Uptake of ozone and modification of lipids in Betula Pendula pollen.

Pollen allergy risk is modified by air pollutants, including ozone, but the chemical modifications induced on pollen grains are poorly understood. Pollen lipidic extract has been shown to act as an adjuvant to the allergenic reaction and therefore, the modification of lipids by air pollutants could have health implications. Birch pollen was exposed in vitro to ozone to explore the reactivity of O3 on its surface and on its lipidic fraction. Uptake coefficients of ozone were determined for ozone concentration of 117 ppb on the surface of native birch pollen (8.6 ±â€¯0.8 × 10-6), defatted pollen (9.9 ±â€¯0.9 × 10-6), and for crushed pollen grains (34±3 × 10-6). The mass of ozone uptaken was increased by a factor of four for crushed pollen compared to native pollen showing a higher susceptibility to ozone of cytoplasmic granules and broken pollen grains. A total mass of extractible lipids of 27 mg per gram of birch pollen was found and a fraction of these lipids was identified and quantified (fatty acids, alkanes, alkenes and aldehydes). The distribution of lipids was modified by ozone exposure of 115 and 1000 ppb for 16 h with the following reactivity: consumption of alkene, formation of aldehydes and formation of nonanoic acid and octadecanoic acid. The quantity of ozone trapped in the lipidic fraction during 15 min at 115 ppb is enough to contribute to the reactivity of one-third of the alkenes demonstrating that pollen could be susceptible to an atmospheric increase of ozone concentration even for a very short duration complicating the understanding of the link between pollen allergy and pollution.

Influence of feeding supplements of almond hulls and ensiled citrus pulp on the milk production, milk composition, and methane emissions of dairy cows.

Almond hulls and citrus pulp have been fed to dairy cows with variable responses for milk production, but no information exists on their effect on enteric methane emissions. This experiment examined the effects of dietary supplementation with either almond hulls or ensiled citrus pulp on the milk yield, milk composition, and enteric methane emissions of dairy cows. Thirty-two Holstein dairy cows in mid lactation were offered 1 of 3 diets over a 28-d experiment. Twelve cows received a control (CON) diet, 10 cows a diet containing almond hulls (ALH), and 10 cows a diet containing ensiled citrus pulp (CIT). All cows were offered 6.0 kg of dry matter (DM)/d of crushed corn, 2.0 kg of DM/d of cold-pressed canola, and 0.2 kg of DM/d of a mineral mix. In addition, cows fed the CON diet were offered 14.5 kg of DM/d of alfalfa cubes; cows fed the ALH diet were offered 10.5 kg of DM/d of alfalfa cubes and 4.0 kg of DM/d of almond hulls; and cows on the CIT diet were offered 11.5 kg of DM/d of alfalfa cubes and 3.0 kg of DM/d of ensiled citrus pulp. Milk yield was measured daily and milk composition was measured on 4 d of each week. Individual cow methane emissions were measured by a sulfur hexafluoride tracer technique on d 24 to 28 of the experiment. The mean milk yield of cows fed the CON diet (27.4 kg/d) was greater than the mean milk yield of cows fed the ALH diet (24.6 kg/cow per day), whereas the mean milk yield of cows fed the CIT diet (26.2 kg/cow per day) was not different from the mean milk yield from cows fed the other 2 diets. Dietary treatment did not influence the concentrations of milk fat, protein, and lactose or fat yields, but the mean protein yield from cows fed the CON diet (0.87 kg/d) was greater than that from cows fed the ALH diet (0.78 kg/d) but not different to those fed the CIT diet (0.85 kg/d). In general, we found no differences in the proportion of individual fatty acids in milk. The mean pH of ruminal fluid from cows offered the CON diet was not different to the pH in the ruminal fluids of cows offered the ALH or the CIT diets. The mean methane emissions (g/d) and yields (g/kg of DM intake) were not influenced by dietary treatment. These findings indicate that, although almond hulls and ensiled citrus pulp can be used as a low-cost feed supplement, almond hulls did negatively affect milk production and neither inhibited enteric methane emissions.

Relationships of CO2 assimilation rates with exposure- and flux-based O3 metrics in three urban tree species.

The relationships of CO2 assimilation under saturated-light conditions (Asat) with exposure- (AOTX, Accumulated Ozone exposure over a hourly Threshold of X ppb) and flux-based (PODY, Phytotoxic Ozone Dose over a hourly threshold Y nmol·m-2·s-1) O3 metrics was studied on three common urban trees, Fraxinus chinensis (FC), Platanus orientalis (PO) and Robinia pseudoacacia (RP). Parameterizations for a stomatal multiplicative model were proposed for the three species. RP was the species showing lower species-specific maximum stomatal conductance (gmax) and experiencing lower cumulative O3 uptake along the experiment, but in contrast it was the most sensitive to O3. PODY was slightly better than AOTX metric at estimating relative Asat (R-Asat)for PO and RB but not for FC. The best fittings obtained for the regressions between R-Asat and AOTX for FC, PO and RP were 0.904, 0.868, and 0.876, when the thresholds of X were 60ppb, 55ppb and 30ppb, respectively. However, AOT40 performed also well for all of them, with R2 always >0.83. For PODY, the highest R2 values for FC, PO and RB were 0.863, 0.897 and 0.911 at thresholds Y=7, 5 and 1nmolO3m-2s-1, respectively. Given the potentially higher O3 removal capacity of FC and PO by stomatal uptake and their lower sensitivity to this pollutant than RP, the former two species would be appropriate for urban gardens and areas where O3 levels are high. Parameterization and modeling of stomatal conductance for the main urban tree species may provide reliable estimations of the stomatal uptake of O3 and other gaseous pollutants by vegetation, which may support decision making on the most suitable species for green urban planning in polluted areas.

Effects of quebracho tannin extract on intake, digestibility, rumen fermentation, and methane production in crossbred heifers fed low-quality tropical grass.

The aim of this work was to evaluate the effect of quebracho tannins extract (QTE) on feed intake, dry matter (DM) digestibility, and methane (CH4) emissions in cattle fed low-quality Pennisetum purpureum grass. Five heifers (Bos taurus × Bos indicus) with an average live weight (LW) of 295 ± 19 kg were allotted to five treatments (0, 1, 2, 3, and 4% QTE/kg DM) in a 5 × 5 Latin square design. Intake, digestibility, and total methane emissions (L/day) were recorded for periods of 23 h when cattle were housed in open-circuit respiration chambers. Dry matter intake (DMI), organic matter intake (OMI), dry matter digestibility (DMD), and organic matter digestibility (OMD) were different between treatments with 0 and 4% of QTE/kg DM (P < 0.05). Total volatile fatty acid and the molar proportion of acetate in the rumen was not affected (P < 0.05); however, the molar proportion of propionate increased linearly (P < 0.01) for treatments with 3 and 4% QTE. Total CH4 production decreased linearly (P < 0.01) as QTE increased in the diet, particularly with 3 and 4% concentration. When expressed as DMI and OMI by CH4, production (L/kg) was different between treatments with 0 vs 3 and 4% QTE (P < 0.05). It is concluded that the addition of QTE at 2 or 3% of dry matter ration can decrease methane production up to 29 and 41%, respectively, without significantly compromising feed intake and nutrients digestibility.

Air pollution tolerance index and heavy metal bioaccumulation in selected plant species from urban biotopes.

This research was carried out on plants Taraxacum officinale, Plantago lanceolata, Betula pendula and Robinia pseudoacacia growing in urban biotopes with different levels of heavy metal contamination in the city of Dabrowa Górnicza (southern Poland). Based on the pollution index, the highest heavy metal contamination was determined in the site 4 (connected with industry emitters) and 6 (high traffic). The metal accumulation index (MAI) values ranged within the biotopes in Dabrowa Górnicza between 7.3 and 20.6 for R. pseudoacacia, 4.71-23.1 for P. lanceolata, 4.68-28.1 for T. officinale and 10.5-27.2 for B. pendula. Increasing tendency in proline content in biotopes connected with high traffic was found in the leaves of investigated plants (except R. pseudoacacia). Similar tendency was observed for ascorbic acid content in the foliage of the plants as well as in T. officinalle in stands connected industrial emission. Non-protein thiols content increased especially in the leaves of R. pseudoacacia in biotopes with high traffic emissions as well as in T. officinale in stands connected with industry. The mean values of APTI (Air Pollution Tolerance Index) within the city of Dabrowa Górnicza for investigated plants were found in the following ascending order P. lanceolata < R. pseudoacacia < B. pendula < T. officinale. Among the investigated plants B. pendula and T. officinale may be postulated as appropriate plants in urban areas with considerable soil and air contamination, especially with heavy metals. The results indicate that species deemed tolerant according to APTI are suitable plants in barriers areas to combat atmospheric pollution.

Effects of xylanase supplementation on growth performance, nutrient digestibility, blood parameters, fecal microbiota, fecal score and fecal noxious gas emission of weaning pigs fed corn-soybean meal-based diet.

This study was conducted to evaluate the effects of xylanase supplementation on nutrient digestibility, growth performance, blood parameters, fecal microflora shedding, fecal score and fecal noxious gas emission of weaning pigs fed corn-soybean meal based diet. A total of 150 weaning pigs with an average initial body weight (BW) of 7.85 ± 0.93 kg were randomly allocated to three treatments based on BW and sex (10 replicate pens with five pigs, two gilts and three barrows) were used in this 42-day trial. Dietary treatments were: (1) CON, basal diet; (2) X1, basal diet +0.005% xylanase; (2) X2, basal diet +0.01% xylanase. The xylanase supplementation linearly increased (P < 0.05) average daily gain (ADG), and gain : feed ratio (G:F) from days 29 to 42 and the in overall period, dry matter, nitrogen and energy digestibility, and fecal Lactobacilli counts, and linearly decreased (P < 0.05) blood urea nitrogen (BUN) concentration, fecal NH3 and H2 S emission. Additionally, at weeks 5 and 6, there was a linear decrease in fecal score with xylanase supplementation. In conclusion, dietary supplementation of xylanase improved growth performance, nutrient digestibility, shifted microbiota by increasing fecal Lactobacillus counts, decreased BUN concentration, fecal score, and fecal NH3 and H2 S emission in weaning pigs.

Effect of Bacillus spp. direct-fed microbial on slurry characteristics and gaseous emissions in growing pigs fed with high fibre-based diets.

A 26-day trial with 18 Pietrain×(Landrace×Duroc) pigs was conducted to investigate the effect of two dose levels of a specifically selected Bacillus spp. direct-fed microbial (DFM) product, on the emission of environmentally harmful gasses (methane, ammonia and hydrogen sulphide) from manure. Pigs were assigned to one of three treatments in a randomized complete block design according to their sex and initial BW. Each treatment contained three replications with two pigs per pen. The test treatments included a Bacillus spp. DFM containing 3×108 colony-forming unit/g, added at a low (250 mg/kg) and high (500 mg/kg) dose to an antibiotic free high fibre-based diet, and a non-supplemented control diet. Manure from pigs fed with the supplemented diets emitted lower amounts of atmospheric contaminants. The most significant reduction was observed with low DFM supplementation, in which methane and ammonia volatilization decreased (P40% and 50%, respectively, on fresh weight basis in relation to the control. Microbiome analysis of manure by high through put sequencing techniques on eubacterial and archaeal 16S rRNA genes highlighted the complex interactions between indigenous gut microflora and inoculated Bacillus spp. The tested Bacillus DFM could be considered as a best available technique in reducing the environmental impacts of growing pigs fed with high fibre-based diets.

Improving productive performance and mitigating harmful emissions from laying hen excreta via feeding on graded levels of corn DDGS with or without Bacillus subtilis probiotic.

An experiment that included some inclusions of corn distillers dried grains with solubles (DDGS) with or without supplementation of probiotic bacteria to Hi-sex Brown laying hen diets was conducted to evaluate the impacts on performance, egg quality, blood metabolites and nitrogen and phosphorus excretion in the manure. A total of 216 twenty-two-week-old Hi-sex Brown laying hens were randomly divided into eight treatment groups in a factorial design (4 × 2) experiment, which included four levels of DDGS (0, 50, 100 and 150 g/kg diet) plus two levels of Bacillus subtilis probiotic (0 or 1000 mg/kg diet, with a concentration of 1.5 × 108 CFU/g of dried product). The experimental period extended from 22 to 34 weeks of age. The results showed that linear increase in DDGS level up to 150 g/kg improved (p ≤ 0.01) the values of feed consumption, egg shape index and yolk colour compared to the control and other treatment groups. Inclusion of dietary DDGS up to 150 g/kg in layer diets led to a significant decrease in egg mass and a significant increase in Haugh unit score compared to other groups. In the bacillus group, the values of feed conversion, egg weight and egg mass enhanced by 6.45, 3.27 and 7.60% respectively compared with the control diet. Total protein, albumin, triglycerides, cholesterol, calcium and ammonia in serum were significantly (p ≤ 0.01) influenced by DDGS inclusion. The excreted nitrogen decreased by 8.62 and 4.31% in hens fed 50 or 100 g/kg of DDGS respectively, while excreted phosphorous decreased by 3.33, 7.22 and 10.56% in hens fed 50, 100 or 150 g/kg of DDGS respectively as compared to the control group. It could be concluded that increasing DDGS inclusion level in the diet up to 10% and the supplementation of probiotic bacteria improved the productive performance of laying hens and mitigated the harmful emissions from chicken manure; this means better production within environmentally friendly conditions.

Cleanup of trimethylamine (fishy odor) from contaminated air by various species of Sansevieria spp. and their leaf materials.

Removal of trimethylamine (TMA) by 10 different living Sansevieria spp. and their dried leaf materials was studied. The results showed that living Sansevieria kirkii was the most effective plant while Sansevieria masoniana was the least effective in TMA removal. Two major pathways were involved in stomata opening and epicuticular wax on the leaf surface. In the presence of TMA, the stomata opening in Sansevieria spp. was induced, which enhanced TMA removal under light conditions. Dried leaf powders of Sansevieria spp. adsorbed TMA through their waxes. Therefore, both living and non-living Sansevieria spp. can be effectively used for removal of TMA.

Efficacy of ß-mannanase supplementation to corn-soya bean meal-based diets on growth performance, nutrient digestibility, blood urea nitrogen, faecal coliform and lactic acid bacteria and faecal noxious gas emission in growing pigs.

A study was conducted to determine the efficacy of ß-mannanase supplementation to a diet based on corn and soya bean meal (SBM) on growth performance, nutrient digestibility, blood urea nitrogen (BUN), faecal coliforms and lactic acid bacteria, and noxious gas emission in growing pigs. A total of 140 pigs [(Landrace × Yorkshire) × Duroc; average body weight 25 ± 3 kg] were randomly allotted to a 2 × 2 factorial arrangement with dietary treatments consisting of hulled or dehulled SBM without or with supplementation of 400 U ß-mannanase/kg. During the 6 weeks of experimental feeding, ß-mannanase supplementation had no effect on body weight gain, feed intake and gain:feed (G:F) ratio. Compared with dehulled SBM, feeding hulled SBM caused an increased feed intake of pigs in the entire trial (p = 0.05). The G:F ratio was improved in pigs receiving dehulled SBM (p < 0.05). Dietary treatments did not influence the total tract digestibility of dry matter, nitrogen and gross energy. Enzyme supplementation reduced (p < 0.05) the population of faecal coliforms and tended to reduce the NH3 concentration after 24 h of fermentation in a closed box containing faecal slurry. Feeding hulled SBM tended to reduce NH3 emission on days 3 and 5 of fermentation. In conclusion, mannanase supplementation had no influence on growth performance and nutrient digestibility but showed a positive effect on reducing coliform population and tended to reduce NH3 emission. Dehulled SBM increased G:F ratio and hulled SBM tended to reduce NH3 emission.

Assessing biofiltration repeatability: statistical comparison of two identical toluene removal systems.

Biofiltration of volatile organic compounds is still considered an emerging technology. Its reliability remains questionable as no data is available regarding process intrinsic repeatability. Herein, two identically operated toluene biofiltration systems are comprehensively compared, during long-term operation (129 days). Globally, reactors responded very similarly, even during transient conditions, with, for example, strong biological activities from the first days of operation, and comparable periods of lower removal efficiency (81.2%) after exposure to high inlet loads (140 g m(-3) h(-1)). Regarding steady states, very similar maximum elimination capacities up to 99 g m(-3) h(-1) were attained. Estimation of the process repeatability, with the paired samples Student's t-test, indicated no statistically significant difference between elimination capacities. Repeatability was also established for several descriptors of the process such as the carbon dioxide and biomass production, the pH and organic content of the leachates, and the moisture content of the packing material. While some parameters, such as the pH, presented a remarkably low divergence between biofilters (coefficient of variability of 1.4%), others, such as the organic content of the leachates, presented higher variability (30.6%) due to an uneven biomass lixiviation associated with stochastic hydrodynamics and biomass repartitions. Regarding process efficiency, it was established that less than 10% of fluctuation is to be expected between the elimination capacities of identical biofilter set-ups. A further statistical comparison between the first halves of the biofilter columns indicated very similar coefficients of variability, confirming the repeatability of the process, for different biofilter lengths.

[Atmospheric Particle Retaining Function of Common Deciduous Tree Species Leaves in Beijing].

In order to explore the atmospheric particle-retaining function of common deciduous tree species leaves in Beijing, six typical tree species (Populus, Robinia pseudoacacia, Koelreuteria paniculata, Salix babylonica, Acer truncatum, Ginkgo biloba) were chosen to measure retaining amount of unit leaf area of air total suspended particles (TSP), coarse particles and fine particulate with aerosol generator (QRJZFSQ-I). The results showed that (1) All six tree species leaves had a certain level of retaining ability to different sizes of atmospheric particles, and different species exhibited some differences. For different sizes of atmospheric particle, retaining amounts of unit leaf area were higher in Koelreuteria paniculata and Robinia pseudoacacia than those of other four species, and the amount of Populus was the lowest among all tree species; (2) The retaining amount of unit leaf area for different tree species was not entirely increased with sampling time. The retaining amounts of TSP and coarse particles for all tree species on the eighth day after rain were significantly higher than those on the fifth day after rain, however, the retaining amount of fine particles was not significantly different under different sampling times. In order to select deciduous tree species for ecological management of air pollution in Beijing, Koelreuteria paniculata should be considered as the priority, followed by Robinia pseudoacacia, compared with Ginkgo biloba, Salix babylonica, Acer truncatum and Populus.

Crystal structures of apo-DszC and FMN-bound DszC from Rhodococcus erythropolis D-1.

UNLABELLED: The release of SO2 from petroleum products derived from crude oil, which contains sulfur compounds such as dibenzothiophene (DBT), leads to air pollution. The '4S' metabolic pathway catalyzes the sequential conversion of DBT to 2-hydroxybiphenyl via three enzymes encoded by the dsz operon in several bacterial species. DszC (DBT monooxygenase), from Rhodococcus erythropolis D-1 is involved in the first two steps of the '4S' pathway. Here, we determined the first crystal structure of FMN-bound DszC, and found that two distinct conformations occur in the loop region (residues 131-142) adjacent to the active site. On the basis of the DszC-FMN structure and the previously reported apo structures of DszC homologs, the binding site for DBT and DBT sulfoxide is proposed. DATABASE: The atomic coordinates and structure factors for apo-DszC (PDB code: 3X0X) and DszC-FMN (PDB code: 3X0Y) have been deposited in the Protein Data Bank (http://www.rcsb.org).

Kinetic of NO2 uptake by Phleum pratense pollen: chemical and allergenic implications.

Phleum pratense pollen was exposed to NO(2) in a reactor allowing a continuous analysis of NO(2) concentration by FTIR. The uptake coefficient of NO(2) on pollen was calculated postulating a first order kinetic reaction and a value of (1.1 ± 0.1) x 10(-7) was determined. NO(2) uptake was faster when the pollen water content was increased and when the pollen was pre-treated with ozone. The effect of NO(2) exposure on pollen allergic properties was investigated by quantifying Th2- and Th1-associated chemokines in a model of human dendritic cells. Cellular analysis clearly showed that cells exposed to fumigated pollen favored the production of chemokines known to promote Th2-cell responses. Altogether these data demonstrate that NO(2) uptake by pollen directly correlates with increased Th2 response in human cells,and are in favor of the involvement of NO(2) pollution in the increase of allergic diseases.

Effect of continuous ozone injection on performance and biomass accumulation of biofilters treating gaseous toluene.

Biofilters treating high-concentration gaseous volatile organic compounds (VOC) can be subject to bed clogging induced by excess biomass accumulation. In this study, O3 was continuously injected into biofilters to control biomass. Its effects on the performance of the biofilters and on biomass accumulation were investigated. Four identical biofilters designed to treat gaseous toluene were operated for 70 days, and three of them were continuously injected with O3 at different concentrations (from 80 to 320 mg/m(3)). The results showed that continuous O3 injection could effectively keep the bed pressure drop stable and had no adverse effect on toluene removal when O3 concentrations were 180-220 mg/m(3). The maximum toluene elimination capacity of the four biofilters was 140 g-toluene/m(3)/h, and the bed pressure drop of the biofilter fed with 180-220 mg/m(3) O3 remained below 3 mmH2O/m throughout the operation period. The biomass accumulation rates of the three biofilters with O3 at 80-320 mg/m(3) were lowered by 0.15-0.25 g/L/day compared with the biofilter without O3. The decreases in biomass accumulation resulted in higher void fractions of the filter beds with O3 injection. Carbon balance analysis indicated that CO2 production had increased while biomass accumulation and leachate waste production decreased in response to O3 injection. Based on the experimental results, it was concluded here that continuous O3 injection can reduce increases in bed pressure effectively, preserve VOC removal capacity, and prevent production of extra leachate waste.

Functional relationships with N deposition differ according to stand maturity in Calluna-dominated heathland.

Plant and soil bio(chemical) indicators are increasingly used to provide information on N deposition inputs and effects in a wide range of ecosystem types. However, many factors, including climate and site management history, have the potential to influence bioindicator relationships with N due to nutrient export and changing vegetation nutrient demands. We surveyed 33 heathlands in England, along a gradient of background N deposition (7.2-24.5 kg ha(-1) year(-1)), using Calluna vulgaris growth phase as a proxy for time since last management. Our survey confirmed soil nutrient accumulation with increasing time since management. Foliar N and phosphorus (P) concentrations in pioneer- and mature-phase vegetation significantly increased with N deposition. Significant interactions between climate and N deposition were also evident with, for example, higher foliar P concentrations in pioneer-phase vegetation at sites with higher temperatures and N deposition rates. Although oxidized N appeared more significant than reduced N, overall there were more, stronger relationships with total N deposition; suggesting efforts to control all emissions of N (i.e., both oxidized and reduced forms) will have ecological benefits.

Nitrogen and phosphorus addition impact soil N2O emission in a secondary tropical forest of South China.

Nutrient availability greatly regulates ecosystem processes and functions of tropical forests. However, few studies have explored impacts of N addition (aN), P addition (aP) and N × P interaction on tropical forests N2O fluxes. We established an N and P addition experiment in a tropical forest to test whether: (1) N addition would increase N2O emission and nitrification, and (2) P addition would increase N2O emission and N transformations. Nitrogen and P addition had no effect on N mineralization and nitrification. Soil microbial biomass was increased following P addition in wet seasons. aN increased 39% N2O emission as compared to control (43.3 µgN2O-N m(-2)h(-1)). aP did not increase N2O emission. Overall, N2O emission was 60% greater for aNP relative to the control, but significant difference was observed only in wet seasons, when N2O emission was 78% greater for aNP relative to the control. Our results suggested that increasing N deposition will enhance soil N2O emission, and there would be N × P interaction on N2O emission in wet seasons. Given elevated N deposition in future, P addition in this tropical soil will stimulate soil microbial activities in wet seasons, which will further enhance soil N2O emission.

Invited review: Enteric methane in dairy cattle production: quantifying the opportunities and impact of reducing emissions.

Many opportunities exist to reduce enteric methane (CH4) and other greenhouse gas (GHG) emissions per unit of product from ruminant livestock. Research over the past century in genetics, animal health, microbiology, nutrition, and physiology has led to improvements in dairy production where intensively managed farms have GHG emissions as low as 1 kg of CO2 equivalents (CO2e)/kg of energy-corrected milk (ECM), compared with >7 kg of CO2 e/kg of ECM in extensive systems. The objectives of this review are to evaluate options that have been demonstrated to mitigate enteric CH4 emissions per unit of ECM (CH4/ECM) from dairy cattle on a quantitative basis and in a sustained manner and to integrate approaches in genetics, feeding and nutrition, physiology, and health to emphasize why herd productivity, not individual animal productivity, is important to environmental sustainability. A nutrition model based on carbohydrate digestion was used to evaluate the effect of feeding and nutrition strategies on CH4/ECM, and a meta-analysis was conducted to quantify the effects of lipid supplementation on CH4/ECM. A second model combining herd structure dynamics and production level was used to estimate the effect of genetic and management strategies that increase milk yield and reduce culling on CH4/ECM. Some of these approaches discussed require further research, but many could be implemented now. Past efforts in CH4 mitigation have largely focused on identifying and evaluating CH4 mitigation approaches based on nutrition, feeding, and modifications of rumen function. Nutrition and feeding approaches may be able to reduce CH4/ECM by 2.5 to 15%, whereas rumen modifiers have had very little success in terms of sustained CH4 reductions without compromising milk production. More significant reductions of 15 to 30% CH4/ECM can be achieved by combinations of genetic and management approaches, including improvements in heat abatement, disease and fertility management, performance-enhancing technologies, and facility design to increase feed efficiency and life-time productivity of individual animals and herds. Many of the approaches discussed are only partially additive, and all approaches to reducing enteric CH4 emissions should consider the economic impacts on farm profitability and the relationships between enteric CH4 and other GHG.

Removal of odorous compounds from poultry manure by microorganisms on perlite--bentonite carrier.

Laboratory-scale experiments were conducted using poultry manure (PM) from a laying hen farm. Six strains of bacteria and one strain of yeast, selected on the base of the previous study, were investigated to evaluate their activity in the removal of odorous compounds from poultry manure: pure cultures of Bacillus subtilis subsp. spizizenii LOCK 0272, Bacillus megaterium LOCK 0963, Pseudomonas sp. LOCK 0961, Psychrobacter faecalis LOCK 0965, Leuconostoc mesenteroides LOCK 0964, Streptomyces violaceoruber LOCK 0967, and Candida inconspicua LOCK 0272 were suspended in water solution and applied for PM deodorization. The most active strains in the removal of volatile odorous compounds (ammonia, hydrogen sulfide, dimethylamine, trimethylamine, isobutyric acid) belonged to B. subtilis subsp. spizizenii, L. mesenteroides, C. inconspicua, and P. faecalis. In the next series of experiments, a mixed culture of all tested strains was immobilized on a mineral carrier being a mixture of perlite and bentonite (20:80 by weight). That mixed culture applied for PM deodorization was particularly active against ammonia and hydrogen sulfide, which were removed from the exhaust gas by 20.8% and 17.5%, respectively. The experiments also showed that during deodorization the microorganisms could reduce the concentrations of proteins and amino acids in PM. In particular, the mixed culture was active against cysteine and methionine, which were removed from PM by around 45% within 24 h of deodorization.

The influence of plants on atmospheric methane in an agriculture-dominated landscape.

The primary objective of this study was to clarify the influence of crop plants on atmospheric methane (CH4) in an agriculture-dominated landscape in the Upper Midwest of the United States. Measurements were carried out at two contrasting scales. At the plant scale, CH4 fluxes from soybean and corn plants were measured with a laser-based plant chamber system. At the landscape scale, the land surface flux was estimated with a modified Bowen ratio technique using measurements made on a tall tower. The chamber data revealed a diurnal pattern for the plant CH4 flux: it was positive (an emission rate of 0.4±0.1 nmol m(-2) s(-1), average of soybean and corn, in reference to the unit ground area) during the day, and negative (an uptake rate of -0.8±0.8 nmol m(-2) s(-1)) during the night. At the landscape scale, the flux was estimated to be 14.8 nmol m(-2) s(-1) at night and highly uncertain during the day, but the available references and the flux estimates from the equilibrium methods suggested that the CH4 flux during the entire observation period was similar to the estimated nighttime flux. Thus, soybean and corn plants have a negligible role in the landscape-scale CH4 budget.