As spring and planting season approach, an important question arises: Should inoculants be reapplied annually? In this week’s edition of Growing Possibilities, we explore the significance of yearly inoculant applications and their impact on soil health and crop yields.

Soil bacteria thrive and move within the thin water film surrounding soil particles (1). However, as winter’s freezing temperatures set in, this water gradually solidifies. When freezing occurs slowly, bacteria can survive by migrating to unfrozen areas. While some microbes can endure extreme cold—down to -39°C (-38°F) (2)—various environmental factors reduce their tolerance, making it unlikely that all soil bacteria will survive.

Beyond seasonal changes, soil fertility is also affected by the use of chemical fertilizers. While fertilizers play a crucial role in sustaining crop yields, excessive applications can disrupt native microbial ecosystems. A study from the University of Colorado Boulder estimates that one-third of the fertilizer used to grow corn in the U.S. each year compensates for declining soil fertility in cultivated land, costing an estimated $500 million annually. Given this financial loss, improving soil biological health is critical for long-term sustainability (3).

Soil microbes also suffer from reduced moisture retention and erosion, challenges that can be mitigated through no-till farming and cover cropping (4). However, after adopting these physical practices, farmers must ask: How do we restore soil biology? While manure can enhance microbial activity, applying it across every acre isn’t always feasible (5).

This is where agricultural biologicals step in, offering targeted solutions to restore microbial populations. Beneficial microbes provide numerous advantages, such as improved nutrient availability and disease suppression. Yet, due to the complex interactions between microbes, plants, and soil ecosystems, our understanding of these relationships is still evolving (6).

For these reasons, annual inoculant applications remain a best practice. Yearly treatments replenish beneficial microbes, supporting soil health and optimizing plant growth. Research indicates that consistent inoculant use can significantly enhance crop yields, reinforcing the importance of proactive biological management (7).

Given the combined effects of winter temperatures and fertilizer applications, inoculating annually ensures soils remain biologically active and productive. At Xitebio Technologies, we offer inoculant products such as XiteBio® SoyRhizo® for soybeans and XiteBio® PulseRhizo®, both designed to optimize nitrogen fixation and microbial balance. Additionally, XiteBio® Yield+ contains Bacillus firmus, a bacteria known to enhance nutrient availability and promote plant growth. By prioritizing annual inoculant applications, growers ensure healthier soils, better yields, and more sustainable farming practices (8). Isn’t it time to give your soil the biological boost it deserves?

References

1. https://ohioline.osu.edu/factsheet/anr-36 (1)
2. https://www.sciencedirect.com/science/article/abs/pii/S0038071705002890 (2)
3. https://www.colorado.edu/today/2021/01/12/soil-degradation-costs-us-corn-farmers-half-billion-dollars-every-year (3)
4. https://www.nature.com/articles/s41396-021-00913-1 (4)
5. https://www.canr.msu.edu/uploads/files/AABI/Manure%20effects%20on%20soil%20organisms.pdf (5)
6. https://extension.psu.edu/understanding-and-managing-soil-microbes#:~:text=Due%20to%20their%20close%20proximity,that%20leads%20to%20soil%20aggregation (6)
7. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.693535/full (7)
8. https://xitebio.ca/inoculant-and-biological-faqs/ (8)