03/26/2025
Maximizing Profits and Minimizing Inefficiencies
Nutrient applications, such as nitrogen applications, is undoubtedly one of the most important “make or break” economic and environmental decisions growers make. Not only can nitrogen affect yields and productivity, but growers can see a huge difference in their profit margins if applied efficiently.
When we think about managing nutrients such as nitrogen, our goal is the balance between supply, all of the inputs of nitrogen into the system, and the demand of the crop with the goal of maximizing your efficiency. Because nitrogen application can differ from one crop to the next, ProGro encourages growers to fully understand the conditions of their individual crops and farming practices before applying fertilizer. This includes when it is needed, how much should be applied, the placement, and source.
Minimizing losses
The goal when using these considerations is to minimize losses, with environmental concerns being top of mind. Any loss is a lack of efficiency, but any loss is also a source of greenhouse gases for pollution or a source of nitrates for pollution into the groundwater. Research has shown that nitrates move through the soil very rapidly, and as you increase applications, uptake of nutrients from the soil is not uniform. For example, if fertigation is infrequent and application exceeds a certain rate, saturation can occur causing waste or leaching.
“A large proportion of that nitrogen will sit in the root zone waiting for the plant to catch up. This is an important principle because it underlies where and how inefficiencies occur.” Growers can avoid these scenarios if they follow the 4 Rs of nutrient management: right rate, at the right time and in the right place, using the right source of nutrients.
Right Time
Firstly, it’s important to understand the ideal time to apply nitrogen to the crop you are raising. Studies show there is limited nitrogen uptake from the soil very early in the season. Each crop we raise as various uptake depends at various times throughout the growing season. Having Nitrogen available at these times is critical for development of the crop along with yield production. If the Nitrogen is available at a different time than crop uptake the applications that we are making are at a greater risk of environmental impact. Optimal fertilization will occur with multiple applications in a season, timed accordingly with the demand of any crop.
“Those early excesses are particularly prone to losses from rainfall, irrigation, and other events, so you have an increasing number of periods where there’s excess availability of nutrients and hence, the potential for loss.”
Active Root Zone Placement
Another key aspect of nitrogen application is placement. This is where growers must be educated in understanding the relationship between irrigation and nitrogen movement. Nitrogen that sits on the surface of the soil and remains in the top five inches will be lost if water moves through the profile.
To be utilized properly, nitrogen must be kept within the active root zone, which through research, has proven to typically be within the top 12 inches of soil. This is especially true for the young roots that are highly active in feeding.
So, how can growers like you ensure fertilizer applications remain within the active root zone?
Less is More
This “spoon-feeding” method is known as continuous fertigation (fertilizing with every irrigation) as opposed to episodic fertigation (fertilizing once every month or two). If there is too much excess caused by episodic fertigation, that is where inefficiencies occur causing leaching or gaseous nitrogen losses, which can come with several implications.
Another factor that needs to be considered is how irrigation distribution uniformity determines nitrogen distribution uniformity.
If you have a very uniform irrigation system, you inject 250 pounds of nitrogen in a year, and you will be able to deliver those 250 pounds uniformly across the orchard. If you have a distribution uniformity that’s poor, not only are you not distributing water uniformly, but every time you do an injection of a fertilizer, you’re also not distributing the fertilizer uniformly. Just because you have an irrigation system, and you are injecting throughout the season does not necessarily mean you are doing it correctly.
It’s very clear that for profitability, efficiency, lack of nitrogen loss, and environmental considerations, that continuous fertilization strategies are the secret to growers’ success. If this topic intrigues you, or if you would like more information about timing of applications for the crops you are raising, please feel free to reach out. I am here to be a valued member of your team, feel free to reach out at any time.
“Agronomy Never Lies”
