生态系统与农业生态系统人类从农业生产中所获得的物质和能量,都在不断地转移和循环着。植物通过代谢活动,不仅吸收太阳能,把无机物质合成碳水化合物、蛋白质等有机物质,同时,也把许多物质返还给环境,这是植物与环境间物质代谢交换。另一方面,植物在被食草动物吞食时,将物质和能量转移给动物,食肉动物又吃食草动物,动、植物的残体和某些排泄物又都被微生物利用和分解,返回环境,以后再度为植物吸收,在 Ecosystems and Agro-ecosystems The material and energy that people derive from agricultural production are constantly being transferred and recycled. Through metabolic activities, plants not only absorb solar energy, synthesize inorganic substances such as carbohydrates and proteins, but also return many substances to the environment, which is the exchange of matter and metabolism between plants and the environment. On the other hand, when plants are swallowed by herbivores, they transfer their materials and energy to animals, and carnivores and herbivores eat animals, animals and plants, and some excrements are also utilized and decomposed by microorganisms and returned to the environment. After the plant is absorbed again, in