24
Feb
Perennial Crops Identified as Tools to Fight Biodiversity Collapse
(Beyond Pesticides, February 24, 2023) Among the solutions to the dire state of global biodiversity is, Civil Eats reports, perennial agriculture, which improves biodiversity both on- and off-farm. Increased adoption of perennial cropping provides critical on-farm habitat for many kinds of pollinators, insects, birds, and myriad additional creatures. Below ground, where plant roots remain active year-round, perennials create far-richer ecosystems for microbial communities and fungal networks. Planting annual crops — and often, the same ones year after year across huge swaths of acreage, as conventional agriculture generally does — leads to multiple bad outcomes: intensive synthetic pesticide and fertilizer use and the harms that flow from them; poor soils; erosion; inefficient holding and use of water; depleted carbon capacity; and a denuded above-soil landscape and diminished microbial, fungal, and nutrient environment below. Thus, perennial cropping boosts on-farm biodiversity as noted, and benefits off-farm biodiversity by reducing the unsavory impacts, on the broader environment, of traditional, chemically intensive, monoculture farming.
Biodiversity loss has emerged in the past decade as yet another crisis humanity faces — one that continues to go unaddressed at the level the loss requires. Beyond Pesticides has written extensively about the crisis and the central solution of ending the use of toxic, synthetic pesticides ASAP, and certainly within the next decade. Doing so would eliminate one of the chief contributors to the diminution of biodiverse populations, and of pollinators, in particular.
Speaking to the capacity of perennials to impact species, a chief scientist at the Kansas-based The Land Institute (TLI) — which has conducted extensive and foundational work on perennial agriculture — Tim Crews, cuts to the chase: “A vegetated landscape is going to accommodate species that a tilled, denuded landscape as far as the eye can see does not. There are going to be a lot of species that take advantage of it.”
The Land Institute website notes, “Many fruit, forage, and some vegetable crops, including fruit trees, alfalfa, grapes, asparagus, and olive trees, are perennials that have been grown for thousands of years. The Land Institute is working to add perennial grains, legumes, and oilseed crops to the list.” Among the perennial crops the institute is investigating and promoting are: Kernza®, a wheatgrass whose seeds provide grain, and whose foliage, post-harvest, can be forage for livestock.
Research in 2022 in Frontiers in Plant Science concludes that, “Perennial grain crops could make a valuable addition to sustainable agriculture, potentially even as an alternative to their annual counterparts. . . . Presently, perennial grain crops are not grown at large scale, mainly due to their early stages of domestication and current low yields.” Yet TLI has made significant headway, especially with Kernza, which has successfully moved into small, niche markets as a viable grain crop. The TLI researchers note that the roots of this plant can extend as much as 10 feet into the soil, “delivering atmospheric carbon to the soil and efficiently taking up nutrients and water.” They also say that its slender, long seed heads can, under good growing conditions, actually contain more seeds than a typical annual wheat head. The researchers are working, with each breeding cycle, to increase Kernza’s seed size, which achievement would enhance its marketability.
Agricultural perennials can include orchards (fruit and nut trees), row crops, agroforestry, and integrated pasture lands (silvopasture). In addition to the biodiversity benefits, perennials yield multiple soil, food security, and climate benefits. For the agricultural producer, they also, compared with annual crops:
- do not have to be reseeded or replanted every year
- do not require annual plowing/tilling
- do not need pesticides to help get them established
- protect soil from erosion
- improve soil structure
- increase ecosystem nutrient retention, carbon sequestration, and water infiltration
- reduce farmers’ costs via lowered need for pricey inputs (e.g., synthetic fertilizers and pesticides) and laborious tilling and planting
The Land Institute website asserts that increased use of perennials “stands to catalyze a rich culture around food production and supply chain development. Research is emerging to understand the social and economic strategies needed to support these new agricultural systems. . . . Given that grains make up over 70% of our global caloric consumption and over 70% of our global croplands, transitioning from an extractive annual model to a perennial model is the best chance we have to create a truly regenerative food future.”
A primary ethos in perennial agriculture is learning from Nature and using approaches that mimic or reproduce what works in the natural world. For instance, “monocrops” are not generally found growing naturally; rather, diverse plant species grow together and in relationship. (The dominant use of monocropping in conventional agriculture, in fact, contributes to pollinator decline and biodiversity loss.) TLI conducts ecological intensification research that seeks to find optimal combinations of perennial species — polycultures that mimic the benefits found in native and natural ecosystems.
A chief TLI scientist, Ebony Murrell, explains: “The idea with perennial crops is that you want them to stay in the ground for many years, which means you’re not rotating anymore. So how do you take that diversity in time and move it to diversity in space?” One important answer: planting together different perennial plant crops that will benefit one another. Examples of such a strategy might include:
- planting silflower (a perennial sunflower) with a perennial groundcover as a natural weed barrier
- alternating rows or areas of Kernza and alfalfa; the alfalfa provides nitrogen, and prevents Kernza from clumping together, which can result in lowered production; without its companion, Kernza will tend to produce less after a few years
- supporting pollinators by growing together two flowering species that bloom at slightly different times
- incorporating into a farm system trees or shrubs that generate fruits and/or nuts, edible leaves, and/or mushrooms that help support growth of other species
Polycultures have a lot to offer re: restoring biodiversity. The title of 2022 research published in Environmental Entomology reveals its conclusions: Native Flowering Border Crops Attract High Pollinator Abundance and Diversity, Providing Growers the Opportunity to Enhance Pollination Services. The research found that non-crop plantings, as borders, hedgerows, buffer strips, or crop strips, diversify landscapes and offer more habitat in heavy production areas. The research found that such plantings, with various combinations of natives — silflower, cup plant, sanfoin (a forage legume), Kernza, white alfalfa, and a mix of “prairie” species (including liatris, helianthus, mints, native grasses, and asters) — yielded “a significant, positive relationship between pollinator abundance and floral resource amount and bloom duration.”
The title of another bit of research from 2022, published in Ecosphere, is similarly revealing of its findings: Woody Perennial Polycultures in the U.S. Midwest Enhance Biodiversity and Ecosystem Functions. The paper points to the potential, saying “Concepts from ecology and complex adaptive systems suggest that persistent structural heterogeneity and functional diversity are key for supporting biodiversity, ecosystem services, and resilience, but these concepts have not been extensively applied in agriculture, which is still dominated by annual monocropping systems. Perennial agriculture seems to embody these ecological concepts.”
The paper continues, “We found that perennial fields had (1) more diverse soil fungal, invertebrate, plant, and bird communities . . .; (2) less compacted soil; (3) denser ground cover; (4) more active carbon, organic carbon, and nitrogen and the same available phosphorus in the top layer of soil; and (5) more species of predatory, detritivorous, and herbivorous insects, and approximately fourfold higher abundance of herbivorous insects. . . . [T]hese findings indicate that woody perennial polyculture fields in the U.S. Midwest are characterized by higher biodiversity and ecosystem functions than adjacent conventional fields.”
Research published early in 2023 in Frontiers in Sustainable Food Systems emphasizes not only the many benefits of perennial agriculture, but also, the need for changes in federal policy and “a range of support structures. Federal policymakers should support perennial agriculture by establishing safety nets like those available for annual crops, centering perennial practices in cost-sharing conservation programs, facilitating market opportunities, and investing in perennial agriculture research and development.”
There has been some increasing governmental support to advance aspects of the perennial agriculture movement. In 2020, the U.S. Department of Agriculture (USDA) awarded “$10 million to a coalition of farmers, scientists, educators, policymakers, and food industry players to help scale up Kernza production. The five-year Kernza CAP initiative, spearheaded by The Land Institute and the University of Minnesota, recently released its year-two annual report.” Civil Eats identifies the Savanna Institute as a nonprofit that works on advancing agroforestry and perennial agriculture in the Midwest. The organization will use some of the $60 million allocated by USDA in 2022 to ramp up its work to “catalyze the development and adoption of resilient, scalable agroforestry.”
To the argument for the transition off of synthetic chemical inputs should be added those for the transformation of what and how farmers grow. The biodiversity benefits of using more perennial crops, as noted above, are one part of the story, but expanding the profoundly narrow range of food crop varieties currently grown is another biodiversity issue.
The International Development Research Centre (IDRC) asserts that most agriculture across the world is focused on a very small number of varieties designed for intensive production. Indeed, IDRC notes that the food supply depends on roughly 150 plant species. Of those, a mere 12 provide three-fourths of the world’s food, and more than half of the world’s caloric food energy comes from rice, wheat, and maize. This reduced diversity, coupled with increased industrialization, leads to dramatically reduced genetic diversity, aka, genetic erosion, which can spell trouble for the future of successful and sustainable food production.
In the 2022 research paper Perennials as Future Grain Crops: Opportunities and Challenges, researchers highlight some of the risks of our current agricultural modus operandi. “For millennia, the repeated selection and breeding of plants has led to the development of multiple, high-yielding annual grain crops finely tuned for growth under specific environmental regimes. In the twentieth century, cropping systems were developed that took advantage of readily available resources and agrichemical development, with the focus primarily on grain yield. However, considering the current range of complex challenges that agriculture faces, including climate change, pandemics, [biodiversity loss], and war, the focus must now be on ensuring food security in a more environmentally friendly and socially robust way. Continued climate change is rendering our existing cultivars increasingly vulnerable to stress, and ultimately unfit for many regions of the world, serving as another impetus for reinventing agriculture.”
Research published in 2020 by the U.S. National Institutes of Health/National Library of Medicine reinforces the role of perennials in a revisioned agricultural landscape. “Greater adoption of a wider array of perennial vegetables could help to address some of the central, interlocking issues of the 21st century: climate change, biodiversity, and nutrition. The great diversity of PVs [perennial vegetables] is a powerful tool to address the loss of crop biodiversity. As perennials, PVs sequester carbon, particularly the woody species. Many PVs are high in the key nutrients needed to remedy nutrient deficiencies that impact billions of people.”
The Savanna Institute’s Fred Iutzi sees, in perennial agriculture, powerful potential for solving multiple problems, including biodiversity loss. Civil Eats cites his conviction that “[W]e need to think of agricultural productivity in a more holistic way that includes factors like biodiversity. ‘One of the biggest challenges in front of humanity is how we get both ample food while providing a stable climate, healthy soil, clean water, and biodiversity. . . . We have to expect both from our agricultural landscapes.”
Source: https://civileats.com/2023/02/16/perennial-crops-boost-biodiversity-farms-habitat-science-kernza/
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
