Grass-Fed Farming Done Right Can Regenerate Soil and Farm Livelihoods
The following article contains edited highlights from Prof. Richard Teague’s* presentation at the Twenty-Fifth International Conference on the Unity of the Sciences (ICUS XXV), “Managing Grazing to Regenerate Soil Health and Farm Livelihoods.”
A growing number of scientists are hard at work to make farms and ranches more sustainable. They understand that cattle can play a role in returning degraded land, especially in semi-arid regions, to fertility and associated ecosystem stability. One grasslands management tool they are researching and testing is managed grazing.
Semi-arid grazing ecosystems take up about one-third of Earth’s land mass. These lands are being degraded mostly because of poor land use.
Maintaining artificially high numbers of grazers [cattle]—with no time for the grazed vegetation to recover—has led to widespread overgrazing, degradation of vegetation and soils, declines in productivity and biodiversity, and a reduction in ecosystem resilience.
There are huge economic and social costs associated with the degradation of these ecosystems. At least one billion rural and urban people depend on them for their livelihoods, often through livestock production, and for essential ecosystem services that affect human well-being.
Manage for Improvement, Then Sustainability
Trying to persuade land managers to adopt sustainable ecosystem management systems is common, but humans have degraded nearly every ecosystem they have lived in and managed. Sustaining a degraded situation makes no sense. Instead, the focus should be on regenerating ecosystem function, which is the basis for providing livelihoods of people living in these ecosystems and all the living beings who depend on the ecosystem services provided. Fortunately, worldwide there are numerous land managers who have done so. We have studied how they have done so in dry to wet grazing ecosystems.
Improving or sustaining the long-term productivity and resilience of semi-arid rangelands requires management strategies based on an understanding of the feedback between vegetation and livestock in a changing environment. Adaptable decision-making strategies are required to make decisions under constantly changing circumstances. In other words, there must be a way to take advantage of positive events and reduce the damage of negative events.
Soil Health is Fundamental to Sustainability
Restoring soil health is fundamental to achieving sustainable agriculture. For instance, the biggest limiting factor in grazing land ecosystems is not the amount of rainfall received, but the amount of rainfall infiltrating the soil and how long it stays there.
But, of course, this is not the only important ecosystem function. Ensuring optimal ecosystem function also requires efficient solar energy capture via photosynthesis, soil organic matter (SOM) accumulation and retention, efficient nutrient cycling, and ecosystem biodiversity.
Soil health is fundamental for ecosystem function because 90% of soil function is mediated by microbes. There is a mutual dependency among microbes, plants, and animals. Plants, for instance, enable microbial life. They also benefit from nutrients released through the synergistic interdependence between plants and archaea, bacteria, fungi, and other microbial and eukaryotic species.
The major portion of energy required to facilitate ecosystem functions comes from plants capturing energy in the process of photosynthesis and conversion into carbohydrates that provide the energy for the ecosystem community to function.
How plants are managed in grazing or cropping ecosystems is critical to maintaining or regenerating full ecosystem function. The major portion of energy required to facilitate ecosystem functions comes from plants capturing energy in the process of photosynthesis and conversion into carbohydrates that provide the energy for the ecosystem community to function.
The Synergistic Networks in Soil
Synergistic networks of soil organisms provide many ecosystem services. They improve soil aggregation, aerate and stabilize soil, improve its water holding capacity, improve nutrient acquisition and retention for the ecosystem community, cycle nutrients to improve their availability, enhance tolerance for biotic and abiotic stress, and buffer the impact of environmental factors on plants.
Arbuscular mycorrhizal fungi (AMF) are tiny keystone species in these terrestrial ecosystems, particularly grasslands, as they maintain plant diversity, mediate interactions among plants and other microbes, and positively impact plant photosynthesis.
Plants increase photosynthesis in symbiosis with AMF and legumes for a dual association with rhizobia and AMF that enhances photosynthesis by 50% on average. AMF contribute directly to the soil organic matter pool and through secretion of soil glycoproteins, increase water-stable soil aggregates that enhance soil water infiltration and aeration vital to ecosystem function.
Grasslands Management for Optimal Outcomes
Grasslands management decisions support profitable operations and help with sequestering carbon and providing ecosystem services. Good examples of management approaches that have restored degraded grassland ecosystems are seen where ranches are managed to achieve resource conservation goals.
Improved management, such as adaptive multi-paddock (AMP) grazing, has been shown to reverse degradation by decreasing bare ground, restoring productive plant communities, increasing water infiltration rates and soil water storage capacity, increasing fungal-to-bacterial ratios, and increasing soil carbon.
The best examples of grazing management have been produced by farmers who manage specifically to enhance soil health and ecosystem function. This is the foundation for improving profitability, and these leading farmers have achieved substantial improvements in ecosystem function, plant species composition and productivity, soil carbon and fertility, water infiltration and water-holding capacity, biodiversity, wildlife habitats, and profitability.
Successful farmers use multiple paddocks [fenced areas] per herd with short grazing periods and long recovery periods.
These successful farmers use multiple paddocks [fenced areas] per herd with short grazing periods and long recovery periods. They also adapt when biomass, animal numbers, and growing conditions change within and between years.
It is becoming increasingly clear that the key to sustainable recovery from land degradation involves using well-planned and adaptively managed multi-paddock grazing management protocols that match forage biomass with stock [farm animals] numbers to achieve desired resource and financial goals, while avoiding unintended consequences such as soil loss and decline in function, and reduced plant biomass and species makeup.
Improved Grazing Lowers Carbon Footprint
One of the major concerns in grazing-land ecosystems is the quantity of greenhouse gases (GHG) emitted by ruminant [cud-chewing] livestock. Although many scientists have concluded that ruminant production systems are a particularly large source of GHG emissions, others have found it is possible to convert ruminant-based production into net carbon (C) sinks by changing management.
Previous assessments of GHGs such as natural methane (CH4) uptake in grazed rangeland ecosystems have not considered improved livestock management practices and have underestimated potential for GHG uptake. Appropriate adaptive stocking, moderate grazing with adequate recovery, and intensification of livestock grazing management significantly contribute to GHG mitigation potential.
As soils can be a significant sink of carbon, depending on management practices, soil carbon (C) dynamics are an important part of calculating accurate ruminant lifecycle-assessments (LCAs)—LCAs are tools for measuring environmental impacts. However, changes in C have usually been unaccounted for in LCAs, even though such changes have been found to have a large impact on net GHG footprints when explicitly included in calculations of the net carbon footprints of alternate combinations of agricultural management options.
When conducting LCAs on emissions from ruminants in a food production chain, it is fundamentally important to include all elements in the chain that are influencing the net carbon footprint in the whole system under review. This includes accounting for the beneficial ecosystem services—such as those from carbon sequestered in grazing ecosystems—that well-managed grazing systems can provide.
Most cattle in North America are finished in feedlots on grain-based feeds. Proponents of this finishing method claim that this results in lower GHG emissions per kilogram of beef produced and a lower carbon footprint because it reduces the overall production time to slaughter and the enteric fermentation [a stage in the animal’s digestive process] during this time, relative to grass-based finishing.
However, these authors do not consider the full food-chain carbon footprint of grain-based finishing because they do not account for the full GHG emissions associated with the production of grain-based feeds, inorganic fertilizer, and other elements adding to C footprint levels and soil erosion.
The full food-chain carbon footprint of grain-based finishing does not account for the full GHG emissions associated with the production of grain-based feeds, inorganic fertilizer, and other elements adding to C footprint levels and soil erosion.
Ruminant dams [mother cows] and their offspring spend most of their lives on perennial grass, during which the C sequestered by the grassland they graze exceeds their emissions. This needs to be considered when calculating the complete carbon footprint through any food-chain option.
In developed countries—that routinely finish ruminants on grains—another factor decreasing the C footprint of a production chain is the crop finishing of ruminants based on regenerative cropping practices with a negative GHG footprint (C sink). This practice reduces the carbon footprint considerably.
Modification of agroecosystem production systems and conversion to regenerative cropping and AMP-based, grass-finished livestock would also provide other important ecological benefits, as mentioned earlier. In addition, human food supplies would increase by 70% if crop production currently used for animal feed and biofuels and such were instead used for human food products. This change would provide sufficient resources for billions of people.
Conclusions
To ensure long-term sustainability and ecological resilience of agroecosystems, agricultural production should be guided by policies that ensure regenerative cropping and grazing-management protocols.
Changing current unsustainable, high-input agricultural practices to low-input regenerative practices enhances soil and ecosystem function and resilience, improving long-term sustainability and social resilience.
A primary challenge is increasing the scale of adoption of land-management practices that have been documented to affect soil health positively.
In areas where no cropping is possible, grazing of ruminants in a manner that enhances soil health will reduce the C footprint of agriculture much more than reducing domesticated ruminant numbers to reduce enteric GHG emissions. This will also provide highly nutritious food that has sustained pastoral livelihoods and cultures for centuries.
Ruminant livestock are an important tool for achieving sustainable agriculture and, with appropriate grazing management, can increase C sequestered in the soil to more than offset ruminant GHG emissions. They also support and improve other essential ecosystem services for local populations such as better water infiltration, less soil erosion, improved nutrient cycling, soil formation, carbon sequestration, biodiversity, and wildlife habitat.
Research conducted on managed landscape shows that ecologically managed AMP grazing strategies incorporating short, high-impact grazing with long recovery periods can regenerate ecosystem function on commercial-scale agroecological landscapes. These include: 1) build soil carbon levels and soil microbial function; 2) enhance water infiltration and retention; 3) control erosion more effectively; 4) build soil fertility; 5) enhance watershed hydrological function; 6) improve livestock production, economic returns, and the resource base; 7) enhance wildlife and biodiversity; and 8) increase soil function as a net greenhouse gas sink.
Collectively, conservation agriculture aims at regenerating soil health and ecosystem function, supports ecologically healthy resilient agroecosystems, improves net profitability, and enhances watershed function.
To accomplish all of this, it is important for scientists to collaborate with environmentally progressive managers who have excelled financially by improving their resource base; identify the processes associated with improvement; and convert experimental results into sound environmental, social, and economic benefits regionally and globally.
*Richard Teague, PhD, is Professor, Department of Ecosystem Science and Management, Texas A&M University and Texas A&M AgriLife Research, Vernon, Texas, USA.