Over the last several decades there have been substantial yield improvements in soybean.
Are you seed-placing your phosphorus (P) and basing application rates on seed safety rather than crop requirements? You may be leaving yield on the table. Recent research out of the University of Manitoba examining seed-safe rates of P and sulfur (S) in canola is showing that P applied at rates based on seed safety may not be adequate to maximize canola yields.
Corn growers need balanced crop nutrition to maximize a corn crop's yield potential and get the most out of their fertilizer investment. In practice, this requires making all of the required nutrients available to the corn crop at the right time.
Farmers and retailers who have been in the business for a while probably find themselves wondering why so much attention has been paid to sulfur the past several years. After all, sulfur used to pretty much take care of itself, supplied to plants by organic matter and deposited by rainfall. Today, if you don’t keep a close eye on sulfur levels, it’s a question of not if, but when, yields will be affected.
The oxidation of elemental sulfur (S⁰) to sulfate sulfur (SO₄) in soil is a biological process and is carried out by several kinds of microorganisms. The rate at which this conversion takes place is determined by three main factors:
1. the microbiological population of the soil;
2. the physical properties of the S⁰ source; and
3. the environmental conditions in the soil.
The first occurrences of sulfur (S) deficiency in corn were reported in the 1960s. At the time, sulfur deficiency was virtually unheard of. Textbooks devoted chapters to nitrogen (N), phosphorus (P) and potassium (K) and their roles in crop production. Sulfur received only short paragraphs.
Sulfur is an essential component of two amino acids, methionine and cysteine. These amino acids are key building blocks needed for protein formation in the cotton plant. Research studies indicate that high-yielding cotton will take up nearly 40 pounds of S during the growing season. That’s about the same amount as magnesium (Mg) and about two-thirds of the phosphorus (P) needed for developing cotton roots, stems, leaves and bolls. A shortage of S can also trigger inefficient plant use of nitrogen (N), since both are required for protein development.
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.
Sulfur (S) is widely distributed throughout the world in many forms. Yet in some soils, insufficient S levels can’t meet crop needs. The good news: No such shortage applies to the many excellent S-containing fertilizer products that can address S deficiencies where they occur.
The signs may mimic nitrogen deficiency — yellowing leaves, reduced yield — or there may not even be any overt signs. But make no mistake, unless you are feeding your crops sulfur, you are probably underfeeding them, according to crop nutrition experts.
A variety of coatings have been applied to fertilizer particles to control their solubility in soil. Controlling the rate of nutrient release can offer multiple environmental, economic, and yield benefits.