Foliar Feed Applications to Soybeans and Their Benefit:

This article was written by Randy Anderson from CPS.

When it comes to plant development, common stresses are caused by moisture, nutrients, wind and cold. During development these factors can affect a crop for the entire growing season.  We try to plant our soybeans as early as possible to gain a yield advantage by increasing the number of nodes a plant develops.  Each of these nodes have the potential to produce 9-12 flowers that we hope develop into pods and eventually have beans fill those pods.  Typically the plant aborts about 70% of these pods due to plant health and how many beans the plant feels it can bring to maturity. (Unless our last name is Cullers and we abort closer to 25%).  There are many “roadblocks” or “speed bumps” we hope to get through during this process.  The use of a product called Awaken® can help us get through many of these trying times and lead to higher yields.

I am going to talk a little on the foliar feed applications that many of you have already used successfully.  First, the product Awaken®, at its core is Zinc Ammonium, Nitrogen, and Potassium in a well-rounded micronutrient package.  The soybean plant receives the majority of its nutrients through mass flow as water is brought into the plant.  The leaves and stems are also efficient at absorbing small amounts of nutrients. Up to 80% of plant needs can be supplied during critical periods by the leaves and stems.  Many of the nutrients applied also have a positive effect on chlorophyll levels and increase the photosynthetic rate of the plant.  Green is good, greener is better! 

The above ground portion of the plant acts as a solar panel to catch and process the energy from the sun.  Bigger, greener leaves are better solar panels and raise the metabolism of the plants.  In the vegetative stages, this increase in energy increases the amount of growth and number of nodes that can develop in a given period of time.  If we can get two more nodes on a plant prior to maturity, the potential is there for 18 – 24 more pods. Due to the plant having raised its metabolism level, it has a need to increase its uptake of water.  When this occurs we get the advantage of bringing in additional nutrients from the soil through mass flow.

This is a clear win-win situation.  We get an advantage from applied nutrients as well as better intake of soil nutrition.  Foliar feeding during the reproductive stages (after last week of June) has an additional benefit.  The foliar application, through increased metabolism and better plant health, sends a signal through the plant that it is “worthy of reproducing.  The message sent to the plant is that it is healthy enough to retain more flowers and pods. Instead of aborting 70% of flowers and pods, it reduces that number to 50 – 55%.  In Awaken® the following nutrients and functions in the plant are listed below:

• Nitrogen – essential component of proteins and necessary for chlorophyll
• Potassium – essential for N metabolism, promotes root growth, and stalk strength
• Zinc – Catalyst for plant growth, chlorophyll production and essential for seed maturity
• Iron – Promotes the formation of chlorophyll
• Copper – A major part of the photosynthesis enzyme and very important during the reproductive stages
• Manganese – Part of enzymes involved in respiration, protein synthesis, and herbicide metabolism
• Molybdenum – Essential for N fixation
• Boron – Producer of starch, promotes maturity, seed development and is involved in N and carbohydrate metabolism

Our goal in using foliar feed products is to increase yields and profitability. 

Keys to high yielding soybeans:

• Achieve more nodes
• Retain the flower
• Develop the pod
• Increase test weight

Remember to keep in mind foliar feeding does NOT and is NOT intended to replace soil nutrition.  It is meant to bring us to a higher level of production that is limited by soil nutrient amounts and the plant’s ability to extract them. We can accomplish a lot through foliar applications!