Whether growing plants for food, medicinal or ornamental purposes or farming livestock; the air quality of the local environment is paramount to the lowering of energy costs, productivity, health of the organism, transport, and storage in the case of edible fruits and vegetables.
Temperature, humidity, CO2 sensors and differential pressure transmitters are employed in many outdoor and indoor growing environments such as green houses, vertical farms, polytunnels, mushroom farms, hatcheries, incubators, and livestock barns. Ethylene, C2H4, may be measured in addition to CO2 to control ripening and storage of some fruits and vegetables and NH3 is monitored in indoor livestock barns and poultry houses.
What role does the indoor climate and environment play in the growth and health of plants and animals and in the ripening of produce?
Temperature and plant growth
Temperature is the most important environmental factor affecting plant growth. Plants vary in their temperature needs. Cold freezes plant cells, causing damage and interrupting the flow of nutrients and water. High temperatures affect plant growth in many ways. The most obvious being the effect of heat on photosynthesis, the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar. The rate of photosynthesis increases as the temperature rises. Photosynthesis is controlled by enzymes , which become denatured if the temperature is too high, so the rate of photosynthesis will fall above the optimum temperature.
In plants, respiration is essentially the reverse process of photosynthesis. In the mitochondria of the cell, sugars are combined with oxygen in a series of chemical reactions. This creates carbon dioxide, water and energy. Respiration rate is directly linked to the Ambient Temperature, with respiration rate peaking at an optimal temperature. Changes in temperature from this optimum will decrease efficiency. Different plant species have varying optimal ranges that are generally between 18 and 40 °C. If the rate of respiration exceeds the rate of photosynthesis photosynthates are used faster than they are produced. For growth to occur, photosynthesis must be greater than respiration.
Effect of temperature on livestock and poultry
High temperatures cause heat stress in beef cattle and dairy cows. Dairy cows have an optimal thermal temperature of between -13°C and +25°C. Above this threshold, the animal feels stressed and energy normally directed towards increasing yields is used to lower body temperature. A dairy cow generates a lot of energy, the equivalent heat of 14 100-watt lightbulbs, so when placed near one another as in the case of cow sheds, the likelihood of heat stress is increased. The best way to avoid this is to monitor the temperature and ventilate as required.
Pigs have a smaller range of temperatures that allow them to optimally prioritise nutrients for growth or reproduction rather than struggle to maintain body temperature, outside of this thermal neutral zone they will experience heat, or conversely cold stress. Heat stress causes lower feed intake with grow-finnish pigs and harmful effects in sows during breeding, gestation and lactation and in their offspring. Cold stress will also reduce feed efficiency resulting in reduced growth rates and weight loss.
Poultry, similar to pigs, have a very narrow optimal temperature zone. The most efficient temperatures for layers are between 20 – 24°C. When temperatures rise above 24°C, shell quality and egg weight will reduce. When temperatures drop below 20°C feed requirements increase. The optimum temperature conditions for broilers and rearing birds is highly dependent on age.
Temperature for storage and ripening of produce
Temperature influences ripening changes: colour (which pigments are favoured), texture ( enzymatic cell wall changes) and flavour ( taste and aroma compounds which are biosynthesised)
Different fruits have different optimum ripening temperatures. If the optimum temperature is exceeded, it may inhibit ripening or cause heat injury.
Once ripe, fruit should be stored at their lowest safe temperature until ready for retail display:
0 °C for non-chilling sensitive fruits, 2.2 to 14.4 °C for chilling sensitive fruits (the specific temperature depends on the type of fruit)
Humidity and plant growth
Humidity control in the greenhouse and around the plant enables the plant to keep its stomata open, this ensures the absorption of CO2 for photosynthesis and regulation of plant temperature through evaporation.
High humidity can promote the growth of mold and bacteria causing plants to die and crops to fail, as well as conditions like root or crown rot. Humid conditions also invite pests such as fungus gnats, whose larva feed on plant roots and thrive in moist soil.
Effect of humidity on livestock and poultry
The occurrence and prevalence of climate-sensitive infectious diseases are significantly associated with ambient humidity. High humidity levels impair the trachea and bronchi in the respiratory system providing a favourable environment for pathogen infection, this is enhanced by the fact that infectivity of pathogens increases with humidity.
In addition to the incidence of infectious diseases, relative humidity is also associated with other animal health issues, e.g. dehydration in chickens, ear necrosis in pigs, tracheobronchial damage in lambs.
An indirect effect of high humidity is an increased litter moisture resulting in high ammonia concentrations which impact both animal health and the environment.
Impact of gaseous environment on plant growth, fruit ripening and animal health
Higher carbon dioxide levels spurs growth and yields through increased rate of photosynthesis, and also reduces transpiration and tissue concentrations of nitrogen and protein.
CO2 levels aren’t typically monitored in growing environments today but may be in the future as CO2 levels rise affecting agricultural production and food quality.
Carbon dioxide, CO2, is a by-product of the ripening process, as concentration increases, the ripening process slows. Some produce like apples have their ripeness retarded by storing them in CO2, other produce such as bananas, tomatoes, and avocadoes are ripened just before they are ready to sell by bathing them in ethylene gas to initiate the ripening process. As the fruit ripens, it gives off CO2 so to prevent CO2 levels building up above 5000 ppm, keep ripening times to a minimum and meet HSE regulations, it’s necessary for shippers to ventilate ripening rooms.
Ammonia, NH3, emissions from housed cattle, pigs and poultry production can impact the environment, the health and development of animals or birds, occupational health of farm workers and directly affect the economics of the business. Ammonia is created by bacterial break down of poultry manure and this is exacerbated by high temperature and moisture conditions. With controlled ventilation of the poultry houses the concentration of NH3 can be lowered to safe levels.
Monitoring the indoor climate enables manual or automatic intervention to maintain optimal conditions
Precise measurement of a combination of the following parameters: humidity, temperature, differential pressure, CO2, NH3 and C2H4 enables the local environment to be optimised for its specific application.
Omnisensors and transmitters offers a range of robust, reliable and accurate sensors engineered for use in harsh environments.
Humidity and Dewpoint: EE212 wall or duct mounted transmitter, EE211 transmitter with remote probes, EE33 wall mounted transmitter with remote probe, Probes ( EE08 and EE07), Aranet T/RH sensor with radiation shield, T/RH IP67 Aranet sensor, T/RH with probe( optional NH3 resistant probe), Sigma 05 with EE072 probe
Temperature: Aranet T-probe, PT100 Temperature sensor, sigma 05 and EE074
Pressure: Aranet differential pressure sensor, EE 600 differential pressure sensor, Halstrup and Walcher PS17 and PS27 pressure transducer
Gas: EE820 wall mounted sensor and EE 872 “4 in 1 probe” for CO2, humidity, temperature, and pressure, Sigma 05 sensor platform, Aranet CO2 and Temperature sensor, SmartGAS CO2 transmitter
C2H4 levels: SmartGAS C2H4 Transmitter
NH3 levels: Aranet NH3 sensor kit
Moisture in cereal, legume and grass crops grown for food and animal feed
Moisture content (%MC) is a critical factor in maximising crop quality and yield at the time of harvest. If the harvest is made at just the right moisture content, farmers can make sure that their crops have the maximum nutritive value and the lowest possible chance of loss or spoilage. Moisture content is also important during storage, prior to transportation and further processing, and so finds applications not only in the farming and trade industries but also in food and animal feed industries.
Sampling can be on discrete samples without the need for any sample preparation or in some instances, e.g. with grains, seeds and beans it can be carried out continuously upon harvesting and prior to storage.
Moisture meters-application specific: FS1 for field control in farming, FS2 for corn, pulses and grain, FSA automatic grain analyser and FSO online analyser, RHL for cereal grain storage, FLH for hops and FL1, FL2 and FLS.
Product range
Humidity and dew point
Temperature
Pressure
