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Humidity and Temperature in Agriculture

Posted on May 13, 2019

Any first-schooler knows that plants need four things to survive: light, water, soil and air. In terms of raising healthy plants however, one of the most important of these is actually the effect of water with regards to relative humidity.

Relative humidity is a measure of how much water the air can hold at any given temperature. This means that say the air is at 60% humidity at 20 degrees, then the air is at 60% of its total moisture capacity for that temperature.

This measure of air moisture, along with temperature, can make or break an agricultural operation, so it’s vital to get it right.

Humidity and temperature go hand-in-hand when it comes to raising crops in a greenhouse, partially because imbalances in either can often give similar results.

Plants are by nature extremely responsive to their environments and depend on a certain set of air conditions in order to survive. This is primarily due to their need to respire.

Respiration in plants is the process of water leaving the leaves through evaporation via the stomata on the underside of the leaves.

Stomata are tiny openings, usually in the surface of a plant’s leaves, which allow for the regulation of gas exchanges and moisture regulation during photosynthesis.

How can high humidity and temperature affect agriculture?

Imbalances in humidity can affect this process. For example, if humidity levels are too high then there’s nowhere for the evaporating water from the stomata to go, the air is already saturated.

This means that, despite having the stomata constantly open, the plant fails to respire and can essentially drown in a soup of trapped CO2 and water. The plant failing altogether is obviously the worst-case scenario here but at best this will still result in stunted growth in the plant due to an inability to conduct its everyday processes.

As well as this, crops are more susceptible to a variety of diseases, fungus and parasites that thrive in humid conditions.

High temperature has similar effects in terms of influencing the stomata, though it can have the opposite effect.

At high temperatures, with low relative humidity, plants tend to close their stomata in order to preserve water. However, warm air is more capable of holding larger volumes of moisture, meaning that the combination of high relative humidity and high temperature can be lethal.

How can low humidity and temperature affect agriculture?

Once again, low humidity affects those all-important stomata. Air with low levels of relative humidity can cause plants to close their stomata, in an attempt to conserve water, much like the effects of high temperature.

In tandem with this is the effect of cold air, which is less capable of retaining moisture. Cold temperatures also cause many plants to stunt their growth as a self-protection mechanism, much like the effects of winter when most plants lose their leaves and lie dormant.

Imbalances in either temperature or humidity can have a roster of detrimental effects upon plants and potentially cause whole crops to be wasted.

Monitoring heat and humidity

Thankfully there are ways to observe and prevent these imbalances.

As we move ever more into the age of the Internet of Things, the range of sensors and transmitters to aid agricultural processes growing rapidly.

From relatively basic, hand-held devices all the way through to smart sensors that feed information direct a central source for in-depth analysis.

This means that large-scale greenhouse management is no longer a guessing game, it is now possible to measure the exact conditions of your growing environment and base your actions upon that or even automate these processes.

With smart sensors coupled to responsive automation systems which can perform functions such as regulate the temperature and humidity of your greenhouse growers can leave these basis functions to the technology.

This frees more time for more demanding, less mundane operations.

If you want to find out more about how you could improve your agricultural processes, contact Omni today.

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