Saved The figure below shows the marginal private benefit to a farmer in Ontario for irrigating his land. It costs $100 per acre to irrigate the land. Each acre of land irrigation generates a litre of salty runoff that winds up in the Great Lakes. It costs $50 per litre to desalinate the river water so that other farmers can irrigate their crops. Price ($) 275 Tools 250 1 225 MCp MCs 200 175 150 125 100 75 50 25 MB p 0 10 20 30 40 50 60 70 80 90 100110 Irrigation (acres)