Nitrogen-fixing plants provide the major source of fertility in natural ecosystems, and this natural source is reestablished in the farm by planting rows of nitrogen-fixing trees in the orchard.
(Nitrogen-fixing plants; provide; the major source of fertility in natural ecosystems) (this natural source; is reestablished; L:in the farm)
Nitrogen-fixing plants this natural source
provide is reestablished
the major source of fertility in natural ecosystems
L:in the farm