i looked up marl in the oxford dictioary after montereyjack suggested it and it came up with -
an unconsolidated sedimentary rock or soil consisting of clay and lime, formerly used as fertilizer: the ancient right to dig marl for fertilizer
[count noun]: the road cuttings show red and green marls
and meal i couldnt find anything to with fertiliser in it, but i know what you mean, i thought of bone meal, fish meal, blood meal as they too are fertilisers.
Now im really stumped