Subsoil compaction is more difficult to be regenerated than topsoil compaction. The soils used are typically subsoil which conserve the topsoil for agriculture. Soil organic carbon tends to be concentrated in the topsoil. Soils in Columbia are well drained in most cases, with grayish brown loamy sand topsoil. The Chamomile plant grows best on well balanced soil with good topsoil. They grow best in deep well-drained loam which has thick dark topsoil. Overgrazing and erosion have removed much of the topsoil from the island. The company has developed a technique of mixing sawdust with chicken manure to produce topsoil. Wind-dropped loess and organic matter accumulated, resulting in deep levels of topsoil. Calcium hydroxyapatite and calcite precipitates can be found around bacteria in alluvial topsoil. Improper and intensive farming led to erosion and the loss of topsoil. Their jobs were to clear away the nitrous topsoil that made the land arable. Replenishing the topsoil with lost nutrients provided for bountiful harvests. Mosses, ferns, grasses, and fungi grow on the topsoil. Concrete causes damage to the most fertile layer of the earth, the topsoil.