Cover crops are planted in order to protect the soil when the main cash crop is not being planted which means that they are not planted to be harvested and can be planted after the cash crop is harvested.
The two main purposes of cash crops are to protect the soil from erosion and to improve soil fertility. Their presence reduces surface runoff of soil when it rains and slows down rain before it hits the ground at force and splits soil.
Some cover crops are planted to improve soil fertility because they improve the level of nutrients in the soil and they can also be ploughed before they mature causing them to decay and add organic matter to the soil.
All igneous rocks the basis of the rock cycle are formed by plate tectonics. ... The heat from the mantle that fuels plate tectonics causes both igneous and sedimentary rocks to be turned into metamorphic rocks. The metamorphic rocks can be eroded into sedimentary rocks are remelted back into igneous.
