However, a lack of fertilizer and lack of moisture are the two most important factors contributing to low pasture production.
(a lack of fertilizer and lack of moisture; are; the two most important factors contributing to low pasture production) (the two most important factors; contributing; to low pasture production)
a lack of fertilizer and lack of moisture the two most important factors
are contributing
the two most important factors contributing to low pasture production
to low pasture production