Role of nutrients in soybeans

Jun 22, 2020


    Nutrient functions in plants, like in humans or any other living creature, are essential for life to exist. They must be held in balance for plants to remain healthy and productive.  There are sixteen essential nutrients required for plant growth with three of them — carbon, hydrogen, and oxygen — being provided by the environment.  The other thirteen nutrients must come from the soil or be applied. 

The first six are considered macro nutrients because they are needed in the largest quantities; they are nitrogen, phosphorus, potassium, sulfur, calcium, and magnesium.

Nitrogen is a key element in producing proteins that aid in the function of cells throughout the plant as well as in the production of DNA and RNA, which are the building blocks of life. Nitrogen and magnesium together are the main constituents of chlorophyll that allow a plant to produce food.

Phosphorus is a main component of ATP, which is an energy and storage transport medium. Phosphorus drives many of the biochemical processes that occur in the plant and is the backbone of DNA and RNA. Limited phosphorus will cause plants to grow and develop slowly.

Potassium is essential for photosynthesis and is another component of ATP. It also aids in the conversion of nitrogen into proteins in the plant. Potassium helps crops fight diseases and often called a poor man’s irrigation because adequate amounts allow the plant to use water more efficiently.

Sulfur is part of every plant cell and works with nitrogen to produce protein. It is important for protein syntheses and helps plants regulate the photosynthesis process. 

Calcium, in the plant, is responsible for calcium pectate that gives cell walls strength.   

Magnesium works with nitrogen in plants to help produce chlorophyll and helps with several plant enzyme systems. It also plays a key role in phosphorus metabolism.    

The remaining seven nutrients are considered micronutrients because they are needed in smaller quantities.  They are zinc, iron, boron, copper, manganese, molybdenum, and chloride.  While only needed in small quantities, their importance is still significant and deficiency will limit yields. 

Plants need varying amounts of nutrients at different growth stages.  Consider potassium in soybeans for example.  A study conducted by Dr. Ray Flannery shows soybeans produced 101bu/ac took up 149lbs/ac of potassium at full bloom. Then 36 days later during pod fill, the amount of potassium stored in the plant increased by 190 percent to 433lbs/ac.  It is during this time that foliar applied nutrients are required because the plant is limited by root size and is usually not capable of pulling up enough nutrients at this stage to keep up with demand.
 
 

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