Abstract: In 1981, the author investigated the animal and insect resources in mountainous regions of north Guangdong. From the fact of denudation and misuse of chemicals in farmland, this paper illustrates the effects of the changes of forest-and agroecosystem on the structure and amount of animal and insect population and the harm of the decrease of animals and beneficial insects to the forest and agricultural production.

Key words: Rare earths, Urea, Mineral N, Nitrification, Lu visol