Well there's a couple reasons why. First, the land itself can become “tired" and less fertile<span>. This is because the same type of </span>crop<span> planted repeatedly in the same area keeps draining the land of the same nutrients needed for that plant's growth. Pest can also plant their nest near the crop if the farmer continues to plant the same crop in the same place.
Which is the reason why things such as "crop rotation" exist to keep things fresh, and prevent what I described above from happening.</span>
Convection is the transfer of heat by liquid.
Frenkel defect is a defect in crystalline solids in which an atom is displaced from its lattice position to an interstitial space. This creates a vacant space at the original site and an interstitial defect at the new site within the same element. This defect does not affect the chemical properties of the compound. This defect usually occur in ionic solids with large size difference between the anion and cation.
LiCl does not exhibit Frenkel defect because the size difference between the anion and the cation of the compound is very small.
