The Benefits of Selenium for Plants and Soil Microbes

Selenium has been described as a fundamental building block, essential for most forms of life – human, plant & microbes. If insufficient levels of selenium, life in general struggles to thrive, even perishes. Selenium (‘Se’ in the periodic table) was discovered in 1817 and it takes its name from selene, the Greek word for “moon,” because of its similarities to tellurium, which was named after the Greek word “earth”. Selenium is an odourless metalloid (an element which has both metallic and non-metallic properties). It can be a grey, red or black solid and can commonly be found as water-soluble selenate in well-aerated, alkaline soils (where in tends to be more bio-available, though not always) plus in some water and foods. Selenium compounds include selenium oxide or selenium dioxide, selenium fluoride or selenium hexafluoride, selenium hydride or hydrogen selenide, selenium oxychloride, selenium sulfide or selenium disulfide, selenic acid, selenous acid and the premium form of Selenium Colloid and Selenium Methionine. Upon erosion of selenium-rich rocks, selenium particles disperse via water, wind and sedimentation processes. The atmosphere is also supplied with selenium through soil dust, volcanoes, burning of fossil fuels, industrial emissions and volatile products produced by plants and animals. Often lowlands and poorly drained areas receive more selenium. Selenium moves through topsoil until adsorbed by clay particles, iron hydroxides or organic particles.


SOURCES OF SELENIUM… Meat can be a good source of selenium, namely pork, beef, turkey, chicken, fish, and shellfish, as well as eggs. Studies have shown that levels in animal tissues tend to be reflections of the amount and types of selenium in their diets. Fruits and vegetables on the other hand have poor dietary sources of selenium with less than 0.01 ppm (parts per million). Cucumbers, carrots, cabbages, onions, and radishes have higher values, 0.015 to 0.140 ppm, and mushrooms and garlic between 0.060 and 0.249 ppm. Some beans and nuts, especially Brazil nuts, contain selenium. Some plants growing on seleniferous soils absorb low levels of selenium. White clover, buffalo grass and gramma grass are poor accumulators of Selenium. However, high sulfur-containing plants in the cabbage & mustard family including brassica species of broccoli and cauliflower are stronger concentrators of selenium.


Selenium helps plants cope with stress by stimulating the plant cell antioxidant capacity through the enhancement of the activity of antioxidant enzymes and the synthesis of GSH, PCs, ascorbate, alkaloids, carotenoids proline, and flavonoids. Selenium also enhances crop growth and crop tolerance to abiotic stresses, such as low or high temperature, deficient or excessive water, high salinity, heavy metals, and ultraviolet radiation. Benefits of Selenium for Plants include: • Better able to Cope with Stress… hot/cold, dry/wet, wind, contaminants, disease. • Less Uptake of Toxic Metals… which can harm plants and be dangerous for humans and animals • Improved Plant Development… health, size, and appearance • Increased Quality of Yield… including form, colour, nutrients, taste & shelf-life • Increased Quantity of Yield! A side benefit is humans & animals can benefit from higher levels of selenium in plant foods. In general, total soil Selenium of 0.1 to 0.6 mg/kg is considered deficient. Unfortunately, the selenium level in most soils is generally less than 1 mg Se/kg soil. An exception is seleniferous soils which can be as high as 4 to 100 mg Se/kg soil. There is a possibility that soil and plants can have too much selenium which may lead to symptoms of toxicity. There tends to be a considerable threshold for that. You can easily find out if your soil has enough Selenium through soil testing. Note, however, that in acidic soils, the bioavailability of selenium is less than in alkaline soils. If soil is low in selenium, there are a few ways to increase the level available. Applying manure for example, from animals fed selenium-adequate feeds increases the soil selenium content slightly. Slow-release fertilizers can be used. For faster response, you can add Selenium through liquid fertilisers which can be applied directly to the soil or on the leaves. If adding Selenium, follow a strategic plan. In other words, the right form, at the right rate (not too much, not too little), at the right time and the right place. The molecular form of Selenium compounds should be considered for bio-availability and any compound residuals. In terms of applying Selenium at the right time, it must be when the crops need them the most and can best use them. In terms of the right place, Selenium must be applied either to the soil for the roots to absorb or sprayed directly on the plants. From country to country, there are wide differences in the selenium level in foods, depending on the kind of food and location where the food is produced. There are broad areas of Canada and the United States where plants contain low levels of selenium. In the United States the most selenium-deficient areas are the Northwest, Northeast, the Atlantic coastal area, Florida, and regions surrounding the Great Lakes. The selenium content of most soils lies between 0.1 and 2 ppm. The maximum quantity of selenium found in several thousand soil samples in the United States did not exceed 100 ppm, and the majority of the seleniferous soils analysed had on average less than 2 ppm. Australian soils are generally low in selenium as shown in the map below:
Source: ResearchGate
This means that livestock may suffer from Selenium deficiency. Selenium deficiency in livestock has been linked to muscular weakness and muscular dystrophy, reduced appetite, poor growth and reproductive capacity, and embryonic deformities. To overcome this problem, chemical fertilisers and manures are being used. However, modern soil tests are revealing that chemical fertilisers and harsh manures are causing imbalances that lock-up nutrients, kill-off important soil microbes and reduce water retention. Unfortunately, these imbalances restrict roots, diminish plant health and invite unwanted weeds, pests and diseases which further affect your quality and yield, and the extra expense of treatments are cruel. Some people turn to soil conditioners such as seaweed and worm castings, but with hardly any macro-nutrients, the results are often minimal. This is why we recommend UGF 6-in-1 which includes premium-grade Selenium Colloid and Selenium Methionine, not cheaper concoctions or less effective alternatives. Its 6 main functions are: 1. To Act as a Natural Growth Stimulant 2. To Act as a Root Hormone 3. To Act as an Organic Fertilizer 4. To Act as a Plant Tonic 5. To Act as a Soil Conditioner 6. To Act as a Microbes Booster UGF 6-in-1 is a super-concentrated liquid, ready for you to simply dilute with water, apply and quickly notice the difference it makes. You will notice a marked improvement in the health of your farm (crops & grazing livestock), lawns & sporting fields, gardens and pot plants.   For more information, click here:

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