Without food aid, farmers cannot survive a famine, and therefore any economic incentive or disincentive is a moot point. The cycle depicted in the chart is false, because it relies on a model of famine that is outdated and incomplete.
The cycle in the graphic depicts a speculative economic model based on famines caused by FAD - Food Availability Decline. Unfortunately, the FAD model does not take into account important characteristics of a famine, the most notable to this question being that agricultural workers suffer famines disproportionately. Farmers are the first to starve and the first to die of hunger. This is because famines work according to the FEE model - Failure of Entitlement Exchange, which replaced FAD as a more complete and accurate model in the early '80s. (Entitlement here being an academic term for "stuff to buy or barter.") What happens is that food and labor are both commodities - and a farmer's Endowment (an academic term meaning stuff he can use to trade or buy) is insufficient to exchange for enough food to survive. A bag of rice is worth X amount of hours of labor - but in times of famine, no amount of labor is going to be enough to exchange for food.
Non-agricultural workers - tradesmen, professionals, merchants and the political class - will usually have enough resources - endowments - to secure a share of a dwindling supply of food, or to import their own supply - entitlements. Farmers, who rely on part of their harvest as their entitlement, cannot do likewise. Similarly, once conditions improve, they need to return to farming to obtain other, non-food entitlements, such as clothing, education, phone bill, etc. - a depressed market due to food aid means poor prices initially after a famine, but that's better than, you know, dying.
This paper (in PDF) includes a good overview of the FEE model, with clear explanations for laymen, as well as various criticism of FEE and the responses to them.