What is meant by annual, perennial, and polyculture?
Annual plants must be sown every year; they die at some point after reaching maturity and will not re-grow. Perennials plants live for more than one year.They may go dormant, but will re-emerge from their roots. A polyculture is when you have different species in an area. Prairies are apolyculture. They have a variety of many different plants growing interspersed, about 80 percent of which are perennials that remain alive for many years; the rest are annuals that grow for only one season.
You talk about growing perennial grains in polycultures (mixtures) to get the benefits of a prairie-type ecosystem. How can this be harvested? Will new machinery be necessary?
This question arose so frequently over the years that we finally decided to plant a polyculture of four annual crop species: corn, soybean, sorghum, and sunflower. The seed mixture was planted with an air drill. At harvest we opened the concave on the combine and cut the air (so as not to blow the sunflower seeds out the back). Progress through the field was slow, but not prohibitively so. Seeds were separated with a standard seed cleaner. The point is that mechanical equipment already in existence, and with a little fine tuning can do the job. The larger problems are agronomic, not engineering.
Can I use perennial plants to effectively combat erosion?
Perennial plants will hold the soil more effectively than any annual, to be sure. But not all perennials grow equally well in different regions of the country. We suggest you talk to a horticultural agent at your local Coop Extension office (now called USDA National Institute of Food and Agriculture) or your local county extension agent. You can find a local office via the web by searching for USDA.gov.extension, which gives info for local offices via an interactive US map. Once the plants you require have been identified, there are numerous on-line sources for perennials and grasses.
A recent study called Losing Ground published by the Environmental Working Group gives some very effective methods for helping contain runoff. Grass or tree strips, also called filter strips planted in strategic locations and along the edges of fields has been proven to tremendously reduce erosion and runoff. Their research states that these buffers trapped 41-100% of the sediment, 9-100% of the runoff water, 27-96% of the phosphorous and 7-100% of the nitrogen (www.ewg.org/losingground/).
Do you use genetic modification as part of your perennial grain development?
In our case, breeding new crops involves time-honored methods of pollen transfer. After generations of crossing and selection, we assemble desired traits into a new variety. Many techniques that can assist in this process have become available in past decades. Any of these techniques may be used by us or our collaborators as needed to make perennial grains a reality. At this time, we do not plan to utilize transgenic plants, also known as genetically modified organisms. Transgenes have little to offer in the development of perennial grains at the current time. We can accomplish our task using sexual hybrids and traditional breeding, augmented by forms of genetic technology other than transgenics.
Small-scale testing has proven to be ineffective in predicting consequences of large-scale transgene release; therefore, if use of transgenes were deemed necessary in the future, only those thoroughly tested (already released, used by farmers, and studied over large geographical areas for several years with no negative effects) would be considered.
It is expected to take at least twenty-five years to achieve more than two or three profitable, productive perennial grain crops. Isn’t that too late to address the problems facing the world today?
We hope not, but we do need to move as fast as possible. New strategies are needed that emphasize efficient nutrient use in order to lower production costs and minimize negative environmental impacts. The sooner that successful alternatives are available, the more land we can save from degradation. It is likely that global agricultural acreage will expand over the next two to three decades especially if the human population increases to 8 to 10 billion people. Recent projections predict an 18% or more increase in agricultural land by 2020.
The best soils on the best landscapes are already being used for agriculture. Much of the future expansion of agriculture will be onto marginal lands (Class IV, V, and VI) where risk of irreversible degradation under annual grain production is high. As these areas become degraded, expensive chemical, energy, and equipment inputs will become less effective and much less affordable.
38 percent of global agricultural lands are currently designated as degraded, and the area is increasing. To minimize encroachment onto non-agricultural lands in the future, currently degraded lands will need to be kept in production AND restored to higher productive potential. In regions of the world where high inputs of fertilizers, chemicals and fuels are not an option, agricultural systems that are highly efficient, productive, and conservative of natural resources are needed…and will be needed even more 25 years from now.
Can we expect perennial grain crops to be as productive as annual grain crops and, if not, won’t they actually worsen environmental problems by requiring more land for agricultural production?
There is sufficient evidence that reasonable reference yields of annual crops can be matched on high-quality lands and exceeded on poor-quality lands by diverse perennial systems with fewer negative impacts.
It depends on which annual yields are used as a standard. For example, the world record wheat yield was harvested in the Palouse region of Eastern Washington State where wheat yields can top 100 bushels per acre. Annual wheat production in that region, though, has resulted in extensive erosion. All of the topsoil has been lost from over ten percent of the region’s landscapes. On eroded sites Palouse wheat yields may be less than 25-30 bushels per acre. Crop yields that come at such a high cost to the soil resource, or that depend on an extravagant use of chemical fertilizers, should not be used as a standard of comparison.
But won’t the seed yield of perennials always be limited by the need to save some energy for overwintering that could have been used to produce seed?
The short answer is no. The theoretical limitations to seed yield in perennials are no more serious than in annuals. In annuals, yield is limited by shorter growing seasons, water shortage due to short roots and poor seedling establishment. In perennials, yield can be constrained by the need to overwinter, but rapid spring growth of perennials, combined with season-long access to water deep in the soil profile, means that perennials such as alfalfa are over-all more productive than related annuals like soybeans. Much of the journey-work of plant breeders has been to shift the allocation of resources from leaves, stems, crowns, and roots toward seed in the development of perennial grain crops.
With advances in no-till production of annual grain crops, do we need perennial grains to mitigate the environmental problems associated with agriculture?
Unfortunately, yes. Although no-till technology has reduced erosion in many areas, some problems remain due to the biological limitations of annual plants. Chief among the problems associated with no-till is water quality. Annual crops, even in no-till situations, are relatively inefficient in capturing nutrients and water. Because annual crop plants are often either absent or too small to use and manage water during times of rainfall, as much as 45% of precipitation may drain below root zones of annual crops, whether produced with no-tillage or conventional tillage practices. These rates of water loss under annual crops can be five times greater than under perennials.
This is a problem because water flowing through the soil profile carries soil nutrients and agrochemical that pollute rivers, lakes and coastal waters. This problem can be compounded under no-till production, which often requires greater inputs of agrochemical and fertilizers. A 2002 EPA survey of the nation’s water quality shows a downward trend from the late 1990s. The problem is getting worse, despite increased adoption of no-till and minimum-till systems.
Crop seeds need warm, well-drained seedbeds in order to properly germinate. No-till limits this. That is why tillage remains an attractive practice in northern regions. Warming and drying of the seedbed can be hastened. Advances in plant breeding may eventually allow for optimal germination in cooler, wetter conditions, but in the Midwest, seedlings will still be small when the rains come.
If our farming systems “mimic,” to some degree, natural ecosystems, what level and kind of plant diversity is needed and how will it be deployed?
The answer to both parts of the question is, “It depends.” It depends on the resilience and fertility of the soil, climate, disease pressures, and types of crops. Nearly all of nature’s land-based ecosystems feature perennial plants grown in diverse mixtures. Natural ecosystems, in general, use and manage water and nutrients most efficiently and build and maintain soils. For that reason, nature is our standard. The level and spread of diversity varies. The characteristics of the region in which they are to be grown will have to be assessed.
Diversity is of two kinds: multiple species and genetic diversity within species. Current grain production practices commonly involve planting a single genotype (near-zero genetic diversity) across a field often larger than 100 acres. Furthermore, that single genotype and other genetically similar plants are being grown on millions of acres in a region. Increases in genetic diversity at the species, field, and landscape levels are needed. The final ordering of the components of that diversity will be determined by what is useful and can be practically achieved by local farmers.
Several serious attempts have been made in the past to perennialize grain crops and we have none to date. What has changed that offers promise of success now?
History need not be a source of discouragement. In the case of wheat, most involvement with perennials had to do with bringing desirable genes (e.g., for resistance) from a wild perennial relative into the annual crop. The perennialization effort, in most cases, was carried on, more or less as a hobby, by an interested researcher but with no institutional commitment for a sustained program to guarantee continuity. When the researcher retired, the effort ended. The Soviets had the most ambitious perennial wheat program, but political decisions halted these efforts in the late 50s or early 60s.
We are now in a new era in two ways:
1) In recent years, the costs to our soils and waters due to annual cropping are increasingly weighed against bushels per acre, making some reduction in yields acceptable.
2) With recent advances in plant breeding, more knowledge of the genome and greatly increased computational power, thinking about breeding limits has changed and we have prototypes in our fields.
Since mechanical tillage and annual rotations are largely eliminated in perennial systems, don’t the perennial plants become “sitting ducks” for pests and disease?
Perennials dominate most native landscapes and constitute roughly 80% of North America’s native flora. Perennials have thrived throughout the evolutionary history despite the pressures of pests and disease. In some fields or some regions, some perennial crops will prove to be more problematic than others and breeding for complex traits like yield and perenniality can unintentionally purge genes involved in resistance responses. There will undoubtedly be pest and disease problems. But these problems also afflict our most productive annual crops. And there are many examples of herbaceous perennial plants (alfalfa, switchgrass, brome) that remain highly productive for many years despite exposure to pests or disease. Diversity (whether at the field or landscape scale or over time), field burning, and selecting for resistance in a plant breeding program are essential elements of our work.
How do alternative methods of production such as permaculture, biointensive, or organic fit in with perennial grain crops? What about vegetables and fruits? How do community-supported agriculture farms fit in?
We focus on the crops that occupy 68 percent of global cropland and provide about the same percentage of food calories: annual grain crops grown primarily in monocultures. Any number of approaches, alternative or conventional, could be used in managing perennial crops and distributing the harvest.
This is not to say that efforts aimed at reducing the scale of industrial agriculture and increasing local food security are misguided. They are not! They are necessary to transform our food system over the long term. But while promoting local, small-scale, organic agriculture we must also assess how and where the bulk of our calories can best be produced. If all or even a large portion of the calories consumed by New Yorkers came from New York State there would be few trees left and the state’s thin, poor soils would be quickly degraded. The bulk of the calories consumed by New Yorkers must come directly or indirectly from grain crops which grow well in the Midwest and Great Plains states.
Will the public eat perennial grains?
People like to eat our Kernza (a perennial wheatgrass seed) and we see little reason for people to find significant or undesirable taste differences in perennial grains generally. Greatest short-term success in developing suitable perennial crops will come with perennializing current grain crops with which the public is already familiar. Indeed, one of the strongest arguments for perennializing those grains is that it does not require large dietary shifts.
–Adapted from The Land Institute’s Frequently Asked Questions page