Meliorator
The Century Dictionary and Cyclopedia
noun.
One who or that which meliorates or makes better.
the GNU version of the Collaborative International Dictionary of English
noun.
One who meliorates.
Wiktionary, Creative Commons Attribution/Share-Alike License
noun.
One who
meliorates
; an
improver
.
Word Usage
"With the banks of my meadow ditches, I have greatly enriched my upland fields, those which I intend to rest for a few years, I constantly sow with red clover, which is the greatest meliorator of our lands."