This year farmers have faced a range of climate challenges, from late spring snowfall, to lack of rainfall and heatwaves as crops mature. All have coped with these challenges to varying degrees, but the trends show that most had higher expectations of crop quality than the results showed.
Different micro-organisms have a decisive influence on the quality and abundance of yields and the disease resistance of crops. Laurynas Kaučikas, farmer and “HeavyFinance“
sustainable farming expert, points to 4 plant health indicators that allow farmers to protect their crops themselves.
Photosynthesis
Ensuring complete photosynthesis allows the production of a large number of simple sugars, which are fully converted into more complex carbohydrate forms within the daily photosynthetic period. The sugars are used for the growth of the plant’s aboveground and belowground biomass and for feeding soil micro-organisms through root secretions.
The concentration of photosynthates in the plant increases as the plant’s nutritional requirements improve. Carbohydrate levels may therefore exceed the genetic potential of the plant and thus exceed the standards of the variety.
When photosynthesis is fully established, plants become resistant to soil fungal pathogens. These conditions are created by the plant itself, by releasing through the roots better quality food for the micro-organisms in the rhizosphere, and the quality of this food determines the micro-organism communities that can establish themselves in the rhizosphere. Plants become resistant to fungi that cause diseases such as fusariosis, phytophthora, rhizoctonia, etc. Thus, the microbiome in the rhizosphere can be either disease-causing or disease-inhibiting, depending on how efficiently photosynthesis occurs in the plant.
5 minerals are essential for complete photosynthesis.
Manganese and nitrogen
are the structural minerals of the green pigment chlorophyll, without which the chlorophyll molecule would not form, while iron is involved in the biochemical pathway by which chlorophyll is formed.
Manganese is involved in the breakdown of the water molecule, without which photosynthesis would not be complete. When water enters the plant, it is broken down into H and OH by an enzyme whose constituent mineral is manganese. Phosphorus reserves must also be ensured to ensure that there is enough ATP (Adenosine Triphosphate), the energy unit in the plant, which is essential for the production of sugars, especially when the photosynthetic process becomes more efficient. When there is any deficiency of these minerals in the plant, the photosynthetic process is stunted and incomplete.
How to measure photosynthetic efficiency at farm level? With the simplest refractometer. At midday, when the sun is shining, the refractometer should show a high brix number, and in the afternoon, as the intensity decreases, the brix number should also decrease, indicating that the sugar produced in the leaves is being flushed down into the root system.
Complete protein synthesis
Full protein synthesis within 24 hours plays an important role in ensuring plant health and quality. All the nitrogen absorbed by the plant in the form of nitrate, ammonium, amide or amino acids is converted into protein and at the end of the day, there should be no free nitrate or ammonium left in the plant. This condition makes the plant resistant to all organisms with a weak digestive system that suck up plant juices rich in free nitrogen. These include all kinds of moth larvae, aphids, etc.
Complete protein synthesis is ensured when the need for Magnesium, Sulphur, Molybdenum is met for all processes to run smoothly. Boron not directly involved in protein synthesis, but when used in combination with magnesium, sulphur and molybdenum in foliar sprays, has a strong effect in the event of a visible infestation of any larvae or aphid. Analysis of leaf fluids once or twice a season can reveal a great deal of information about the concentration of mineral elements in the plant.
Production of oils
Leaf sheen occurs when a plant has more energy than it needs to meet its physiological needs. Plants begin to store excess energy and can increase their oil production by 4-5% compared to plants with only minimal physiological needs.
To increase oil production and leaf gloss, plants need to obtain most of their nutrients through the soil food web, as this uses less of the plant’s energy than the standard way of converting nitrate into amino acids. Plants can feed through the roots on ready-made amino acids and other intermediates, which require much less energy to combine into complete proteins.
What does this stage look like in reality? When pathogens are dropped onto the leaf by airborne droplets and secrete proteolytic enzymes to penetrate the plant cells. Once a waxy layer or oil has formed on the plant leaves, entry into the cells becomes impossible and the plant becomes resistant to rust, powdery mildew, bacterial blight and spotted wilt.
The production of oils is also accompanied by an increase in the absorption of the elements calcium and silicon, which, as structural elements, are also important contributors to the strength of the cell membrane and its resistance to infection.
In the fourth health stage, plants start to synthesise more phytochemicals: salicylic acid is the main signalling molecule produced in stage 4, which activates defence reactions in the plant. When a plant is infected by a pathogen, salicylic acid accumulates at the site of infection and triggers a systemic defence reaction throughout the plant. The systemic acquired resistance
system allows the plant to develop an overall resistance not only to a specific pathogen but also to other potential pathogens, which is similar to the plant’s “immune system”.
Jasmonic acid is a signalling molecule that is activated by beneficial micro-organisms such as rhizobacteria. This acid stimulates defence processes in the plant, increasing its resistance to various pathogens and pests. The systemic mechanism
of acquired resistance does not depend on pathogen attack, but on the plant’s interaction with beneficial microorganisms.
Also, at the fourth stage, the plant’s ability to produce antioxidants, bioflavonoids, alkaloids, essential oils and other substances responsible for the plant’s resistance to biotic and abiotic stresses is greatly improved. Plants become resistant to Colorado potato beetle, flea beetles, root-feeding nematodes and viruses.
The nutritional quality of produce grown according to the Bionutrient Food Association is directly linked to the biological activity of the soil, demonstrating the close links between the soil food web, plant productivity, disease resistance and the nutritional quality of the end product.
Certain micro-organisms can enhance the uptake of nutrients by plants or, as mentioned above, produce nutrient intermediates for plants. Nitrogen fixation and phosphate mobilisation are improved by the introduction of rhizobacteria that promote plant growth. These rhizobacteria produce hormones (auxins, cytokines, etc.) that signal nutrient availability to plants.
Nutrients are absorbed mainly through the roots of the plant. Rhizobacteria can regulate root morphology. Plants can absorb more nutrients due to the increased root surface area. Plants with thicker or stronger root systems are also more resistant to abiotic stress conditions such as drought or high heat.
As rhizobacteria have evolved alongside plants, they have also developed ways to protect their hosts from phytopathogens. Many species of rhizobacteria can synthesise antipathogenic substances, antibiotics, antimicrobial peptides and enzymes that are toxic to pathogens.
Rhizobacteria can function as long as the soil environment is suitable for them to live. Intensive tillage, the use of synthetic fertilisers and the prolonged leaving of bare soil surfaces make the soil unsuitable for this symbiosis. Often, after intensive practices, populations of these bacteria are severely reduced or extinct, so it is worth introducing them with the seed at sowing or by spraying after the plants have emerged. In other cases, a readily available foodstuff such as molasses should be added along with conventional fertiliser.
Bacteria are not the only micro-organisms present in the rhizosphere of your plants, but they are the most abundant. Fungi are also very beneficial to plants. We often think of fungi as pathogens, but most fungi are beneficial. Arbuscular mycorrhizal fungi (AMF) can increase the root zone of plants by more than 100% and form a symbiotic relationship with plants.
Other fungi also form relationships with plants, and farming practices affect fungi more than any other micro-organism. The benefits of fungi to plants are their long filaments, hyphae, which can penetrate far beyond the roots of plants. Particularly in times of drought or when the soil is nutrient deficient, these long filaments search for what the plant needs, which can be various trace elements and even water molecules.
Plants secrete root secretions, simple sugars, amino acids and fatty acids, which are necessary for the survival of fungi. These secretions act as signals that repel pathogens and attract beneficial organisms to the rhizosphere.
Throughout the plant’s life, it needs different nutrients. The plant sends signals to its microbiological partners, and these partners change throughout the growing season. Interestingly, fungi do not disappear in a minimally cultivated field over a long period of time; they become dormant. In the absence of ploughing to disturb their life, they become active when new crops are sown and new living roots start to grow.
Therefore, as always, we strongly recommend sowing a wide variety of catch crops, and trying out intercropping and intercropping even for a very short period of time between sowings. If the field is not fertile, sow pioneer catch crops such as peas and oats. If the field is already fertile, the diversity can be increased and the result can be even better later on, because each plant family cooperates with unique micro-organisms in the soil that have different soil-keeping functions, release a wider variety of nutrients and, because the intercrops remain in the soil once they have grown up, the harvest is not carried away, everything that is stored is retained for the following crop. It is also advisable to monitor the health of the catch crop, to observe the stages of plant health and even to apply additional foliar fertiliser and micro-organism cultures along with the seeds, as this is an investment in the next year’s yield and the viability of the whole farm.
