As nutrients are absorbed from the soil, they are replenished from several sources, such as exchangeable ions on clay minerals and humus, the slow decomposition of soil minerals and the decomposition of soil organic matter.
(nutrients; are absorbed; from the soil) (they; are replenished; from several sources, such as exchangeable ions on clay minerals and humus)
nutrients they
are absorbed are replenished
from the soil
from several sources, such as exchangeable ions on clay minerals and humus