Farmland ecosystem is an agricultural production system with various forms and different levels of development established by human beings in agricultural production in a certain period of time and region, using the relationship between agricultural biological and abiotic environments and biological populations under artificial control. Natural ecosystem is a relatively stable ecosystem maintained by natural adjustment ability in a certain time and space.
So the answer is: the natural ecosystem is relatively stable by natural regulation, while the farmland ecosystem can only maintain its balance under artificial regulation.