marl

a loose and crumbling earthy deposit consisting mainly of calcite or dolomite; used as a fertilizer for soils deficient in lime

A mixed earthy substance, consisting of carbonate of lime, clay, and sand, in very variable proportions, and accordingly designated as calcareous, clayey, or sandy. See Greensand.

To cover, as part of a rope, with marline, marking a pecular hitch at each turn to prevent unwinding.

To overspread or manure with marl; as, to marl a field.