What are some practices that you can implement to maximize both types of benefits?
Fine tune your nutrient inputs
The first step to reducing nutrient loss is to fine tune your fertility program to only the nutrients your crop needs. Start by utilizing a grid or zone soil sampling program. The smaller the grids or zones, the better picture you have of the soil properties. You can use the results from this sampling program to create Variable Rate fertilizer plans for all nutrients or soil amendments required for your yield goals with the help of an Agronomist or Soil Scientist.
Grass and Cereal crops often require Nitrogen and Sulfur fertilization to maximize crop yields/returns, however they are both stored in the soil as anions and are subject to leaching. Strategies to reduce nutrient loss of these nutrients include: Split applications, use of a nitrification inhibitor, utilizing scavenger crops, and in-season plant tissue testing.
Minimize soil loss
Topsoil is an extremely valuable resource, and as such keeping it in place should be a high priority. Bare soil is most at risk to erosion, so anything covering the soil will help absorb the impact of rainfall and keep it in place. Some tools for minimizing soil loss include, the use of cover crops, no-till and strip till, grassed waters, prairie strips, terraces, and contour farming. Most of these practices will also help water infiltrate into the soil instead of running across, also lessening erosion potential.
Filter the water going out
Water leaving the farm will always contain some amount of nitrate, even if no farming actives are present, however our farming activities do affect the natural water and nitrogen cycles of fields. Water leaves our fields in two ways:
- Surface water which can be filtered by installing grass waterways, buffer strips, prairie strips, or riparian buffers.
- Internal drainage ways such as field tiles which can be filtered through some of the practices listed below.
Bioreactors – A bioreactor is a buried trench filled with a carbon source, such as wood chips, through which tile water is directed to flow. The wood chips serve as a home for microorganisms that breakdown the nitrate in the tile water flowing through.
Saturated Buffers – Saturated buffers divert the tile water into a buffer area such as a riparian buffer between the field and the stream. As the water passes through the buffer area on its way to the stream it interacts with plants and microbes that are seeking nutrients.
Wetlands – Strategically placed wetlands are very effective at removing nitrate, sediment, or other pollutants from the water. Tile water is brought to the soil surface upstream of the wetland and allowed to slowly filter through all the biologic life living in the wetland. Wetlands are a great source of plant, microbial and wildlife that together will recycle much of the nutrient load back into the ecosystem.
All the practices mentioned above can help both improve water quality and help the profitability of your farm long term. Work with your agronomist, crop advisor, or extension specialist to explore these practices in depth.