Key Laboratory of Agricultural Engineering in Structure and Environment

Beijing, China

Key Laboratory of Agricultural Engineering in Structure and Environment

Beijing, China
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Wang C.,China Agricultural University | Wang C.,Tarim University | Song W.,China Agricultural University | Song W.,Key Laboratory of Agricultural Engineering in Structure and Environment | And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2017

In order to efficiently solve the shading problem between the upper layer and lower layer in the same cultivation system and between adjacent cultivation systems in multi-layer stereo-cultivation of strawberry, and to improve the fixed A-shaped frame system, a novel sun-tracking cultivation system was developed, which could keep the line of cultivation frame parallel to sunray to make the best use of direct light. In this study, some instruments, including the CANUOL intelligent remote control door opener, supporting multi-function controller, and the time control switch, were installed on the fixed A-shaped frame. So the fixed frame could rotate about its central axis according to a preset procedure, and the door opener revolved through the multi-function controller operation, thus boosting the cultivation frame motion. Time controller may set the start time of cultivation shelf running, running times, running time interval and the time length of operation as cultivation shelf homing according to the different needs of different seasons. The operating parameters of the cultivation frame were determined according to the changes of solar elevation and azimuth of the sun in winter in Beijing, based on the characteristics of the light environment of Beijing. This test set the running time of the sun-tracking frame to be 9: 00-16: 00 every day from November 2015 to March 2016, rotating once every 55 min, and turning 9 times every day. In November and next February and March, the total daily movement angle was 103.5°, each rotation angle was 11.5°, and each exercise took 4 s; the total daily movement angle was 96°, each rotation angle was 10.5°, and each exercise took 3.6 s in December and January next year. Parameters could be adjusted according to the actual situation in the process of actual production and application. In this study, the strawberry planting time was September 8th, 2015, and the harvest time was from January 13th to March 17th, 2016. Experimental design was that 5 sun-tracking frames were set as the test group, and 5 fixed frames were as a control group; then the difference between the 2 light environments was compared, and the temperature of canopy and root, the yield and the profit of strawberry were used to validate whether the sun-tracking frames could improve light environment and increase the production. Results showed that integrated photosynthetic photon flux density (PPFD) of sun-tracking system was higher than that of fixed system on both middle and lower layers. Within 3 months of winter, compared with fixed system, integrated PPFD on upper, middle and lower layer of sun-tracking system increased by 28.0%, 79.3% and 38.6% respectively in the east side and 30.1%, 41.0% and 18.2% respectively in the west side. So, the sun-tracking frame could change the light-shielding. The strawberry canopy and rhizosphere temperature of the sun-tracking cultivation were better than the fixed stereo cultivation frame, and the minimum value of the cultivated strawberry rhizosphere temperature of fixed frame at each layer was lower than the sun-tracking cultivation frame. Meeting the most suitable rhizosphere temperature of 15-20℃ for upper, middle and lower layer of west side, the time of the sun-tracking cultivation frame was 60, 40 and 120 min longer than the corresponding position of the fixed cultivation frame, respectively. Accordingly, the time of the former canopy temperature below 5℃ was 130, 170, 230 min shorter than the latter, respectively. The strawberry yield per plant on sun-tracking frame was higher than the corresponding position on fixed frame. During the trial, compared with the fixed system, the strawberry output of the sun-tracking system was increased by 214.8 kg/667 m2. Benefits were increased by 6 498.5-12 942.5 yuan. So, the sun-tracking system can improve the light and temperature environment condition, which promotes the output of strawberry and benefit. Therefore, it is valuable cultivation technology and should be widely applied. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.


Wang C.,China Agricultural University | Wang C.,Tarim University | Song W.,China Agricultural University | Song W.,Key Laboratory of Agricultural Engineering in Structure and Environment | And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2017

In the process of facility horticulture cultivation, the model of three-dimensional cultivation has been paid more and more attention. "H" type cultivation frame is widely used in stereo-cultivation of strawberry at present. In practical applications, growers choose the different layers of cultivation for planting. The most common arrangement of planting frame is two or three layers, which way can reduce the costs with higher yields and benefits, we do not know now. Therefore, an experiment aimed to select a better combination of cultivation frame was performed in this study. In this experiment, three combinations of "H" type cultivating shelves were set up, namely, two-layer frames arranged adjacently (T1), two-layer frame and three-layer frame are alternately arranged (T2), three-layer frames are arranged adjacently(T3), to compare the light conditions, growth status and yield differences. The experiment was carried out in a solar greenhouse in Changping district of Beijing from August 2015 to April 2016. The length of the greenhouse is 100 m and the span is 8 m. Strawberry varieties is "Hong Yan", planting date was August 29, 2015. Photosynthetic photon flux density (PPFD) of strawberry canopy and growth index were measured during the trial. Growth index include strawberry plant height and leaf chlorophyll relative content (SPAD), strawberry yield per plant, the number of fruits per plant, the average weight of fruit. Measured production time was three months. Results showed that under T1 treatment, the strawberries light conditions were the best of the upper and lower cultivars. During the experiment, the trend of light curves of the three cultivars in T2 and T3 were basically the same, but PPFD of the upper, middle and lower layers in T2 were higher than that in T3 corresponding position. During the experiment, the time length that light intensity at strawberry canopy reached light saturation point (LSP) of T2 upper layer was longer than that of T3 corresponding position; the time length of T2 middle layer reached the strawberry LSP was 240 min, and that of T3 middle layer was always below the LSP. In addition, the light intensity at strawberry canopy in the lower layer of T2 reached light compensation point was 230 min, and that of T3 lower layer was always below the light compensation point (LCP) all day. During the experiment, the time length that light intensity at strawberry canopy reached the LSP within two days of T1 and T2 were calculated, results showed that the time length reached LSP in T1 upper layer increased by 40% compared with that of T2. The time length of reaching at LSP in lower of T1 and T2 was 100 min and 0 min, respectively. The time length of reaching the LCP in the upper, lower layers of T1 increased by 9.3%, 21.4% compared with that of T2, respectively. Thus, the light environment of T1 was better than that of T2. Growth index of T1 strawberry was the best, yield per plant and the number of fruits per plant in T1 was higher than that of other treatments. Correlation indexes of strawberry yield were the worst in T3. During the test period, the yield per unit area of T1 was 50.8 kg, and the cost of T1 was the lowest in three treatments, yield per unit area of T1 was increased by 2.8%, 33.7% compared with that of T2 and T3, respectively. Therefore, strawberries of all two layers arrangement of "H" type cultivation frame got better lighting conditions, reduced costs and obtained better economic benefit. All two layers arrangement of "H" type cultivation frame (T1) was suitable for application in actual production. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.


Wang Y.,Key Laboratory of Agricultural Engineering in Structure and Environment | Wang Y.,China Agricultural University | Wang C.,Key Laboratory of Agricultural Engineering in Structure and Environment | Wang C.,Beijing Engineering Research Center for Animal Healthy Environment | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2017

The CO2 concentration is required to be below 1500 mg/m3 (Environmental Quality Standards for the Livestock and Poultry Farm of China, published in 1999) in layer hen houses where the manure is disposed by powered scraper, the litters generally need to remind and the drinking device has water leak. Consequently, moisture and NH3 levels in such barns are much high. Also, air temperature is much lower in winter, because the minimum ventilation rate is large in winter. However, the manure is cleaned daily in new poultry house with manure convey belt. Meanwhile, the aerial pollutants (CO2 and NH3) are reduced and the relative humidity is decreased. Indoor air quality in this kind of poultry house is dramatically improved. A new standard of CO2 concentration and the minimum ventilation rate of layer house with manure convey belt should be reconsidered. Determining the CO2 concentration standards for the manure convey belt in layer hen houses is needed. The objectives of this work were to draw a conclusion about the CO2 concentration levels and use it as a reference to calculate the minimum ventilation rate in winter. This review summarized the recent measurements of the emission rates of aerial NH3 and the CO2 concentrations in poultry houses in which the laying hens were kept in cages. The relationship between CO2 and NH3 was also described based on the data got in the poultry houses with different manure removing way from the domestic and foreign study. In addition, the minimum ventilation rate is important for ensuring the ideal air quality in poultry house in winter. The optimum ventilation is one of the factors affecting poultry production and energy consumption. Considering the mass conservation under steady-state conditions in the layer hen building, there are 2 main sources of CO2 in poultry house, and most of the CO2 is produced by respiration processes of layer hens, if neglecting the amount of CO2 emitted from manure. The minimum temperature value for layer houses was 13℃ in this study. The following conclusions were drawn in this study: 1) There was a positive and significant correlation between CO2 and NH3 concentration in layer houses based on analyzing the data of previous researches. The standards of CO2 concentration and NH3 concentration were suggested to be 5000 mg/m3 and less than 15 mg/m3 respectively in the layer hen houses with manure convey belt. This condition would not reduce the hen's performance and defenses. Primary CO2 concentration standards persisted when the feces were scraped by powered scraper to a cross conveyor at the end of the barn; 2) Average NH3 concentrations in the layer house with manure convey belt was largely less than the traditional house with the scraper. Therefore, rebuilding new layer hen's building equipped with the manure convey belt is crucial not only for indoor environment, but also for ventilation system; 3) Ventilation rate was calculated using the rate of laying hen in winter based on CO2 mass balances from the literature. The constantly minimum ventilation rates were 0.40-0.50 m3/(h·kg) for the layer houses with manure convey belt. The new standards of CO2 concentration and ventilation rate were beneficial for improving indoor environment control and ventilation energy efficiency, and saving constructional costs. Furthermore, the results of this paper provide the reference for solving the contradiction between ventilation and insulation system in layer house. Also, it can improve the versatility of poultry environment and provide the support for emission studies using the new standard of the CO2 to evaluate the poultry building environment. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.


Song W.,China Agricultural University | Song W.,Key Laboratory of Agricultural Engineering in Structure and Environment | Yao L.,China Agricultural University | Ding T.,China Agricultural University | And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2011

The low energy efficiency of solar regenerator has been a common concern in the solar evaporation-dehumidification cooling system. In order to enhance the energy utilization efficiency, a gas-gas heat exchanger was used as an additional heat-recycle unit to capture residual heat from hot air. Two types of regenerators with(GGHEW) and without(GGHEN) gas-gas heat exchanger were studied and their performances were compared. The results showed that both dehumidification capability and efficiency of regenerator were enhanced with the increase of the temperature of water heated by solar energy. The basic performance of regenerator was significantly improved by adding gas-gas heat exchanger. Dehumidification capability of GGHEW was in a range from 40 to 55 g/kg, which was 35-45 g/kg more than that of GGHEN. The regeneration efficiency of GGHEW could reach up to 60% at 90°C of hot water, which was 30%-50% higher than that of GGHEN. It was concluded that installation of gas-gas heat exchanger on the solar regenerator can improve the solar energy utilization efficiency and the regeneration efficiency, which indicates that heat recycle is necessary for solar regenerator.


Gu Z.,Chongqing Academy of Animal Science | Gao Y.,Chongqing Academy of Animal Science | Lin B.,Chongqing Academy of Animal Science | Zhong Z.,Chongqing Academy of Animal Science | And 5 more authors.
Preventive Veterinary Medicine | Year: 2011

The limited space in farrowing crate imposes many challenges, such as prolonged farrowing duration and high piglet stillbirth rate. Although the features of farrowing pens compensate for the drawbacks of farrowing crates, they are associated with high piglet crushing mortality caused by the greater space afforded to sows and their rolling-over behaviour. Therefore, a freedom farrowing pen was designed to overcome the drawbacks of both farrowing crates and farrowing pens. The main features of the freedom farrowing pen are its left anti-crushing bar and detachable right anti-crushing bar on the sides of the sow lying area. It also has a 10. cm-high anti-crushing bar in the non-lying area. Eighteen healthy, multiparous Yorkshire sows (3-7 parity) were averaged and randomly assigned to farrowing crates, farrowing pens, and freedom farrowing pens to compare the effects of the farrowing systems on sow behaviour and performance. Results showed that the farrowing duration and the mean piglet birth intervals were longer for the sows in farrowing crates than for those in farrowing pens and freedom farrowing pens (P< 0.05), but there was no difference between the sows in farrowing pens and those in freedom farrowing pens (P> 0.05). The piglet stillbirth rate was higher for the sows in farrowing crates than for those in farrowing pens and freedom farrowing pens (P< 0.001). Crushing mortality was higher among piglets in farrowing pens (P< 0.001), but there was no difference between piglets in freedom farrowing pens and those in farrowing crates (P> 0.05). The freedom farrowing pen and the farrowing pen allowed sows to turn around and move freely, but because of the different structures of their anti-crushing bars, the increase in sow movement did not cause higher piglet crushing mortality (P> 0.05). Sows in freedom farrowing pens were found to be more protective of their piglets. © 2011 Elsevier B.V.


Ding T.,China Agricultural University | Ding T.,Key Laboratory of Agricultural Engineering in Structure and Environment | Huang Z.,China Agricultural University | Huang Z.,Key Laboratory of Agricultural Engineering in Structure and Environment | And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2010

The technology of liquid desiccant and solar regeneration is the key technical problems of evaporative cooling in high temperature and humidity region, and the most important thing is the dehumidification/regeneration efficiency. The calculating relationship between the humidity content of in/out air and dehumidification efficiency was established through the experimental measurement. And the relationships of temperature of regeneration heat source to regeneration quality, diffusion coefficient and regeneration efficiency were researched. The results showed that with the regeneration temperature increasing, the regeneration quality, diffusion coefficient and regeneration efficiency were rising. When the regeneration temperature was 104°C, the regeneration quality was 10 g/kg, diffusion coefficient 0.277 cm2/s, and regeneration efficiency 55%. But when the regeneration temperature was lower 50°C, the regeneration cannot work. So the effective temperature regeneration was at least 70°C in solar energy mixed solution dehumidification system. Based on the Chung model, the calculation formula of dehumidification efficiency in the multistage cross flow dehumidifier was established for the solar energy dehumidification system, and the dehumidification efficiency was 56.8%. This research for greenhouse facilities dehumidifying technology provides a study basic.


Hassanien R.H.E.,China Agricultural University | Hassanien R.H.E.,Cairo University | Hou T.-Z.,China Agricultural University | Hou T.-Z.,Key Laboratory of Agricultural Engineering in Structure and Environment | And 2 more authors.
Journal of Integrative Agriculture | Year: 2014

Sound waves technology has been applied to different plants. It has been found that sound waves were at different frequencies, sound pressure levels (SPLs), exposure periods, and distances from the source of sound influence plant growth. Experiments have been conducted in the open field and under greenhouse growing conditions with different levels of audible sound frequencies and sound pressure levels. Sound waves at 1 kHz and 100 dB for 1 h within a distance of 0.20 m could significantly promote the division and cell wall fluidity of callus cells and also significantly enhance the activity of protective enzymes and endogenous hormones. Sound waves stimulation could increase the plant plasma-membrane H+-ATPase activity, the contents of soluble sugar, soluble protein, and amylase activity of callus. Moreover, sound waves could increase the content of RNA and the level of transcription. Stress-induced genes could switch on under sound stimulation. Sound waves at 0.1-1 kHz and SPL of (70±5) dB for 3 h from plant acoustic frequency technology (PAFT) generator within a distance ranged from 30 to 60 m every other day significantly increased the yield of sweet pepper, cucumber and tomato by 30.05, 37.1 and 13.2%, respectively. Furthermore, the yield of lettuce, spinach, cotton, rice, and wheat were increased by 19.6, 22.7, 11.4, 5.7, and 17.0%, respectively. Sound waves may also strengthen plant immune systems. It has been proved that spider mite, aphids, gray mold, late blight and virus disease of tomatoes in the greenhouses decreased by 6.0, 8.0, 9.0, 11.0, and 8.0%, respectively, and the sheath blight of rice was reduced by 50%. This paper provides an overview of literature for the effects of sound waves on various growth parameters of plant at different growth stages. © 2014 Chinese Academy of Agricultural Sciences.


He H.,China Agricultural University | Zheng L.,China Agricultural University | Li Y.,China Agricultural University | Song W.,China Agricultural University | Song W.,Key Laboratory of Agricultural Engineering in Structure and Environment
Ozone: Science and Engineering | Year: 2015

This research combined micro/nano bubble techniques with ozone disinfection to determine feasibility of applying micro/nano bubble ozonated water in preventing tomato airborne disease. Results indicated that dissolving ozone in micro/nano bubbles is more efficient than using a mixing pump. In our in vitro studies, when dissolved ozone concentration was 1.6 mg/L, a 5.2 to 3.3 log reduction in Alternaria solani Sorauer conidia was observed; with concentration of 1.8 mg/L, there was a 5.0 to 3.7 log reduction in Cladosporium fulvum conidia. Furthermore, spraying ozonated water in a certain concentration range (0.6–1.8 mg/L) had no significant negative effects on tomato growth. © 2015 International Ozone Association.


Zheng W.,China Agricultural University | Zheng W.,Key Laboratory of Agricultural Engineering in Structure and Environment | Kang R.,Sichuan University | Wang H.,Sichuan University | And 4 more authors.
Journal of the Air and Waste Management Association | Year: 2013

Spraying slightly acidic electrolyzed water (SAEW) has been considered as a potential approach to reduce airborne bacteria in laying-hen houses. In this study, the effects of spraying SAEW on airborne bacterial reduction were investigated in a laying-hen house as compared with using diluted didecyl dimethyl ammonium bromide (DDAB). Averaged air temperature reduced by approximate 1 °C and average relative humidity increased by 3% at a stable ventilation rate (about 2.5 m3 hr-1 per bird) in the laying-hen house 30 min after spraying (120 mL m-2). Compared with the control without spraying, the airborne bacterial concentration was reduced by about 0.70 and 0.37 log10 colony-forming units (CFU) m-3 in the 4 hr after spraying 120 mL m-2 SAEW (available chlorine concentration [ACC] of 156 mg L-1) and diluted DDAB (active compound concentration of 167 mg L-1), respectively. Compared with spraying diluted DDAB, spraying SAEW was determined to be more effective for reducing airborne bacterial in laying-hen houses. The effects of spraying SAEW and diluted DDAB on airborne bacterial reduction in the laying-hen house increased with the increasing available chlorine concentrations for SAEW (156, 206, 262 mg L-1) and increasing active compound concentrations for diluted DDAB (167, 333, 500 mg L-1), respectively. Spraying SAEW and diluted DDAB with two levels of spraying volumes (120 and 90 mL m-2) both showed significant differences on airborne bacterial reduction in the laying-hen house (P < 0.05). It is difficult to effectively reduce airborne bacteria in laying-hen houses. This work describes the application of spraying slightly acidic electrolyzed water as a new approach for reducing airborne bacteria in a laying-hen house. The effects of active compound concentrations and spray volumes on the airborne bacterial reductions by spraying SAEW were also investigated. This study provided a new effective and environmentally friendly approach to reduce the airborne bacteria in poultry houses, contributing to bird housing environment management and improving bird health. © 2013 Copyright 2013 A&WMA.


PubMed | Key Laboratory of Agricultural Engineering in Structure and Environment
Type: Journal Article | Journal: Preventive veterinary medicine | Year: 2010

Modern commercial swine farrowing crates are typically equipped with slatted iron floor to improve management efficiency (e.g., ease of manure handling, cleanliness of the farrowing crates and hence improved animal hygiene). However, the bare and hard floor surface can impair the welfare of the sow-litter because of some undesirable impacts on the pigs, such as foreleg abrasion, large temperature gradients between the cold floor surface and the abdomen of the piglets (hence higher susceptibility to diarrhea), and higher pre-weaning mortality or morbidity. Although straw bedding has been shown to be conducive to providing better environment for the sow-litter, use of straw creates challenges in terms of economics, hygiene and manure handling. This study investigates the use of neoprene mat (NM) in key areas of the farrowing crates - underneath the sow and in the piglet suckling area to improve the microenvironment and hence welfare of the sow-litter. Two experiments were conducted, each involving 12 sow-litters. The first experiment was to evaluate the thickness of a rectangular-shaped NM (7, 10 or 13 mm) vs. the slatted iron floor (control or Ctrl) and collect the corresponding animal response data; while the second follow-up experiment was to verify the benefits of supplying an improved, double concave (or H)-shaped NM with 10mm thick (CNM10) vs. Ctrl for the farrowing operation. Results of both experiments demonstrated considerable benefits of the NM placement in the farrowing crates. Specifically, the NM reduced the piglet foreleg lesion area and joint swellings (0% for NM vs. 8-10% for Ctrl during suckling periods in both Expts 1 and 2, P<0.001); reduced pre-weaning piglet crushing mortality (18.5+/-5.0%, 6.7+/-3.3% and 9.1+/-5.2% and for Ctrl, NM7 and NM10 and in Expt 1, P<0.05); and reduced piglet diarrhea morbidity (0.6+/-0.2% for CNM10 vs. 2.7+/-0.3% for Ctrl in Expt 2, P<0.01). Piglets in the NM litters had smaller temperature gradients between the abdomen and the contact floor surface (3.8+/-2.3 degrees C for NM vs. 7.6+/-0.5 degrees C for Ctrl in Expt 1, P<0.001; 9.2+/-0.5 degrees C for CNM10 vs. 15.9+/-0.5 degrees C for Ctrl in Expt 2, P<0.001). Moreover, sows in the NM regimens showed longer transition time when changing from standing to lying position (7.4+/-0.3s for CNM10 vs. 4.5+/-0.2s for Ctrl in Expt 2, P<0.05), indicative of more floor comfort for the NM condition. Results of this study suggest that supply of NM underneath the sow and in the piglet suckling area is conducive to enhancing comfort, health and welfare of the sow and litter.

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