There is considerable discussion in the market about new regulations coming out of the California Department of Food and Agriculture requiring less use of nitrogen on crops. While this can be disturbing news for many growers, the fact is there are a host of ways to get more from less in nitrogen applications, and we’ve been doing it for years.
One of the great paradoxes of farming is that a lack of nitrogen is regarded as one of the great and most prevalent limitations on plant growth, yet plants are bathed in nitrogen, which makes up 78 percent of our atmosphere. We’ve all heard of the nitrogen cycle, but we may not have heard that soil biology plays a vital role in the conversion of nitrogen into a form that plants can utilize. And here is where the conflict starts. We learned to synthesize ammonia to improve crop production, but it was a flawed plan because the fertilizers simultaneously degrade our Soil Organic Matter (SOM), the stuff that holds water in our soils and helps transport nutrients – nitrogen and many others – to our crops. Faced with this degradation, to hold onto past yields farmers have had to steadily increase their use of synthetic fertilizers and pesticides as their soils steadily degrade further and further. It’s a vicious cycle that needs to be broken.
The good news is that the process of turning nitrogen in the air into plant-available forms occurs naturally in healthy soil systems, through a multitude of microorganisms. This is called biological nitrogen fixation and is done by symbiotic organisms such as Rhizobium bacteria in legumes and free-living nitrogen-fixers: azotobacteria, cyanobacteria/blue green algae and countless thousands of other species. Andaman Ag sells a nitrogen fixing bacteria called TwinN that has shown impressive results in many crops and, frankly, represents a product category of the future as we wean ourselves off synthetic nitrogen. Biological fixation is the major source of plant-available nitrogen in natural soil systems.
The buffering capacity of soils is important here. We don’t have to have perfect timing for the application of our nutrients if they’re already buffered in the soil and available. Negatively charged anions like nitrate, as well as sulfur and boron, are readily leached from the soils with low levels of organic matter. But the humus in organic matter has charged sites that will attract and store the nitrate anions. Most of the nitrogen in the soil is stored on humus or the dark organic matter, so the higher the level of SOM, the better the soil can retain and, when necessary, make available usable nitrogen.
A high percentage of the nitrogen in soil organic matter is in amino acid form. Amino acids are some of the most important building blocks of life because they are the basis of DNA, RNA, proteins and hormones and they are key to many vital functions. Plants generally synthesize the amino acids that they need by combining the nitrate form of nitrogen with the glucose sugar that they form through photosynthesis. This is why nitrate is so important. Our product, Pacific Gro is high in amino acids.
How do we improve our soils so we can rely less on synthetic nitrogen inputs? Well, the key is
a continuous supply of organic matter, and you need to grow it. Farm management should be about producing as much biomass as possible and avoiding bare earth. Legumes should be incorporated as much as possible in all rotation systems in cropping, and they should be a permanent component in all perennial systems such as pastures and orchards. Cover crops should be cultivated to maturity. This not only produces more biomass on the surface, but it helps ensure that the roots get deep into the soil helping to generate additional SOM as they expand into the soil profile. We can also add compost teas like our MetaGrow compost tea, made from worm castings, to boost the level of microbiology in the soil. The more microbes, the more biomass that’s processed into useful organic matter.
Finally, the efficient production and use of N requires the correct mineral balance. Some of the key nutrients tied to the processing of nitrogen by the plant are calcium, phosphorus, sulfur, selenium, molybdenum and cobalt. Andaman Ag sells a number of micronutrient products, including many forms of calcium.
Pulling back on synthetic nitrogen is an opportunity to get on the long-term SOM playbook. By combining natural nitrogen fixers, with natural nitrogen sources like fish and soy and having a plan that includes a broad application and includes trace levels of micronutrients, you will quickly be on your way to increasing SOM. Conventional growers typically see an immediate benefit from introducing biological practices.
An important note: As harvest approaches, it is time to plan for post-harvest applications to give your perennials their best chance at a high level of production in the next season. Post-harvest is a critical application and should not be dismissed, regardless of the season’s challenges.
