Cash rent means the operator pays you a fixed dollar amount per acre for the season, usually part up front and part after harvest, and everything else is theirs. Their seed, their fertilizer, their chemicals, their machinery, their yield. If corn does well you still get $285. If hail flattens the field you still get $285, assuming they can pay.
Crop share means you and the operator split the actual crop by an agreed percentage, commonly something like 25 to 50 percent to the landowner depending on the region and how costs are divided. In most share arrangements the landowner also pays that same share of some inputs, typically fertilizer and sometimes seed, so it isn't free money for a percentage of grain. Your income then moves with both yield and the commodity price. There's a middle version called a flexible cash lease, where a base rent is set and a bonus kicks in above a certain gross revenue per acre.
So to your last question, under a straight cash lease the recovery in net farm income mostly reaches you later, through the rent you negotiate for the following season, rather than this year's check.
One thing worth having in front of you before you compare the two: the income return on farmland is modest either way, historically in the 2 to 5 percent range on land value. On a parcel priced anywhere near current cropland averages, $285 an acre isn't unusual and it isn't going to feel like a rental property. Most of the long-run return sits in the land value, and that only shows up when you sell or refinance.
