While I’ve been with GrizzlyCorps and the McConnell Foundation, working with cattle has brought up a lot of talk about soil health. Soil “health” being this agro-ecological benchmark of how well soil components interact to meet a desired outcome be it growing productive crops to sustaining a natural system like an oak woodland. Some soil ecosystems, primarily in grasslands, have evolved to accommodate and consequently depend on grazing. Cattle and grazing seem to be a vector that, depending on the management techniques used, could restore depleted rangeland or even turn desert into lush grassland à la the work of Zimbabwean ecologist and livestock manager Allan Savory. It can also be a destructive force that turns health grassland ecosystems into compacted, bone-dry wastelands. Often, the results of land management are not this stark or absolute. But soil health is integral to agricultural production, ecological services, and climate change resilience. And service at the McConnell demonstration ranch, Ross Ranch, has shown me how many tools we have to positively influence soil health.
One of the projects that GrizzlyCorps service members have helped work on at the McConnell Foundation is BEAM (Biologically Enhanced Agricultural Management), which uses bioreactors to restore or even enhance the complex fungal biota of local rangeland. Essentially, the philosophy behind this is to avoid sustaining agricultural production and soil fertility only through artificial fertilizers and simply restore the soil to its non-depleted original state, in part by increasing the level of beneficial fungi in the soil. But that’s actually a lot harder than it sounds.
Traditional compost normally contains more bacteria than fungi; we are trying to do the opposite. I am currently working on testing our second attempt at producing these endemic, symbiotic soil fungi. Dr. David Johnson of CSU Chico’s regenerative agricultural program made an interesting comparison of the role microorganisms play in soil to the role bacteria play in our own stomachs.
These microorganisms often play a bigger role in how plants process and have access to nutrients, protect themselves against pest and pathogens, and even express their own genetic code than the plants themselves. They’ve found that biodiverse soil ecosystems to break down pollutants, have less soil pathogens and pests, and retain more water than depleted, “unhealthy soil.
With diverse, beneficial soil ecosystems, farmers and ranchers may find that they are growing healthier, more nutritious, and higher yielding crops or forage without any change in what they are planting! A lot of this microbiology goes over my head. My head hurts when I hear terminology like beneficial rhizobacteria and saprotrophic nutrition. But even through simple observation it’s obvious how much soil health can impact grazing management and agricultural production. One of the largest dry pasturelands on McConnell’s demonstration ranch has compacted, relatively-unhealthy soil due to poor land management under the previous owners. Consequentially, it offers only a few days of sufficient grazing for cattle, whereas a much smaller pasture area where the soil has not been as heavily impacted — seeded with native perennial grasses and grazed in a sustainable manner — can sustain the same amount of cattle for 10+ days. Then that same pasture can be given approximately 30 days to “rest”, after which there is robust enough regrowth for it to be grazed again. The former, impacted pasture will likely only be grazed one to two times depending on rainfall for the year. Depending on how that pasture is implemented into a grazing program, that may mean that a rancher would need to buy hay to feed their cattle or increase the acres of grassland needed to sustain their cattle. Worst case scenario, they would allow the cattle to overgraze the pastures, due to lack of forage, and ruining and health of the pasture for years, continuing a vicious cycle of soil degradation. From an agronomic perspective it's clear how much soil health matters to forage yields, stocking rates, and even nutrient content of the forage -- obviously the benefits on agriculture are similar.
In respect to climate change and soil health, there is a large discussion about carbon sequestration. How and to what extent grazing and rangeland management influences this is a pretty contentious topic. In arid grasslands, like the northern Sacramento Valley, the science seems to suggest that there is very slow sequestration and that climate and geography play a greater role in how much carbon can be sequestered than anthropogenic land management techniques, such as compost application, prescribed fire, and managed grazing. There is also a complex calculation of how much the grazing animals’ own methane emissions undermine their role in facilitating grassland carbon sequestration. That can be frustrating to hear because there are claims that simply through land management and regenerative agricultural practices enough carbon would be sequestered that climate change could be halted or even reversed. I sincerely doubt there will ever be a magical single solution to climate changes, especially one that will be implemented in the immediate future. It will likely require a comprehensive multifaceted solution/response that carbon sequestration in the context of rangelands can play a small yet meaningful role in.
I think there is strong ecological argument for soil health restoration. Prior to extensive European settlement, a large portion of the Sacramento Valley was grassland. These resilient perennial bunchgrasses, such as Purple Needle Grass, developed rich nutrient and biological matter, increased water retention, resulted in deep topsoil layer that in addition to sediments brought in from the flooding of the Sacramento River make the valley such a productive agricultural region.
There is obvious value in restoring the gradual damage done by western agricultural techniques. It is not only integral in preserving and expanding the little grassland and oak savanna left there, but also preventing the imminent threat of desertification.
What the McConnell Foundation has had a lot of success with, with the help of GrizzlyCorps fellows and the California Department of Food and Agriculture Healthy Soils Program funding, is establishing lush perennial grass rangeland on land that had been abused from decades of hoop house strawberry production, overgrazing, and gravel mining. Sometimes looking at hundreds of hours of labor and thousands of dollars spent to what appears to be a grass field comes off as mundane. But I think that is because it is difficult to see where the majority of the work is being done. Through natural soil amendments, managed grazing, and prescribed fire, we’ve managed to create and conserve an invaluable ecosystem services and biodiversity. And we reconcile this process with agro-economic activity, namely, beef and honey production.
Naturally, critiques come to mind of how the average rancher can afford to implement some of these practices – even with state funding/assistance. And frankly how can this information be communicated to farmers and ranchers who have done it their way, have a deep connection to and understanding of their land, and agronomic goals that, especially in the short run, come into conflict with the practices we are implementing? That is a really hard question to answer, and at times makes demonstration projects, like Ross Ranch, seem unrealistic. On the other hand, it’s incredibly fulfilling to work first hand and slowly see the land restore itself from the legacy and abuse of modern agriculture.
Works Cited
1. K. Booker, L. Huntsinger, J.Bartolome, N.Sayre, W. Stewart What can ecological science tell us about opportunities for carbon sequestration on arid rangelands in the United States?, Global Environmental Change, vol. 23, 1, 2013. Pp. 240-251. https://doi.org/10.1016/j.gloenvcha.2012.10.001.