Using Soil DNA to Better Understand Yield-Limiting Factors
In an ideal world, growers would plant a seed in the ground, the seed would grow into a healthy plant, and the plant would produce the maximum output possible, be it grain, fruit, or vegetable. Throughout history, the process of domestication and breeding led to improvements in yield through crop genetics (1). As technology in agriculture has advanced through time, other limiting factors have been identified and addressed. Liebig’s Law of the Minimum tells us that the maximum crop yield is determined by the most limiting essential nutrient (2). In the early 1900s, the process for synthesizing nitrogen fertilizer was developed, and commercial production of other macro- and micronutrients followed (3). Today, the genetic potential of modern corn hybrids is over 600 bushels per acre (4), and growers can apply any nutrients that are lacking. With fertility and genetics research being well-established, what other limiting factors can be addressed with emerging technologies?
While it’s not a new problem, pathogens and pests are responsible for 20-40% of yield loss (5). Misdiagnosis and lack of above-ground symptoms lead to difficulties in pest management and contribute to significant drops in yield. To determine which nutrient is limiting, soil chemistry labs developed a comprehensive soil test that allows growers to identify and address the limiting factor. Trace Genomics has built onto this foundation and developed a comprehensive biological soil test for pathogens and other pests, allowing agronomists to identify what threats are present in their soil and develop a plan to reduce their risk.
Using 21st century biotechnology for informed management
Historically, as limiting factors for crop yield have been identified, technology has been developed to address them. Synthetic fertilizers addressed nutrient deficiencies, and genetic limitations continue to be improved through advanced breeding techniques and biotechnology. Traditionally, the only available pest diagnostic tool has been to collect and submit soil or plant tissue to an analytical laboratory, generally only done after damage has occurred. While onset of a disease depends on environmental conditions, it would be most beneficial to have knowledge of a soil’s pest profile before seeds are planted. This information allows agronomists to make management decisions before disease has a chance to take hold. Trace Genomics offers the most comprehensive pathogen panel on the market, providing agronomists and crop advisors the tools to make informed decisions to tackle pests through seed selection, seed treatment, potential in-season treatments, and crop rotation.
Other diagnostic technologies may only identify a handful of pathogens or pests at a time, grouped into small packages. At Trace Genomics, we use metagenomics to sequence all soil DNA, testing for over 225 pests at once. While metagenomics technology began with a focus on bacteria and fungal pathogens, DNA from insects and nematodes can also be detected. Trace reports on notable pests such as Soybean Cyst Nematode (SCN) and Western Corn Rootworm (CRW).
Comprehensive diagnostics from Trace Genomics
At Trace Genomics, our goal is to provide a thorough soil profile, so agronomists can identify their true limiting factor. Our flagship product TraceCOMPLETE™, includes a full suite of chemistry analytics and microorganism functions beyond pathogens: more than 20 biological nutrient cycling indicators. Insights into microbial nitrogen and phosphorus cycling can improve nutrient management by identifying the most suitable acres for placing products such as phosphorus chelating agents, slow release nitrogen, or biologicals (phosphorus solubilizers/ mineralizers, free-living nitrogen fixers, etc.)
Using insights presented on TraceVIEW, agronomists have more information than ever before to use for pathogen and nutrient management recommendations, including:
- Seed selection based on tolerance to the most abundant or damaging identified pests is a strong first line of defense.
- Seed treatment to provide protection against significant pests that may not be preventable using seed genetics.
- In-season treatment plans can be budgeted in preparation for potential outbreaks to ensure all the tools needed to protect your crop are on-hand.
- Crop rotation can be used to place a different crop with fewer or less damaging pathogens present, saving a susceptible host crop for a later year.
- Phosphorus product placement of other products such as chelating agents in areas where phosphorus saturation is low and applied P is at risk for tie-up.
- Nitrogen product placement of slow-release nitrogen or nitrification inhibitors where the soil has a high risk of biological loss.
- Biological product placement of phosphorus mineralizers, solubilizers, and free-living nitrogen fixers where the abundance of these functions are low for higher confidence in success.
In situations where in-season pesticide application is not feasible due to the proximity of fields to sensitive areas such as schools, nursing homes, hospitals, residential, or inaccessible areas, a good defense is often the best offense. Soil biological analysis through metagenomics provides a means for understanding what pathogens and pests are present before they have an opportunity to cause damage. The comprehensive, actionable soil profile delivered with TraceCOMPLETE allows agronomists to make preventative management decisions to reduce loss and maximize yield.
References
- Vaughan, D.A., Balazs, E., and Heslop-Harrison, J.S. (2007). From Crop Domestication to Super-domestication. Annals of Botany 100, 893–901. https://doi.org/10.1093/aob/mcm224.
- Barak, P. (2000). Law of the Minimum. soilsfacstaff.cals.wisc.edu. https://soilsfacstaff.cals.wisc.edu/facstaff/barak/soilscience326/lawofmin.htm.
- Appl, M. (1982). The Haber-Bosch Process and the Development of Chemical Engineering. In A Century of Chemical Engineering (Springer), pp. 29–54.
- Association, N.C.G. (2019). Records Broken in 2019 NCGA Corn Yield Contest. National Corn Growers Association. https://www.ncga.com/stay-informed/media/in-the-news/article/2019/12/records-broken-in-2019-ncga-corn-yield-contest.
- Savary, S., Willocquet, L., Pethybridge, S.J., Esker, P., McRoberts, N., and Nelson, A. (2019). The global burden of pathogens and pests on major food crops. Nature Ecology & Evolution 3, 430–439. https://doi.org/10.1038/s41559-018-0793-y.
About the authors: Dr. Tuesday Simmons is the Science Communication Manager at Trace Genomics. She earned her Ph.D. in Microbiology from the University of California, Berkeley, studying the root microbiome of cereal crops. John Grandin is an agronomist with over 40 years of experience in the field. He is currently the Director of Agronomy at Trace Genomics.