Mitigating Greenhouse Gas Emissions from Winter Production of Agricultural Greenhouses

Consuming conventional fossil fuel, such as coal, natural gas, and oil, to heat agricultural greenhouses has contributed to the climate change and air pollutions regionally and globally, so the clean energy sources have been increasingly applied to replace fossil energies in heating agricultural greenhouses, especially in urban area. To assess the environment performance (e.g., greenhouse gas (GHG) emissions) of the ground source heat pump system (GSHPs) for heating agricultural greenhouses in urban area, a GSHPs using the shallow geothermal energy (SGE) in groundwater was applied to heat a Chinese solar greenhouse (G1) and a multispan greenhouse (G2) in Beijing (latitude 39°40′ N), the capital city of China. Emission rates of the GSHPs for heating the G1 and G2 were quantified to be 0.257–0.879 g CO2 eq. m−2 day−1. The total GHG emissions from heating greenhouses in Beijing with the GSHPs were quantified as 1.7–2.9 Gt CO2 eq. year−1 based on the electricity from the coal-fired power plant (CFPP) and the gas-fired power plant (GFPP). Among different stages of the SGE flow, the SGE promotion contributed most GHG emissions (66%) in total due to the higher consumption of electricity in compressors. The total GHG emissions from greenhouses heating with the coal-fired heating system (CFHs) and gas-fired heating system (GFHs) were quantified as 2.3–5.2 Gt CO2 eq. year−1 in Beijing. Heating the G1 and G2 with the GSHPs powered by the electricity from the CFPP, the equivalent CO2 emissions were 43% and 44% lower than directly burning coal with the CFHs but were 46% and 44% higher than the GFHs that burn natural gas. However, when using the GFPP-generated electricity to run the GSHPs, the equivalent CO2 emissions would be 84% and 47% lower than the CFHs and the GFHs, respectively

Computer Vision-Based Animal Preference Assessment – Do Laying Hen Chicks Prefer Light with UVA Radiation?

Poultry have a fourth retinal cone that allows them to see in the ultraviolet A (UVA) wavelength (315-400 nm) and may use UVA perception to modify various behavioral functions such as feeding, peer recognition, mate selection, and social encounters. As UVA perception is an essential part of poultry vision, it may be of socio-economic significance to provide certain amount of UVA light in poultry production facilities, particularly in most of modern facilities where artificial lighting is the only light source for the birds. However, there is limited scientific information regarding how to provide the UVA supplementation to birds as well as the behavioral responses of birds to UVA radiation. The objective of this study was to assess preference of W-36 chicks (day-old) for light-emitting diode (LED) light supplemented with or without various levels of UVA radiation (0%, 5%, 10%, and 15%), i.e., LED vs. LED+UVA. A total of 108 chicks (day-old) in 18 groups over nine successive batches were assessed for their choice via preference test. For each group (six chicks), each bird was individually identified with one of the six colored marks (yellow, green, blue, purple, pink, and orange) on the head. Each group of chicks involved an 8-day preference test, during which the birds could move freely between two inter-connected compartments that contained LED and LED+UVA, respectively. A real-time monitoring system was employed to record behaviors of chicks at a capture rate of 5 frames per second. Trajectory of each bird was tracked using automated computer vision based on color detection algorithms. Time spent and feed intake by the birds under each light condition were measured daily and analyzed with generalized linear mixed models. The following results were found. In the scenario of 0% vs. 5% UVA, the chicks spent significantly lower amount of time under LED+UVA than under LED (45.6% vs. 54.4%), but had comparable feed use under both light conditions. In the scenario of 0% vs. 10% UVA, the chicks showed similar amount of time spent and feed use. In the scenario of 0% vs. 15% UVA, the chicks spent significantly higher proportion of time (61.3% vs. 38.7%) and consumed significantly more feed (60.5% vs. 39.5%) under LED+UVA than under LED. The study demonstrates the attracting effect of UVA light at 15% inclusion rate under LED illumination on chicks in terms of time spent and feed use. A large-scale and long-term study to further verify the positive effects of UVA inclusion seems warranted

Mitigating Ammonia Emissions from Liquid-Sprayed Litter of Cage-Free Hen House with a Solid Litter Additive

A number of restaurant chains, retailers, and grocers in the US have pledged to source cage-free (CF) eggs only in the foreseeable future (e.g., by 2025 or 2030) due to marketing reasons or concerns over animal welfare. However, CF housing has some inherent challenges and a predominant one is poor air quality (ammonia gas – NH3 and particulate matter – PM) and increased emissions. The high NH3 levels primarily arise from the extended accumulation of manure on the litter floor, whereas the high PM levels are generated from dustbathing and foraging activities of the birds on the litter. Spraying liquid agent such as electrolyzed water (EW) has been shown to effectively suppress PM from litter of CF hen houses. However, liquid spray could enhance NH3 emissions as it increases the litter moisture content (LMC). Application of low pH liquid to the litter would help control NH3 while suppressing PM, but concerns arise about the potential corrosive effect of acidic liquid on the housing equipment. To overcome this dilemma, this study evaluated the effect of applying a commercial poultry litter additive (LA, PLT®) on NH3 emissions of CF hen litter sprayed with neutral EW (NEW) at dosage of 25 mL (kg dry litter)-1 d-1. The PLT application rates were 0.3, 0.6, and 0.9 kg m-2, denoted as Low-LA, Med-LA, and High-LA, respectively. The litter samples were placed inside dynamic emission chambers (DECs) and stirred to mimic hen scratching. PLT was topically applied onto the litter on day 1; NEW was sprayed daily for 11d, followed by a 3-d non-spray period (i.e., 14 d per trial); and each regiment was replicated four times. Ammonia emission rate (ER) of the control-no LA, Low-LA, Med-LA, and High-LA regimens (mean±SE) was 0.76±0.05, 0.55±0.06, 0.37±0.04, and 0.16 ±0.02 g (kg dry litter)-1d-1, respectively, namely 28-79% reduction by the treatments. The NH3 reduction efficiency is linearly proportional to the PLT® application rate, with higher application rate resulting in significantly lower litter pH (P\u3c0.05). On the last day of each trial (d14), the Med-LA and High-LA regimens continued to show relatively low NH3 emissions, suggesting the need for a longer measurement period in the field verification that will follow. The NEW spray increased LMC by up to 60% after 11 once-a-day sprays, which reduced PM2.5, PM10, and TSP levels from 3.83, 6.39, and 7 mg m-3 to 0.07, 0.14, and 0.15 mg m-3, respectively. After a 3-day spray suspension, the PM levels rebounded to 0.72, 1.02, and 1.12 mg m-3 for PM2.5, PM10, and TSP due to decreased litter moisture. The trade-off between NH3 emission reduction and the cost associated with the litter additive application needs to be assessed under commercial CF production conditions

Behavioral and Production Responses of W-36 Chicks to Supplementary UVA Light

UVA (315-400 nm) light perception is an essential part of poultry vision, which may be used to modify behavioral traits of birds such as feeding, peer recognition, and social encounters. The objectives of this study were to assess behavioral and production responses of W-36 chicks reared under LED light with or without various levels of UVA supplementation (0%, 5%, 10%, and 15%), i.e., LED+UVA vs. LED. For behavioral response, a total of 108 chicks (day-old) in 18 groups were assessed for their lighting preference. Each group of chicks was involved an 8-d preference test, during which the birds could move freely between two inter-connected compartments that contained LED and LED+UVA, respectively. For production response, a total of 180 chicks (day-old) in 12 groups were used to assess the effects of the UVA supplementation (5%) on growth performance of chicks. For each batch, two groups were randomly assigned to two compartments, one with LED and the other with LED+UVA. In the scenario of 0% vs. 5% UVA, the chicks spent significantly lower amount of time under LED+UVA than under LED (45.6% vs. 54.4%), but had comparable feed use under both light conditions. In the scenario of 0% vs. 10% UVA, the chicks showed similar amount of time spent and feed use. In the scenario of 0% vs. 15% UVA, the chicks spent significantly higher proportion of time (61.3% vs. 38.7%) and consumed significantly more feed (60.5% vs. 39.5%) under LED+UVA than under LED. Chicks had comparable growing performance under LED and LED+UVA (5%) and no eye pathology was detected at 5% UVA supplementation level. The study demonstrates the attracting effect of UVA light at 15% inclusion rate under LED illumination on chicks in terms of time spent and feed use. A large-scale and long-term study to further verify the positive effects of UVA inclusion seems warranted

Surface Permittivity Estimation of Southern Utopia Planitia by High-Frequency RoPeR in Tianwen-1 Mars Exploration

China’s Tianwen-1 successfully landed in the southern Utopian Planitia of the Martian surface on 15 May 2021. The Zhurong Rover, equipped with a high-frequency full polarimetric Rover Penetrating Radar (RoPeR), traveled 1921 m to investigate the shallow geological structure and material composition of the Martian weathered layer. In this study, we propose a new processing strategy to estimate surface relative permittivity using the HH and VV reflections of the high-frequency RoPeR data. This new strategy is based on the induced field rotation (IFR) effect, which occurs when orthogonally polarized electromagnetic (EM) waves propagate into an uneven surface with incident angles. Three-dimensional time-domain finite-difference simulations were performed using random surfaces with various relative permittivities under the same geometry as the Zhurong Rover. Polarimetric alpha angle versus relative permittivity was then calculated based on the simulation results. At the same time, direct coupling (DC) removal, bandpass filtering, and channel calibration were performed on the real RoPeR data, and clear surface reflections were extracted. The surface reflection amplitudes of the HH and VV were then obtained and the polarimetric alpha angle was calculated. Finally, relative permittivity was estimated through the relationship obtained from the simulation results. The average value of the relative permittivity estimated by the proposed approach is 3.292, with a standard deviation of 0.235. This result is consistent with that obtained by orbiting radar systems and the low-frequency RoPeR system. This study will contribute to the further signal processing and accurate interpretation of real radar data captured by way of RoPeR on Mars

A RFID-Based Monitoring System for Characterization of Perching Behaviors of Individual Poultry

Perching is a natural behavior of poultry. However, it is difficult to distinguish individual birds in a large group in order to relate perching behavior to health condition or productivity. To enable such research, this study developed and validated a radio frequency identification (RFID)-based automated perching monitoring system (APMS) for characterizing individual perching behaviors of group-housed poultry. The APMS consisted of a RFID module, a load cell module, and a round wooden perch. The RFID module was comprised of a high-frequency RFID reader, three customized rectangular antennas, and multiple RFID transponders. The load cell module was comprised of a data acquisition system and two load cells supporting the two ends of the perch. Daily number of perch visits (PV) and perching duration (PD) of individual birds were used to delineate perching behavior. Three identical experimental pens, five hens per pen, were equipped with the monitoring system. Two RFID transponders were attached to each hen (one per leg) and a distinct color was marked on the bird‘s head for video or visual identification. Performance of the APMS was validated by comparing the system outputs with manual observation/labeling over an entire day. Sensitivity and specificity of the system were shown to improve from 97.77% and 99.88%, respectively, when using only the RFID module, to 99.83% and 99.93%, respectively, when incorporating weight information from the load cell module. This study revealed that the APMS has an excellent performance in measuring perching behaviors of individual birds in a group. The APMS offers great potentials for delineating differences in perching behavior among hens with different social status or health conditions in a group setting