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Is the savanah really an effective carbon sink, or is this still based on the (recently discredited) humus theory of soil?
by Robotbeat 5y ago
Is the savanah really an effective carbon sink, or is this still based on the (recently discredited) humus theory of soil?
- thatcat 5y agoHumus stabilizing in soil is the result of mycorhizzae extracting mineral elements from the soil and exchanging that for carbohydrates. The humus theory was that humus is an essential nutrient. If humus theory were true carbon would be removed, not added to soil. That theory was debunked more than 20 y ago. https://blog.nutri-tech.com.au/mycorrhizal-magic-new-biological-breakthrough/ https://blog.nutri-tech.com.au/mycorrhizal-magic-new-biologi...
- jnmandal 5y agoNot related. The suspected importance of savanna is more based on biodiversity than soil science. In these biomes, you have comparatively large amounts of animal and insect biomass. You have animals constantly eating the plants. This causes deep rooted plants which can regenerate quickly to dominate as they grow back intermittently. The sequestered carbon is mostly in the plants and animals as opposed to soil. Measuring biomass accumulation below ground is more difficult than above ground (counting trees is pretty easy). However some land use pattern studies have looked at which areas have historically been savanna normally show overlap with heavy agriculture regions as the soil is so good. In some cases these former oak savannas in the US will have dozens of feet of fertile topsoil. So there's some speculation that the high soil fertility in such biomes is due to compaction from grazing animals, which I guess is not related to the humus theory, but would be a similar idea about how so much carbon can accumulate.