Magnesium (Mg) is one of three secondary macronutrients, along with calcium and sulfur, required for balanced crop nutrition. Often overlooked, Mg deficiencies can lead to reduced crop growth and yield.
Historically, many soybean fertility programs are based on the philosophy of “make do with what’s left.” But progressive growers are finding it’s important not to forget this crop’s primary job is to pull nutrients out of the soil, and that those nutrients need to be replenished.
Crops need magnesium to achieve proper growth and development, which is why it is important to choose a fertilizer source that provides an adequate amount of magnesium.
Without photosynthesis, plant life wouldn’t exist. And without magnesium (Mg), there would be no photosynthesis. Plants couldn’t produce our food, and hunger would become our No. 1 concern.
In order to thrive, and ultimately achieve higher yields, crops need to receive the right amount of nutrients throughout the growing season.
A fertilizer plan designed to reach top yields ensures adequate plant nutrition is available and often relies on ideal weather conditions.
Some growers are considering a shift from a corn and soybeans rotation to continuous corn. More nitrogen (N) will be needed since soybeans will no longer provide some residual N. Other nutrient needs will also change, especially phosphorus (P). Corn, unlike soybeans, is planted early in soils that are more likely to be cool, moist and with a heavier residue cover. These conditions can suppress the uptake of P by corn and increase the likelihood of crop response to fertilizer P. Research shows that P, with some N, applied in a band two inches to the side and below the seed, boosts seedling access to a readily available supply of P.
Sulfur deficiency in corn can masquerade as nitrogen deficiency. Boron deficiency in soybeans may remain hidden — the only sign being a yield below optimal.
Plant experts often say that high yields of good quality crops don’t result from any one factor (such as fertilizer application, or planting the best variety), but to a whole set of effective management inputs, generally defined as “best management practices.” Keeping the importance of best management practices top of mind, it’s instructive to consider the interactions of soil fertility and soil compaction in affecting plant growth.
Soil scientists and consultants often get confronted with these questions: “My soil analysis showed a high level of nutrient ‘X.’ Is all this ‘X’ actually available for uptake by plants? Might I see a response to applications of ‘X’?”
Justus von Liebig, a 19th century German chemist, made great contributions to the science of plant nutrition and soil fertility. While Carl Sprengel, a German botanist, formulated the “theory of minimum,” Liebig investigated and popularized the scientific concept we know today as “Liebig’s Law of the Minimum.” This concept demonstrates that plant growth is not controlled by the total amount of available resources but by the scarcest.