Trace Elements- Micronutrients
Micronutrients are often overlooked, but are critical to plant vitality. They should be in suitable supply and balance within the soil. Comprehensive soil tests can detect levels, and indicate deficiencies. If you are deficient in micronutrient, you are advised to spread your application over months, or years into the soil in an attempt to avoid a shock in the system which could throw the soil out of balance. Foliar feeding, (direct spray) to plant vegetation can also help apply these nutrients.
Trace elements are vital to enzymes, which are catalysts that govern many thousands of physiological and metabolic functions in plants. Enzymes are able to speed up biological reactions up to one million times. These sped up reactions can increase crop production and performance.
Tissue and forage tests are useful in this regard, and visual observation of leaf, stem, root, tuber, and fruit reveal what’s happening with your crop.
Micronutrient deficiencies are known to increase the likelihood of plant disease.
Plant Immunity
Mineral nutrition supports the synthesis of complete proteins, complete carbohydrates, lipids, and chlorophyll production.
Plant secondary metabolites (PSMs) -Category of Plant Physiology contribution to plant immunity. There are three main categories.
Phenols, Terpenes/Terpendoids, Alkaloids
Phenols include flavonoid compounds, and Isoflavones, also called phytoestrogens (compounds produced in legumes which ward off mildews). Legumes depend on micronutrients as raw materials to build phytoestrogens. Also included within Phenols are the non-flavonoids such as phenolic acids, tannins, hydroxycinnamates, stilbenes, and lignins.
Aspirin is a popular phenolic acid known as salicylic acid, which is essential for a plant’s immune response to attack.
Tannins are effective against internal parasites and bloat. They detoxify bad proteins. Tannins deter insects and excessive grazing by animals, also acting as sunscreens against ultraviolet radiation.
Stillbenes are produced by plants as phytoalexins, compounds released as a SAR response to insect attack.
Lignins are second to cellulose as the most abundant plant carbon compound on earth. Their importance is attributed to strength in the cell wall and a role in water transport. Lignins are a shield against environmental extremes in the fungi, bacteria, insect and root nematode categories. It synthesizes when there are adequate copper and manganese uptake. It also protects the plant against elevated temperatures and drought.
Terpenes are the largest group of Plant secondary metabolites, including carotenes, and carotenoids. Magnesium, copper, manganese, zinc, and iron are required to synthesize carotenes (tetraterpenoids). Terpenoids are volatile, acting to communicate with molecules to repel threats. Terpenoids are also able to attract the predatory insects that feed upon parasitic species. Plant hormones gibberellins and abscicic acid are diterpenes and react as phytoalexins in response to plant adversaries.
Alkaloids are highly present in root systems, and repel pests through their toxicity.
Micronutrient Function
Zinc– a vital element for energy, that partners with phosphorus. The ideal ratio between the two is ten parts of elemental phosphorus to one part of zinc when phosphorus levels do not exceed the norm. Zinc’s role with phosphorus the production of ADP (adenosine diphosphate) and ATP (Adenosine triphosphate) both critical energy components. Mycorrhizae are essential to maximize zinc uptake from soils. Over Fertilizing soils with phosphorus can suppress root colonization of mycorrhizae, lowering zinc uptake.
Copper– Copper acts to increase the uptake of the preferred form of nitrogen (Ammonium (NH4)). Copper is necessary to produce polyphenol oxidase, which is important for the synthesis of lignin and alkaloids to resist pests, as well as flowering and maturation. Copper deficiencies can be found in high-calcium soils, peat soils, high iron soils, high zinc levels, sandy soils, and excessive nitrogen and phosphate application.
Manganese– Manganese is critical for seed germination and early maturity of plants. It has a role in metabolizing nitrogen. It’s necessary for the assimilation of C02 to produce plant carbohydrates. Symbiotic rhizobia and their root nodules are rich in Manganese. Manganese also helps synthesize lignin, the plant protecting against heat, drought, diseases, and insects. Deficiencies can result in silent heats, reproductive failures, abortions, and a predominance of male births. Source of manganese are Manganese sulfate (28 %), and Chelated Manganese (5-15%).
Iron– Iron is widely abundant in soils, however there is often an unavailability due to alkaline soils, cold wet soils, and sulfur deficiencies. Excesses of phosphorus, manganese, and zinc (at low ph) can also interfere with iron availability. Foliar feeding is a good way to address low iron levels. Humic acid can be a contributing factor to make iron more available.
Boron– Boron is an anion, and doesn’t attach to a negatively charged soil colloid. It is found in the soil solution, or complexed with the humus fraction of organic matter. Boron is a potent partner with calcium and is the catalyst that facilitates the release of calcium out of the soil into the plant. Excess calcium in soils will hinder boron solubility, and uptake. Potassium uptake is improved with boron, but excess potash suppresses boron solubility and availability to plants. Boron aids in sugar translocation, the synthesis of nucleic acids, and the activation of cell division. Drought can be a detrimental factor in the uptake of boron. Boron deficiency can cause hollow stems in alfalfa, brassicas, and cause soft pith in apples. Boron also helps with the assimilation of nitrogen in plants, and translocates accumulated carbohydrates from daytime photosynthesis in the leaf down into the root overnight. Boron can be sourced from Borax (11%), Sol-U-Bor (20.5 %), and Boric acid (17%).
Molybdenum– Molybdenum is a trace mineral that increases in availability at a higher pH. It is essential for the production of the enzyme nitrogenase, required for nitrogen-fixing bacteria, especially in the root nodules of legumes. Molybdenum is a core element of the nitrate reductase enzyme necessary to convert nitrate into animes, and then into amino acids and finally protein. To reduce undesirable levels of nitrates in plants, make a soup mix containing about ten pounds of magnesium sulfate, four to six ozs of sodium molybdenate, two gallons of molasses, one pint of fulvic acid, and one pound of soluble humic acid powder in forty gallons of water per acre. The sources of molybdenum are Sodium molybdenate (47 %), and Ammonium molybdenate (58 %).
Cobalt- Cobalt is essential for nitrogen-fixation microorganisms. Three important enzymes depend on cobalt, Methionine synthatse, for healthy plant protein production, Ribonucleotide reductase, essential for DNA synthesis, and methylmalonyl coenzyme A mutase, required to produce “heme” in root bacteria. Cobalt is associated with yield and nutrient density on a legume. Foliar spratys dusting the seed with cobalt sulfate increase yields. Sources of cobalt are Cobal Sulfate.