Soil Health Friday – Tissue Sampling
I took tissue samples of Carbon Load in a 3x3 square in a HEAVILY browsed plot (planted last fall, taken this spring). The timing for sampling was not ideal for getting nutrient readings, specifically nitrogen. A few reasons for this:
- It was early in May and many of the crops were still fairly young in their growth, and not yet at seed head stage.
- This field is small and the browse pressure was very heavy. This can set back the grains (from a tissue sampling perspective, they were still growing – which is a plus for soil!).
- We had several large rain events, that will push nitrate (noticed on the soil test) deeper into the soil profile. If the previous crop is unknown, Ward Labs assumes 25lbs/ac of nitrate in soil profile below the 6inch mark. However, in no-till, heavy legume and balance systems, like Vitalize Seed, we can see this number become far larger. Assuming the most conservative of numbers, we have 30lbs of nitrate readily available, even on this small plot. With our legumes in this mix, this number is likely higher. Our crops in the Nitro boost will also mine nutrients deep in the soil, and further drive the nutrient cycling.
We still want to keep in mind that we also have 2.6% OM (which will mineralize and provide nutrients to plants) and of course, our tissue sample is showing additional 15lbs per acre that will be broken down and available for plant uptake. I am confident that, had I taken this sample in a larger field where the rye was more headed out, the N reading would have been higher per acre for tissue sampling, and my nitrate value would be greater in a 12-24inch depth. I am satisfied with the results and, as they are, I will not fertilize this plot again this year (more to explain why below). I also am not solely focused on N assimilation since, as we have discussed, there are various other benefits (discussed in other blogs) to highly diverse systems and how they benefit the microbiome to plants to animals consuming such plants.
What is most impressive is when we look at the phosphorus and potassium that are being taken up by the plant. Due to the fungal networks in the soil in a highly diverse, no-till system, we can make much of this more bio-available than what shows on a typical soil test. You will notice the discrepancies between the soil test fertilizer recommendations, and plant decaying nutrients back into the soil profile.
Soil sample recommendations are very useful, but they don’t take into account above-ground biomass or even OM mineralization. There isn’t a real way to tell how functional a system is without a full in-field audit or a combination of soil health assessment tests, knowing the growers’ practices, etc. We know that with the Vitalize One-Two system, we can optimize our nutrient cycling and by doing so, we can allow our subsequent plantings to benefit from the last.
Another item I must highlight is that this is JUST a tissue analysis. This does not figure in the root biomass, organic matter mineralization, or additional N-P-K fixing inputs from our Nitro-Boost that was planted into this soil (on this same day). The Nitro-Boost has both legumes and non, so we can not only take advantage of massive N-fixation but also mine our nitrate from deeper in the soil profile, as discussed above.
Let’s take a further dive into phosphorus. According to the soil test recommendations we need 50lbs of P to achieve a top yield goal of a cover crop mix. In the past, we would take this number and go buy P. By cycling nutrients using Carbon Load in the fall and Nitro-boost in the spring, we can see our results and fertilizer needs or non-needs.
According to the soil test, we have 19lbs of Phosphorus available. Now take a look at the tissue testing (much of which will break down quickly due to our high microbial systems), we have an additional 6lbs. OM mineralization will give us another 2lbs per % - adding up to 5.2lbs. This gives us over 30+lbs of phosphorus available! This doesn’t count any of the root biomass (huge amount of nutrients there) in the calculations of the terminated fall crop. Furthermore, if we use the same method with K, we will see in the tissue sample alone, that we have assimilated almost enough K for the next crop!
The reason this is important is that we are continuing to record and research how our mixes are impacting biology to interreact with the macro/micronutrients within the soil. Over-fertilization can lead to less productive microbes and the breakdown of stable organic matter. Over tillage can lead to the destruction of fungal networks - these networks help to break down these higher C: N, lignin-filled plants and are crucial to nutrient cycling. They also help to release enzymes that further drive the nutrient uptake of plant-available NPK.
We are not anti-fertilization but we are HUGE advocates for research so we know exactly what needs to be put down, when, why, and in what amounts. This helps to reduce the grower’s reliance on fertilization as well as enhance our microbial communications with the plant communities.
In conclusion – this is about the worst-case scenario I could highlight on my farm: the plots were still fairly immature, tremendous amounts of rain had occurred recently, it’s been a cold spring, and the plot size is about ¼ of an acre. On top of all that, this is in a high deer density area, further reducing my above-ground biomass, relative to my other larger fields with inherently higher OM, above-ground biomass, etc.
This field was a good one to show as it is more representative of what many folks are planting and dealing with. By quantifying what we can achieve and build from over time through the Vitalize Seed One-Two System, I am extremely satisfied with the results!
I hope you find this useful. I promise to never stop researching, learning, and sharing information about the robust world of soil health.
Thank you for considering Vitalize Seed as your seed source.
Albert
vitalizeseed.com
ocj.com
