As if 2019’s moisture-laden growing and harvest conditions weren’t enough, the very soil that farmers everywhere depend on may also suffer long-term effects of this challenging year. Recent plant analysis data that’s been processed by Wisconsin-based Rock River Laboratory is showcasing a new story, heavily impacted by moisture’s capabilities to leach away minerals in the soil and contribute non-nutritive components to the crop.
“We’re observing lower macro minerals than past years in the 2019 corn silage crop,” explains John Goeser, Rock River Laboratory Animal Nutrition, Research and Innovation Director. “And mineral content of corn silage is indicative of less plant-available nutrients in the soil.”
Mineral content in soils
As showcased in Figure 1, sulfur in 2018 and 2019 corn silage significantly diminished in the fall of each year.
“The heavy moisture throughout 2018 and 2019 leached soils of some key minerals,” explains Dustin Sawyer, lab director and agronomy expert for Rock River Laboratory. “Potassium and sulfur are the most susceptible to washing away when we see significant moisture throughout the growing season as we did this year.”
Similar sulfur diminishes also showed up in legumes, as shown in Figure 2. “2019 alfalfa saw reduced sulfur levels in May and June, around the first or second cutting,” explains Sawyer. “Sulfur is a limiting or indicator nutrient, revealing that yield may have taken a hit.”
While the extreme moisture of 2019 is a likely contributor to this phenomenon, Sawyer points toward lacking foliar feeding as another factor. “2019 brought about management decisions and changes that other ‘normal’ years may not require,” he explains. “One of these decisions was less foliar feeding by farmers due to the small windows of opportunity.” Foliar feeding adds key nutrients throughout the growing season for plant uptake.
Ash in the crop
While the tell-tale signs of nutrient loss in the soil are becoming apparent, high ash content in the crop is also rearing its ugly head, as seen in Figure 3.
Ash, or soil and minerals that are splashed up on crops during wet weather or in the process of harvest, can lead to long-term repercussions in the crop. “Ash dilutes energy, as sand and dirt take up space in the diet,” explains Goeser. “Microbial contamination – both fungal and bacterial – also usually follows suite as microbes in the soil are picked up with the crop.” Alfalfa and grasses are more susceptible to these microbial contaminations than other crops. Goeser also warns against ash’s risks when it comes to fermentation. “Ash can act as a buffer, making it harder to ferment and stabilize feeds.”
Despite the nutrient leaching seen over the course of the last two years, Goeser and Sawyer see opportunities to mitigate these challenges. “Greater analysis of forages can help you watch your soil nutrients so that you’re not paying extra for nutrients or minerals in the diet,” recommends Sawyer. “Plus, soil sampling and analysis now in the fall or even in the spring can help monitor soil fertility to supplement efficiently in the spring.”
As farmers, nutritionists, and agronomists wind down and assess 2019 while trying to learn for what 2020 will bring, monitoring both plant and soil nutrients could be the key to successful management decisions. “Work with your team of consultants to review baselines and fluctuations throughout the year to best prepare and supplement what’s to come in both the field and bunk,” advises Goeser.