Abstract: The effectiveness of sequential application of gypsum followed by matured mixed municipal solid waste (MSW) compost was investigated for the reclamation of saline-sodic soils. Soil plots were treated with 50 dt/ha (dry tone/hectare) of gypsum, followed by the addition of matured MSW compost at the 50, 100, and 150 dt/ha with five replications for each treatment. A number of physical, chemical and biological properties were investigated. The results from different treatments were compared with the Tukey-Kramer method. The results of this study show that the sequential application of gypsum followed by matured MSW compost can effectively restore degraded soils suffering from high soluble salts and exchangeable sodium content.

Abstract: The use of compost with high salt concentration was evaluated, under commercial conditions, as a potential growing media constituent for vegetable transplant production. Two composts were prepared from sweet sorghum bagasse, pine bark, and either urea (compost A) or brewery sludge (compost B) as N source. Three vegetable species — broccoli (Brassica oleracea), tomato (Lycopersicum esculentum), and onion (Allium cepa) with different tolerance to salinity were used. Eleven substrates were formulated and tested: a control consisting of a moss peat-based commercial substrate; compost A; compost B; and, eight mixtures containing 33 or 67% by volume of each compost with either raw peat moss or commercial substrate as diluent. All the substrates prepared had suitable physical, physicochemical and chemical properties for use as growing media, except for the electrical conductivity (ranging from 3.20 to 13.21 dS m−1) which was above the reference levels for soilless cultivation. Broccoli was the least affected by ...

Abstract: Loss of mass and volume during composting of various feedstocks is an important consideration for compost operation management and facility design. Direct measurements of mass and volume in piles and windrows require specialized equipment and skills that render such measurements impractical for most commercial operations. A study was undertaken to develop a technique for calculating reductions in mass and volume during composting based on the change in concentration of an internal standard and bulk density measurements. Of the various physicochemical parameters investigated, nonvolatile solids (NVS) content proved the most reliable internal standard because of its strong inverse correlation with organic C (r2 = −0.95) and low coefficient of variation (CV = 0.15). Reductions in mass and volume during composting of six windrows comprised of various feedstocks were then calculated using initial and final measurements of NVS and bulk density. Reductions in mass averaged 19.4% of initial mass and ranged from 1...

Abstract: An industrial-scale composting plant has been designed for producing organic fertilizers from olive mill waste using the windrow pile system. Materials to be composted, two phase olive mill waste (TPOMW) and sheep litter (SL), were characterized and made into three piles consisting of different proportions of each. Throughout the composting process, temperature (T), moisture (M), organic matter (OM), total organic carbon (Corg), total nitrogen (NT), germination index (GI), pH and electrical conductivity (EC) were monitored. The potential agronomic value of the final composts was ascertained by analyzing the bulk density, OM and Corg concentration, pH, EC, macro and micronutrient content (N, P, K, Ca, Mg, Fe, Cu, Mn, Zn, B), the concentration of humic and fulvic acids and inorganic nitrogen (NH4+,NO2−,NO3−). Each compost was applied to an area of one hectare within a six year-old olive plantation. Four months after application, the soils showed an increased OM concentration and cationic exchange capacity (...

Abstract: 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 there...

Abstract: Compost water extracts (compost teas) are gaining popularity among organic growers, largely because of their disease suppressive activity when applied to foliage or soil. Production methods often include addition of supplemental constituents, particularly molasses, to stimulate plant-beneficial microbial populations. We have found that molasses amendments also favor regrowth of human pathogenic bacteria, raising public health concerns about potential contamination of treated crops, particularly produce intended for fresh consumption. Using disease outbreak strains marked with green fluorescent protein (GFP) and spontaneous antibiotic-resistance, we found that regrowth of Salmonella enterica serovar Thompson and Escherichia coli O157:H7 was positively correlated with molasses concentration. For Salmonella, regrowth was also dependent on the type of starter compost material used. Salmonella populations increased from 1 at time 0 to over 1000 CFU ml−1 in dairy manure compost tea with 1% molasses, and from 1 ...

Abstract: An experiment was performed for evaluating the most suitable biochemical parameters to measure dynamics of substrate transformation during composting of the organic fraction derived from preselected urban wastes and wood bark mixture. Changes of chemical (organic C, hydrosoluble sugars, total and mineral N, humified fraction, volatile acids and phenolic compounds) and biochemical (microbial respiration, biomass C, qCO2, dehydrogenase, catalase, urease activities, FDA, and BIF) parameters were monitored for 120 days. Limited changes in organic C, total nitrogen, and humification characteristics were observed during composting. Dehydrogenase and catalase activities, BIF and FDA showed small changes during composting. Urease activity and, with some limitations regarding the early stages of composting, microbial respiration and qCO2, were found to be the most suitable parameters to measure dynamics of substrate transformation during composting of preselected urban wastes.

Abstract: Soil disturbance often results in loss of soil organic matter and nitrogen (N) fertility, making revegetation of barren areas difficult. Yard waste composts are a potential source material to regenerate soil fertility so that revegetation success is improved. The N release behaviors of several compost materials produced within California were evaluated during a long-term, 586-day aerobic incubation. Two general types of compost were tested, including yard waste compost materials (lawn clippings and chipped brush) and cocomposted materials (biosolids bulked and composted with yard waste materials). Nitrogen release from composted material was measured using periodic soil solution extraction and soluble N analysis. Nitrogen release rates varied widely between source materials during the initial portions of the incubation period, with cocomposts having much greater release rates than the yard waste composts. Yard waste composts that were poorly cured or had high woody fiber content showed net immobilization ...

Abstract: The ability of fungi to break down complex carbon sources makes them of vital importance in both the generation and application of compost. This paper illustrates the diversity and functions of the mycoflora of both a green compost (made solely thermophilically from plant debris) and a vermicompost (made mesophilically by the action of earthworms on plant and animal wastes). The soil dilution plate technique was applied on 3 media (PDA, CMC, PDA plus cycloheximide) and at 3 incubation temperatures (24°C, 37°C and 45°C) to isolate and identify fungal entities. Enzymatic activities (amylase, cellulase, chitinase, esterase, ligninase, pectinase, phosphatase, plastic degradation and xylanase) of most species from both composts were evaluated with a semiquantitative method on 15 substrates. There were substantial qualiquantitative differences in the species composition of the two composts. A total of 193 entities were isolated: 54 from green compost only, 77 from vermicompost only, 62 from both. This taxonomic...

Abstract: Oil palm empty fruit bunches (EFB) composting is increasingly being considered by tropical farmers as a worthwhile alternative to direct spreading in the field. EFB are ligno-cellulose residues comprising 46% cellulose and 16.5% lignin with a high C:N ratio ranging from 45 to 70. In hot regions, it is essential to control variations in the water content of the substrate. This case study set out to optimize the EFB composting procedure by monitoring two key factors, namely the nutritional balance of the biomass and its water content. The trial was conducted on a composting platform belonging to the PT SMART Tbk company (Indonesia) in windrows comprising shredded EFB watered weekly with oil mill effluents. The quantity of effluent to be added was calculated so as to systematically top up to 60% humidity. The initial C:N ratio of the EFB was reduced by urea and/or ripe compost applications (seeding). Application times and rates were studied on two windrows, one in an open area, the other in. an area sheltered by a root to prevent over-rapid drying. After ten weeks the compost could be considered ripe for all the treatments; at that stage, composting had reduced the volume and initial weight of the fresh EFB by 85% and 50% respectively. The combined action of a temperature rise and. windrow turning led to substantial water losses through evaporation, resulting in a sudden drop in windrow humidity at the start of composting. When rainfall was insufficient, effluent applications became essential. The total amount of effluent to be applied during composting (without rainfall) was around 3 m3 per initial tonne of EFB. This amount approximately corresponded to the standard effluents: EFB ratio in the oil mill. Inoculation of the mass of EFB to be composted with ripe compost had a significant effect on the speed with which the mixture was reduced. A urea application a fortnight after the start of fermentation seemed to be beneficial. The resulting compost had a good agronomic value. However, the mineral balance was considerably affected, as the nutrients provided by the effluents were poorly retained by the substrate, and partially lost in percolation water following the weekly watering operations. For instance, almost 50% of the phosphorus, 70% of the potassium, 45% of the magnesium and between 10% and. 20% of the calcium theoretically applied were lost ten weeks into the trial. Better distribution of the effluent applications, combined with a system to recover the leachi.ngs, should substantially reduce these losses, while maintaining suitable humidity for microbial degradation. (Resume d'auteur)

Abstract: High moisture content bovine manure from a farm dairy (milking parlor) holding yard was successfully composted in a pilot-scale passively aerated system, without prior dewatering, using sawdust or paper as amendments and woodchips as the bulking agent. The amendments were used to adjust the manure total solids content from an initial average level of 10% (w/w) to approximately 20% (w/w), prior to structural conditioning with the woodchips. Initial total solids levels for the mixture were approximately 35% (w/w) in both cases. Rapid temperature increases were obtained and peak values of 73.9°C and 79.5°C were recorded for the sawdust and paper amendment systems respectively. Thermophilic conditions were maintained in the pile centers for 17-54 days and temperatures above 55°C for 6-37 days. However, susceptibility to environmental influences was demonstrated, with downward temperature excursions, coincident with cool ambient conditions, recorded on several occasions. Final mixture moisture levels were appr...

Abstract: Electrical conductivity (EC) was measured on extracts from four different types of compost using two different dilution techniques. When EC was measured on extracts obtained using a saturated paste method, EC varied by 20-25% of the mean measurement. When EC was measured on extracts obtained using a quantitative dilution procedure over a range of dilution ratios, EC varied by less than 10% of the mean. For dilution ratios less than 8 (ml water/g dry compost), the increase in EC was less than expected, suggesting that at the lower dilution ratios salts were incompletely extracted or did not completely diffuse from the particle interior to the extractable solution. A method of comparing compost EC measurements obtained using different dilution ratios, including the saturated paste dilution, is presented. This method predicted the EC of the saturated paste extract in three of the four compost samples tested. These methods could be integrated into a computer data spreadsheet for a typical composting operation...

Abstract: Weathering of piled material in the field is a popular method to treat spent mushroom substrate (SMS) before reuse. During the weathering process, rainfall and snowmelt pass through SMS piles and a large amount of solutes is released in the leachate. To investigate solute release patterns, the field weathering process was simulated under controlled conditions in the laboratory. Fresh SMS was packed in an acrylic column (20 cm i.d.) to 150 cm height and leached intermittently with a cumulative total of 230 cm of deionized water over 180 days. Leachate was collected and analyzed for dissolved organic carbon (DOC), dissolved organic nitrogen (DON), electrical conductivity (EC), and inorganic salts. Solute release patterns were described using first order models, and total released solutes were calculated. The SMS leachate had DOC, DON and EC values ranging from 450 to 15,500 mg L−1, 50 to 1,700 mg L−1, and 3 to 50 dS m−1, respectively. The major inorganic cations were K+, Na+, Ca2+, Mg2+ and NH4+, and anions...

Abstract: The physical parameters of four different Elephant grass “Miscanthus ogiformis” ‘Giganteus’ composts and four of the most used types of peat products in Denmark, along with a wood fiber growing medium (Culti), were compared to determine possible physical differences, and to test whether compost could be used as an alternative substrate to peat. The Miscanthus straw was composted with three different N sources: ammonium sulfate, liquid pig manure and urea plus tap water (as a control). Compared to peats, the composts tested had low total bulk density, high air-filled porosity and a high diffusion coefficient of oxygen. None of the 9 products tested had the optimum levels of all the different physical parameters. Mixing the tested compost and peat will possibly increase the air-filled porosity of the substrates compared to pure peat, and brings the substrates physical parameters closer to the ideal recommended range. These compost media require further investigation before they can be used directly as an al...

Abstract: Temperature and oxygen profiles evolution in windrows were monitored in windrows located at a commercial composting plant. Controlled turning of the windrows was executed using a turning machine. Measurements were made from the onset of turning, when temperature and oxygen were uniform throughout, onward, to evaluate the development of the relevant profiles. Temperatures rose and oxygen declined soon after turning. In fresh active windrows, a temperature maxima at a depth of 50-70 cm was detected, with temperatures as high as 65°-70°. The outward layers were cooler due to the effect of the ambient air temperature. Inward cooler core region seemed to be due to limited oxygen availability and the resulted restricted metabolic activity. No temperature maxima were observed as windrows approached stability. At this stage, the temperature of the core was as high as that of mid-layers. Oxygen, assumed to be in equilibrium with the atmosphere at the instance of turning, dropped down rapidly and reached steady levels within a period of about 4 hours. Oxygen concentration was lowered with depth, demonstrating a linear gradient down to about 70 cm depth. These data iterated the notion that oxygen is an important limiting factor in windrow composting. For any given point, high temperature may be a limiting factor. However, it seems that in properly managed windrows, high temperature is not limiting overall, due to an intrinsic correction feed back mechanism. If temperature in the hottest mid-layers gets to a level where microbial activity is hampered, less oxygen is consumed as it moves toward the core. Thus, more oxygen can penetrate into the core and the overall activity is not affected. It should be stressed that oxygen and temperature are not the only factors affecting composting rates. Other factors such as moisture, nutrients, substrate and porosity do have an important role.

Abstract: Ammonia assimilating bacteria were isolated from composting processes and their abilities to assimilate ammonia were evaluated. In the prefermentation stage of the composting, 104.7 and 103.7 (CFU/ g) of ammonia assimilating bacteria were detected on the medium which contained ammonia as a sole nitrogen, at 37°C and 55°C, respectively. They were 104.6 and 103.2 in the end of the primary fermentation, and 105.1 and 103.2 in the end of the secondary fermentation, respectively. When isolates were purely cultivated in sterilized compost extract medium, many of them consumed ammonia not by nitrification but by assimilation. They still assimilated ammonia even in nonsterilized compost extract medium, i.e. mixed culture with the live microbial flora of the compost. However, isolates which showed high ammonia assimilating ability in the pure culture did not always show high abilities in nonsterilized compost extract media. Isolates which showed high ammonia assimilating ability in the nonsterilized medium were id...

Abstract: A survey of Nevada residents in the Las Vegas Valley was conducted to determine perceptions and attitudes as they may contribute to the marketing potential of composted biosolids for residential use. Currently only 5 percent of Nevada's sludge is being composted, 15 percent is land applied while 80 percent is being sent to landfills. Sludge generated in the Las Vegas Valley is extremely low in heavy metals due to the low presence of industries that are characterized with the release of heavy metals. A residential survey was developed and mailed to over one percent of the valley's households resulting in a 21.5 percent return. Seventy-six percent of the respondents rated recycling as important or very important and 74 percent indicated that it is important or very important to find uses specifically for sewage sludge. A large percentage of residents were not aware of how sewage sludge is disposed (73.7%), but felt the community should be examining sewage sludge recycling options (75.1%). After a descriptiv...

Abstract: The aims of this work were: i) to evaluate, during a composting process, some parameters in two contrasting raw materials: one a ligneous material (C1) and the other (C2) a mixture of horse and poultry manure with a low straw percentage and ii) to compare results from microbiological and chemical analyses of both composting material during the process. Total carbon, total nitrogen, C: N ratio, ash, organic matter, organic matter destroyed, CEC, soluble organic carbon, soluble ammonium and nitrate, ammonium: nitrate ratio and respiration rate were evaluated during 18 weeks. C1 material showed a lower rate of organic matter mineralization probably due to the high proportion of ligneous material. This material reached a greater CEC during the experiment. Increase in CEC during composting is due to conversion of the remaining organic material into humic substances. These results would imply that C1 presented a greater humification level and consequently, a better quality. On the other hand, the greater decrea...

Abstract: Total phosphorus, water-soluble phosphorus and total nitrogen concentrations in cocomposted yard trimmings and broiler litter were quantified in a 2 m wide × 1 m deep × 55 m long channel composter using batch mixing. The batch mixing occurred by using a rotor tiller type turner mounted on rails for the length of the composting channel. Phosphorus and nitrogen concentrations of the compost were measured as they varied with treatment and time during a 63 day compost process followed by a 30 day curing time. The treatments contained a single mix of 50% yard trimmings, 50% poultry litter, by volume, using four aeration and turning treatments. The first treatment was a control, which received no turning or aeration unless the moisture content dropped to 40% and additional water was added to bring the mix up to 50-55% moisture, mix consolidation was required, or mixing to obtain accurate samples and moisture contents, as necessary. Both treatments two and three were aerated by negative pressure ventilation. Tre...

Abstract: This paper evaluates the influence of operating conditions (pH, Kjeldahl-N losses, NO3−-N, NO4+-N,C/N ratio and biodegradation) used in the vinasse/grape marc incubation on the properties of products obtained to determine the best incubation conditions (time and amount of vinasse proportion) to aid in the design of an in-vessel composting system. A second-order polynomial model consisting of two independent process variables was found to accurately describe, with <10% differences between experimental values and model prediction, the vinasse-grape marc incubation. The dependent variables measured were pH, Kjeldahl-N losses, NO3-−N, NO4+-N, C/N ratio and biodegradation and the independent process variables were operation time and amount of vinasse. Results determined products with acceptable chemical properties, high biodegradation and germination index and minimum Kjeldahl-N losses entails operating at medium-to-short operation time (20-35 days) and medium-to-low vinasse percentages (0-20%).

Abstract: Effects of composting on odorous chemicals in dairy manure were investigated in replicated pilot-scale studies. Three 16-day composting trials were conducted, using 205 L vessels containing 83 kg mass. Fresh or 12-day-aged manure, from lactating cows, was mixed with sawdust (3man:1saw w/w). Vessels were either aerated continuously with high (2.3 kg/hr)/low (0.8 kg/hr) air flow controlled by thermostats or intermittently on a 5 min high air flow/55 min off clock controlled cycle. Six vessel replicates were conducted on each manure/air flow treatment combination. Temperatures, air flow, O2 consumption, and CO2 production were recorded every 10 minutes. Trapped NH3 emissions were determined daily. Exhaust air was passed through water-cooled condensers to analyze emitted volatiles, and condensate volume, pH, and volatile fatty acids (VFAs) were quantified at 12 or 24 hour intervals. Solids were collected from each vessel initially, at remix at the end of day 7, and at the end of each trial (day 16) for analys...

Abstract: PAH-contaminated waste wood is a serious environmental problem. As an alternative to incineration and landfill disposal, wood containing PAHs may be detoxified by composting. The efficiency of this process depends on the composting conditions. The aerobic treatment of PAH-containing wood was therefore investigated under varying environmental conditions with particular attention to the kinetics of PAH degradation and wood mineralization. The composting of pine wood spiked with 2 g/kg phenanthrene, anthracene and pyrene each and subsequently artificially aged was studied on a laboratory-scale using a respiration analyzer. The temperature was found to highly influence both PAH degradation and wood decay. The fastest and most extensive PAH degradation and wood mineralization were found at 30°C. Higher temperatures particularly inhibited the degradation of anthracene and pyrene. The addition of urea markedly accelerated both PAH degradation and wood mineralization. Only small amounts of urea were needed to maximize PAH degradation, whereas higher amounts of urea were required to maximize wood mineralization. Urea hydrolyzes to ammonium carbonate, which in turn forms highly volatile ammonia. When more then 2 g/kg urea-N was added to the wood, excessive nitrogen disappeared as ammonia via the gas phase. Using nitrate instead of urea dramatically reduced both PAH degradation and wood mineralization. Although a slightly alkaline pH seemed to promote PAH degradation, it has to be taken into account that this experiment was carried out with nitrate as an N source rather than urea to avoid any N losses at high pH values. Glucose as a cosubstrate neither accelerated PAH degradation nor stimulated wood decay. Molasses as a cosubstrate actually inhibited PAH degradation since it contains much salt and alkalinized the rot material.

Abstract: Separated municipal solid waste (SMSW) was composted using poultry manure (PM), to lower moisture content and the C/N ratio. Two different mixtures (3:2 and 2:3, SMSW:PM w.w. ratio) and two particle biomass sizes (1 cm and 0.2 cm) were studied to assess the final compost quality and the feasibility of composting. Results suggest that the 3:2 SMSW:PM starting mixture ratio gave less compost yield than the 2:3 ratio, although the compost characteristics were very similar for both mixtures. Results also showed that a smaller particle size (0.2 cm) increased the degradation rate of the waste matter and the degree of evolution to the final products, but only slightly. The final compost products, regardless of the initial mixture ratios and particle size, appear very similar and of good quality, suggesting composting to be a useful biotechnology for processing waste matter produced in Morocco.

Abstract: The field experiments presented here investigated the required thickness of wood waste materials used as a mulch to protect a soil slope against erosion Each of the materials was subjected to large-scale erosion control testing at a field site with a slope of 1 vertical to 2 horizontal Fourteen test cells (5′ W × 30′ L each) were prepared with different wood waste treatments; nine contained erosion control mulch applications at thicknesses of 3/4 to 3 inch Two cells were left untreated as reference cells and three other cells were untreated but contained erosion control structures including wood waste filter berm, geosynthetic silt fence and hay bale silt barrier The erosion control performance of each cell treatment was evaluated for 11 storm events of varying rainfall magnitude and intensity Calibrated tipper buckets were used to measure the runoff from each cell and collection buckets were used to sample runoff and determine the mass of sediment eroded from each cell Total rainfall and intensity

Abstract: Three windrows were constructed from a mixture of horse manure and soiled bedding collected from four equestrian centres in the Fraser Valley, British Columbia, where stables were bedded with hemlock, spruce, and fir wood shavings. Composting was accomplished by turning the windrows twice a week during the first four weeks and once a week for eight additional weeks. At the end of 12- week composting period, windrows were combined and allowed to cure for three months. The cured compost was tested for the ability to promote cucumber (cv Enigma) seedling growth, supply micronutrients, and suppress mycelial growth of plant pathogen Fusarium oxysporum f.sp. radicis cucumerinum (FORC). The heights and dry weights of cucumber seedlings grown in 20% compost in sawdust were significantly greater than those grown in sawdust alone. When fed with nutrient solutions lacking micronutrients, seedling grown in 20% compost gave significantly greater height, dry weight, and chlorophyll concentrations compared to seedlings ...

Abstract: Nutrient management plans require an accurate assessment of P fertilizer additions to soil. The fertilizer equivalents of manures and composts must be estimated in order to comply. A previous study...

Abstract: A two-year study was conducted to determine the crop yield and nutrient uptake in canola and elemental levels in soils amended with biosolids applied at four rates for seven years. The biosolids application rates of 0, 1.9, 5.8, and 11.7 Mg ha -1 (dry basis) were based on providing the following amounts of total N (in kg N ha -1 ): 0 (control), 57 (low), 170 (medium), and 340 (high). After second year harvest, soil samples were collected from 0-15 and 15-45 cm depths and analyzed for total and water-extractable essential (N, Ca, Mg, K, P, S, B, Mn, Zn, and Cu) and nonessential elements (Cd, Cr, Co, and Ni), pH and electrical conductivity (EC). Generally, biosolids application significantly increased the concentrations of total and water extractable essential elements at the 0-15 cm depth, whereas concentrations of total and water extractable nonessential elements (Cd, Cr, Co, and Ni) were only detected at trace levels for both depths. There was a significant increase in soil EC and soil organic matter content with biosolids application at the 0-15 cm depth. Biosolids treatments significantly increased the total dry matter yields 1.5 to 3.8 times above that of the control and increased concentrations of most essential elements in canola leaves. The overall results suggest that amending sandy loam soils with biosolids of the tested quality can increase yield and forage quality of canola leaves with negligible increases in nonessential trace element concentrations in soil and/or in leaves.

Abstract: Yard trimmings from sources rich in grass clippings have the potential to supply nutrients for crop production. Our objectives were to estimate N availability from yard trimmings and determine their effects on crop production, soil nutrients, and organic matter levels. We conducted a field experiment, comparing three consecutive years of yard trimmings applications (22, 44, or 66 Mg ha−1 yr−1 dry weight) with inorganic N (112 kg N ha−1 yr−1) and zero-N controls in a silage corn (Zea mays L.) - winter triticale (Triticosecale spp.) rotation. The yard trimmings were screened and ground, and allowed to heat for a short period. They were incorporated each spring before planting corn. We measured crop yield and N uptake, and estimated apparent N recovery (ANR). We measured soil inorganic N two weeks after yard trimmings application and after corn harvest. In a one-year on-farm demonstration, we compared three sources of yard trimmings applied at a single rate. Yard trimmings applied at 44 Mg ha−1 dry weight pr...

Abstract: Vermicompost filtration is a new on-site waste treatment system. Consequently, little is known about the filter medium properties. The aim of this preliminary study was to quantify physical and compositional properties of vermicompost filter beds that had been used to treat domestic solid organic waste and wastewater. This paper presents the trials performed on pilot-scale reactors filled with vermicompost from a full-scale vermicompost filtration system. Household solid organic waste and raw wastewater at the rate of 130 L/m2/d was applied to the reactor bed surface over a four-month period. It was found that fresh casts laid on the bed surface had a BOD of 1290 mg/g VS while casts buried to a depth of 10 cm had a BOD of 605 mg/g VS. Below this depth there was little further biodegradation of earthworm casts despite cast ages of up to five years. Solid material in the reactor accounted for only 7-10% of the reactor volume. The total voidage comprised of large free-draining pores, which accounted for 15-2...