Either calcitic or dolomitic limestone can be used when magnesium test results are greater than 100 ppm and potassium levels are below 250 ppm. Other things being equal, a high Calcium soil will have more oxygen, drain more freely, and support more aerobic breakdown of organic matter, while a high Magnesium soil will have less oxygen, tend to drain slowly, and organic matter will break down poorly if at all. You can have your soil tested to see where your particular soil may be lacking and adjust the levels accordingly. reportwill suggest an applicationof magnesium. … To have a successful garden, test your soil and amend it if necessary to create the best possible growing environment for plants. It is particularly important to use dolomitic limestone when the level of potassium is high because high potassium levels make magnesium deficiency more likely. In soil, magnesium is present in three fractions: ... dry soil conditions and high levels of competing elements, such as potassium and calcium, reduce the availability of magnesium. Effect of Soil pH on magnesium availability: In low-pH soils, the solubility of magnesium decreases and it becomes less available. Mostsoils low in magnesiumare often acidic and low incalcium. While too much magnesium for plants does not directly affect plant production, it can cause deficiencies in the other nutrients in the soil such as calcium and potassium. 2+Magnesium Mg Manganese Mn2+ 2+Copper Cu Zinc Zn2+ Anions (–): Nitrogen NO 3 – Phosphorus H 2 PO 4 – and HPO 4 2– Sulfur SO 4 2– Boron H 3 BO 3 and H 2 BO 3 – –Molybdenum HMoO 4 and MoO 2– Chloride Cl– 2 Most soil test values do not vary greatly from year to year. Use dolomitic limestone on soils with a magnesium soil test of 100 ppm or less. Testing your soil means you determine the pH level and nutrient content. Very little amount of Mg may reach to plant roots by interception. The soil test value for a given nutrient does not give you the total amount of that nutrient in the soil; it instead provides an index of nutrient availability that is correlated with plant response. Magnesium is absorbed by plants from the soil solution as Mg 2+ ion. Plant Mg needs in most soils can be satisfied by the process of mass flow similar to that of Ca. Too much of this nutrient or too little of that, and you have problems. Phosphorus, potassium, calcium, and magnesium soil test values are indicators of the relative available nutrient levels in the soil and not equal to the total amounts of these nutrients available in the soil for plant uptake. Epsom salts are a natural way to add magnesium to plant soil without affecting the pH, or acidity, of the soil. Importance of pH levels and nutrients. Both are important factors in how well your garden grows. Under such conditions, magnesium deficiency is more likely.