The Creator placed our Earth at the right distance from the Sun. The heat from our nearest star is the source of energy for all living creatures on Earth. Besides the heat, the sun is the source of proper radiation in visible spectra (and a little bit of ultraviolet radiation) that initiates the most important chemical reaction on our planet. It is called photosynthesis. Without this reaction, there are no plants, and no plants mean no food for bacteria, fungi, insects, animals, or humans. All living creatures are dependent on this photosynthetic reaction.
The last time, I presented the three-leg concept of healthy plants. Having two basic elements (sunshine and water), the concept consists of good photosynthesis, available balanced minerals, and flourishing biology in the soil (Figure 1). Let’s repeat it. For good photosynthesis in plants, balanced minerals in an available form are needed. Plants feed the biology in the soil with abounded products of photosynthesis. And, without biology, unavailable minerals in the soil are not transformed into a form available for plants. It is a cycle that is often broken (sometimes in many different places) resulting in an unhealthy garden/farm. How to turn on the cycle? By knowing the principles, one can help to run the cycle properly. We can become guardians of the soil. The solution dwells in balanced available minerals in the soil, and practices that enhance photosynthesis and soil biology.
Figure 1. The healthy plant requirement cycle.
Let me present the second leg –photosynthesis. The process looks simple. Carbon from the air (CO2 part) mixed with water and supported by photons (out of sunlight) produces sugars (carbohydrates) and essential breathable oxygen (6 CO2 + 6 H2O + light --> C6H12O6 + 6 O2). A nice lecture about photosynthesis you can find on Khan Academy (see link below).
God provided zillions of tiny factories for producing sugars and oxygen. The factory is called chloroplast and it is an organelle in the mesophyll cell of a leaf. As simple as the process of photosynthesis looks, it is not so easy. Some other components are needed. A plant needs to have an available form of magnesium, iron, manganese, nitrogen, and phosphor. They help to make the process of photosynthesis, speed up the process or optimize it most efficiently. If any of these elements is missing, the process of photosynthesis will slow down or stop at a certain level of the sugar development. For example, Mg is needed to make chlorophyll in a plant and without chlorophyll, the light does not absorb into a plant. Imagine a car factory. When the conveyor of car wheels is working slowly or does not work at all, the result will be few wheel present at the assembly line and few finalized cars or no finalized cars at all.
The process of photosynthesis is not running at full capacity. Crops in a field produce approximately 10 – 30 % of sugars out of the full 100 % potential in ideal laboratory conditions defined as proper light intensity, available water, and ideal structure and resources for the process. This 10 % means that the plant barely covers its own needs, but an additional 10 or 20 % makes a huge difference. On one side, poor photosynthetic conditions create poor structure and biomass volume of plants. However, vital photosynthesis makes abounded sugar mass. Simple sugars are chained together and create more structured saccharides and the proportion of complex saccharides increased in sap. Consequently, a plant increases natural immunity against soil pathogens such as Verticillium, Fusarium, Rhizoctonia, Pythium, Phytophthora, and others (see Kempf’s presentation).
The remaining surplus of sugars is dumped into the root zone. A plant starts to fulfill its commission and surplus sugars become a basic food resource for soil biology. Recent research shows that this sugar-storing process is targeted for a specific need of a plant. For example, when a plant needs copper, it starts to feed beneficial bacteria and fungi that can collect missing copper located out of the root zone. God's law of taking and giving brings life abundantly.
Having sugars, soluble nitrogen, and other minerals in available forms, a plant starts to produce amino acids and create proteins (nitrogen is the basic element of proteins). This requires the presence of magnesium, sulfur, and molybdenum in the plant sap. Again, if a plant has limited resources of components, the proteins are not chained into a more complex form of proteins and unused nitrogen is remaining in sap. This is, of course, beneficial for an insect with a simple digestive system such as cabbage loopers, white flies, aphids, corn borers, leafhoppers, thrips, and others. On the other hand, having completed proteins and no remaining nitrates or ammonium in sap for 24 hours photosynthetic period the immunity of plants boosts against these sucking insects (for more details, please refer to Kempf's presentation below).
Now, let’s be more practical. How can we enhance the photosynthesis process? How can we become good stewards and support something that was once perfectly made?
1. The ideal intensity of sunshine
Place your garden in a proper spot on your land which gets full sun during the day. I know from my own experience that this is not always manageable if you already have a garden or land, and it is as it is. But if you have a choice, use it wisely. The full sun could mean that you can extend your growing season for more than one month, or that you can grow your crops in an unheated greenhouse during the winter.
Plant your crops in ideal spacing. A high density of plants causes the shadowing of neighboring plants and lower leaves, which decreases available sunlight for one plant. Prune plants or trees if necessary.
Too much sun is also a problem. Depending on the specific requirements of a plant, sunlight could be too intensive especially in the greenhouse during clear sky summer days. Professionals use automatic systems for covering greenhouses between 10 am and 3 pm. A simple shade cover or white paint for the greenhouse is a well-known practice.
Speaking of greenhouses, glass or other used materials filter specific wavelengths of the sunlight in the ultraviolet region that is required by plants. For example, UV light is involved in the processing of lycopene, a beneficial antioxidant in tomatoes. Special lamps are used but simply opening a window of the greenhouse or roof ventilation openings could help too. The light finds its way through reflection.
2. The ideal balance of minerals
At this moment you know that some minerals in plant sap are required. In the best scenario, the minerals in the soil are converted by soil biology into the available forms. If this is not the case, soil amendments or foliar applications are used. Once you balance your minerals, living biology will keep them at the optimal level. Of course, the overall goal is to be independent of any amendments (see my previous blog).
3. The ideal irrigation
Water present in a plant is directly involved in photosynthesis. This is especially important over the last dry years. Water is a must in the garden, so make sure you have an adequate amount of water in the soil. Without water, the soluble minerals will not get to the plant, and sugars, products of photosynthesis, will not get into a plant and its root zones.
4. The ideal air conditions
This is usually not a big deal. Although CO2 is only 0.04 % of air volume, it is widely available. Just make sure that you have enough air circulation in greenhouses. Interestingly, the air in the soil pores contains 0.2 % of CO2. The soil also breathes (exchanges gases with the air above the ground) and well-aerated soil could be another source of CO2 for photosynthesis.
Remember, good photosynthesis is just the second leg of the healthy plant cycle. You must take care of the soil biology to close the loop of the wonderfully made living system and watch and taste how magnificent the Creator is.
Dr. Rastislav Lagana
He works at the Technical University in Zvolen, Slovakia, as a teacher in the field of Wood Science. Together with his wife, they find joy in gardening for family and friends. Rastislav volunteers as a lecturer of Health Clubs supported by the Health Division of SDA in Slovakia providing public services in sharing and promoting practical information about organic gardening methods and a healthy lifestyle. If you will have any questions or suggestions, please do not hesitate to contact him at rastolagana@gmail.com.
Resources:
Photosynthesis lecture: https://www.khanacademy.org/science/ap-biology/cellular-energetics/photosynthesis/v/photosynthesis
Plant health pyramid by John Kempf: https://www.youtube.com/watch?v=D1wJefaFrVI&ab_channel=AdvancingEcoAgriculture
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