When the topic of nitrogen comes up as it relates to plant science, most associate it with the deep green color of plants and lush vegetative growth.

With the exception of carbon, hydrogen, and oxygen, there is more nitrogen in a plant than any other element. It serves as a crucial part of many essential plant functions such as:

  • Primary component in chlorophyl, the compound responsible for photosynthesis and what gives plants their green color
  • Part of the necessary elements needed to create amino acids, which are the building blocks of proteins and enzymes
  • Serves as a key building block of multiple different vitamins
  • Improves the quality and quantity of vegetative growth

With all the benefits nitrogen provides to the growth of a plant, it is easy to fall into the trap of thinking “if a little works well, then a lot will work even better.” Like all things, balance, timing, and moderation are key.

Methods of Applications

Nitrogen fertilizers come in a host of different forms, but the two methods of applications are either application to the soil or to the foliage of a plant. Both methods have positive and negatives, however both methods are critical. In the beginning stages of a plant growth cycle, nitrogen needs are relatively low and foliar applications can provide adequate levels of nutrients. As the plant grows though, the nutrient needs grow along with it and foliar fertilizers alone cannot keep up without help. This is where the need for soil applied fertilizers are needed as well.

The next question is, “Are there any downsides to applying nitrogen in general or too much of it?” The simple answer is yes. Like all things, moderation is the key to success. The nitrate form of nitrogen can end up in groundwater sources, which can lead to health concerns. Careful planning is done to ensure excess amount of nitrogen fertilizers aren’t applied in susceptible areas.

With fertilizer prices skyrocketing in the last 12 months, financially it is in our best interest to apply only what is necessary. In some parts of the United States, local governments have even gone so far as to regulate the total amounts of fertilizer that can be applied per year.

California Ag Order 4.0

One such example of legislation limiting future fertilizer applications, is California Ag Order 4.0. Adopted on April 15, 2021, this order sets forth multiple new regulations for the agricultural industry with the key piece being future nitrogen restrictions. December 31, 2023 is a looming date that California growers should take note of.

On that day, California state regulations of nitrogen begin, but only as a target amount. A target is simply a goal that growers need to meet, but this target amount will take a legal twist in 2027, when the word target becomes limit.

Once this occurs, the total allowable nitrogen per acre per year will then be legally enforced. To add additional complexity, that limit will continue to decrease every few years. If a grower is over the legally allowed N, there will be a significant penalty.

By the year 2050, the amount of nitrogen allowed per year will bottleneck all the way down to only 50 lbs. per acre per year.  This will lead to a significant challenge to growers unless changes are made.

The University of California has shown through research, that to produce one crop of lettuce for example, it requires approximately 100 units of nitrogen.  The 2024 season target for Ag Order 4.0 is 300 units of nitrogen per acre per year. This may not seem like a significant issue as 100 is well below the target of 300, but in areas such as Salinas, where approximately 61% of all the leaf lettuce in the United States is grown, growers need roughly 3 crops per field per year to break even. That will put growers right at the target amount, assuming things go exactly to plan.

Changes to legislation can occur at any time. For the most up to date and complete information, contact your local representative.

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