Good Afternoon All!
Welcome to the October edition of Health Soil Solutions Monthly. Last month’s publication was dedicated to unpacking the very convoluted definition of “Regenerative Ag” with the goal of making it a bit more approachable and less confusing for our readers. To reiterate, we simply view regenerative ag as farming with an emphasis on soil health, and healthy soil is that which is rich in organic matter and microbial biodiversity. Regardless of how you refer to such an approach, the economic and environmental benefits of achieving healthier soil really can’t be overstated. In keeping in line with our theme of making things approachable, we’re dedicating this edition to gaining a better understanding of cover crops (a practice that is highly-encouraged by proponents of soil health), the purpose they serve, and how to get the most out of them while avoiding the pitfalls that can make them more trouble than they’re worth.
Wikipedia defines cover crops as “plants that are planted to cover the soil rather than for the purpose of being harvested”. So what are they for? A simple way to think about a cover crop would be as a living soil amendment, and there are numerous ways through which they do that amending, so let’s break a few of those down.
Reduction in soil compaction - it’s pretty straightforward if you think about it, but the more roots you have boring holes in your soil for longer periods throughout the year the less opportunity there will be for compaction to take place. The soil will be better aerated and this segues nicely into our next benefit...
Increased water infiltration - again, pretty straightforward but through adding more roots you’re essentially sticking a bunch of drinking straws in your soil, and the reduced compaction leads to better infiltration
Root exudation - there’s a pretty cool give and take between soil microorganisms and plants: the plants produce carbohydrates and amino acids via photosynthesis that soil microbes can’t produce on their own, but the nutrient building blocks needed for photosynthesis to take place and for those molecules to be constructed within the plant come from the diligent work of those soil microbes. Cover crops provide a continual and supplemental source of sugars and amino acids for soil microbes that they exude out their roots and into the soil, which, in turn, supports a larger population of soil microbes that will mine even more nutrients on behalf of your cash crop. A very happy cycle! This leads to…
Reduction in fertilization rates - including a legume in your cover crop mix is recommended due to their ability to fix nitrogen whereas cereals can help increase the availability of phosphorus. The USDA-NRCS compelling video that highlights the results from a multi-year replicated cover cropping trial on 5 farms in South Carolina, where the yield necessary to achieve break-even was cut nearly in half due to the reduced spend on fertilizer. Those interested can check it out here.
Crop residue and root mass - similar to the root exudates, the crop residue and leftover root mass provide a source of organic material that the soil microbes can decompose and turn into organic matter (think of it as free compost!). The greater the presence of organic matter the more suitable an environment in which those nutrient mining soil microbes can thrive. Once again, these benefits can have a cyclical and compounding effect as your soil gets healthier over time.
As great as these benefits sound, some folks may have had a negative experience with cover cropping. The primary cover crop mixes being sold to growers in CA has been in the form of cereal crops, and these can be great, but they’re also very high in fiber/lignin (chaff) and this can make it very difficult to integrate the crop residue into your soil if you’re just getting started on a program that emphasizes microbial propagation and increased soil organic matter. That’s why we’ve developed the Silver Bullet Blend, the ideal place to start cover cropping for CA growers. It’s been specifically designed to balance the benefits of atmospheric nitrogen fixation, phosphorus extraction, and easy integration of crop residue.
The species we selected are all very cold tolerant and should prove resilient against the coldest days of the upcoming winter. Not to mention, all we really care about is getting them somewhat established by late Winter/early Spring as the real magic is taking place below the surface of the soil. Even with the minimal establishment, the root mass will add significant organic material to your soil and generate the benefits listed above. The only thing needed to be done from a management perspective, besides planting, is to mow them right around the time almonds are coming into bloom and the residue can be left to be broken down and integrated into your soil as organic matter.
Keeping your soil covered, year-round, with a diverse array of plant species is a core tenant of the soil health movement. There are numerous products and methods that can facilitate the development of healthier soil, like Full Spectrum and Live Earth’s Humic Products, but it’s critical these methods be integrated into a comprehensive approach, and there will never be a product that can replace what cover crops can accomplish.
So how about planting with us this Fall? Give us a call and we’ll get you started!
-The Team at Penny Newman Farm Products Division