Poor water quality has been a persistent challenge in agriculture, particularly due to sediment and nutrient loss from farmland. It is considered a “wicked problem” with conflicting social, political, economic, and environmental aspects that prevent solutions. In this blog series I will challenge the notion that degraded water is something we all have to live with because fixing the problem is too difficult or requires too many tradeoffs. I propose that the reason we have not been able to seriously address water quality is because we primarily focus our efforts on treating the symptoms of poor water quality rather than addressing the underlying cause of the problem. This is a very broad topic so I will focus for the most part on nitrogen management and nitrate leaching, but addressing the underlying cause of N loss will deal with almost all water quality impairments.
Most current N management recommendations focus on the 4R strategy (the right source, rate, time, and place) for managing nutrients in the field and edge-of-field practices to treat water that leaves the field. Vegetated buffers along waterways are a good practice. More questionable are engineering techniques to treat tile drainage water. The logic behind bioreactors and saturated buffers is that nitrate leaching is inevitable, so we should treat drainage water to remove the nitrate before it ends up in a body of water. These are engineering fixes applied to a biological problem. They treat the symptom (nitrate leaching) rather than address the underlying cause, which is poor soil function due to the way we manage cropland.
Edge-of-field engineering practices come at significant taxpayer expense, are only marginally effective, and will never scale to the point of doing anything meaningful to address water quality concerns. Everyone in industry, government, and academia who is honest with themselves knows this. Unfortunately, these practices have been co-opted to use as greenwashing to convince the public that the agricultural community is serious about addressing poor water quality, without doing anything that would require the industry to change. It’s time to move beyond the idea that we can engineer solutions and focus our energy on efforts that will deal with the underlying cause of the problem.
That brings us to in-field management. The 4Rs is a catchy slogan, but who decides what the right source, rate, time, and place for nutrients are? There are some restrictions on timing and amount of manure and/or nitrogen application in some locations, but enforcement is minimal and the 4Rs are voluntary. It’s really up to the farmer to decide what to do. Research on implementing 4R practices shows that they have very little effect on improving water quality. So, what is the underlying problem, and how do we address it?
Education, Understanding is Key
We are not fans of using regulation to solve environmental problems. Nobody likes being told what they can or cannot do. But one requirement that would make sense is education. Why not require every landowner, renter, and agribusiness professional to attend an annual soil stewardship training? We already do this for pesticide and manure applicators. This would be a far better use of taxpayer money than any other farm program or practice payment. If everyone worked together to implement the soil health principles, states would have no problem meeting their nutrient reduction strategy goals. The people managing our land hold everyone’s future in their hands. There should be some minimal expectations for soil stewardship in exchange for taxpayer support.
To start with, everyone in agriculture must understand soil function and ecosystem processes. The current 4R strategy is well intended, but it does not address the underlying cause of poor nutrient use efficiency and nutrient loss, which is dysfunctional soil. For that we need a different strategy – a 6P strategy – as in the six principles of soil health. Implementing the soil health principles should be priority one for all of agriculture, not just lip service. Soil needs to be well aggregated so it can breathe and infiltrate water or it will not efficiently cycle nutrients. Soil without adequate biological activity is prone to erosion and nutrient loss. The role that good soil function plays for nutrient stewardship cannot be overstated. It is nearly impossible to eliminate nutrient and sediment loss from bare soil. We must keep living roots in the soil year-round if we are serious about addressing water quality. This topic has been explored further in previous blog posts.
The Role of our Soil Microbiome
Here’s the unfiltered truth. None of the solutions proposed here will work if we keep starving and killing the soil microbiome with excessive tillage, pesticides, overapplication of nutrients, and lack of ground cover. Soil does not function properly without an intact soil food web. Mycorrhizal fungi are the lynchpin of good soil function, and they are missing from many agricultural soils due to excessive physical and chemical disturbance. Simply having adequate AMF colonization of plant roots would vastly improve nutrient use efficiency, add organic matter, help fix our broken water cycle, reduce the need for nutrient applications, and give us cleaner water.
We will never seriously address water quality until we embrace the fact that soil is a living ecosystem and needs to be managed accordingly. Pesticides are damaging soil, plant, animal, and human health and will need to be phased out over time. The agricultural community needs to take this issue seriously. More biologically friendly herbicides, combined with sound agronomic management and a bit of technology can address weed control issues. We can make this transition while enhancing productivity and profitability by focusing efforts on growing a healthy plant with a strong immune system.
In subsequent posts, I’ll explore a biological approach to the 4Rs that will enhance the 6P strategy to more effectively addresses soil function, water quality AND keep more money in your pockets.
