With spring approaching, attention is turning to fertilizers and their use. Farmers are gearing up for topdressing wheat and there are more meetings planned regarding Lake Erie and phosphorus and algae. The International Plant Nutrition Institute (IPNI) (the old Phosphate and Potash Institute) has issued a new series of fact sheets about crop nutrients. This series of 17 fact sheets was written by IPNI scientific staff and focuses on essential plant nutrients and their use. Listed in alphabetical order, these include the following elements and their use.
Boron (B) is a widely used micro-nutrient for many agricultural crops, especially alfalfa as well a large number of fruit and vegetable crops.
Calcium (Ca) is a “secondary” nutrient that plays a vital role in the production of high quality crops. It plays a key role in plant stability, strong cell walls that help prevent invasion by numerous fungi and bacterial. It also has an important function as a valuable soil amendment.
Chloride (Cl) is commonly found in nature, including water, soil and air. It was generally recognized as a plant nutrient in the mid 1950’s though studies about crop response and optimal management practices have been done since.
Cobalt (Co) has been occasionally reported to benefit crop growth, but the need for supplemental Co is rather rare. Cobalt has only recently been recognized as a potentially essential nutrient for plants because it is necessary for nitrogen fixation within the nodules of legume plants.
Copper (Cu) is one of eight essential plant micronutrients. Cu helps plant resist plant diseases and improve crop growth and quality. Commonly applied Cu sources include fertilizer, animal manures, biosolids and pesticides.
Iron (Fe) is a component of many vital plant enzymes and is required for a wide range of biological functions. Most soils contain abundant Fe, but in forms that are low in solubility and sometimes not readily available for plant uptake.
Magnesium (Mg) is one of the micronutrients that is taken up by plants in quantities similar to that of phosphorus. It is essential for many plant functions, including the production of chlorophyll.
Manganese (Mn) is essential for plant growth and reproduction. It is needed in only small quantities by plants, but is essential to photosynthesis reactions and root growth. Crop deficiencies often show up on high pH soils in dry years.
Molybdenum (Mo) is a trace element required in very small amounts for both plant and animal normal growth and development. In legume crops, it is needed by the root nodule bacteria for nitrogen fixation.
Nickel (Ni) is the most recent element to be added to the list of essential plant nutrients. Although needed in very low amounts, Ni helps in the nitrogen nutrition of plants and playing a role in protecting against some plant diseases.
Nitrogen (N) is a part of the makeup of all plant and animal proteins. The nutritive value of the food we eat is largely dependent on having an adequate supply of N. About 80 percent of the air we breathe is nitrogen gas. However plants cannot utilize N until it is changed from the ammonium and organic to the nitrate form.
Phosphorus (P) is present in every living cell of both plants and animals. No other nutrient can be substituted for it when it is lacking. P is a “macro nutrient” that is essential for plant health.
Potassium (K) is the last of the “big three” macro nutrients, along with nitrogen and phosphorus. Plants with sufficient K are better able to withstand stress, insect damage and many plant diseases as compared to plants low in K.
Selenium (Se) is not essential for plants, but is required for many physiological functions in humans and animals. It is essential in more than 20 human proteins where it is involved in many diverse roles such as cancer protection, anti-oxidants, maintaining defenses against infection and regulating proper growth and development.
Silicon (Si) is also generally not considered an essential element for plant growth. However it plays an important role in plant nutrition, particularly under stressful growing conditions. Therefore it is recognized as a “beneficial substance” or “quasi-essential.”
Sulfur (S) is used by plants in the fourth most needed quantities. Due to the cleaning of the atmosphere and the Clean Air Act, farmers now are adding S to provide stalk strength and plant metabolism. Wheat grown in soils with low levels of available S results in lower quality of grain protein, making the flour less suitable for making bread.
Zinc (Zn) is another trace element though is a common deficiency in many crops grown for human food production.