Magnesium (Mg) is a secondary nutrient and the only mineral component of chlorophyll, the green pigment in plants. Without magnesium, there would be no chlorophyll and without chlorophyll, there would be no photosynthesis.
Besides being integral to the process of capturing and converting sunlight to energy, magnesium also helps a plant efficiently use carbon dioxide (C02).
Magnesium plays an important role in the translocation of phosphorus, aids in the functions of several plant enzymes, and helps the plant form and transport sugar and starches. Insufficient magnesium will cause a lack of vigor, delayed reproduction and a serious reduction in yield.
A wide range of crops, including cereals, oilseeds, corn and vegetables are sensitive to magnesium deficiency, even if grown on high Mg soil. Oilseeds lacking Mg will see their oil content dropping at harvest.
Signs of a magnesium deficiency will appear in the leaves. As magnesium moves freely from older to younger tissues in the plant, older leaves will show symptoms first. Watch for interveinal chlorosis – leaves turn pale yellow to brown, but veins remain green – leading to necrosis and premature dropping. These symptoms can be similar to other nutrient deficiencies, so it is important to conduct a soil and tissue or SAP test if magnesium deficiency is suspected.
There are several factors that can limit the availability of magnesium, including cold, wet conditions; sandy, acidic soils, especially in areas with high rainfall; coarse textured soils in humid conditions; soils that have had heavy inputs of potassium or high in Mg (>20 per cent in the base saturation); and soils that have received frequent manure application.
Deficiency or excess of Mg in the soil affects potassium uptake and the K:Mg ratio, which controls productivity and yield, and excess Mg will affect the pH of the soil.
OMEX’s Uptake Mg and PK Bulk are liquid foliar fertilizers containing magnesium that are very effective at preventing or quickly correcting Mg deficiency to protect yield and quality. PK Bulk contains high concentrations of phosphorus, potassium and magnesium. It is suitable for all major field and horticultural crops and vegetables, and can be combined with other pesticides and fertilizers to help mitigate or correct nutrient deficiencies. Expect to see a greener crop, increased biomass and improved grain fill. PK Bulk is also effective for preventing damage from late-season oxidative stress and optimizing yields.
Talk to your retailer or OMEX sales professional about how balanced, proactive plant nutrition can help your crop live up to its full potential.
In our next post: Zinc – a key factor in germination and root development.