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Composting is an effective management practice for converting animal waste to a valuable soil amendment that has the potential to reduce pollution. Rectangular bed composting with daily turning is widely used in China, but gas emission from this method has not be reported. The goals of this study were to evaluate seasonal differences in greenhouse gas (GHG) emissions and the relative contributions of the GHGs from a commercial swine manure composting facility with daily turning. The compost mixture of swine manure and mushroom residues was turned and moved forward 2 m every day, and it took approximately 20 d to move the raw materials from the head side to the end side of the composting bed. The gases were sampled daily with the static chamber method, and gas concentrations were measured with a gas chromatograph. Compost and air temperatures were monitored. The compost was sampled every 3 d for nitrogen and carbon contents. Cumulative emissions in spring, summer, autumn, and winter were 14.1 ±4.0, 24.1 ±2.2, 10.5 ±0.8, and 11.9 ±3.4 kg CO2 m-2, respectively; 311 ±106, 482 ±44, 113 ±9, and 105 ±21 g CH4 m-2, respectively; and 2.1 ±0.3, 2.7 ±0.4, 0.5 ±0.2, and 1.3 ±0.4 g N2O m-2, respectively. Averaged over the four seasons, greenhouse gas flux was 12.38 ±8.90 g CH4 m-2 d-1 and 0.083 ±0.048 g N2O m-2 d-1. The reason for the lowest emission in autumn was unclear. Excluding CO2, methane contributed approximately 87.5% to 94.9% of the CO2e emissions, whereas N2O contributed the rest. Because the static chamber did not capture emissions during turning, it is recommended that more robust methods (such as dynamic plume or mega dynamic chamber) should be applied to measure the emissions for inventory studies. The high temperatures in the last few days indicated that composting was still ongoing and the duration should be increased. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) emissions from laying hens are affected by nutrient content of the diet, manure quantity, and manure properties such as moisture content, nitrogen content, and pH. These production traits may vary with strain of the hen. However, limited information is available concerning the effects of laying-hen genetics on manure properties and NH3 emission. This study was conducted to comparatively quantify production performance, manure properties, and NH3 emissions (through N mass balance) of four white-egg-laying strains (Hy-Line W-36, Hy-Line W-98, Lohmann LSL Lite, and Bovans White) and four brown-egg-laying strains (Hy-Line Brown, Lohmann Brown, ISA Brown, and Bovans Brown) during two production periods of 27-28 weeks (PI) and 35-36 weeks (P2) of age. The diets were formulated to meet the nutritional needs of the brown and white hens. As a result, crude protein contents during PI and P2 were, respectively, 13.2% and 15.2% for the brown hens but 14.5% and 17.4% for the white hens. The results showed that the brown and white hens had similar hen-day egg production (97.5% to 89.2% for brown hens and 96.0% to 88.2% for white hens) and egg mass output (57.1 to 52.6 g d-1 hen-1 for brown hens and 55.6 to 51.2 g d-1 hen-1 for white hens) but different feed consumption (112 to 98 g d-1 hen-1 for brown hens and 101 to 93 g d-1 hen-1 for white hens, p < 0.01) and feed efficiency (1.97 to 1.87 g feed g-1 egg for brown hens and 1.82 g feed g-1 egg for white hens, p < 0.0001 and p = 0.11). The higher feed consumption for the brown hens stemmed from their heavier body mass (1.81 to 1.78 kg vs. 1.56 to 1.53 kg for white hens). Manure moisture content was higher for the brown hens than for the white hens, although the dry-matter manure production was not significantly different. The results further revealed that under the experimental conditions (i.e., higher CP contents of the diet for the white hens than for the brown hens) the white hens had higher NH3 emissions than the brown hens as expressed per hen (37% to 19% higher, p = <0.001 to 0.016), per animal unit (AU, 500 kg live body mass; 59% to 39% higher, p = 0.0007 to 0.007), per unit of egg mass output (41% to 24% higher, p = 0.01 to 0.09), per unit of feed N consumed (39% to 27% higher, p = 0.01 to <0.0001), and per unit of dry manure (56% to 39% higher, p = 0.001 to 0.007). Certain differences existed in production performance among strains within the brown or white hens, but no differences in NH3 emissions were detected. Because of the relatively small sample size (number of hens involved) and the relatively short monitoring period, the results should be referenced with these limitations in mind. Further larger-scale studies with longer monitoring periods to verify these findings are warranted. [ABSTRACT FROM AUTHOR]

This study quantifies concentrations and emission rates (ER) of ammonia (NH3) and greenhouse gases (GHG) including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from a naturally ventilated cage layer (Hy-Line brown strain) house with daily manure removal, located in northeast China during four seasons of one year, with each monitoring episode lasting five consecutive days. Gaseous concentrations of background and exhaust air were measured using an infrared photoacoustic multi-gas monitor with a multi-channel sampler. Building ventilation rate (VR) was determined by CO2 mass balance using literature metabolic rate data for modern laying hens. Both gas concentrations and ER showed considerable diurnal and seasonal variations. Annual mean (±SD) ER of NH3, CO2, CH4, and N2O for the monitored layer house were, in mg d-1 bird-1, 129 ±40.3, 78,250 ±15,384, 112 ±56.5, and 9.4 ±2.5, respectively, or in g d-1 AU-1 (AU = 500 kg live body weight), 33.4 ±11.4, 19,975 ±3,071, 29.2 ±15.2, and 2.5 ±0.7, respectively. Ammonia ER from the current study was within the ranges of values reported for high-rise houses with annual manure removal and manure-belt houses with daily manure removal. Results of the study contribute to improving ammonia and GHG emissions inventory for animal feeding operations in China and worldwide. [ABSTRACT FROM AUTHOR]