Removal of volatile organic compounds by natural materials during composting of poultry litter

The objective of this study was to reduce volatile organic compounds (VOCs) produced during composting of poultry litter. The natural zeolite, expanded perlite, pumice and expanded vermiculite as the natural materials were used for the reducing of VOCs. Composting was performed in a laboratory scale in-vessel composting plant. Poultry litter was composted for 100 d with volumetric ratio of natural materials:poultry litter of 1:10. The VOCs were tested using the FT-IR method by VOCs analyzer. Studies showed that VOCs generation was the greatest in the control treatment without any natural materials. The natural materials significantly reduced VOCs. At the end of the processes, removal efficiency was 79.73% for NZ treatment, 54.59% for EP treatment, 88.22% for P treatment and 61.53% for EV treatment. Potential of removal for VOCs on poultry litter matrix using natural materials was in order of: P>NZ>EV>EP.     

Identification of a Brevibacterium marker gene specific to poultry litter and development of a quantitative PCR assay

Aim: To identify a DNA sequence specific to a bacterium found in poultry litter that was indicative of faecal contamination by poultry sources. Methods and Results: Faecally contaminated poultry litter and soils were used as source material for the development of a quantitative polymerase chain reaction (qPCR) method targeting the 16S rRNA gene of a Brevibacterium sp. The identified sequence had 98% nucleotide identity to the 16S rRNA gene of Brevibacterium avium. The qPCR method was tested on 17 soiled litter samples; 40 chicken faecal samples; and 116 nontarget faecal samples from cattle, swine, ducks, geese, and human sewage collected across the United States. The 571‐bp product was detected in 76% of poultry‐associated samples, but not in 93% of faecal samples from other sources. Marker concentrations were 10⁷–10⁹ gene copies per gram in soiled litter, up to 10⁵ gene copies per gram in spread‐site soils, and 10⁷ gene copies per litre in field run‐off water. Results were corroborated by a blinded study conducted by a second laboratory. Conclusion: The poultry‐specific PCR product is a useful marker gene for assessing the impact of faecal contamination as a result of land‐applied poultry litter. Significance and Impact of the Study: This study describes the first quantitative, sensitive and specific microbial source tracking method for the detection of poultry litter contamination.     

Compatibility of ammonia suppressants used in poultry litter with mushroom compost preparation and production

Ammonia suppressants are applied to chicken litter to decrease ammonia levels. And mushroom (Agaricus bisporus) producers use poultry litter to increase the nitrogen in the compost. To determine the influence of ammonia suppressants used in poultry litter on compost preparation and mushroom production, four mushroom crops were cultivated from compost prepared using litter treated with PLT, Barn Fresh and Impact-P at 25.22 kg/100 m2, 40 kg/100 m2, and 0.49 kg/100 m2, respectively, during the poultry production process. In general, no significant differences (P>0.05) were noted between treatments for total nitrogen, ammonia, pH, EC, ash, and moisture when compost or the headspace air was sampled during compost preparation throughout all stages. Nor were mushroom yields or counts significantly affected (P>0.05) by the presence of ammonia suppressants in the poultry litter. Thus, the mushroom industry can confidently use poultry litter amended with PLT, Impact-P, and Barn Fresh when used at the recommended rates.     

Accelerated coffee pulp composting

The effect of two abundant, easily available and very low-cost agro-industrial organic residues, i.e., filter cake from the sugar industry and poultry litter, on the composting stabilization time of coffee pulp and on the quality of the produced compost, was evaluated. Piles of one cubic meter were built and monitored within the facilities of a coffee processing plant in the Coatepec region of the State of Veracruz, Mexico. Manual aeration was carried out once a week. A longer thermophilic period (28 days) and a much lower C/N ratio (in the range of 6.9–9.1) were observed in the piles containing the amendments, as compared to the control pile containing only coffee pulp (14 days and a C/N ratio of 14.4, respectively). The maximum assimilation rate of the reducing sugars was 1.6 g kg-1 d-1 (from 7.5 to 5.3%) during the first two weeks when accelerators were present in the proportion of 20% filter cake plus 20% poultry litter, while they accumulated at a rate of 1.2 g kg-1 d-1 (from 7.4 to 9.13%) during the same period in the control pile. The best combination of amendments was 30% filter cake with 20% poultry litter, resulting in a final nitrogen content as high as 4.81%. The second best combination was 20% filter cake with 10% poultry litter, resulting in a compost which also contained a high level of total nitrogen (4.54%). It was concluded that the use of these two residues enhanced the composting process of coffee pulp, promoting a shorter stabilization period and yielding a higher quality of compost.     

Heat inactivation of Salmonella spp. in fresh poultry compost by simulating early phase of composting process

Aims: The purpose of this study was to determine the effect of moisture on thermal inactivation of Salmonella spp. in poultry litter under optimal composting conditions. Methods and Results: Thermal inactivation of Salmonella was studied in fresh poultry compost by simulating early phase of composting process. A mixture of three Salmonella serotypes grown in Tryptic soy broth with rifampin (TSB‐R) was inoculated in fresh compost with 40 or 50% moisture at a final concentration of c. 7 log CFU g^?1. The inoculated compost was kept in an environmental chamber which was programmed to rise from room temperature to target composting temperatures in 2 days. In poultry compost with optimal moisture content (50%), Salmonella spp. survived for 96, 72 and 24 h at 50, 55 and 60°C, respectively, as compared with 264, 144 and 72 h at 50, 55 and 60°C, respectively, in compost with suboptimal moisture (40%). Pathogen decline was faster during the come‐up time owing to higher ammonia volatilization. Conclusions: Our results demonstrated that Salmonella spp. survived longer in fresh poultry compost with suboptimal moisture of 40% than in compost with optimal moisture of 50% during thermophilic composting. High nitrogen content of the poultry compost is an additional factor contributing to Salmonella inactivation through ammonia volatilization during thermal exposure. Significance and Impact of the Study: This research validated the effectiveness of the current composting guidelines on Salmonella inactivation in fresh poultry compost. Both initial moisture level and ammonia volatilization are important factors affecting microbiological safety and quality of compost product.     

Sawdust and natural zeolite as a bulking agent for improving quality of a composting product from anaerobically stabilized sewage sludge

This study has dealt with the production of compost from dewatered anaerobically stabilized primary sewage sludge (DASPSS) and sawdust (SWD). SWD is added in order to increase the humic substances in the final product. The DASPSS is mixed with clinoptilolite (Cli), which is used as a bulking agent at 20% w/w, and the mixture is amended with sawdust at 10%, 30% and 40% (w/w). The final results have indicated that by increasing the sawdust concentration in the initial mixture, the humic substances in the final product increase too. The natural zeolite that was added in the initial mixture takes up a significant amount of heavy metals. In order to observe the maturity of the final product, the germination index is used in oat cultivation. The results indicate that the substrate appears to be non-phytotoxic after 75 d of maturity. Also, in order to estimate the metal leachability of the final compost product, the generalized acid neutralization capacity procedure is applied, and it is found that by increasing the pH values, the heavy metal concentrations decrease.     

Relative effectiveness of various types and methods of zinc application on rice and maize crops grown in calcareous soil

Summary Application of zinc sulphate mixed with compost/poultry manure proved to be equivalent to the effect of dipping the seedling roots in 4% ZnO suspension with respect to rice yields but Zn-amended organic manures were superior to other treatments with regards to total Zn uptake. A marked residual effect of soil applied treatments was recorded on the succeeding maize crop. Application of poultry manure alone was about one and a half times more effective than compost alone in increasing the rice and maize grain yields. Poultry manure surpassed compost in increasing zinc uptake by the crops and at the same time it built up more available Zn in soil than compost for the following crop. The magnitude of yields and Zn uptake response were magnified when zinc sulphate was applied along with organic manures. Application of 25 kg zinc sulphate/ha alone had the same effect as 50 quintals poultry manure alone or 12.5 kg zinc sulphate applied with 50 quintals compost/ha with respect to crop yields. A significant positive correlation was, recorded in both the crops between Zn concentration in grain or straw and their respective yields.     

Transgene and mitochondrial DNA are indicators of efficient composting of transgenic pig carcasses

Composting is an environmentally sound method for the disposal of on-farm livestock mortalities that generates material suitable for use as fertilizer; however, this method is not generally permitted for disposal of transgenic livestock mortalities during the research and development phase. This study has explored the application of the polymerase chain reaction (PCR) as a method for assessing the persistence of transgene and mitochondrial DNA markers during the composting of euthanized transgenic pig. There was at least a 10(7) fold reduction of genetic material to a level that not either transgene or mitochondrion markers were detectable. At the end of the composting period, only bone fragments that were completely demineralised and chalky were detected. Chemically the compost was similar to that from pig litter and poultry mortalities, except the copper content was lower. Based on these data, composting appears to be an appropriate method for the disposal of transgenic animals.     

Solid state fermentation of broiler litter for production of biocontrol agents

Several varieties of heat-sterilized broiler litter with 60% (wet basis, wb) moisture content were substrate in solid-state fermentations to produce biocontrol agents. Litter varieties included litter produced by one flock of broilers from medicated and non-medicated controlled rations, and litter produced by two flocks and four flocks on a single application of bedding material from medicated commercial sources. Litter preparations were inoculated with monocultures of Bacillus thuringiensis serovar japonensis strain Buibui, a pathogen of Japanese beetle larvae (Popillia japonica), or Pseudomonas fluorescens 2-79. B. thuringiensis did not grow in unextracted 1-flock litter nor in water extracted litter, but grew in methanol extracted litter to 5 x 10(10) cell forming units (CFU)/g litter (dry weight, dw) and a spore count of 1 x 10(10) CFU/g litter (dw). B. thuringiensis also grew in unprocessed 2-flock and 4-flock litter, achieving cell counts of 3 x 10(9) and 1 x 10(9) CFU/g litter (dw), respectively, and spore counts of 1 x 10(9) CFU/g litter (dw). P. fluorescens grew in medicated 1-flock litter with no extraction to a cell density greater than 4 x 10(11) CFU/g litter (dw). Bioassays in soil containing over 0.5% (db) litter fermented with B. thuringiensis resulted in over 90% mortality in 21 days for first instars of Japanese beetle when compared to a control treatment using compost without fermented litter. The investigations demonstrate that bacterial biocontrol agents produced via solid substrate fermentations using broiler poultry litter have potential in biocontrol applications in the soil environment.     

Comparative evaluation of different carrier-based multi-strain bacterial formulations to mitigate the salt stress in wheat

The application of liquid bacterial consortia to soil under natural conditions may fail due to various environmental constraints. In this study, the suitability and efficiency of compost, biogas slurry, crushed corn cob, and zeolite as carriers to support the survival of plant growth-promoting rhizobacteria (PGPR) and improve the performance of multi-strain bacterial consortia to mitigate the effects of salinity stress on wheat under pot conditions were evaluated. The survival of strains of Pseudomonas putida, Serratia ficaria, and Pseudomonas fluorescens labelled with gusA was evaluated for up to 90 days. Seeds coated with different carrier-based formulations of multi-strain consortia were sown in pots at three different salinity levels (1.53, 10, and 15 dS m⁻¹). Results showed that salinity stress significantly reduced wheat growth, yield, gas exchange, and ionic and biochemical parameter values, but the 1-aminocyclopropane-1-carboxylate (ACC) deaminase-containing multi-strain consortium used mitigated the inhibitory effects of salinity on plant growth and yield parameters. However, carrier-based inoculation further improved the efficacy of multi-strain consortium inoculation and significantly (P < 0.05) increased the growth, yield, and physiological parameters value of wheat at all salinity levels. On the basis of the observed trends in survival and the outcomes of the pot trials, the inoculation of multi-strain consortia in compost and biogas slurry carriers resulted in more successful wheat growth under salinity stress compared to that in the rest of the treatments tested.     

Compost tea as soil drench: an alternative approach to control bacterial wilt in brinjal

An experiment was conducted in the field laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh, to evaluate the efficacy of compost tea and poultry litter extract along with their economic feasibility of their usage in controlling bacterial wilt of brinjal under natural incidence condition. A significant variation was observed among the treatments on the incidence and severity of bacterial wilt in brinjal. The results showed that the lowest wilt incidence was recorded in T₂ (Compost tea as soil drenching), T₅ (Poultry litter as soil application) and T₆ (IPM Lab Biopesticide as soil application) while the highest wilt incidence was recorded in control treatment in both counting periods. Similar trend regarding the performance of these treatments was observed on the bacterial wilt severity of brinjal. The effects of compost tea and poultry litter extract on the growth and yield parameters of eggplant were observed to be significant. The results revealed that plant height, number of branches per plant, number of fruits per plant and fruit yield per ha were recorded as maximum in T₂ (Compost tea as soil drenching), followed by T₅ (Poultry litter as soil application) and T₆ (IPM Lab Biopesticide as soil application), while the minimum plant height, number of branches per plant, number of fruits per plant and fruit yield were recorded in control treatment (T₁). The other treatments showed significant effect in increasing all the growth and yield parameters of brinjal as compared to control. Benefit cost analyses (BCR) showed that T₆ (IPM Lab Biopesticide as soil application) resulted in the highest BCR (99.21) as compared to control, followed by T₇ (BAU-Biofungicide as foliar spray) and T₂ (Compost tea as soil drenching) with BCR 35.7 and 19.5, respectively. The results indicated that an investment of Tk. 1.00 may lead to a profit up to Tk. 99.21 by soil application of IPM Lab Biopesticide which gave the maximum profit in the present study. T₇ (BAU-Biofungicide as foliar spray) followed T₂ (Compost tea as soil drenching) where the investment Tk. 1.00 returned a profit of Tk. 35.70 and Tk. 19.5, respectively. Soil drenching of compost tea showed comparatively lower BCR but the highest percent increase of gross margin was obtained when compost tea was applied as soil drench (T₂). Therefore, it may be concluded that soil drenching of compost tea may be an alternative approach to control bacterial wilt of brinjal along with other possible organic amendments.     

Fate of Salmonella enterica serovar Typhimurium on carrots and radishes grown in fields treated with contaminated manure composts or irrigation water

Three different types of compost, PM-5 (poultry manure compost), 338 (dairy cattle manure compost), and NVIRO-4 (alkaline-pH-stabilized dairy cattle manure compost), and irrigation water were inoculated with an avirulent strain of Salmonella enterica serovar Typhimurium at 10(7) CFU g(-1) and 10(5) CFU ml(-1), respectively, to determine the persistence of salmonellae in soils containing these composts, in irrigation water, and also on carrots and radishes grown in these contaminated soils. A split-plot block design plan was used for each crop, with five treatments (one without compost, three with each of the three composts, and one without compost but with contaminated water applied) and five replicates for a total of 25 plots for each crop, with each plot measuring 1.8 x 4.6 m. Salmonellae persisted for an extended period of time, with the bacteria surviving in soil samples for 203 to 231 days, and were detected after seeds were sown for 84 and 203 days on radishes and carrots, respectively. Salmonella survival was greatest in soil amended with poultry compost and least in soil containing alkaline-pH-stabilized dairy cattle manure compost. Survival profiles of Salmonella on vegetables and soil samples contaminated by irrigation water were similar to those observed when contamination occurred through compost. Hence, both contaminated manure compost and irrigation water can play an important role in contaminating soil and root vegetables with salmonellae for several months.     

Microbial Properties of Composts That Suppress Damping-Off and Root Rot of Creeping Bentgrass Caused by Pythium graminicola

Composts prepared from a variety of feedstocks were tested for their ability to suppress seedling and root diseases of creeping bentgrass caused by Pythium graminicola. Among the most suppressive materials in laboratory experiments were different batches of a brewery sludge compost and a biosolids compost from Endicott, N.Y. Batches of these composts that were initially not suppressive to Pythium damping-off became more suppressive with increasing compost age. Leaf, yard waste, food, and spent mushroom composts as well as certain biosolids, cow manure, chicken-cow manure, and leaf-chicken manure composts were not suppressive to Pythium damping-off. In some cases, turkey litter, chicken manure, chicken-leaf, and food waste composts were inhibitory to creeping bentgrass seed germination in laboratory experiments. Microbial populations varied among all of the composts tested. Bacterial populations were high in all composts except the turkey litter compost, in which populations were 1,000- to 10,000-fold lower than in the other composts tested. Among the highest populations of heterotrophic fungi and antibiotic-producing actinomycetes were those found in all batches of the brewery sludge compost, whereas the lowest populations were found in turkey litter, chicken manure, and food waste composts. Heat treatment of suppressive composts reduced populations of bacteria, fungi, and actinomycetes in all composts tested. Disease suppressiveness was also reduced or eliminated in heated composts. Amending heated composts with small amounts of nonheated compost restored suppressive properties and partially restored microbial populations to wild-type levels. A strong negative relationship between compost microbial activity (as measured by the hydrolysis of fluorescein diacetate) and Pythium damping-off severity was observed. When composts were applied to creeping bentgrass in field experiments, a significant level of suppressiveness was evident with some composts when disease pressure was high (i.e., disease ratings high in uninoculated plots). A 1991 batch of turkey litter compost and the 1990 batch of Endicott biosolids were consistently suppressive to foliar symptoms of Pythium root rot on creeping bentgrass. This study indicates that suppression of Pythium diseases of creeping bentgrass in batches of brewery sludge and Endicott biosolids composts, and possibly in other suppressive composts examined in less detail in this study, is related directly to the microbial activities in the composts. On the other hand, the mechanisms of Pythium suppression in turkey litter and perhaps other poultry-based composts is not related directly to the compost microbial activity. Although turkey litter showed a lack of suppressiveness in laboratory bioassays and low microbial populations and activity, it resulted in a significant and consistent level of suppressiveness in field experiments. Therefore, the microbiological properties of Pythium-suppressive composts may differ substantially, and measurements of microbial populations and activity may not be predictive of the level of disease suppression in all composts.     

Effect of bioaugmentation and nitrogen supplementation on composting of paddy straw

A composting experiment was conducted to evaluate the effect of a hyperlignocellulolytic fungal consortium and different nitrogen amendments on paddy straw composting in terms of changes in physicochemical and biological parameters. A fungal consortium comprising four lignocellulolytic mesophilic fungal cultures was used as inoculum for bioaugmentation of paddy straw in perforated pits. The comparative effect of farmyard manure (FYM), soybean trash, poultry litter and urea on the composting process was evaluated at monthly intervals in terms of physicochemical (pH, EC, available P, C:N ratio and humus content) and biological (enzymatic and microbial activity) parameters. The compost prepared from bioaugmented paddy straw composting mixture, with poultry manure as nitrogen supplement attained desirable C:N ratio in 1 month and displayed least phytotoxicity levels along with higher production of β-1,4-Exoglucanase. The combined activity of the autochthonous composting microbiota as well as the externally applied fungal inoculum accelerated the composting process of paddy straw. Supplementation of paddy straw with poultry manure in 8:1 ratio was identified as the best treatment to hasten the composting process. This study highlights the importance of application of fungal inoculum and an appropriate N-amendment such as poultry manure for preparation of compost using a substrate having high C:N ratio, such as paddy straw.     

Bacterial community profiles on feathers during composting as determined by terminal restriction fragment length polymorphism analysis of 16S rDNA genes

Composting is one of the more economical and environmentally safe methods of recycling feather waste generated by the poultry industry, since 90% of the feather weight consists of crude keratin protein, and feathers contain 15% N. However, the keratin in waste feathers is resistant to biodegradation and may require the addition of bacterial inocula to enhance the degradation process during composting. Two keratin-degrading bacteria isolated from plumage of wild songbirds and identified as Bacillus licheneformis (OWU 1411T) and Streptomyces sp. (OWU 1441) were inoculated into poultry feather composts (1.13×10⁸ cfu g^–1 feathers) and co-composted with poultry litter and straw in 200-l compost vessels. Composting temperatures, as well as CO₂ and NH₃ evolution, were measured in these vessels to determine the effects of inoculation on the rate and extent of poultry feather decomposition during composting. Terminal restriction fragment length polymorphisms of 16S rRNA genes were used to follow changes in microbial community structure during composting. The results indicated that extensive carbon conversion occurred in both treatments (55.5 and 56.1%). The addition of the bacterial inocula did not enhance the rate of waste feather composting. The microbial community structure over time was very similar in inoculated and uninoculated waste feather composts.     

Impacts of poultry house environment on poultry litter bacterial community composition

Viral and bacterial pathogens are a significant economic concern to the US broiler industry and the ecological epicenter for poultry pathogens is the mixture of bedding material, chicken excrement and feathers that comprises the litter of a poultry house. This study used high-throughput sequencing to assess the richness and diversity of poultry litter bacterial communities, and to look for connections between these communities and the environmental characteristics of a poultry house including its history of gangrenous dermatitis (GD). Cluster analysis of 16S rRNA gene sequences revealed differences in the distribution of bacterial phylotypes between Wet and Dry litter samples and between houses. Wet litter contained greater diversity with 90% of total bacterial abundance occurring within the top 214 OTU clusters. In contrast, only 50 clusters accounted for 90% of Dry litter bacterial abundance. The sixth largest OTU cluster across all samples classified as an Arcobacter sp., an emerging human pathogen, occurring in only the Wet litter samples of a house with a modern evaporative cooling system. Ironically, the primary pathogenic clostridial and staphylococcal species associated with GD were not found in any house; however, there were thirteen 16S rRNA gene phylotypes of mostly gram-positive phyla that were unique to GD-affected houses and primarily occurred in Wet litter samples. Overall, the poultry house environment appeared to substantially impact the composition of litter bacterial communities and may play a key role in the emergence of food-borne pathogens.     

Quality evaluation of co-composted wheat straw, poultry droppings and oil seed cakes

Poultry droppings, neem cake, castor cake, jatropha cake and grass clippings were used separately as organic nitrogen additives to decrease the high C:N ratio of wheat straw. Composting was carried out aerobically in presence of fungal consortium developed by including Aspergillus awamori, Aspergillus nidulans, Trichoderma viride and Phanerochaete chrysosporium. The degraded product was characterized to assess the technical viability of organic nitrogen supplements as well as fungal consortium in improving the quality of compost and hastening the process of decomposition of high lignocellulolytic waste. Evaluation of maturity showed that mixture of wheat straw, poultry dropping and jatropha cake had the lowest C:N ratio of 10:1, the highest humic acid fraction of 3.15%, the lowest dehydrogenase activity and a germination index exceeding 80% in 60 days of decomposition. Inoculated and grass clipping amended wheat straw–poultry dropping mixture resulted in compost with highest humus content of 11.8% and C:N ratio of 13.5, humic acid fraction of 2.84% and germination index of 59.66%. Fungal consortium was effective in improving the humus content of all the composted mixtures. In some treatments, germination index could not be correlated with C:N ratio. Non edible oil seed cake supplemented substrate mixtures did not respond to fungal inoculation as far as C:N ratio was concerned.     

The development of soil physical properties and vegetation establishment on brownfield sites using manufactured soils

The physical properties of natural soils have been researched extensively. However, there is a paucity of information on the short and longer term effects on a manufactured soil after the addition of municipal green waste compost as an organic component. Two field trials were set up using different soil forming materials. Trial 1 (Chorley), added compost to degraded subsoil, whilst trial 2 (Bidston) utilised compost added to a mixture of sand and silt. The trials were established to determine what effect the addition of municipal greenwaste compost had on the development of soil physical properties, and the soils subsequent ability to support vegetation establishment. The compost was introduced as a blend and mulch at varying ratios in an attempt to establish the most appropriate mix to support the establishment of grassland vegetation. It was found that the addition of compost reduced the bulk density proportionally across the majority of the blends at both trial sites which in turn had a positive effect on porosity and infiltration rates. At trial 1 there was evidence of a good suite of meadow plants present in many plots with reasonable similarity to the Natural Vegetation Classification MG5/5a except for the treatment with 33% compost mulch. At trial 2 the soil mixture treatments that supported vegetation most similar to the Natural Vegetation Classification MG5 suite of sown species were the mixes with 15% and 30% compost. The compost mulch treatment and the mix with 45% compost content were probably too fertile as they became dominant with ruderal weed species due to natural succession and inhibited the growth of the meadow plants. Overall, the initial findings of the two trials suggest that adding green waste compost at specific rates could be used as a successful strategy in the early stages of establishing and managing controlled vegetation growth on a manufactured soil.     

Fate of Salmonella enterica Serovar Typhimurium on Carrots and Radishes Grown in Fields Treated with Contaminated Manure Composts or Irrigation Water

Three different types of compost, PM-5 (poultry manure compost), 338 (dairy cattle manure compost), and NVIRO-4 (alkaline-pH-stabilized dairy cattle manure compost), and irrigation water were inoculated with an avirulent strain of Salmonella enterica serovar Typhimurium at 10⁷ CFU g⁻¹ and 10⁵ CFU ml⁻¹, respectively, to determine the persistence of salmonellae in soils containing these composts, in irrigation water, and also on carrots and radishes grown in these contaminated soils. A split-plot block design plan was used for each crop, with five treatments (one without compost, three with each of the three composts, and one without compost but with contaminated water applied) and five replicates for a total of 25 plots for each crop, with each plot measuring 1.8 × 4.6 m. Salmonellae persisted for an extended period of time, with the bacteria surviving in soil samples for 203 to 231 days, and were detected after seeds were sown for 84 and 203 days on radishes and carrots, respectively. Salmonella survival was greatest in soil amended with poultry compost and least in soil containing alkaline-pH-stabilized dairy cattle manure compost. Survival profiles of Salmonella on vegetables and soil samples contaminated by irrigation water were similar to those observed when contamination occurred through compost. Hence, both contaminated manure compost and irrigation water can play an important role in contaminating soil and root vegetables with salmonellae for several months.     

Effect of aluminum sulfate on litter composition and ammonia emission in a single flock of broilers up to 42 days of age

New alternatives are necessary if the environmental impact linked to intensive poultry production is to be reduced, and different litter handling methods should be explored. Among these, acidifying amendments added to poultry litters has been suggested as a management practice to help reduce the potential environmental effect involved in multiple flock cycles. There have been several studies on the use of aluminum sulfate (alum) and its benefits, but almost no data are available under farm conditions in Europe. An experiment with Ross 308 broilers from 1 to 42 days of age was conducted to evaluate the effect of alum on litter composition, the solubility of some mineral elements and NH₃ emission during a single flock-rearing period in commercial houses located in southeast Spain. Broilers were placed on clean wood shavings in four commercial houses, containing 20 000 broilers each. Before filling, alum was applied at a rate of 0.25 kg/m² to the wood shavings of two poultry houses, whereas the remaining two were used as control. Litter from each poultry house was sampled every 3 to 5 days. Ammonia emissions from the poultry houses were monitored from 37 to 42 days of age. In comparison with the control group, alum treatment significantly reduced the pH level of the litter (P < 0.001) with an average difference of 1.32 ± 0.24 units. Alum-treated litter showed, on average, a higher electrical conductivity than the control litter (5.52 v. 3.63 dS/m). The dry matter (DM) and total N and P contents did not show differences between the treatments (P > 0.05). Regarding the NH₄⁺-N content, alum-treated litter showed a higher value than the untreated litter, with an average difference of 0.16 ± 0.07% (on a DM basis). On average, alum-treated litter had lower water-soluble P, Zn and Cu contents than the untreated litter. Alum noticeably reduced the in-house ammonia concentration (P < 0.001), with an average of 4.8 ppm at 42 days of age (62.9% lower than the control), and ammonia emissions from 37 to 42 days of age were significantly reduced by the alum treatment (P < 0.001), representing a reduction of 73.3%. The lower pH values might have reduced ammonia volatilization from the litter, with a corresponding positive effect on the building environment and poultry health. For these reasons, litter amendment with alum could be recommended as a way of reducing the pollution potential of European broiler facilities during a single flock cycle.