The most common and most likely answer to this crossword clue is the 7 letter word ALFALFA
I've seen this crossword clue in The Times
A
L
F
A
L
F
A
More clues leading to the result ALFALFA
- Chap repeatedly treading on a leguminous plant
- A couple of blokes introducing a form of forage
- Two equal parts? Not hard at all, with a fodder plant
- Small boy with what sounds like top-quality fodder
- Chap twice given a forage crop
- Forage in area by Florida, doubling back
- Fodder plants: one flourished about Florida? The reverse
- Twin boys arrive initially in Lucerne
- Twin boys first to arrive in Lucerne
- Crop Cockney’s equally split with another adult
Buddy explains!

The straight part
We know that "form of forage" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case form of forage = alfalfa.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ALFALFA mean?
ALFALFA noun- A plant, principally of Medicago sativa, grown as a pasture crop.
- A type or breed of this plant.