Greenhouse Humidity Research Articles

Combined Effects of Ventilation and Irrigation on Temperature, Humidity, Tomato Yield, and Quality in the Greenhouse

Ventilation and soil moisture influence greenhouse cultivation. Experiments were conducted at Xinxiang Irrigation Research Base of the Chinese Academy of Agricultural Sciences, Henan Province, China, to identify how ventilation and irrigation affected the greenhouse microenvironment. To develop ventilation and irrigation protocols that increase crop yield and improve the quality of drip-irrigated tomatoes grown in the greenhouse, three ventilation modes (T1, T2, and T3) were developed by opening vents in different locations in a completely randomized pattern. T1 had open vents on the north wall and roof of the greenhouse. T2 had open vents on the north and south walls and the roof. T3 had open vents on the north and south walls. Three irrigation treatments (W1, W2, and W3) were designed based on the accumulated water surface evaporation (Ep) of a standard 20-cm evaporation pan. The irrigation quantities were 0.9×Ep (W1), 0.7×Ep (W2), and 0.5×Ep (W3). The spatial and temporal distributions of temperature and humidity were analyzed for different combinations of ventilation and irrigation to identify their effects on tomato yield and fruit quality. Major results were as follows: 1) In addition to solar radiation, ventilation had an important influence on Ep and, on a daily scale, ventilation had a significant effect on Ep (P < 0.05). 2) Ventilation had a significant effect on indoor wind speed, but the effect varied during different growth stages. During the flowering and fruit setting stage, wind speed for T2 significantly differed from those of T1 and T3 (P < 0.01). During the harvest stage, the three ventilation treatments had significantly different effects (P < 0.01). A correlation analysis showed high correlation between T2 wind speed and T3 wind speed (R = 0.831), but low correlation between T2 wind speed and T1 wind speed (R = 0.467). 3) The effect of ventilation on greenhouse humidity and temperature was greater than the effect of irrigation. The differences in air temperature among various combined treatments of ventilation and irrigation were significant for the flowering and fruiting stages (P < 0.05), but they were not significant for the late harvest stage (P > 0.05). There were significant differences in humidity on sunny days (P < 0.01), but no significant differences on cloudy or rainy days (P > 0.05). Air temperature at 2 m was greater than canopy temperature, but humidity at 2 m was less than that at canopy level. 4) Irrigation water quantity was positively correlated with tomato yield and negatively correlated with the fruit quality indicators total soluble solids, vitamin C content, organic acid content, and soluble sugars content. Ventilation had an effect primarily during the harvest period; it had no significant effect on yield (P > 0.05). However, it had a significant effect on vitamin C content and the sugar:acid ratio (P < 0.01). The combination treatment of T2W2 is recommended as the optimal treatment for greenhouse tomatoes using drip irrigation to produce an optimal combination of crop yield and fruit quality. This study provides theoretical and technical support for the improvement of greenhouse climate control by optimizing greenhouse ventilation and irrigation techniques to promote tomato yield and improve fruit quality.

Smart Farming for Lowland Strawberry (Fragaria x ananassa) Production

The developed system monitors the humidity levels, moisture content of the soil and surrounding temperature. Parameter values such as maximum and minimum temperature, maximum and minimum humidity values can be monitored accordingly by sending an sms to the system using arduino microcontroller, gsm module, moisture sensor and dht11 temperature/humidity sensor. This design maybe used for monitoring and controlling temperature and humidity value via sms. This system monitors and control the water content of the soil using a moisture sensor which runs under the control of a microcontroller, a dht 11 sensor to control and monitor the greenhouse humidity and proper temperature and a short messaging system (sms) to notify the caretaker/ owner on the moisture level content and temperature/humidity of the greenhouse. The system monitored and maintains the proper temperature, humidity and soil moisture content inside the greenhouse. The device has been successfully tested under simulated conditions and showed the ability of controlling temperature, humidity and soil moisture. The system notified the caretaker/farmer via short messaging system (sms) for the notification status (information) and triggering the water pump. The device showed the capability of sending sms holding the latest temperature and humidity information and also the status of the greenhouse.

Adjustment Pattern of pH Using Random Forest Regressor for Crop Modelling of NFT Hydroponic Lettuce

IoT makes it possible to automatically adjust pH based on sensor numerical data for NFT hydroponic lettuce. In this research, we use sensors of light intensity, farm temperature, farm humid, reservoir level, reservoir temperature, humid on the outside farm, outside farm temperature at Kartika Farm and Turus Asri. Data were taken for five cropping periods. We got different adjustment pattern of pH based on these sensors and Total Dissolved Solids (TDS) control. Furthermore, Kartika Farm’s cropping was different from Turus Asri. In a kilogram of Kartika Farm cropping ingredient seven holes of hydroponic lettuces while Turus Asri cropping ingredient ten holes of hydroponic lettuces. Economically, Kartika Farm harvests more benefits than Turus Asri. In this research, we modeling the pattern of pH adjustment at Kartika Farm using random forest regression. The result showed that the important variable for pH adjustment modeling is water level, TDS and green house humidity. We got an accurate value for the model is 78,37% with MAE and MSE consecutively 0.19 and 0.15.

The efficiency of using a combined solar plant for the heat and humidity treatment of air

The authors of this work have proposed a combined solar heating unit for the heat and humidity treatment of greenhouse air supplies. The object of research is a combined solar collector for the simultaneous heating of water and air. The heat and humidity treatment of supply air is an energy-intensive technological process that requires a very large consumption of thermal energy and water resources. For the operation of such a system, electric heating installations are often used; however, these systems are not always available and economical. In this paper, to reduce the consumption of traditional energy for the heat treatment of the air supply, a combined solar collector is proposed, and the results of an experimental study of the operating modes of the installation in the conditions of the city of Karshi are presented. It has been developed combined solar collector, the temperature of the heat carriers at the outlet in the heating mode “water + air” reached up to 48 °C (air) and up to 60 °C (water), which are acceptable for air treatment systems of heat and humidity in greenhouses. As a result of the experimental studies, the high energy efficiency of the combined solar collector in the “water + air” heating mode is shown. It has been established that the efficiency of the installation is in the range of 0.45 - 0.69.

Relative humidity in green houses

Any change in temperature causes a change in relative humidity. The need for good knowledge of this growth factor is caused by the fact that vegetable plants develop best, and the main greenhouse crops give a greater yield at a certain relative humidity. Large deviations from optimal air humidity create the conditions for the development of certain diseases and pests, and therefore, the patterns of changes in air pollution during the day are of scientific and practical interest. Relative humidity is generally the same in all sections of the greenhouse due to turbulent air exchange due to the accumulation of solar energy, the action of the heating system and air infiltration. Despite this peculiarity of air humidity, due to the higher temperature in the greenhouse due to heating and heat accumulation during hours of sunshine, the air removed from the greenhouse during ventilation contains more water vapor than the air entering the greenhouse. Wind humidity also affects air humidity in a greenhouse with closed transoms. The ventilation pressure is determined by the difference in air pressure outside and inside the greenhouse, as well as the height of the greenhouse.

Constrained Discrete Model Predictive Control of a Greenhouse Relative Humidity

In this paper, we present a Constrained Discete Model Predictive Control (CDMPC) strategy application for relative humidity control. In this sense, and for our system inside humidity dynamics description, a green-house prototype is engaged and a state space form which fits properly a set of collected data of the greenhouse humidity dynamics is presented as mathematical model. This latest is used for the CDMPC starategy application, which purpose is to select the best control moves based on an optimization procedure regarding the constraints on the control. By the means of Matlab/ Simulink and Yalmip toolbox algorithms, numerical simulations were held to proove the effectiveness of the controller, garanteeing both the constraints feasibility and system stability.

Comprehensive review on dehumidification strategies for agricultural greenhouse applications

Humidity is one of the important climate parameters in greenhouse food production. Maintaining humidity levels within the optimal growth range enhances yield. Moreover, excessively high relative humidity leads to diseases and deterioration of the crops. This paper presents a state-of-the-art review of the various dehumidification technologies available in the agricultural industry. Several novel conceptual designs from the literature are also discussed. The principal humidity control approaches utilized in greenhouses are ventilation (natural and forced), maintaining a high temperature, condensation on a cold surface, and adsorption by hygroscopic materials. The most common method for dehumidification is ventilation due to its minimal infrastructure. Although this method is considered the simplest, it causes additional sensible heating loads, particularly in colder climates. The added heating load can be reduced, ideally eliminated, by employing heat recovery systems. Furthermore, dehumidification by controlled condensation on a cold surface enables the capture and re-use of the latent energy released in condensation. By adsorption of water vapor using hygroscopic material, the latent heat of condensation is converted to sensible heat, which can be used for space heating in the greenhouse. Such a system can reduce the greenhouse humidity while maintaining a more uniform temperature profile over the crop canopy and reducing energy consumption. Finally, it is essential to emphasize that an appropriate dehumidification method should prevent condensation on plant surfaces, and also its operational cost should be as low as reasonably achievable to remain beneficial for growers.

Analysis on the Effect of Greenhouse Humidity Controlby Counter-flow Ventilator in Winter

Analysis on the Effect of Greenhouse Humidity Controlby Counter-flow Ventilator in Winter

Automatic Temperature and Humidity Detection and Alarm System for Greenhouse

With the continuous development of agricultural production technology, greenhouses have been widely used in the production of agricultural products. Temperature and humidity are important parameters in greenhouses. The real-time detection and regulation of temperature and humidity in greenhouses plays an important role in crop cultivation. This paper designs an automatic detection and alarm system for greenhouse temperature and humidity based on STM32. The system uses STM32F103C8T6 single chip core module as the microcontroller, uses temperature and humidity sensor DHT11 to obtain temperature value and humidity value, and uses LCD1602 liquid crystal module to display monitoring data and Bluetooth module. Together form a temperature and humidity detection system. Through system function testing, the system can operate stably according to the expected requirements and meet the expected requirements. Finally, an intelligent temperature and humidity monitoring and alarming system that can monitor the temperature and humidity in the greenhouse in real time is realized. The system has the advantages of good stability, high precision and convenient operation, which is of great significance for improving the monitoring and management of temperature and humidity and agricultural production.

PERANCANGAN SISTEM REKAYASA LINGKUNGAN SMART GREENHOUSE MENGGUNAKAN FUZZY LOGIC CONTROLLER PADA TANAMAN CABAI

In Indonesia, chili can be planted in various areas, both in the fields or moor, sea coast, and mountains. However, chili productions is not good, it is only increasing little by little and is not proportional to the rapid market needs. Efforts are neede to encourage the advancement of technology so that chili cultivation is more efficient. Smart Greenhouse is one of technology that can be used to help humans produce their own chili plants. The concept of smart greenhouse is the integration of data into the internet that connected to a accessed database using an android smartphone application compatible with features such as reporting, updating feeds, and controlling. DHT 22 is used as a sensor for reading temperature and humidity in Greenhouse, Moisture Sensor is a sensor for reading soil moisture. Fuzzy Logic Controller is applied for controlling temperature, humidity and soil moisture in Greenhouse. From the testing that has been done, Fuzzy Logic Controller that is applied can reach the reference temperature at 27oC in 465 seconds, the humidity control can reach 80% in 150 seconds and the soil moisture control can reach 80% in 10 seconds.

Transcriptomic analysis reveals Apis mellifera adaptations to high temperature and high humidity

Temperature and humidity are the most important factors affecting the growth, reproduction, and survival of bees. Apis mellifera are important pollinating bees that are widely used in agricultural systems. However, the higher temperatures and humidity in greenhouses are not conducive to the survival of bees. Although previous research has revealed the behavioral responses and physiological mechanisms of honeybees to adapt to high temperature and humidity, there are few data on the exact molecular mechanisms involved. In our study, we investigated gene expression in A. mellifera under different temperature and humidity treatments, using transcriptomic analysis to identify differentially expressed genes (DEGs) and relevant biological processes. Based on the transcriptomic results, we selected several genes with significant differences in expression, and detected the expression patterns of these genes at different temperatures or humidity or different treatment times by q-RT PCR. In the high temperature treatments, 434 DEGs were identified; in the high humidity treatments, 86 DEGs were identified; in the combined high temperature and humidity treatments, 266 DEGs were identified. Analysis results showed that DEGs were enriched in pathways related to amino acid and fatty acid biosynthesis and metabolism under each treatment. In addition, heat shock proteins, zinc finger proteins, serine/threonine-protein kinases, and antioxidase were differentially expressed between the different treatments. The results of the q-RT PCR showed that the expression levels of these genes increased with increasing temperature and over treatment time. Our findings provide a general expression profile of the adaptive expression of heat-resistance genes responding to high temperature and high humidity in A. mellifera, including the expression patterns of several DEGs. Our data provide a basis for future research on the mechanisms underlying the adaptation of insects to high temperature and humidity.

Greenhouse Modeling, Validation and Climate Control based on Fuzzy Logic

This paper deals with the modeling and control of the air temperature and humidity in greenhouses. A physical model of the greenhouse used in the Simulink/Matlab environment is elaborated to simulate both temperature and indoor humidity. As a solution to the non-linearity and complexity of the greenhouse system, a fuzzy logic method is developed to control the actuators that are installed inside the greenhouse for heating, ventilation, humidification and cooling to obtain a suitable microclimate.

Prediction of Air Temperature and Relative Humidity in Greenhouse via a Multilayer Perceptron Using Environmental Factors

Prediction of Air Temperature and Relative Humidity in Greenhouse via a Multilayer Perceptron Using Environmental Factors

Sistem Pengendalian Suhu dan Kelembaban Kumbung Jamur Tiram secara Realtime Menggunakan Esp8266

Oyster Mushroom is one of the high-value consumption mushrooms. The development of mushroom experienced rapid growth marked by the increasing number of farmers breeding mushroom is directly proportional to number of mushroom food business. The process of mushroom cultivation in mushroom’s greenhouse depends on physical factors such as temperature, humidity, light, pH of planting medium, and air aeration. Watering activity is done if the condition and humidity of mushroom's greenhouse was dry, three times a day at the morning, afternoon and evening. If the conditions of temperature and humidity fluctuate in the current seasons, it is not enough to be sprayed. High temperature and humidity fluctuations disturbed harvest. The results of this research are realtime temperature and humidity control system, esp8266 12-F and DHT22 sensor to read humidity value that can do watering and keep humidity greenhouse. The best humidity limit is 65% and maximum is 80%. If the humidity condition reaches 65%, then esp8266 will activate the relay to turn on the DC pump machine and nozzle spray. If humidity reached 80%, then esp8266 will turn off the DC pump. 80% humidity limit setting to avoid mushrooms from getting too wet. Humidity conditions monitored with android smartphone in realtime.

Effect of Polyolefin Film and Light Transition Film on the Growth of Lettuce

In this study, effects of polyolefin(PO) film and light transition film on the growth of lettuce were investigated compared with ethylene-vinylacetate (EVA, antifogging, no drops and longevity type) film covering. Results showed that the temperature and humidity in greenhouse covered with PO film and light transition film were significantly increased. The average temperature in the greenhouse was 4 oC higher than outdoor temperature. The average illumination intensity in the greenhouse covered with PO film was 293.22 umol m-2 s-1, light transmittance was 80.37%, the average illumination intensity in the greenhouse covered with EVA film was 193.04 umol m-2 s-1, light transmittance was 52.91%. Compared with the common film, light transmittance of the PO film was significantly increased. Light transition film increased the chlorophyll content of lettuce by changing the element of the sunlight and increased production of vegetables. PO film and light transition film display a good application prospective in the production of vegetables.

Design of Greenhouse Temperature and Humidity Measuring System based on Zigbee Technology

Design of Greenhouse Temperature and Humidity Measuring System based on Zigbee Technology

Particle Swarm Optimization of BP-ANN Based Soft Sensor for Greenhouse Climate

In this article, the authors develop the Particle Swarm Optimization algorithm (PSO) in order to optimise the BP network in order to elaborate an accurate dynamic model that can describe the behavior of the temperature and the relative humidity under an experimental greenhouse system. The PSO algorithm is applied to the Back-Propagation Neural Network (BP-NN) in the training phase to search optimal weights baded on neural networks. This approach consists of minimising the reel function which is the mean squared difference between the real measured values of the outputs of the model and the values estimated by the elaborated neural network model. In order to select the model which possess higher generalization ability, various models of different complexity are examined by the test-error procedure. The best performance is produced by the usage of one hidden layer with fourteen nodes. A comparison of measured and simulated data regarding the generalization ability of the trained BP-NN model for both temperature and relative humidity under greenhouse have been performed and showed that the elaborated model was able to identify the inside greenhouse temperature and humidity with a good accurately.

Sliding Mode Control Based on Disturbance Observer for Greenhouse Climate Systems

Greenhouses are closed environments that require careful climatic control, which can benefit from a system control method to cope with the high nonlinearity, complex coupling, and robustness of unknown disturbances. This paper presents a general framework for an integral sliding mode controller based on a disturbance observer combined with feedback linearization for a greenhouse temperature and humidity system. The first-principle greenhouse climate model is described as a standard affine nonlinear system. The feedback linearization control law is used to achieve a system consisting of two separate integrator channels for temperature and humidity. System compound disturbances are estimated by applying a sliding mode disturbance observer. Based on the observer, an integral sliding mode control is incorporated to enhance the robustness against uncertainties and guarantee satisfactory tracking performance even when there are unknown estimation errors. The validity and efficacy of the proposed control technique for greenhouse climate tracking were verified by comparison with simulation results obtained using the common sliding mode control method using feedback linearization without the disturbance observer. Based on this comparison, the developed controller shows a faster system response speed, higher control precision, and stronger anti-interference ability. This method can be applied to improve greenhouse climate control systems.

First Report of Podosphaera xanthii Causing Powdery Mildew on Ageratum conyzoides in China

Ageratum conyzoides L. is a member of the Asteraceae and a competitive weed for crops in the subtropics and tropics. In September 2016, we observed that a plant community of A. conyzoides was 85% infected with powdery mildew in a forest park at Fujian Agriculture and Forestry University (FAFU), Fuzhou, China. Initially, circular to irregular white powdery colonies or thinly effuse white mycelial patches formed on both sides of the leaves and on the stems. In later stages, entire leaves were covered with white mycelium, followed by leaf yellowing and senescence. Fungal hyphae were septate, branched, flexuous to straight, and 5 to 7 μm wide. Appressoria were indistinct to slightly nipple-shaped and solitary. Conidiophores (80 to 215 × 10 to 12 μm) were erect and unbranched, slightly constricted at the basal septa, with cylindrical foot-cells (35 to 70 × 10 to 12 µm) and 1 to 3 cells shorter than the foot-cell. Conidia (25 to 40 × 14 to 23 μm) were hyaline, catenescent, ellipsoid-ovoid to barrel-shaped, with a length/width ratio of 1.3 to 2.0, and containing distinct fibrosin bodies. Simple to forked germ tubes were observed on subterminal or lateral position of germinating conidia. No chasmothecia were observed in the collected infected samples. Based on the morphology of the imperfect state, the isolate was identified as Podosphaera xanthii (Castagne) U. Braun & N. Shishkoff (Braun and Cook 2012). A 565-bp amplicon (KY274485) of the internal transcribed spacer (ITS) region generated with primers ITS1/ITS4 (White et al. 1990) was 100% identical with other P. xanthii sequences (AB040351, AB462804) and showed phylogenetic grouping with P. xanthii isolates from Asteraceae and Verbenaceae. Pathogenicity tests were completed by dusting conidia from an infected leaf onto young leaves of three asymptomatic, potted plants and covered with plastic bags. Noninoculated plants were used as controls. Inoculated leaves showed powdery mildew symptoms after 6 days at 20°C and 80% relative humidity in green house. Control plants exhibited no disease symptoms. The fungal morphology on inoculated leaves was identical to that observed on initially diseased leaves. A voucher specimen (HMAS 247182) was deposited in Institute of Microbiology Chinese Academy of Sciences (CAS) Herbarium Mycologium (HMAS), Beijing, China. Previously, Euoidium agerati has been mentioned as powdery mildew pathogen on A. conyzoides in Taiwan (Braun and Cook 2012). However, this pathogen is quite different from the present collection by not having fibrosin bodies in conidia. Powdery mildew of A. conyzoides caused by P. xanthii has been recorded in Pakistan and India (Gautam 2015; Mukhtar et al. 2013). In China, A. conyzoides is used as medicinal plant to treat a variety of conditions and diseases. Incidence of P. xanthii on this plant will add information on pathogen’s range and will be helpful for future investigation. To our knowledge, this is the first report of P. xanthii on A. conyzoides in China.

A Study on the Control of the Temperature and Relative Humidity in Greenhouse by Adjusting the Amount of Natural Ventilation and Fog Spray Quantity

To develope a greenhouse fog cooling system to control the temperature and relative humidity simultaneously to the target value, a theoretical analysis and experiments were done. The control process includes the measuring of environmental variables, setting and coding of the water and heat balance equations to maintain the target temperature and relative humidity in greenhouse, calculating of the open level of the greenhouse roof window that governs the natural ventilation and spray water quantity, and operating of the motor to open/close the roof window and pump to spray for water. The study results were shown to be very good because the average air temperature in the greenhouse was kept to be about 28.2°C with the standard deviation of about 0.37°C compared to the target temperature of 28°C and the average relative humidity was about 75.2% compared to the target relative humidity was 75% during the experiments. The average outside relative humidity was about 41.0% and the average outside temperature was 27.2°C with the standard deviation of about 0.54°C. The average solar intensity in the greenhouse was 712.9 W. The wind velocity of outside greenhouse was 0.558 m/s with the standard deviation of 0.46 m/s.