Dynamic accumulators are plants that gather certain micronutrients, macronutrients, or minerals from the soil through their roots, as opposed to from the air, and store them in their leaves. These plants can be used either for detoxifying soil or for gathering a certain nutrient or mineral from an area. For instance, clovers will mine great quantities of nitrogen out of the air via a symbiotic relationship with bacteria. These bacteria convert gaseous nitrogen into a form available to the clover, and exchange this nitrogen for exudates/sugars given by the clover. When the clover dies or is cut down, the green matter breaks down and releases the nitrogen into the soil.
These plants become rich in a certain substance and can then be cut down. This can be used as a fertilizer or as part of a fertilizer mix for other plants that may be deficient in those particular nutrients. The use of a nitrogen dynamic accumulator, such as a clover patch, could potentially replace nitrogen-rich fertilizers. These types of plants play an important role in many permaculture guilds.
Microbiologist Kristine Nicholas of the University of Maryland showed that grasses like switchgrass, blue grama, Indian grass not only send down deep roots but increase glomalin levels and arbuscular mycorrhizal fungi. These fungi help "glue" the soil together, make it coherent, and shuttle biologically available nutrients from soil to plant. Some land reclamation companies are now using arbuscular mycorrhizal fungi and triticale to accomplish a similar end, and most likely Orchard grass (especially in combination with chicory and clover), and yacon, Jerusalem artichoke, chicory and many other plants will also eventually be shown to increase glomalin. Whatever that mysterious quality of "fertile" and "fertility" turns out to be in the soil, it must have something to do with these processes.
The plants with function as dynamic accumulators are often traditionally regarded as companion plants. In those cases, a plant such as yarrow or alfalfa growing near other plants, or in some cases being used as a green manure or cover crop, will show benefits to other plants due in part to the nutrients selected and exchanged. Among the accumulator plants of broadest nutrient variety are dandelion, plantains, watercress, comfrey, and kelp°. Under good soil and growing conditions, certain plants may extract higher levels of nutrients than others, with consistency, although removing those nutrients from that soil can create a void in availability. Therefore, composts made with accumulator plants should also be reintroduced to those same growing areas upon compost completion.
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