It is hard to go anywhere in the field crops or dairy world without hearing about biologicals. In looking around for a general definition of these crop inputs, we find that Surendra Dara at Oregon State University wrote, “Biologicals in agriculture refer to any biotic and abiotic inputs of biological origin used for crop production or protection purposes.”
There is a lot of interesting work going on in this area as we continue to uncover just how many microscopic organisms are all around us and just how important they are to everyday life — from human gut health to animal gut health to plant and soil health.
For the purposes of this discussion, the focus will be on the category of products related to soil amendments and biostimulants, which are promoted for their role in crop health and potential to enhance productivity. The growing body of knowledge around these products certainly provides more indications of why they could be beneficial; however, measurable results remain quite variable.
Find applicable data
As with any crop input, it is prudent to ask for verifiable data on the expected benefits of a product. Anecdotes, testimonials, and side-by-side comparisons are not acceptable. Beyond this basic tenant of product evaluation, our ability to understand and measure what’s going on in the soil (soil health) leads to many more questions regarding the impact of the cropping system on the potential response to many products in the biological category.
This is not a new phenomenon; soil properties and growing environment have long been recognized as variables that have led to very different fertility recommendations across the country. We manage clay soils differently than sandy soils, nitrogen management for corn varies by soil type and crop rotation, and so on.
Enter in the growing availability of methods to measure soil biological activity and we add a number of new variables to consider. Working with dairy systems in the Northeast, the role of organic inputs, namely manure, and crop rotation are top of mind. Soil health characteristics vary between these systems with manure inputs and perennial sod contributing to different soil microbial communities compared to annual row crop rotations with no manure inputs.
Based on the data I am aware of, in the instances where biological products have resulted in verifiable crop responses, the studies have been performed in annual row crop systems with no organic inputs.
For this reason, when a dairy producer asks about a given product, it is very difficult to provide guidance. Even if data is available showing a potential benefit in a corn and soybean system, for example, it is very difficult to have confidence the reported response will be mimicked in a dairy cropping system. I suggest that the producer not just ask for data but ask for data from similar cropping systems, and if the supplier cannot provide that, then they should consider setting up their own (replicated) trials on the farm.
Research on these type of crop inputs is challenging and time-consuming to perform. It is also important to remember that a lack of response is not equivalent to a lack of data. Products shown to work in row crop systems need to also be vetted in dairy systems and vice versa. The bottom line is that we just don’t have all the data we need. But to partially answer my own question posed in the title, I believe that the system does matter, with more work needed to better understand when and how much.
