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The emission factor method (Tier 1) recommended by the Intergovernmental Panel on Climate Change (IPCC) is commonly used to estimate greenhouse gas (GHG) emissions from livestock and poultry farms. However, the estimation accuracy may vary due to practical differences in manure management across China. The objectives of this study were to estimate the direct and indirect nitrous oxide (N2O) emissions from dairy manure management between 1990 and 2021 in China and characterize its spatial and temporal variations following IPCC guideline Tier 2. The N2O emission factor (EF) of dairy cow manure management systems was determined at the national level and regional level as well. The results showed that the national cumulative N2O emission of manure management from 1990 to 2021 was 113.1million tons of CO2 equivalent, ranging from 90.3 to 135.9 million tons with an uncertainty of ±20.2%. The annual EF was 0.021 kg N2O-N (kg N)−1 for total emissions, while it was 0.014 kg N2O-N (kg N)−1 for direct emissions. The proportions of N2O emissions in North China, Northeast China, East China, Central and Southern China, Southwest China and Northwest China were 32.3%, 18.6%, 11.4%, 5.8%, 6.1% and 25.8%, respectively. In addition, N2O emissions varied among farms in different scales. The respective proportions of total N2O emissions from small-scale and large-scale farms were 64.8% and 35.2% in the past three decades. With the improvement in farm management and milk production efficiency, the N2O emissions per unit mass of milk decreased from 0.77 × 10−3 kg to 0.48 × 10−3 kg in 1990–2021. This study may provide important insights into compiling a GHG emission inventory and developing GHG emission reduction strategies for the dairy farming system in China. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) concentrations in summer were continuously monitored from three typical laying hen houses of CC (conventional cage), AV (aviary), and NM (natural mating colony cage) with manure belt systems in North China Plain to quantify their emission levels, to characterize the diurnal variations, and to investigate the impact of environmental factors. Diurnal profiles were acquired by hourly measurements, and the effect of environmental factors on NH3 emissions was presented by correlation analysis. The results showed that house-level NH3 emissions in summer were the highest in the NM at 27.16 ± 13.12 mg/h·hen, followed by the AV at 4.08 ± 3.23 mg/h·hen and the CC at 3.43 ± 1.46 mg/h·hen within a complete manure removal cycle, which were significantly affected by manure accumulation inside the houses. After manure removal, NH3 concentrations were reduced by 64.29%, 28.57%, and 35.71% in CC, AV, and NM, and consequently their emissions were lowered by 67.12%, 71.36%, and 55.69%, respectively. It was suggested that the manure should not be stored on the belt for more than 4 days in NM. A positive impact of indoor and outdoor temperature and ventilation rate on NH3 emissions from AV and NM were found, while indoor and outdoor relative humidity had a negative effect. However, the above five factors did not significantly affect the emissions from CC. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) from poultry production facilities may strongly affect the health of animals and workers in the houses, and PM emitted to the ambient air is an important pollution source to the surrounding areas. Aviary system is considered as a welfare friendly production system for laying hens. However, its air quality is typically worse as compared with conventional cage systems, because of the higher PM concentration of indoor air and other airborne contaminants. Furthermore, PM's physical property, which has a direct impact on the penetration depth into the lungs of the birds and humans, is largely unknown for the aviary system. Therefore, a systematic method was utilized to investigate the characteristics of particles in the aviary house with large cage aviary unit system (LCAU) in Beijing, China. For the field measurements, three measuring locations were selected with two inside and one outside the house with LCAU to continuously monitor PM concentrations and collect the samples for particle size distribution (PSD) analysis. Results showed that PM2.5, PM10, and total suspended particulate (TSP) concentrations averaged at 0.037 ± 0.025 mg/m3, 0.42 ± 0.10 mg/m3, and 1.92 ± 1.91 mg/m3, respectively. Particle concentrations increased from October to December due to less ventilation as the weather got colder, and were generally affected by stocking density, ventilation rate, birds' activities, and housing system. Meanwhile, indoor PM2.5 concentration was easily impacted by the ambient air quality. Mass median diameter (MMD) and mass geometric standard deviation (MGSD) of the TSP during the measurement were 18.92 ± 7.08 μm and 3.11 ± 0.31, respectively. Count median diameter (CMD) and count geometric standard deviation (CGSD) were 1.94 ± 0.14 μm and 1.48 ± 0.08, respectively. Results indicated that the aviary system can attain a good indoor condition by suitable system design and environment control strategy. Implications: Indoor PM2.5 concentration of the layer house can be significantly affected by ambient air quality when the air quality index (AQI) was larger than 100. PM2.5 and PM10 concentrations of the layer house with a LCAU system were comparable to the cage system. TSP concentration was higher, and PM size was larger than most of the cage system. System design, larger space volume, and higher ventilation rate were the main influence factors. Good indoor environment of the aviary system can be achieved through the reasonable design of the production system and appropriate environment control strategy. [ABSTRACT FROM AUTHOR]

Evaporative pad cooling systems are efficient in decreasing the inside air temperature of animal houses located in those regions characterised by hot and dry summers, but their suitability for hot and humid climates is not yet clear. The climate in China varies greatly from the North to the South, thus, an evaluation of the suitability of the evaporative pad cooling system to different climatic regions could be helpful for the environmental design of animal houses throughout China. In this paper, the suitability of an evaporative pad cooling system in poultry houses to the summer climate was evaluated using a fuzzy mathematical method to analyse 20-year''s weather data from nine representative cities with various climates in China. The results of the evaluation showed that the average air temperature inside poultry houses could be lowered below 28°C by using the evaporative pad cooling system for over 65% of the days in one hot season for Beijing, Xi''an and Jinan, while the temperature of about 70% days could be controlled to below 30°C for the remaining cities. This indicates that evaporative cooling pads can meet the cooling requirements of poultry houses in the regions selected and this provides a scientific basis for the extension and application of evaporative pad cooling systems in China. [Copyright &y& Elsevier]

Open lots are commonly used to provide outdoor free ranging spaces for dairy cows in many countries such as China and the USA. For this type of operation, the manure characteristics, floor types and environmental conditions, which potentially affect gaseous emissions from manure, are quite different from those of indoor systems. The estimation of NH 3 emissions from manure depends greatly on the mass transfer coefficient, an empirical constant determined by environmental factors in the process-based emission model. Using a scale model, this study measured ammonia emissions to be expected from dairy open lots, based on different combinations of different surface air velocities (0.6–2.2 m s−1), air temperatures (15–35 °C) and relative humidity values (20–60%). Based on the two-film theory, the overall mass transfer coefficient (K OL) of NH 3 was calculated from directly measured NH 3 emission rates and the ammonium nitrogen content, temperature, and pH of manure. As an indicator of the driving potential of gaseous volatilisation, the vapour pressure deficit (VPD) was estimated using air temperature and relative humidity. As the VPD and surface air velocity increased, the measured NH 3 emission rates ranged from 1.35 to 19.18 mg kg−1 h−1, and the estimated K OL of NH 3 from dairy open lots was within the range of 1.48 × 10−6 – 7.86 × 10−6 m s−1. Using the air velocity and VPD as variables, a non-linear empirical model was developed to estimate the K OL for NH 3 emissions from manure on dairy open lots (R 2 = 0.69). The normalised mean error of the model was approximately 19.4%. • Overall mass transfer coefficient (K OL) was estimated based on two-film theory. • K OL of NH 3 emission was in the range of 1.48–7.86 10−6 m s−1 from dairy open lots. • Air vapour pressure deficit (VPD) was positively related to NH 3 emission and K OL. • A nonlinear model was obtained to estimate K OL using air velocity and VPD. [ABSTRACT FROM AUTHOR]

Inhaling particulate matter (PM) poses a potential risk on the health of workers and chickens for long-term exposure to highly contaminated air in buildings, while the exceedance of PM concentration limit is still unclear for lack of direct measurement data covering the annual production cycle of laying hen farms. This research investigated the indoor PM characteristics in three typical laying hen building systems of natural mating colony cage (NM), conventional cage (CC), and aviary (AV) in China based on a year-round field measurement of PM concentrations using the Internet of Things. Results suggested that the average PM 2.5 and total suspended particulate (TSP) concentrations in NM were 0.042 ± 0.016 and 0.345 ± 0.143 mg m−3, respectively. The corresponding results were 0.048 ± 0.021 and 0.305 ± 0.171 mg m−3 in CC, 0.025 ± 0.012 and 0.786 ± 0.875 mg m−3 in AV, respectively. During the working period, PM 2.5 concentrations in 3% and 6.5% of the monitored days exceeded the threshold of 0.075 mg m−3 in NM and CC, meanwhile about 11% of the daily mean TSP concentrations in AV were higher than the recommended limit of 2.4 mg m−3. Generally, the average PM concentrations in three building systems with appropriate system designs and management were maintained at relatively low levels, which were beneficial to the health and production performance of laying hens. Occasional exceedance of PM concentration thresholds may chronically impair the respiratory health of the workers, and preventive measures should be therefore taken while working in laying hen houses. • An IoT system was developed to long-term monitor PM concentration in poultry houses. • The PM 2.5 and TSP concentrations of laying hen building systems in China were low. • Occasional exceedances of PM concentration limit were found during working period. • The PM exposure risk on the respiratory health existed but lower than other systems. [ABSTRACT FROM AUTHOR]

The hot and humid summer climates in certain parts of China can adversely impact on the production and welfare of gestating sows. Hence, effective cooling means to alleviate heat stress are essential to pig production. A field experiment was conducted to evaluate the efficacy of a water-cooled cover (WCC) attached to the sow’s stall with regards to thermal microenvironment in the sow occupied zone (SOZ), and the physiological and behavioural responses of the sows. The results showed that black-globe temperature (BGT) in SOZ under WCC with or without the presence of the sow averaged 4.8 or 5.4 °C below that of the control (without WCC) when the indoor air temperature was 34.3 °C. The temperature reduction in SOZ was proportional to the temperature difference between the inlet and outlet water of WCC. Increasing water flow rate through WCC enhanced cooling efficiency up to 4 l min−1 beyond which little additional benefit could be gained from further increase in water flow rate. Respiratory rate and surface temperature of the sows with access to WCC were significantly lower than those for control group (P < 0.001). The WCC sows spent 74% of their time lying under WCC, while the control sows spent 94% of the time lying in the pen. The sow’s thermoregulatory responses and behaviours were observed to lag 1–3 h behind the peak air temperature. Results of the present work suggest that WCC can alleviate heat stress of gestating sows in hot and humid climates. [ABSTRACT FROM AUTHOR]

This study developed a comprehensive nitrogen (N) flow model utilizing localized data in 2000-2019. Enhancements were conducted upon previous models: (1) variations in feed N intake of cows across different production phases was considered; (2) N emission in the Intergovernmental Panel on Climate Change (IPCC) and the European Monitoring and Evaluation Program and the European Environment Agency (EMEP/EEA) was incorporated; (3) emission factor (EF) of NH 3 was corrected based on local climate; and (4) field application of manure was excluded from the system boundary to accommodate China's production status. The effects of farm scale (LF, ≥100 heads; SF, <100 heads) and manure management strategies (dry-cleaning and slurry) were considered. Twelve indicators regarding nitrogen use efficiency (NUE), N emission and N losses were identified to assess the spatiotemporal dynamics of N flow. Sensitivity analysis was performed on NUE and N emission. The efficacy of N management practices was evaluated through simulating 2050 scenarios, which included business as usual (BAU), improved cow productivity (DPI), and manure management building on DPI (FMI). It demonstrated an increase in NUE, with northern and eastern China being the highest. The North and Northwest of China emerged as the primary source of N emission (>56 %). Sensitivity analysis indicated that NUE was mostly influenced by LF milk protein content, followed by milk production, body weight of dairy cow, and herd structure. Different forms of N emission were substantially decided by manure EFs and indoor excretion ratio. The scenario simulation suggested that the use of productive breed, low-protein feed, and N abatement procedures could enhance NUE by >30 % and reduce annual emission of NH 3 and N 2 O to 38 % and 13 % of BAU. The study may provide valuable insights into the policy development of dairy industry in China, aiming at boosting productivity improvement and minimizing N loss., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Globally, massive resource inputs and undesired outputs hindered the further development of the dairy industry. This study proposed a method applying data envelopment analysis to the water-energy-labor-food nexus to assess the eco-efficiency of the milk production system (MEE) from a systemic perspective. Using national statistics on scale farms for the period 2014-2021, we illustrated the effects of scale and intensification on MEE in China. In the study period, the production cost increased by 23 % and milk production rose by 30 % at the same time. Despite the increases in both water and energy inputs, the rise in milk production weakened the resource burdens and thus lifted MEE by 24 %. The resource investment pattern shifted from water- and labor-oriented to energy-oriented. Under current conditions, production technology and system management were at higher superiority to advance than farm scale, while mechanization and on-farm clean energy production are the keys to further lifting MEE., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Environmental impact evaluation of buildings is critical for further analysis and optimization of pig farms for sustainable pork production. This study is the first attempt to quantify the carbon and water footprints of a standard intensive pig farm building using building information modeling (BIM) and operation simulation model. The model was constructed with carbon emission and water consumption coefficients, and a database was built. The results showed that the operational stage of pig farm accounted for most of the carbon footprint (49.3-84.9 %) and water footprint (65.5-92.5 %). Building materials production ranked second in carbon (12.0-42.5 %) and water footprints (4.4-24.9 %), and pig farm maintenance ranked third in carbon (1.7-5.7 %) and water footprints (0.7-3.6 %). Notably, the mining and production stages of building materials contributed the largest carbon and water footprints of pig farm construction. Masonry materials have a significant impact on the overall carbon and water footprints of the pig farm. Pig farm using aerated concrete could reduce 41.1 % of the total carbon footprint and 58.9 % of the total water footprint compared to that using coal gangue sintered brick and autoclaved fly ash brick. This study presented a BIM-enabled method for carbon and water footprint analysis of pig farms and illustrated how the model can be used to facilitate the low carbon design of agricultural buildings., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Unlabelled: The open lots and manure stockpiles of dairy farm are major sources of greenhouse gas (GHG) emissions in typical dairy cow housing and manure management system in China. GHG (CO(2), CH(4) and N(2)O) emissions from the ground level of brick-paved open lots and uncovered manure stockpiles were estimated according to the field measurements of a typical dairy farm in Beijing by closed chambers in four consecutive seasons. Location variation and manure removal strategy impacts were assessed on GHG emissions from the open lots. Estimated CO(2), CH(4) and N(2)O emissions from the ground level of the open lots were 137.5±64.7 kg hd(-1) yr(-1), 0.45±0.21 kg hd(-1) yr(-1) and 0.13±0.08 kg hd(-1) yr(-1), respectively. There were remarkable location variations of GHG emissions from different zones (cubicle zone vs. aisle zone) of the open lot. However, the emissions from the whole open lot were less affected by the locations. After manure removal, lower CH(4) but higher N(2)O emitted from the open lot. Estimated CO(2), CH(4) and N(2)O emissions from stockpile with a stacking height of 55±12 cm were 858.9±375.8 kg hd(-1) yr(-1), 8.5±5.4 kg hd(-1) yr(-1) and 2.3±1.1 kg hd(-1) yr(-1), respectively. In situ storage duration, which estimated by manure volatile solid contents (VS), would affect GHG emissions from stockpiles. Much higher N(2)O was emitted from stockpiles in summer due to longer manure storage., Implications: This study deals with greenhouse gas (GHG) emissions from open lots and stockpiles. It's an increasing area of concern in some livestock producing countries. The Intergovernmental Panel on Climate Change (IPCC) methodology is commonly used for estimation of national GHG emission inventories. There is a shortage of on-farm information to evaluate the accuracy of these equations and default emission factors. This work provides valuable information for improving accounting practices within China or for similar manure management practice in other countries.