Great question, was wondering the same. Bell Potter on 21.4.:...

Great question, was wondering the same. Bell Potter on 21.4.:

Watching water and cattle prices
There are two commodity price linked drivers in the earnings for RFF; temporary water prices and the EYCI, which have been softening and touched on below:
Water prices (~6% of assets):
Since acquiring a $34m water portfolio (Murrumbidgee system) in Oct’16, temporary water prices have fallen ~85% on the Murrumbidgee (to $10-11/ML) and ~65% on the Southern connected System (to ~$29/ML).
Cattle prices (~9% of assets):
We have recently highlighted a belief that the EYCI is ~15% overvalued relative to US90CL pricing (see: The Muster (10/03/17)) and due for a correction as US demand for Australian beef slows. On this point we note the EYCI link in the cattle JV lease which could become a headwind in FY18e.
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...which is probably a fair statement but still would not explain the huge drop? Going bidless below $1.50 (21 buyers for 76,881 shares // 46 sellers for 272,283 shares)...