Three strategies to build up organic matter

While soil health can be defined many ways, Taylor Purucker, crop nutrition lead of eastern North America for Mosaic, says one of the most important defining qualities is the soil’s continued capacity to function.

“The goal is in 40 years when your kids or grandkids take over the farm and are farming the same land, it can produce high yield systems with more efficient inputs,” says Purucker.

Soils with higher organic matter often translate into sustainable systems because of their higher productivity, more consistent yields, and greater long-term profitability.

• READ MORE: Strategies to manage nitrogen from pre-season through harvest

However, many factors can influence the amount of organic matter already in the soil. Purucker says those include climate, soil type or soil-forming factors, cropping history, and even specific measurement practices regionally or across fields.

“I always encourage using local conditions as a benchmark for comparison when implementing practices to either increase or maintain soil organic matter, and to track how practices influence organic matter over time,” he says. “It's really about understanding your specific cropping system and what success looks like.”

How do you build and maintain soil organic matter to contribute to a sustainable, productive system? Purucker shares three strategies that you can implement now.

Reduced Tillage

Tillage can destroy soil organic matter through oxidation, which ultimately allows bacteria and other microbes that use the carbon to quickly decompose organic residues. This over time results in organic matter loss, Purucker explains.

“Reduced tillage slows the organic residue decomposition and helps maintain organic matter levels over time. One of the other benefits of reduced or no-till is that it reduces the potential for erosion,” says Purucker.

Topsoil is rich in organic matter and nutrients. Having more residue on the surface provides protection from the topsoil eroding and helps maintain the organic matter level in the soil profile.

Purucker recommends trying out reduced tillage on one field or one farm to see how it affects your processes. It’s also essential to create a goal and determine how to measure success.

In the process of building organic matter, plan to sample fields you make changes on every couple of years in order to evaluate change in the soil.

Crop Residue and Rotation

Another strategy that contributes to improved organic matter is to add cover crops or high biomass-producing crops to your crop rotation.

Adopting cover crops produces similar results to reducing tillage as the risk of erosion is reduced, keeping the nutrient-rich soil and organic matter in place.

“One of the benefits of cover crops is that you can select certain species with high biomass production. This crop residue contains carbon and ultimately, it will go through the carbon cycle and help maintain or increase organic matter level over time,” explains Purucker.

Cover crops grown in the “off season” have the unique ability to take up excess soil nutrients that may have been left over from the main cash crop.

“Cover crops can supply food to microbes in the soil rather than having microbes use up the organic matter reserves,” Purucker says.

Covers create efficiencies in the system, especially with mobile nutrients that may leach through the soil profile and be lost for the following season. If a cover crop takes up the nutrients, they remain in the zone where microbes are active and can be used by the next crop.

In addition, Purucker says managing a crop rotation with crops that have high biomass production or the ability to sequester high amounts of carbon and return it to the soil can help increase or maintain organic matter over time.

Advanced Crop Nutrition

Advanced nutrition is a combination of knowing exactly what nutrients are needed by plants for healthy growth and healthy soils and managing soils to create a sustainable production system for future generations.

“One of the first steps in an advanced nutrition approach is to soil test to identify and correct any yield-limiting factors,” Purucker says. “This will encourage greater growth of crops that produce high biomass and can be returned to the soil once those limiting factors are identified and corrected.”

In this strategy, utilizing innovative technologies to apply the limiting essential crop nutrients can help create a more productive, sustainable cropping system.

Phosphate fertilizers can be used in a combination for an advanced crop nutrition strategy. One example is MicroEssentials, which provides uniform nutrient distribution, season-long sulfur availability, and increased nutrient uptake. Another is Sus-Terra fertilizer, which is boosted with recycled organic materials to promote greater nutrient efficiency. Both can help achieve higher yields and return on investment.

Soil health is continually evolving. Ultimately, Purucker says that what is important is to track change over time.

“Organic matter is a great example. We implement a new management practice, and after the first year, we might not see a change. That doesn't mean it's not working. What it tells us is that we just have to continue to track changes over multiple years to see the impact on soil health, because it all goes back to the long-term capacity of a soil to function.”

Visit cropnutrition.com for more information about soil health and advanced crop nutrition.