Are Perennial Grains, Oilseeds, and Pulses Ready for Production Ag. Systems?

The Land Institute (TLI) is a Salina, Kansas-based not-for-profit organization which is working to develop perennial varieties of grains, oilseeds, and pulses through the domestication of wild perennial species and through the perennialization long-domesticated annual crops like wheat, rice, and sorghum. TLI has the ambitious goal of building grain, oilseed, and pulse production systems around perennial crops. Importantly, TLI is using an open source development model which allows for the organization’s research and crop varieties to remain in the public domain.

Perennial crops have a number of production advantages when compared to annual crops. They include:

-a single seeding pass for multi-year cropping cycles
-zero tillage after establishment
-year-round soil cover without the need for annual cover crops
-extensive root systems, allowing perennial crops to access water and macronutrients deep in the subsoil
-longer windows of cash crop biological activity, allowing for greater amounts of exudates (in principle) when compared to annual crops

While the production advantages of perennial grain, oilseed, and pulse varieties are attractive, there remains some unanswered questions about the practicality of perennial crops in production systems. Diverse and flexible annual cash crop rotations can provide a significant amount protection against weed infestations, insect pests, and fungal infections. These crop protection advantages may be lost with long-lived stands of perennial crops. At the same time, annual cash crop rotations can more easily be adapted to market conditions. It is expected that stands of perennial crops would be productive between 5-10 years, making them less adaptable to shifts in market demand on a year to year basis.

Most of TLI’s perennial crops are still in the development stage, but two have recently been adopted in production systems at small scales. Intermediate wheatgrass (trademarked as Kernza) and a hybrid rice variety. Kernza is now being grown commerically in Canada and the U.S. for baked goods and beer. However, Kernza’s low grain yield, small seed size, limited productivity after 3-4 years, and limited seed availability ensure that it will remain a low-volume specialty crop for the time being. Perennial rice now produces acceptable yields for 3-4 years and has been used for commercial rice production in China since 2018. Breeding work continues on both Kernza and perennial rice to select for higher yields, improved grain characteristics, and longer plant lifespans.

Crops still in the development stage include silphium (a perennial oilseed sunflower species), perennial wheat, and perennial sorghum. State of the art computer-aided genetic sequencing and year-round greenhouse breeding is being used to accelerate the development of these crops. It is expected that it will be another 15-20 years until silphium, perennial wheat, and perennial sorghum are ready for adoption in production systems.

Beyond current perennial crops in development, TLI is working with Missouri Botanical Garden and St. Louis University to identify herbaceous wild perennial species around the world that would make good candidates for domestication in both temperate and tropical climates. These longer-term projects reflect TLI’s long-term mission for perennial crop selection and breeding over the next 50-100 years. TLI has invested significantly in fund-raising capacity and organizational development to ensure that it will survive long enough as an organization to achieve its ambitious goals.  
As more perennial grain, oilseed, and pulse varieties are developed, TLI anticipates that they can be grown as suites of mixed intercrops. Mixed intercropping can provide specific agronomic benefits, including a decreased need for N fertilizer or help to lower susceptibility to insect pests. A great deal of practical work on mixed intercropping seeding, harvesting, and grain separation has already been done in annual cropping systems on the Canadian Prairies and U.S. Northern Plains, demonstrating that mixed intercropping can be profitable and practical in production agriculture systems.

TLI does not expect that their perennialized crop varieties will completely replace annual crop varieties in the long term. However, mixed stands of perennial grains, oilseeds, and pulses which are commercially viable and which complement annual production systems are an exciting prospect we can realistically look forward to in the next 15-20 years.

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