Perennial agriculture
-
What is perennial agriculture?
Perennial agriculture involves cultivating crops that live for over two years without annual replanting. Unlike mainstream agriculture, it requires less tilling, and in some instances, less labor and fewer pesticides, which helps maintain and improve soil health.
Compared to annual crops, perennial crops limit soil erosion because of their extensive root systems. These crops also don't need yearly replanting, require less labor, and tend to grow rapidly, outcompeting annual weeds. They also cope with environmental stressors and sequester carbon efficiently and can provide habitats for wildlife while producing food. Economically important crops include tree crops, blueberries, cranberries, asparagus, grapes, alfalfa, rhubarb, chives, and mint.
2 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How are perennial crops different from annual crops?
Perennial agriculture uses crops that live for over two years and don't need annual replanting, unlike annual crops that complete their life cycle in one growing season. Perennial crops have extensive root systems that limit soil erosion and require less tilling, labor, and fewer pesticides than annuals. Perennials also grow rapidly, outcompete weeds, handle environmental stressors better, and sequester carbon more efficiently. They can also provide wildlife habitat and improve soil health.
3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What are some common examples of perennial crops?
Perennial agriculture involves cultivating crops that live for more than two years without annual replanting. Unlike annual crops, perennials need less tilling, and sometimes less labor and fewer pesticides, which helps maintain soil health.
Examples of perennial crops include tree crops like apples, citrus, nuts, coffee, chocolate, and oil palm, as well as blueberries, cranberries, asparagus, grapes, alfalfa, rhubarb, chives, and mint. These crops have extensive root systems that limit soil erosion, require less tilling, and can outcompete annual weeds. They also cope well with environmental stressors and sequester carbon efficiently.
The cultivation of perennial fruiting crops began over 11,000 years ago and benefited humans by being less labor-intensive with a long lifespan.
3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
Why might farmers choose to grow perennial crops?
Farmers might choose to grow perennial crops because they do not need to be replanted every year, which saves labor. Perennial crops also limit soil erosion because they have extensive root systems and require less tilling. Additionally, perennial crops tend to grow rapidly in the spring, which allows them to outcompete annual weeds. They have also adapted to local insects and diseases, so they generally require fewer pesticides than annual crops. Perennial crops can also cope with environmental stressors and sequester carbon more efficiently than annuals.
2 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How does perennial agriculture help soil and the environment?
Perennial agriculture involves cultivating crops that live for over two years without annual replanting. Compared to annual crops, perennial crops help the soil and the environment because they limit soil erosion due to their extensive root systems and the limited tilling required.
Because perennial crops do not need to be replanted every year, they require less labor and fewer pesticides than annuals, and they can sequester carbon more efficiently. They also have adapted over time to deal with local insects and diseases. Perennial grains can provide wildlife habitat and improve soil health while producing food for human consumption. Depending on the methods used, perennial agriculture can be considered a form of sustainable agriculture.
1 Britannica SourceCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What challenges do farmers face when using perennial agriculture?
Perennial agriculture, while offering numerous benefits, presents farmers with distinct challenges. A primary limitation is the lower yield of perennial grains compared to annuals, as perennials divert energy to root systems and regrowth rather than seed production. Although perennial crops generally need less tilling, labor, and fewer pesticides, insects, plant disease, nematodes, rodents, weeds, and air pollution are among the many enemies that can reduce crop yields. Overcoming these limitations requires ongoing research and development in plant genetics and breeding to enhance yields and broaden the applications of perennial species.
2 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Perennial agriculture, the cultivation of crop species that live longer than two years without the need for replanting each year. Perennial agriculture differs from mainstream agriculture in that it involves relatively less tilling and in some cases requires less labour and fewer pesticides, helping to maintain or even improve soil health. Perennial crops used in perennial agriculture are grown worldwide in various climates and are adapted to local environmental stressors. Depending on the methods used, perennial agriculture can be considered a form of sustainable agriculture.
Historical developments
The cultivation of perennial fruiting crop species is thought to have begun more than 11,000 years ago. In order to cultivate these species, human settlements had to remain stationary, a change that potentially affected the settlement patterns of some societies. Nonetheless, humans benefited from perennial fruit crops, which were less labour-intensive and had a relatively long lifespan—producing food for many years after a single planting—compared with food-producing plants that required annual planting. Over generations of artificial selection, the species were refined to produce increasingly palatable fruit. Later, the use of perennial species expanded to forage crops, such as alfalfa, and the production of timber crops to produce building materials.
In 1929, American geographer Joseph Russell Smith, concerned by the rapid destruction of the environment following the industrialization of crop farming, wrote Tree Crops: A Permanent Agriculture (1929), in which he described the potential for the sustainable cultivation of trees to combat erosion while also producing food in regions worldwide. The book inspired other researchers to explore the possibility of widespread perennial agriculture and agroforestry. Shortly thereafter, in the 1930s and ’40s, interest in sustainable perennial agriculture grew, in part due to the severe drought that ruined millions of acres of plowed cropland in the Dust Bowl of the Great Plains of the United States.
" height="20" alt="HEW Logo">
Also in the 1930s, Soviet researchers attempted to breed perennial wheat through hybridization techniques, though the idea was abandoned in the 1960s due to limited success. About the same time in the mid-20th century, researchers in California began investigating perennial wheat and were able to produce lines of prototype varieties that produced yields similar to those of existing low-yielding types. Yield increases in annual wheat, however, greatly diminished the economical viability of low-yielding perennial wheat varieties.
Environmental benefits
Compared with annual crops, perennial crops have extensive root systems, making soil particles difficult to dislodge and thereby limiting soil erosion. Erosion is further reduced by the limited amount of tilling needed to maintain the crop. In addition, since perennial crops do not need to be replanted every year, they require less labour than annuals, and perennials tend to grow rapidly in the spring, enabling them to outcompete annual weeds. They also have adapted over time to deal with local insects and diseases and therefore generally require fewer pesticide applications than annuals. Moreover, their large root systems enable them to cope with environmental stressors, such as drought or irregular rainfall, and they are able to sequester carbon more efficiently than annuals. Perennial grains also potentially could be bred to imitate some of the key aspects of threatened grasslands by providing habitat for wildlife and improving or maintaining soil health, while also producing food for human consumption.
Research and limitations
Research into perennial grains slowed until the 2000s, when scientists, aided by a better understanding of plant genetics, began to reassess the plausibility and potential of perennial grains. With advancements in genetic technology, such as genetic mapping and genetic engineering, commercially viable perennial grains could be grown on a wide scale in the future. Researchers also found ways to expand the applications of perennial species. With genetic mapping, for example, researchers have been working to identify genes that can be controlled to increase biomass production in perennial species such as switchgrass (Panicum virgatum), an important source of biofuel.
The value of perennial grains, however, is challenged particularly by their limited yields, which is a result of the nature by which perennials continually regrow every year. Annual grains are able to divert much of their energy into the production of seeds, whereas perennials must divert energy to their root systems and seed development.
The trusted destination for professionals, college students, and lifelong learners.
SUBSCRIBE
