Two rapid, systems-thinking ways to reduce your dependence on off-farm nitrogen inputs
Nitrogen management is an important discussion and one that I am very passionate about, perhaps because there is often strong debate around how it should be handled. Conventional growers and agronomists often think they need to apply lots of it, while others think the stuff is evil.
The truth is that all plants desperately need nitrogen. Without it, they will not grow. They cannot be dark green. They cannot photosynthesize and produce sugars. They cannot make proteins. They cannot produce fats, oils, omega-3s, or any of the other important and healthful compounds we need.
The all-important question “Do plants need nitrogen?” is “Where is the nitrogen coming from?” From the atmosphere? Cover crops? Manure? Synthetic nitrogen applications?
The Ideal and the Challenge
How does the system work naturally? How did God design it to work?
The air we breathe is 78 percent nitrogen, which means there are approximately 32,000 tons of nitrogen over every acre of land. However, this nitrogen cannot be directly accessed and used by plants; it has to be “fixed” into the soil first.
There are two critical pieces that have to be in place for that to happen at scale: First, soils have to be well aggregated, with minimal compaction present in the top 6-12 inches, so that this atmospheric nitrogen can be inhaled into the soil during the earth’s natural inhaling process every evening. Secondly, this nitrogen needs to be fixed into the soil either by soil biology (particularly nitrogen-fixing bacteria) or by legumes that are nodulating (the nodules actually need to be pink inside).
It’s easy enough to say that we need very active soils for reduced dependency on nitrogen inputs. It’s quite another to actually achieve that, because nitrogen is critical for photosynthesis, a process that is critical for feeding the soil microbes, which are critical for active soil. So we come around full circle.
The challenge is to bridge that gap, and until you have done that, you have to be very careful. You have to earn the right to reduce nitrogen inputs.
What makes this all the more challenging is that soluble forms of nitrogen are actually very hard on soil biology. They actively suppress the very thing we are trying to achieve.
The Approaches
Given the challenges we just described, what approach should we take to successfully become less dependent on off-farm nitrogen inputs?
Essentially, there are two good systems-thinking, rapid-response approaches that I’m familiar with. I will start with specifically mentioning the nitrogen aspects and then circle back to the overall concept because the reality is that both approaches must be rooted in biology or they will not reduce nitrogen inputs long term.
The first is to use bedding pack manure and aggressive cover cropping strategies. Many farmers quickly discover that manures and legumes, especially clovers, can do wonders for improving depleted soils and providing nitrogen for the following crops. As the soils improve, past the initial cover crop, they quickly move to more diverse cover crops and grazing systems — because diversity is key to soil regeneration.
The second approach is to use nitrogen inputs carefully while on the path to becoming less dependent on off-farm inputs. For organic growers, this obviously has to be organic forms. For other growers, it means using specific forms of conventional nitrogen for specific plant stages and stabilizing them so that lower application rates can be used and so that they don’t shut down the biological processes we are trying to build.
Here is the short version of what this looks like. First, divide the total units of nitrogen you typically apply by two. If you historically apply 200 units, your answer is 100 units when using this program. Split that into four applications. The first two applications are in the form of nitrate or ammonium, with 40 percent of total units being applied at planting (broadcast or 2×2), and the second application is applied as a sidedress as late as possible, also at 40 percent of total units applied. The key is that both of these applications have to be stabilized with carbon, sulfur, and molybdenum, in such a way that all the nitrogen is no longer in a soluble, water-leachable form.
The last two applications are foliar in the form of urea, applied as late in the maturity stage as possible and about two weeks apart. The rate for each is 10 percent of the total units being applied. For some crops, this rate may need to be adjusted downward to avoid burning effects.
The key in all of this is to use nitrogen to build sugars and proteins so that plants photosynthesize well (and thus feed and enhance soil biology) without becoming dependent on nitrogen and shutting down the very biological systems we are trying to build. In my opinion, from the perspective of photosynthesis, this means also looking at other minerals in addition to nitrogen. The healthiest plants I see have adequate levels of total nitrogen but are balanced with trace minerals, including iron, manganese, boron, and molybdenum. Use them wisely to increase photosynthesis and protein production.
Whichever approach you decide to try, you can start either in spring or fall, although the most effective time to start is in the fall, since this is when soil organic matter is built the easiest.
Ideally, you would start by looking at soil compaction and remediating it with intentional tillage or disturbances (usually subsoiling in fields). This is important because microbes do not thrive in soil that doesn’t have good gas exchange. You don’t want compaction to hinder the inhaling effect that brings the nitrogen into your soil and starts this process.
The next step is to sow good, diverse-species cover crop blends. Diversity is the key to regeneration. A seed treatment can be applied that contains nitrogen-fixing bacteria and mycorrhizae. There are many on the marketplace that cost only a few dollars per acre and are well worth the money.
Another well-worthwhile approach is to apply a soil primer program of biostimulants and microbial inoculants to the soil, usually once the cover crop is several inches tall. The purpose of this is to jumpstart the soil biological system on a broad scale. Remember: this is a system, and when you improve one part of the system, the whole system improves. You will get better nutrient release from the soil, which improves photosynthesis, which feeds more microbes. The other approach we often take is foliar feeding cover crops with trace minerals and either amino acids or urea-based nitrogen — again, with the intent of increasing photosynthesis.
If all this sounds complex, it is. It’s not easy at first. But neither is conventional farming. It’s a system, and the better we work with God’s design, the better off we will be in the long run. Start somewhere, start small, and be intentional. But try it.
