The successional vegetation was able to take up nutrients that were 'unavailable' to crop plants.
(The successional vegetation; was; able to take up nutrients) (The successional vegetation; to take up; nutrients that were 'unavailable' to crop plants) (nutrients; were; unavailable' to crop plants)
The successional vegetation The successional vegetation nutrients
was to take up were
able to take up nutrients
nutrients that were 'unavailable' to crop plants
unavailable' to crop plants