Soil loam soil with a small amount of organic material is considered "ideal", inasmuch as fertilizers or manure are currently used to mitigate nutrient losses due to crop yields in the long term. The mineral constituents of a loam soil might be 40% sand, 40% silt and the balance 20% clay by weight. Soil texture affects soil behaviour, in particular, its retention capacity for nutrients (e.g., cation exchange capacity) and water. Sand and silt are the products of physical and chemical weathering of the parent rock; clay, on the other hand, is most often the product of the precipitation of the
Erosion and tectonics surface. The term erosion refers to the group of natural processes, including weathering, dissolution, abrasion, corrosion, and transportation, by which material is worn away from the Earth's surface to be transported and deposited in other locations. The feedback of erosion on tectonics is given by the transportation of surface, or near-surface, mass (rock, soil, sand, regolith, etc.) to a new location. This redistribution of material can have profound effects on the state of gravitational stresses in the area, dependent on the magnitude of mass transported. Because tectonic processes are highly dependent on the current state of gravitational stresses, redistribution of