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7.1.5: 5 Perennials and Soil Conservation

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  • Because perennials allocate a high proportion of their growth to vegetative structures and regrow for many years, they can: i. protect soil from erosion; ii. return organic matter (carbon-based materials that originated from living organisms) to the soil, providing multiple soil health benefits; and iii. remove carbon dioxide from the atmosphere, potentially sequestering (storing) carbon in the soil or aboveground plant biomass. Forests, for example, sequester carbon above-ground in trees and in below-ground root systems.

    Perennial grasses, in particular, have dense, fibrous roots that protect soil from erosion well and are valuable plants for soil conservation. In addition, over the years, some perennial roots and aboveground plant tissues die when environmental conditions limit growth (ex. drought, winter, grazing), and accumulate organic matter and nutrients in the soil. The majority of the most fertile and deep agricultural soils of the world were formed under natural perennial grasslands, whose deep root systems accumulated organic matter in the soil which contributed many beneficial soil properties, as well as carbon sequestration. Some annual crops can also contribute to conserving soil and add organic matter to the soil if a large portion of the crop residue is left on the soil surface, such corn stalks left on a field after the grain is harvested.


    Figure 6.1.15.: Perennial grass roots, belowground rhizomes, and aboveground plant tissues provide year-round protection from soil erosion on a sloping field in Pennsylvania, while also providing forage for ruminant dairy cows during the spring, summer and autumn months. Credit: Heather Karsten


    Figure 6.1.16.: Some cool-season perennial grasses with rhizomes indicated by the red arrows. Credit: Maria Carlassare


    Figure 6.1.17.: Perennial grass mowed and drying for hay harvest on a steeply sloped field in Pennsylvania. Credit: Heather Karsten


    Figure 6.1.18.: Perennial grass mowed and drying for hay harvest on a steeply sloped field in Pennsylvania. Credit: Heather Karsten

    Knowledge Check (flashcard)

    Consider how you would answer the question on the card below. Click "Turn" to see the correct answer on the reverse side of the card.

    Card 1:

    Front: Can you name some well-known, high-value perennial crops that are produced in the mountainous regions on the steep slopes of the following countries: Switzerland, Costa Rica, Columbia, Peru, Italy?

    Back: Answers could include forage crops for animals that produce milk and meat, coffee, chocolate, cashews, avocados, bananas, plantains, oranges, potatoes, olives, grapes, etc.