Soil Testing--No Longer Just for Fertility Status
Soybean producers know about the importance of soil testing to determine level of fertilizer nutrients. This has long been considered a basic practice that should be conducted to support yield sustainability. A White Paper on this website provides details about this practice and how it should be conducted.
Now comes a new soil test that may be just as important–i.e., testing the soil for the makeup of its microbial population. This new testing process uses advances in DNA sequencing technology to identify the organisms in soil samples to determine, for example, if soil-borne pests such as SCN and the pathogen that causes SDS are present. In essence, the results from such a test will take the guesswork out of how a particular soybean variety might perform on a particular production site since knowledge about the presence of pathogenic microbe(s) in a particular field will guide a producer in selecting a variety with the necessary trait or traits to minimize or negate the effect of the detected pathogen(s).
Tests of this sort are also being developed and used for a comprehensive delineation of the types of microbes that are present in soil. This, coupled with forthcoming knowledge about which soil microbes are most desirable to benefit crop productivity, will allow producers to assess the “health” of their soils so that they can make informed decisions about what soil amendments they should consider adding (or not adding) to benefit microbes that are deemed to enhance crop productivity.
Of course, knowledge gained from such testing will have to be coupled with new knowledge about which of the identified soil microbes are most beneficial to plants. The combining of these two pieces of information will allow producers to make adjustments to soil amendments and/or production practices so that only beneficial soil microbes are enhanced.
In an earlier article on this website, information was provided about companies that are conducting research to identify biological materials that can be added to the soil to provide targeted functions such as enhancement of carbon sequestration in the soil. These biological materials are in essence living microbes that will be applied to enhance positive soil activities and crop productivity. The success of this approach will depend on the accurate identification of beneficial soil microbes, and if their function can be improved by the addition of enhancers and/or an increased food supply.
The following are links to some of the companies that have entered the agricultural sector to provide identification of soil microbes, and to quantify their diversity and abundance in soil.
Producers are encouraged to consider having soils from selected fields tested for microbial content and diversity to determine if current management decisions should be adjusted to account for the microbial population that is estimated to be present. Producers who choose to do this should be aware that this is a relatively new area of endeavor and likely should be adopted on a limited basis to ensure that the information received from such tests does in fact provide a tool for soil and crop improvement. Hopefully, results from research that will be conducted in the near-term will provide guidance about which soil microbes should be enhanced for soil health improvement, and which ones are the most beneficial to crop productivity.
Composed by Larry G. Heatherly, Oct. 2021, larryh91746@gmail.com