B. Conversion of Annual to Perennial Crops

It is clear from the lukewarm reception of global warming by the political establishment in this and other countries of the world, that economic factors operating now are more important than combating global warming in the future. It is very likely that the goal of 80% reduction in the production of green house gases required to just to halt the progression of global warming will NEVER happen. Politicians would rather deny it is a problem or just close their eyes and let their grand children worry about it. Even if the 80% reduction were achieved it would take over a thousand years for atmospheric CO2 levels to return to less than 300 ppm. Thus, it is clear that while shutting down the major offenders, such as coal burning power electrical power plants in this country would help, this would not of itself solve the problem and would not solve the problem unless other countries did the same.

It is clear that what is needed is an economical and effective method of removing the CO2 from the atmosphere.

The ideal method would be one that is a natural byproduct of another process that in of itself is economically beneficial. Such a process is the conversion of food crops from annuals to perennials (Mims, 2011).

Before the modern agricultural era most of the planet was covered with plants that lived year after year, i.e. were perennials. As the need for food progressed, crop plants that were annuals replaced these perennials. As such they had to be replanted each year. This whole process required tilling, fertilizing and irrigating the land. These processes are expensive, energy intensive and the fertilizers, which eventually end up in the ocean, are destructive to the ocean environment.

Agricultural scientists have long dreamed of replacing annual with perennial crops but until recently the technology to do this was unavailable. The following are some of the advantages of perennials over annuals (Mims, 2011):

• Their
deep roots prevent erosion, which helps to hold onto critical minerals such as phosphorus; and they require less fertilizer and water. This would be very helpful if the current droughts continue.
They act as a carbon sink.

The figure shows the dramatic difference in the root systems of perennial and annual summer wheat.

Annuals Perrenials 400

Figure 1. A comparison of the root system of annuals (left portion of each panel except summer) and perennials (right portion of each panel)

Almost all of the advantages of perennials stem from the massively greater root system and the key to perennials being a carbon sink is their deep root system. This results in sequestering of an amount of carbon that is equal to 1 percent of the mass of the dirt. The U.K. Biotechnology and Biological Sciences Research Council had estimated that
replacing just 2 percent of the annual crops with perennial crops would remove enough carbon each year to halt the increases in atmospheric carbon dioxide due to burning fossil fuels. Replacing all annual crops would pull the concentration of carbon dioxide to preindustrial levels.

In addition, with the development of this technology the
yields in some of the worlds most desperately poor places could soar. Raising crops everywhere would be less expensive and require less fuel for tractors, require less water and fertilizer, AND would solve the problem of global warming.

The following text was extracted from the article Future Farming: A Return to Roots by (Glover et al, 2007).

Wes Jackson observed that 10,000 years ago the perennial grasses and flowers of the Kansas tall-grass prairies were highly productive year after year, even as they built and maintained rich soils. They needed no fertilizers, pesticides or herbicides to thrive while fending off pests and disease. Water running off or through the prairie soils was clear, and wildlife was abundant.

In a century-long study of factors affecting soil erosion, timothy grass, a perennial hay crop, proved roughly 54 times more effective in maintaining topsoil than annual crops did. Scientists have also documented a
fivefold reduction in water loss and a 35-fold reduction in nitrate loss from soil planted with alfalfa and mixed perennial grasses as compared with soil under corn and soybeans. Greater root depths and longer growing seasons also let perennials boost their sequestration of carbon, the main ingredient of soil organic matter, by 50 percent or more as compared with annually cropped fields. Because they do not need to be replanted every year, perennials require fewer passes of farm machinery and fewer inputs of pesticides and fertilizers as well, which reduces fossil-fuel use. The plants thus lower the amount of carbon dioxide in the air while improving the soil’s fertility.

Herbicide costs for annual crop production may be four to 8.5 times the herbicide costs for perennial crop production, so fewer inputs in perennial systems mean lower cash expenditures for the farmer. Wildlife also benefits: bird populations, for instance, have been shown to be seven times more dense in perennial crop fields than in annual crop fields. Perhaps most important for a hungry world, perennials are far more capable of sustainable cultivation on marginal lands, which already have poor soil quality or which would be quickly depleted by a few years of intensive annual cropping.

For all these reasons, plant breeders in the U.S. and elsewhere have initiated research and breeding programs over the past five years to develop wheat, sorghum, sunflower, intermediate wheatgrass and other species as perennial grain crops. Perennial crop developers are employing essentially the same two methods as those used by many other agricultural scientists: direct domestication of wild plants and hybridization of existing annual crop plants with their wild relatives. These techniques are potentially complementary, but each presents a distinct set of challenges and advantages as well.

Active perennial grain domestication programs are currently focused on intermediate wheatgrass
(Thinopyrum intermedium), Maximilian sunflower (Helianthus maximiliani), Illinois bundleflower (Desmanthus illinoensis) and flax (a perennial species of the Linum geanus). Of these, the domestication of intermediate wheatgrass, a perennial relative of wheat, is perhaps in the most advanced stages

Of the 13 most widely grown grain and oil-seed crops, 10 are capable of hybridization with perennial relatives, according to plant breeder T. Stan Cox of the Land Institute, a Kansas non-profit that Jackson co-founded to pursue sustainable agriculture. A handful of breeding programs across the U.S. are currently pursuing such interspecific (between species) and inter- generic (between genera) hybrids to develop perennial wheat, sorghum, corn, flax and oilseed sunflower. For more than a decade, University of Manitoba researchers have studied resource use in perennial systems, and now a number of Canadian institutions have started on the long road to developing perennial grain programs as well. The University of Western Australia has already established a perennial wheat program as part of that country’s Cooperative Research Center for Future Farm Industries. In addition, scientists at the Food Crops Research Institute in Kunming, China, are continuing work initiated by the International Rice Research Institute in the 1990s to develop perennial upland rice hybrids.

At the Land Institute, breeders are working both on domesticating perennial wheatgrass and on crossing assorted perennial wheatgrass species (in particular,
Th. intermedium, Th. zponticum and Th. elongatum) with annual wheats. At present, 1,500 such hybrids and thousands of their progeny are being screened for perennial traits. The process of creating these hybrids is itself labor-intensive and time-consuming. Once breeders identify candidates for hybridization, they must manage gene exchanges between disparate species by manipulating pollen to make a large number of crosses between plants, selecting the progeny with desirable traits, and repeating this cycle of crossing and selection again and again.

Hybridization nonetheless is a potentially faster means to create a perennial crop plant than domestication, although more technology is often required to overcome genetic incompatibilities between the parent plants. A seed produced by crossing two distantly related species, for example, will often abort before it is fully developed. Such a specimen can be “rescued” as an embryo by growing it on artificial medium until it produces a few roots and leaves, then transferring the seedling to soil, where it can grow like any other plant. When it reaches the reproductive stage, however, the hybrid’s genetic anomalies frequently manifest as an inability to produce seed.

Global warming potential— greenhouse gases released into the atmosphere by crop production inputs, minus carbon sequestered in soil—is negative for perennial crops. The more resilient perennials are also expected to fare better than annuals in a warming climate.

Annuals vs Perennials

Because of its complexity, transgenic modification (insertion of foreign DNA) is unlikely to be useful in developing perennial grains, at least initially. Down the road, transgenic technology may have a role in refining simple inherited traits. For example, if a domesticated perennial wheatgrass is successfully developed but still lacks the right combination of gluten-protein genes necessary for making good-quality bread, gluten genes from annual wheat could be inserted into the perennial plant.

Global conditions—agricultural, ecological, economic and political— are changing rapidly in ways that could promote efforts to create perennial crops. For instance, as pressure mounts on the U.S. and Europe to cut or eliminate farm subsidies, which primarily support annual cropping systems, more funds could be made available for perennials research.

January 2019 Update:
The Land Institute has developed a grain called
Kernza which is a perennial wheat. The grains are smaller than in normal wheat and the Land Institute is working to increase grain size. They have also developed perennial rice, sunflower and sorghum - which are being tested in the field.

Because the long timeline for release of perennial grain crops discourages private-sector investment at this point, large-scale government or philanthropic funding is needed to build up a critical mass of scientists and research programs.

There are two approaches to the development of perennial crops –
a. Classic plant genetic techniques of hybridization and selection
b. Molecular genetic approaches. Several programs are already in place that have begun this work.

Classic Plant Genetic Techniques.

The Land Institute The prime mover of this approach in the United States is the non-profit Land Institute. The following is their mission statement.

The Land Institute has worked for over 30 years on the problem of agriculture. Our purpose is to develop an agricultural system with the ecological stability of the prairie and a grain yield comparable to that from annual crops. We have researched, published in refereed scientific journals, given hundreds of public presentations here and abroad, and hosted countless intellectuals and scientists. Our work is frequently cited, most recently in Science and Nature, the most prestigious scientific journals. We are now assembling a team of advisors which includes members of the National Academy of Sciences. These scientists understand our work and stand ready to endorse the feasibility of what we have come to call Natural Systems Agriculture.
Our strategy now is to collaborate with public institutions in order to direct more research in the direction of Natural Systems Agriculture. We are seeking funds to construct and operate a research center devoted to Natural Systems Agriculture and to underwrite scientists elsewhere who will engage with us in such research. We estimate the research cost to be $5 million a year for 25 years, which is a small fraction of one percent of the nation's annual agricultural research investment.
Important questions have been answered and crucial principles explored to the point that we feel comfortable in saying that we have demonstrated the scientific feasibility of our proposal for a Natural Systems Agriculture. Because this work deals with basic biological questions and principles, the implications are applicable worldwide. If Natural Systems Agriculture were fully adopted, we could one day see the end of agricultural scientists from industrialized societies delivering agronomic methods and technologies from their fossil fuel-intensive infrastructures into developing countries and thereby saddling them with brittle economies.

The University of Manitoba Perennial Grain Crops Program. The following is from their web site.

In fall 2007, we planted our first perennial grain crop - perennial cereal rye developed at AAFC Lethbridge - at the University of Manitoba Research Farm at Carman, Manitoba. By the summer of 2009, the rye had survived two winters and was allowed to produce seed. Seed was harvested from selected plants and planted in fall 2009 to allow for further selection work.
We have also begun work together with the Land Institute on perennial wheat. Five strains of perennial wheat were planted at various locations in Manitoba in fall 2008. Winter survival was variable, but many plants did survive the winter and produced seed in 2009. A few of these plants exhibited fall re-growth after producing seed, a sign that these plants are behaving as perennials and not just winter annuals. In summer 2010, we had two perennial wheat plants re-grow and produce seed.
In fall 2010, the University of Manitoba Department of Plant Science hired a perennial grain breeder who is now carrying on the work we began.

Molecular Genetic Techniques

Ed Buckner, Ph.D. is one of the country’s leading plant molecular geneticists is interested in using transgenetic techniques for developing perennial corm. He is director of the Cornell University Laboratory for Maize Genetics and Diversity. The tools in this lab include genotyping by sequencing, germ plasm development, Statistical genetics, and studies of draught tolerance. See http://www.maizegenetics.net

Salk: Harnessing Plants Initiative and Suberin
Climate change poses an immediate threat to our future. Rising temperatures from excess carbon dioxide in the atmosphere has led to increasingly extreme and dangerous weather patterns that threaten animals and plants alike.
The Salk Institute’s Harnessing Plants Initiative (HPI) is an innovative, scalable and bold approach to fight climate change by optimizing a plant’s natural ability to capture and store carbon and adapt to diverse climate conditions. We believe that our approach can help draw down and store more carbon and that we can—combined with other global efforts—mitigate the disastrous effects of climate change while providing more food, fuel and fiber for a growing population.
The Harnessing Plants Initiative is only in its second year, but researchers have already identified key genes responsible for root growth and suberin production. They aim to create a sort of gene arsenal with up to 20 to 50 genes which can be modified and tried in new crop plants. Once the key genes are identified, researchers could produce these crops without genetic engineering and proceed with a selective breeding program, but the process would just take a lot longer. Either way, it may be a while before these plants are agriculturally viable and ready for mass production. The Salk Institute aims to begin global distribution in the next 510 years and achieve “significant” carbon drawdown in the next 10–15 years.
Scientists at the Salk Institute have researched a gene called Surberin (and other genes) to dramatically increase the amount of carbon stored in the roots of plants.

Salk Suberin Plant 700

1. Lackner, K.S. A Guide to CO2 Sequestration. Science 300:1677-1678, 2004

2. Mims, C. Crops the Don’t Need Replanting.
Scientific American Dec 2011.

3. Glover, J. D., Cox, C. M. and Reganold, J.P. Future Farming: A Returning to Roots. Scientific American 287:82-89, (August) 2007.

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