compost windrow temperatures remained above 55°C for 30+ d. Carbon dioxide evolved with several 4-h test methods was strongly correlated (r2 > 0.7) with CO2 evolved using a 48-h test. A limited-turn windrow (LTW) composting system produced compost with slightly greater stability than a passively aerated windrow (PAW) composting system. Food waste compost samples had a low CO2 evolution rate after 71 to 99 d using either composting system. Compost CO2 evolution rate at 25°C decreased with composting time, reaching approximately 1 to 4 mg CO2-C g compost C?1 d?1 for the PAW method and 0.5 to 2 mg CO2-C g compost C?1 d?1 for the LTW method. Putrescible organic matter in food waste was effectively decomposed in outdoor windrows using composting methods that did not employ forced aeration, self-propelled windrow turners, or manufactured composting vessels. Several 4-h stability tests showed promise for implementation as quality assurance tools.  相似文献   

7.
In-house composting involves treating manure where it accumulates on the floor of high-rise, caged layer facilities. This process produces a partially composted material and can aid in house fly (Musca domestica L.) control by generating temperatures in the thermophilic range (≥43°C). Two trials were conducted to determine the effect of material volume and the use of previously composted material (starter) or wheat (Triticum aestivum L.) straw as bulking agents on compost temperatures and material properties. In Trial 1, starter combined with wheat straw or wheat straw alone were added to separate quadrants in a layer building, formed into windrows, and turned biweekly. Temperatures were consistently higher with the starter treatment, but both treatments followed a distinct pattern where temperatures peaked on the day of turning and declined rapidly thereafter. The starter treatment had higher initial volume (0.19 m3 m?1 row) than straw alone (0.13 m3 m?1 row), and maintained proportionately higher volumes throughout the trial. Volume in both treatments increased linearly with time and was correlated with peak compost temperature on the day of turning. Regression analysis indicated that a critical volume of 0.18 m3 m?1 row was required to consistently achieve compost temperatures ≥43°C. In a second trial, starter alone was compared to wheat straw at two rates. Volumes for all treatments initially ranged from 0.20 to 0.28 m3 m?1 row and increased linearly throughout the trial. Temperatures consistently exceeded 43°C on the day of turning. Analysis of the materials from both trials indicated that starter or straw had little effect on %moisture, %carbon, %nitrogen, or carbon:nitrogen ratio of composting materials beyond the first week after windrow establishment. These results indicate that material volume is more important than the use of starter or straw materials as bulking agents to achieve in-house composting temperatures ≥ 43°C.  相似文献   

8.
The occurrence of bovine spongiform encephalopathy (BSE) in Canada has resulted in the implementation of regulations to remove specified risk material (SRM) from the food chain. SRM includes the distal ileum of all cattle, and the skull, brain, trigeminal ganglia, eyes, palatine tonsils, and spinal cord and dorsal root ganglia of cattle ≥30 months of age. Composting may be a viable alternative to rendering for SRM disposal. In our study, two bulking agents, barley straw and wood shavings, were composted with beef manure along with SRM in passively aerated, laboratory-scale composters. Both composts heated rapidly, exceeding 55°C after 3 days with oxygen declining in the early composting stage with wood-shaving compost, but returning to near-original levels after 5 days. During composting the two matrices differed (P <0.05) only in water content, TC and bulk density. In the final compost, water content, TC and C/N ratio were higher (P < 0.05), while EC was lower (P < 0.05) in the wood shavings as compared to the straw compost. Approximately 50% of SRM was decomposed after 15 days of composting, with 30% of SRM being decomposed within the first 5 days. Phospholipid fatty acid (PLFA) profiles were used to characterize the microbial communities and showed that Gram positive bacteria were predominant in compost at day 5, a point that coincided with a rapid increase in temperature. Gram negative bacteria and anaerobes declined at day 5 but populations recovered by day 15. Fungi appeared to be suppressed as temperatures exceeded 55°C and did not appear to recover over the remainder of the composting period, with the exception of the straw compost at day 15. On day 5, Actinomycetes increased in the straw compost, but declined in the wood shavings compost, with this group increasing in both types of compost at day 15. Although temporal changes were evident, compost matrices or depth within the composter did not obviously influence microbial communities. Decomposition of SRM also did not differ between compost matrices or with depth in the composters. These results suggest that SRM decompose rapidly during composting and that both mesophilic and thermophilic microbial communities play a role in its decomposition.  相似文献   

9.
ABSTRACT

To ensure the safety of compost products, the Canadian Council of Ministers of the Environment's compost guidelines specify upper limits for certain pathogenic and indicator microbes, which are presumably achieved by exposing every particle of compost to temperatures ≥55°C for at least three consecutive days. A rugged temperature probe that behaves like a random compost particle was used to investigate whether every compost particle meets the time temperature criterion and to measure sanitation efficacy. An inoculum consisting of Salmonella enterica var. Meleagridis, Escherichia coli K12, and phi-S1 bacteriophage (all at levels of ～1 × 106 CFU/PFU mL?1) was added into 17 probes. The probes were randomly introduced into a covered, aerated static pile along with 17 probes that only monitored the temperature. After 56 days of composting, with one pile turn the probes were recovered. Organism levels were determined via culture-based methods. Before turning, 80% of the randomly introduced probes satisfied the time-temperature criterion. After turning, this number increased to 87%, demonstrating that turning is somewhat useful for sanitation. The cool zones largely remained mesophilic with the pile turning having minimal impact, which could potentially be an indication that the pile was not turned thoroughly. One of the 17 probes with cryovials reached only 40.2°C, and survival of S. meleagridis (2.5 × 106 CFU ml?1) was observed. The remaining probes with cryovials exceeded 55°C and were pathogen free. It appears that the specified time-temperature conditions are likely adequate. However, more observations are needed before a firm conclusion can be made.  相似文献   

10.
? Careful monitoring of the composting process — physically, chemically and biologically — enables managers to determine key nutritional and ecological factors vital to production of a quality compost. At La Trobe University, trials compared composts which achieve high temperature (80° C) with those controlled at moderate thermophilic temperatures (45 — 55° C) to demonstrate whether the hot phase is essential or whether composts of equal nutritional status can be produced by processing at lower temperatures.  相似文献   

11.
Composting broiler litter (a mixture of manure, bedding material, and wasted feed) with commonly available high-C substrates may be a viable alternative to reduce current land disposal practices for litter. Broiler litter with wood shavings as a bedding material and broiler litter with peanut hulls as a bedding material were composted with wheat straw, peanut hulls, pine bark and paper mill sludge in 0.33 m3 batch reactors. Litters and C substrates were mixed to achieve C:N ratios of approximately 30:1. Dry weight, total N, total C, temperature, electrical conductivity and pH were determined at regular intervals. Maximum temperatures peaked near 70°C within 2.25 d after mixing peanut hulls with litter and within 2.58 d for pine bark and litter. Composts made from paper mill sludge approached 50°C within 3.71 d. Wheat straw composts never exceeded 40°C which could present potential health problems associated with pathogenic microorganisms. Mass loss and C:N ratio gradually declined and stabilized approximately 84 d after mixing. Mass loss averaged 73 percent for wheat straw compost, 33 percent for peanut hull composts, and 16 percent for the other mixes. Wheat straw compost C:N ratios stabilized near 14:1 and other mixes remained above 20:1, indicating N limited conditions for complete composting. Compost pH was 5.8 after 84 d from pine bark composted with wood shaving litter and was significantly lower than pH from paper mill sludge compost with an average pH of 6.9 but similar to all other compost mixes (pH 6.7). Electrical conductivity ranged from 0.35 S m?1 for paper mill sludge composted with wood shaving litter to 0.91 S m?1 from wheat straw composted with peanut hull litter. Composting temperature varied considerably among C sources and all required at least 72 d of curing to stabilize the C:N ratio. Composts made from wheat straw were most effective for waste reduction but temperatures were below the 50°C level generally considered necessary to kill pathogens.  相似文献   

12.
The purpose of this work was to study the viability of the composting of goat (Capra aegagrus hircus) manure (GM) and rabbit (Oryctolagus cuniculus) manure (RM) and to evaluate the quality of the compost obtained. For this, a mixture of these manures was prepared at a goat/rabbit ratio of 44:56 (fresh-weight basis) and 50:50 (dry-weight basis). The mixture was composted by the Rutgers static pile composting system, with forced aeration and controlled temperature. Throughout the composting process, the temperature was monitored and physicochemical, chemical, and biological parameters were evaluated. The temperature evolution showed the suitable development of the composting process, with thermophilic values (>40 °C) maintained for more than 90 days. The finished compost had stabilized and humified organic matter. However, the pH (9.4) and the salinity (EC of 13.4 dS/m) could limit its potential agricultural use.  相似文献   

13.
The biodegradable portion of city waste is a potential source of plant nutrients, and appropriate techniques of composting can convert it to quality compost with higher nutrient content and lower levels of pathogenic microorganisms. An amount of 68.19 tons of waste is generated in Imphal City, Manipur, India, of which 24.84 tons were biodegradable. Of the total biodegradable municipality waste (MW), 20.7 tons were produced in households and the vegetable markets of the city. The MW were found to contain pathogenic bacteria (PB), namely, Salmonella spp., Shigella spp., Micrococcus spp., and Enterobacter spp. in the range of 6.35–9.28 (log cfu/g dry biomass), and agriculturally beneficial bacteria (BB), namely, phosphate solubilizers, Azospirillum spp., Azotobacter spp., and cellulose degraders in the range of 6.25–8.83 log cfu/g dry biomass. Pre-treatment of the MW by exposure at temperatures of 27°C–50°C in a greenhouse for 5 days could not reduce the level of PB and BB, but by heating at 100°C for 8 h followed by 30°C for 16 h of a day for three consecutive days, the PB (except Micrococcus spp.) could be eliminated. Aerobic composting of the mixture of MW with cow dung (CD) and rice straw (RS) and by inoculation with epigeic earthworm Eisenia fetida, produced high quality manure as evident from more finer particle (56.6%), higher nutrient (2.19% N) content, higher population of BB (7.03–9.19 log cfu/g dry biomass), and reduced level of PB (6.87–8.09 log cfu/g dry biomass).  相似文献   

14.
In this study we report the water release curve of a compost-based carrier for solid matrix priming and its effects on carrot seed germination. ‘Danvers Half Long’ and ‘Nantes Scarlet’ carrot (Daucus carota) seeds were primed for 7 d at 15°C in a carrier consisting of 5:1:5.7 sieved compost: hydrogel:distilled water (based on weight) equaling a water potential of ?1.0 MPa. Seeds were blended with carrier at 1:10, 1:20, 1:30, or 1:40 (based on weight) and compost priming was compared with a polyethylene glycol (PEG) priming procedure. Germination testing at 20-30°C (16-8 h) in darkness indicated that all compost priming treatments hastened seed germination more than PEG priming. Compost priming at 1:30 increased final germination percentage (FGP) for ‘Nantes Scarlet’ (FGP = 85%) compared to PEG primed (FGP = 72%) seeds but ‘Danvers Half Long’ FGP was similar for all treatments. For both cultivars, seeds that were compost primed had reduced G (days to 10% FGP) and G (days to 50% FGP) compared to PEG primed or nonprimed seed. For ‘Danvers Half Long’ carrot seeds, priming ratios of 1:30 reduced G values more effectively than all other treatments. For ‘Nantes Scarlet’ carrot seeds, G10 and G50 values were reduced similarly at all seed-to-carrier ratios. Compost primed seeds could be dried and stored for 35 d at 3 or 20-30°C (16-8 h) for ‘Danvers Half Long’ and for 35 d at 3°C for ‘Nantes Scarlet’ with no loss in priming benefit. We conclude that solid matrix priming with a compost based carrier is a satisfactory alternative to PEG priming to improve germination of carrot seed.  相似文献   

15.
Abstract

Commercial production of genetically modified (GM) potatoes (Solanum tuberosum L.) could represent a risk to conventional production if volunteer plants develop from tubers or true seeds that survive until the following growing season. We studied such risks under northernmost European conditions and monitored the effects of cultivar, tuber size and tuber depth in the soil on winter survival at MTT Agrifood Research Finland, Jokioinen (61°06′N, 23°02′E) from 2004–2007. Tubers of two non-GM cultivars, Saturna and Asterix, and two size classes, 25–30 mm and 45–50 mm, were planted at depths of 10 and 20 cm in autumn, soon after harvest. In winters 2004–2005 and 2005–2006 all tubers planted in the soil in autumn were killed by frost. In 2005–2006, the field was covered by up to 30–40 cm of snow and the minimum soil temperatures ranged between ?0.4oC and ?0.9oC, but only 0.0–3.5% of the tubers survived and there was no difference between cultivars, tuber sizes and planting depths. Under laboratory conditions compared with ?2.0°C and ?2.5°C, treatment at ?3.0°C for 72 h resulted in significantly lower survival rate of the tubers (8.2%). Asterix, a late maturing table potato cultivar, was more resistant to low temperatures than the processing cultivar Saturna. In general, volunteer tubers are not currently a significant risk for coexistence of GM and conventional potato production in northern Europe due to the cold winter conditions but also due to possibilities to control the sporadic volunteers from the next crop. However, we noted that seedlings initiated from true potato seed are able to produce tubers despite the short growing season. Such a risk could be reduced by accepting only non-berry-producing GM cultivars for cultivation.  相似文献   

16.
An experiment comparing the effectiveness of three different bulking agents in the composting of fish processing wastes was carried out using small-scale composters operated at ambient temperatures. Fish offal was mixed with each of peat moss, sawdust and wood shavings in a 5:1 ratio by weight. The mixed materials were left undisturbed in the composters for an initial 55 days. They were then mixed and reloaded into their respective composters for a further 95 days of composting. Temperatures were monitored throughout the experiment, while serial physical and chemical analyses of the compost materials were initiated after the mixing. Headspace-gas chromatography was also used to determine the levels of phytotoxic organic acids and phenol. All the compost piles reached thermophilic temperature levels (40–70°C). Due to insufficient pile mass, temperatures over 55°C were not sustained for a sufficient length of time to satisfy the EPA requirements for pathogen reduction. The temperature profiles suggest that ambient temperatures near the freezing point can significantly influence the temperature of compost piles with volumes of 63 liters or less. The results reaffirm the potential of composting as a viable option for utilizing fish processing wastes and the suitability of peat moss, sawdust, and wood shavings as bulking materials. The physical and chemical qualities of the 150-day old composts were comparable to other seafood compost products. Peat moss gave the best results in terms of nitrogen conservation, but is the most expensive option. Monitoring the concentrations of phytotoxic organic acids and phenol using headspace-gas chromatography proved to be a useful method for establishing compost maturity.  相似文献   

17.
The composting of food waste coupled with urban agriculture presents an opportunity to increase nutrient recycling in urban ecosystems. One potential constraint limiting the expansion of aerobic food waste composting is the availability of carbon-rich recalcitrant materials, such as wood chips. We measured the differences in nutrient retention throughout the compost life cycle for different mixtures of barley mash to wood chips, to assess whether composting using proportionally less wood chips would lead to higher nutrient recycling rates. Nine compost piles (1 m3) were constructed at varying ratios barley mash to wood chips, ranging from 10:90 to 90:10. During the composting process, the 50:50 mixture maintained internal temperatures above 55°C for 30 days, with drop-offs as mixtures diverged in either direction. Food waste content was positively related to internal moisture and CO2, and negatively related to internal O2, throughout the ensuing 3 months. The finished compost was used in raised-bed garden plots during the following summer. Yields of arugula and tomatoes increased with compost barley mash content, saturating at high levels. Across all treatments, <5% of N and <2% of P were recycled from barley mash into new vegetable production. Although the maximum amount of nutrients was recycled using high barley mash compost, these treatments also had lower nutrient recycling efficiency compared to intermediate mixtures. These results indicate that the use of wood chips in composting increases the efficiency nutrient retention from food waste and in turn enhances nutrient recycling in urban environments.  相似文献   

18.
Use of composting technology as a treatment/disposal method for food residuals has been investigated by numerous researchers. This project evaluated the applicability of in-vessel, mechanical, rotating drum composting for food residuals. Three batches of food residuals (plate scrapings) were collected from a Texas prison and mixed with fine-textured soft-wood shavings at 2/1, 3/1 and 4/1 (ratios of shavings to food residual on a volumetric basis) to produce 0.4 m3 of compost blend. Temperature, oxygen, pH, bulk density and porosity were tracked throughout a fifteen-day composting trial. Volume and weight reductions were noticed for all blends. All blends reached thermophilic temperatures (> 45°C) while remaining aerobic during the trials. Initial pH was low in all blends, occasionally reaching 3.55 before returning to optimal levels (6.0 to 7.5) for composting. Temperature increases into the thermophilic range during composting corresponded to increases in compost pH. Most nutrients (P, K, Ca, Mg, S, Na and Zn) increased in concentration during the composting period, with the exception of N, which in some instances decreased over time. Composts utilizing the 3/1 ratio of bulking agent/food residual achieved thermophilic temperatures quickest and maintained temperatures longer than did other blending ratios. From this study, it appears that use of the mechanical, in-vessel, rotating drum composter may be a viable alternative for food residual disposal.  相似文献   

19.
This study investigated the cocomposting of pine bark with goat manure or sewage sludge, with or without inoculated effective microorganisms (EM). Composting was done for 90 days and parameters monitored over this period included temperature, pH, electrical conductivity (EC), C/N ratio, inorganic N, as well as tannin content. Changes in temperature, pH and EC during composting were consistent with those generally observed with other composting systems. The parameters were influenced by the feedstock materials used but were not affected by inoculation with effective microorganisms. The highest temperature measured from pine bark-goat manure composts was 60°C but much lower maximum temperatures of 40°C and 30°C were observed for pine bark sewage sludge and pine bark alone composts, respectively. The C/N ratios of the composts decreased with composting time. Ammonium levels decreased while nitrate levels increased with composting time. Tannin levels generally decreased with composting time but the extent of decrease depended on the contents of the composting mixtures. The trends observed showed that temperature, pH, EC, C/N ratio, tannin levels, and inorganic NH4-N and NO3-N were reliable parameters for monitoring the co-composting of pine bark with goat manure or sewage sludge. The pine bark-goat manure compost had more desirable nutritional properties than the pine bark and pine bark-sewage sludge composts. It had high CEC, near neutral pH, low C/N ratio, and high amounts of inorganic N and bases (K, Ca, and Mg) while pine bark compost had the least amounts of nutrients, was acidic, and had high C/N ratio and low CEC. The final tannin content of the pine bark-goat manure compost was below the 20 g/kg upper threshold level for horticultural potting media, implying that its use as a growing medium would not cause toxicity to plants.  相似文献   

20.
After imposition of fees for disposal of cattle carcasses by the rendering industry, on-farm methods of mortality disposal are being investigated. Three open-air mortality compost windrows were constructed in January (JAN) and February (FEB) of 2004 in the cold, semiarid climate of southern Alberta, Canada. Windrow A included a base of barley straw a minimum of 46 cm thick, a layer of cattle mortalities (n=12) and a layer of stockpiled manure (minimum of 46 cm) covering the mortalities. Windrows B and C also had a bottom layer of barley straw, with windrow B containing 9 mortalities in 2 layers and windrow C containing 12 mortalities in 3 layers. Due to ambient temperatures > 0°C, carcasses (range 236 to 673 kg) were frozen at the time of windrow construction. Type ‘T’ thermocouples were embedded at the base of B and C windrows and temperatures within 120 cm of the surface were measured using a stainless steel dial probe. Windrows were turned 3 times at 3 mo intervals. Samples were collected from initial compost amendments and prior to each turning for determination of dry matter (DM), organic matter (OM), N, C and coliform bacteria. Ambient temperature was 13°C higher (P < 0.05) for the initial heating of FEB as compared to JAN compost, although the rate of compost temperature decline did not differ between replicates in this period. Days at maximum temperature did not differ between replicates and maximum temperatures in all windrows exceeded 55°C. After 3 heating periods and 9 mo, flesh was not evident and only fragments of bones (max wt. 740 g) were found. Results of this study demonstrate that ambient temperatures < 0°C and frozen mortalities provide no barrier to the use of open-air windrows for disposal of cattle mortalities. As well, stacking up to 3 layers of full-sized cattle mortalities in a windrow did not affect temperature profiles, residual flesh or bone, or analyses of the finished compost. Under the climatic conditions of southern Alberta, layering mortalities would reduce space requirements for large-animal mortality composting in a feedlot setting.  相似文献   

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