The Future Of Agriculture: Mars Greenhouses-4

Greenhouse Automation

We mentioned earlier about the continuous nourishment of plant roots with nutrient-rich water in the hydroponic system, also known as the flowing water culture. As is well-known, besides water and oxygen, each plant requires various inorganic compounds to sustain its life cycle.

These compounds, commonly known as fertilizers, mostly consist of elements like nitrogen, phosphorus, potassium, calcium, and magnesium. The type and quantity of inorganic compounds needed for the growth of each plant species may vary. Therefore, to achieve optimal yield in the growth of a plant, it is crucial to provide the appropriate elements in the correct proportions.

In hydroponic agriculture, specific nutrient elements tailored to the type of plant being grown are mixed with the water in the storage tank to create a nutrient solution. However, the critical aspect here is adding the nutrients to the water in the storage tank in the right proportions.

The plant absorbs the water along with the nutrients through its roots. This process is achieved through osmosis, a natural process driven by the difference in concentration between the water surrounding the roots and the nutrient solution.

When the nutrient solution’s density is lower than the water in the roots, absorption occurs. However, if the nutrient-rich solution is denser than the water in the roots, the plant experiences water loss through a reverse process. To ensure this process works correctly, the amount of nutrients added to the water must be carefully adjusted and continuously monitored.

Electrical conductivity (EC) is a measure of the ability of a conductor to carry an electric current. It is also the inverse of the concept of resistance, meaning that as the conductivity value increases, the resistance to electric current decreases. In other words, electrical conductivity indicates how well a material can conduct electricity.

As you may recall from your past knowledge, completely pure water is not electrically conductive. The only way for current to flow through water is if it contains dissolved ions. As the amount (or density) of dissolved substances in water increases, the current can be conducted more easily and with less loss.

Based on this simple principle, EC meters have been developed to measure the density by applying a small current to the water.

In soilless agriculture, producers need to constantly monitor the EC (electrical conductivity) values of water to ensure that plants can uptake water and nutrients optimally. Typically, this monitoring is done by taking a sample of the solution from the main water tank and measuring the conductivity value using a portable EC meter.

Each plant species being cultivated has its characteristic EC value. For instance, this value ranges from 0.8 to 1.2 mS/cm for lettuce and from 2.0 to 5.0 mS/cm for tomatoes. If the conductivity level of the nutrient tank water falls outside these ranges, it can have a negative impact on the plant’s development.

In hydroponic cultivation, this parameter should be monitored at least once a day. If the measured sample value falls below the specified range, more nutrients should be added to the water tank. If it is above the range, more water should be added to adjust the solution’s conductivity to the appropriate range.

Beside all these measurements, the pH value of the nutrient solution should also be monitored. Just as each plant species requires a specific EC value, the nutrient-supplemented water should also have an appropriate pH range for healthy nutrient uptake by plants.

Generally, this value falls within the range of 6.0 to 7.0. If needed, pH adjusters, either pH increasers or pH decreasers, can be added to the solution after measuring its acidity with a pH meter.

Compared to traditional agriculture, the constant monitoring of the environment and the need for timely interventions in soilless applications may seem like a disadvantage. However, the achieved crop yield, thanks to the optimization of all environmental conditions for plant growth, is significantly higher than soil-based farming.

In soilless cultivation, the systematic structure of the hydroponic technique can be a plus to minimize human labor. Essential routine EC and pH checks can be continuously monitored through sensors connected to a microcontroller.

For example, a sensor inside the main tank can automatically open a valve of an external tank containing nutrient solution when the EC value falls below the required level, providing nutrient supplementation to the main tank.

Conversely, when the EC value of the nutrient solution rises or the water level in the reservoir decreases, the valve connecting the main tank to the water supply can be activated to perform the water replenishment task that would normally require human intervention. In the event of a water leakage in the pipes supplying water to plant roots or in NFT channels, the water pump connected to the main tank can be temporarily stopped.

In large greenhouses with numerous water channels and connection points, simple water sensors placed at pipe joints can instantly detect leaks. Detecting water leaks promptly not only prevents water loss but also potential economic losses due to liquid fertilizer loss.

As we mentioned, maintaining a balanced temperature is crucial in greenhouses. During winter months when temperatures drop, greenhouse heaters are occasionally used to protect seedlings and plants from freezing. The geometry of the geodesic dome minimizes heat loss in the environment.

A heater providing 360-degree heat can be placed at the exact center of the dome. As a result, heat can be evenly distributed to all points with the assistance of the dome’s spherical surface. Through temperature sensors, the environment can be maintained at an appropriate temperature according to the specific requirements of the cultivated plant species.

Humidity level is another crucial variable that needs to be carefully monitored in the greenhouse environment. Insufficient ventilation in greenhouses can lead to the accumulation of relative humidity in the air. Excessive exposure to humidity can increase the likelihood of various plant diseases.

To prevent this, humidity sensors can be used to continuously monitor the humidity level. When the humidity exceeds the desired threshold, the ventilation system can be automatically activated to regulate the humidity. Carbon dioxide and oxygen sensors can also work in conjunction with the ventilation system.

The data collected from the sensors can be transmitted to a local network established within the greenhouse. The continuous observation of the data on a network-connected computer and recording the data in a database over time is possible.

By identifying which parameters lead to faster and more efficient production for each plant species, future cultivation can be optimized for higher yields. The accumulated data can also be made available to researchers for further analysis and potential improvements in the future.

Greenhouse automation should not be limited to just control and feedback systems. When cultivation reaches levels that can meet large demands, processes such as planting and harvesting can be delegated from intensive manual labor to machines.

In soilless agriculture, planting is carried out by placing seedlings into slots on NFT (Nutrient Film Technique) channels instead of planting in soil. Soilless planting is simple and fast.

Placing the plants into pre-determined, fixed-distance slots on the channel using movable robotic arms can offer a more efficient production method. Similarly, matured plants can be harvested quickly in a similar manner.

Image-1. With the advancement of robotics, in the future, routine tasks such as planting, harvesting, and caring for plants can be done by machines.

By integrating automation into geodesic domes, it is entirely possible to create large and closed ecosystems for hydroponic production. This approach enables food production to meet the increasing population’s needs without polluting the soil or destroying forests to create new agricultural areas.

Partially independent from environmental conditions, such production can be concentrated around city perimeters to meet local demand. Urban farming practices, in particular, can become more widespread with the implementation of this technique.

Producing food according to the population and demand of cities simplifies countries’ agricultural planning, reduces food waste, and significantly lowers transportation costs. As a result, this approach could open the way to ensuring safe and accessible food for everyone in the world.

Mars Greenhouses

In the near future, manned missions to Mars pose numerous scientific challenges that need to be overcome. While successfully landing humans on another planet is an achievement, sustaining life in an environment with hazardous conditions presents a separate challenge.

Initially, human missions on Mars may be short-term and focused on scientific purposes. However, as the costs in the space industry decrease, the number of journeys to the planet may increase, and establishing permanent stations on Mars may become necessary.

In such a scenario, supplying the increasing Mars population with the necessary food from Earth would become more difficult. Therefore, it becomes crucial for these stations or bases to obtain their basic needs from local resources and become sustainable for the continuity of Mars missions.

In the initial missions to Mars, structures where astronauts will stay will likely be ready-made modules attached to rockets and landed on the surface as a whole. Similar to the lunar module but designed to suit Mars conditions, larger and more complex structures could be prepared as a whole on Earth and sent directly to the planet.

Over time, expanding research stations could be achieved with demountable modular parts that cannot be sent directly from Earth but can be assembled by astronauts on the planet’s surface. These parts should be lightweight, with high chemical and thermodynamic resistance, and designed to be quickly assembled using minimal manpower and a few pieces of equipment. Just like geodesic structures…

Image-2. Mars yüzeyindeki yapıları tasvir eden bir çizim.

You can frequently see designs like domes or half-spheres in many visuals depicting the possible future colonization of Mars. Building such structures on another planet is, of course, still a concept for now. However, these structures are being used in various analog Mars habitats designed to simulate human missions.

The agricultural methods we propose to increase crop productivity on Earth could serve as examples for creating artificial ecosystems to meet the food needs of a future Mars outpost. Adapting soilless farming techniques within geodesic domes to Mars conditions could provide a sustainable solution to the food challenge for the crews in research stations.

Image-3. An illustration depicting the structures on the surface of Mars.

At the end of the day, if the main goal is to keep humans alive on an alien planet and eventually backup Earth in the long run, food production becomes a necessity. While the conditions on Mars are quite different and harsh compared to Earth, the basic principles of growing plants remain the same everywhere.

Who knows; the techniques we develop to make a foreign planet habitable might also serve as solutions to the social and climatic problems our own world faces.

Other Parts Of The Article Series

• The Future of Agriculture: Designing Tomorrow-1
• The Future of Agriculture: Soilless Agriculture-2
• The Future of Agriculture: Geodesic Domes-3