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Due to greater consumption of poultry products and an increase in exports, more poultry houses will be needed. Therefore, it is important to investigate ways that poultry facilities can coexist in close proximity to residential areas without odors and environmental challenges. Ammonia (NH 3 ) is the greatest concern for environmental pollution from poultry production. When birds consume protein, they produce uric acid, ultimately converted to NH 3 under favorable conditions. Factors that increase production include pH, temperature, moisture content, litter type, bird age, manure age, relative humidity, and ventilation rate (VR). NH 3 concentration and emissions in poultry houses depend on VR; seasons also have effects on NH 3 production. Modern ventilation systems can minimize NH 3 in enclosed production spaces quickly but increase its emissions to the environment. NH 3 adversely affects the ecosystem, environment, and health of birds and people. Less than 10 ppm is the ideal limit for exposure, but up to 25 ppm is also not harmful. NH 3 can be minimized by housing type, aerobic and anaerobic conditions, manure handling practices, litter amendment, and diet manipulation without affecting performance and production. Antibiotics can minimize NH 3 , but consumers have concerns about health effects. Administration of probiotics seems to be a useful replacement for antibiotics. More studies have been conducted on broilers, necessitating the need to evaluate the effect of probiotics on NH 3 production in conjunction with laying hen performance and egg quality. This comprehensive review focuses on research from 1950 to 2018.

Azo dyes are one of the largest classes of synthetic dyes being used in textile industries. It has been reported that 15–50% of these dyes find their way into wastewater that is often used for irrigation purpose in developing countries. The effect of azo dyes contamination on soil nitrogen (N) has been studied previously. However, how does the azo dye contamination affect soil carbon (C) cycling is unknown. Therefore, we assessed the effect of azo dye contamination (Reactive Black 5, 30 mg kg −1 dry soil), bacteria that decolorize this dye and dye + bacteria in the presence or absence of maize leaf litter on soil respiration, soil inorganic N and microbial biomass. We found that dye contamination did not induce any change in soil respiration, soil microbial biomass or soil inorganic N availability ( P  > 0.05). Litter evidently increased soil respiration. Our study concludes that the Reactive Black 5 azo dye (applied in low amount, i.e., 30 mg kg −1 dry soil) contamination did not modify organic matter decomposition, N mineralization and microbial biomass in a silty loam soil.

Gaseous emissions from poultry litter causes production problems for producers as well as the environment, by contributing to climate change and reducing air quality. Novel methods of reducing ammonia (NH3) and greenhouse gas (GHG) emissions in poultry facilities are needed. As such, our research evaluated GHG emissions over a 42 d period. Three separate flocks of 1000 broilers were used for this study. The first flock was used only to produce litter needed for the experiment. The second and third flocks were allocated to 20 pens in a randomized block design with four replicated of five treatments. The management practices studied included an unamended control; a conventional practice of incorporating aluminum sulfate (referred to as alum) at 98 kg/100 m2); a novel litter amendment made from alum mud, bauxite, and sulfuric acid (alum mud litter amendment, AMLA) applied at different rates (49 and 98 kg/100 m2) and methods (surface applied or incorporated). Nitrous oxide emissions were low for all treatments in flocks 2 and 3 (0.40 and 0.37 mg m2 hr−1, respectively). The formation of caked litter (due to excessive moisture) during day 35 and 42 caused high variability in CH4 and CO2 emissions. Alum mud litter amendment and alum did not significantly affect GHGs emissions from litter, regardless of the amendment rate or application method. In fact, litter amendments such as alum and AMLA typically lower GHG emissions from poultry facilities by reducing ventilation requirements to maintain air quality in cooler months due to lower NH3 levels, resulting in less propane use and concomitant reductions in CO2 emissions.

Treating manure with aluminum sulfate (alum) is a best management practice (BMP) which reduces ammonia (NH3) emissions and phosphorus (P) runoff from poultry litter. However, the price of alum has increased markedly in recent years, creating a need for less expensive products to control NH3 volatilization. The objective of this study was to evaluate the effects of a new litter amendment made from alum mud, bauxite, and sulfuric acid (alum mud litter amendment or AMLA) on NH3 emissions, litter chemistry, and poultry production in a pen trial. Three separate flocks of 1000 broilers were used for this study. The first flock of birds was used to produce the poultry litter needed for the experiment. The second and third flocks of birds were allocated to 20 pens in a randomized block design with four replicates of five treatments: (1) control, (2) 49 kg AMLA/100 m2 incorporated, (3) 98 kg AMLA/100 m2 incorporated, (4) 98 kg AMLA/100 m2 surface applied, and (5) 98 kg alum/100 m2 incorporated. Ammonia flux measurements and litter samples were collected from each pen at day 0, 7, 14, 21, 28, 35, and 42. The average litter pH for both flocks was higher in untreated litter (7.92) compared to incorporating alum (7.32) or AMLA (7.18). The two flocks’ average NH4-N concentrations at day 42 were 38% and 30% higher for the high rates of incorporated alum and AMLA compared to the untreated litter. Compared with untreated litter, AMLA reduced overall NH3 emissions by 27% to 52% which was not significantly different from reductions in emissions by alum (35%). Alum mud litter amendment reduced cumulative NH3 losses from litter as much as, and in some cases more than, alum applied at the same rate. These data indicate that AMLA, which can be manufactured for lower price than alum, is an effective alternative litter amendment for reducing NH3 emissions from poultry litter.

The experiment was conducted to study the efficacy of different types of litter amendments on litter quality and broiler performance during winter (December-January). A total number of 180, day-old (Vencobb) broiler chicks were randomly assigned to three equal groups. One bearing control group and other two comprise litter amendments with alum (ATL) and sodium bisulphate (SBTL) treatment groups, each having 60 birds in three replications of 20 numbers for 6 weeks. The findings of the study revealed significant variation (p < .05) in the moisture content and pH of the control and treated litter. This clearly indicates the efficiency of litter treatment products improving the quality of litter thus in turn the ambient environment for the bird. The average body weight was significantly highest (p < .05) in the SBTL group (1912 g) followed closely by the ATL group (1865 g) in comparison to the control group (1822 g) at the end of sixth week. The growing chicks gained significantly (p < .05) more body weight with better FCR, PER, EER and survivability in respective order of succession. The overall hygiene of the broiler chicks was better with less cake formation and without any foot pad dermatitis or breast blister lesion in the treatment groups. Thus it can be concluded that litter amendment with alum (ATL) and sodium bisulphate (SBTL) treatment had significant influence on quality of litter and in turn improved the performances of broiler chicks without any adverse effect.

The transformation of poultry litter waste through the pyrolysis process produces a product called biochar which, applied to the soil, improves its characteristics. The objective of this work was to evaluate the effect of biochar produced from poultry litter wastes, submitted to pyrolysis at 350 °C on soil chemical and physical characteristics. For this, an experiment was carried out involving soil incubation treatments during 100 days with six doses of biochar equivalent to 0.0, 2.02, 4.05, 6.07, 8.10, and 10.12 t ha−1, calculated by the base saturation method, with correction levels from 61 to 87%. After the incubation, soil samples were physically and chemically analyzed. Biochar doses promoted significant increase in pH, electrical conductivity, potassium, sodium, carbon, phosphorus, and base saturation, and decrease in potential acidity and in the soil cation exchange capacity contributing to the increase of soil fertility. The application of the biochar to the soil decreased the bulk density and increased porosity, field capacity, wilting point, and available water for plants. In general, the use of the biochar demonstrates great potential of it as a soil amendment.

Trees can have large effects on soil nutrients in ways that alter succession, particularly in the case of nitrogen-(N)-fixing trees. In Hawaiʻi, forest restoration relies heavily on use of a native N-fixing tree, Acacia koa (koa), but this species increases soil-available N and likely facilitates competitive dominance of exotic pasture grasses. In contrast, Metrosideros polymorpha (‘ōhi‘a), the dominant native tree in Hawaiʻi, is less often planted because it is slow growing; yet it is typically associated with lower soil N and grass biomass, and greater native understory recruitment. We experimentally tested whether it is possible to reverse high soil N under koa by adding ‘ōhi‘a litter, using additions of koa litter or no litter as controls, over 2.5 yr. We then quantified natural litterfall and decomposition rates of ‘ōhi‘a and koa litter to place litter additions in perspective. Finally, we quantified whether litter additions altered grass biomass and if this had effects on native outplants. Adding ‘ōhi‘a litter increased soil carbon, but increased rather than decreased inorganic soil N pools. Contrary to expectations, koa litter decomposed more slowly than ‘ōhi‘a, although it released more N per unit of litter. We saw no reduction in grass biomass due to ‘ōhi‘a litter addition, and no change in native outplanted understory survival or growth. We conclude that the high N soil conditions under koa are difficult to reverse. However, we also found that outplanted native woody species were able to decrease exotic grass biomass over time, regardless of the litter environment, making this a better strategy for lowering exotic species impacts.

BACKGROUND AND AIMS: Fine root decomposition contributes significantly to element cycling in terrestrial ecosystems. However, studies on root decomposition rates and on the factors that potentially influence them are fewer than those on leaf litter decomposition. To study the effects of region and land use intensity on fine root decomposition, we established a large scale study in three German regions with different climate regimes and soil properties. Methods In 150 forest and 150 grassland sites we deployed litterbags (100 μm mesh size) with standardized litter consisting of fine roots from European beech in forests and from a lowland mesophilous hay meadow in grasslands. In the central study region, we compared decomposition rates of this standardized litter with root litter collected on-site to separate the effect of litter quality from environmental factors. RESULTS: Standardized herbaceous roots in grassland soils decomposed on average significantly faster (24 ± 6 % mass loss after 12 months, mean ± SD) than beech roots in forest soils (12 ± 4 %; p < 0.001). Fine root decomposition varied among the three study regions. Land use intensity, in particular N addition, decreased fine root decomposition in grasslands. The initial lignin:N ratio explained 15 % of the variance in grasslands and 11 % in forests. Soil moisture, soil temperature, and C:N ratios of soils together explained 34 % of the variance of the fine root mass loss in grasslands, and 24 % in forests. CONCLUSIONS: Grasslands, which have higher fine root biomass and root turnover compared to forests, also have higher rates of root decomposition. Our results further show that at the regional scale fine root decomposition is influenced by environmental variables such as soil moisture, soil temperature and soil nutrient content. Additional variation is explained by root litter quality.

Purpose Litter decomposition is a fundamental process of biogeochemical cycles. Mixing litter of different species can induce non-additive effect (NAE) on decomposition processes. A better understanding of the factors influencing the direction and magnitude of NAE is important for quantification of ecosystem carbon and nutrient cycling. Methods Litter mixing effects on leaf litter decomposition were examined using two parallel experiments (each with leaf litter of four tree species combined into four diversity levels) conducted in Chinese temperate forests for 2 years. Results A significant diversity effect in both experiments demonstrated NAEs of litter mixing on the mass remaining. Separating the diversity effect into species richness and composition showed that composition was statistically significant in both experiments whereas an effect of species richness was only detected in Experiment 2. In both experiments, the NAE on decomposition changed with incubation time and showed a declining trend during decomposition process. However, a slight difference of the NAE in the two experiments was observed in our study. Decomposition in the litter mixtures differed from the predictions based on single species, and the presence/absence of poplar, pine and oak in the litter mixture significantly influenced the direction and magnitude of the NAE. Presence of coniferous species litter significantly reduced decomposition rates even within the same species richness level. The coefficient of variation of remaining litter mass was lower in the treatments with higher number of litter species. Conclusions Our findings showing of changes in the direction and magnitude of NAE with decomposition time and litter species composition indicate that tree species composition and decomposition duration should be considered in predicting biodiversity effect on biogeochemical cycling in temperate forests.