The hard answer is money. Farming is a business. The farmer must choose between the various possible crops to select the most profitable given his available land, climate, labor, experience, inputs, market and tolerance for risk. Each soil best supports only certain plants. For instance, they grow onions in Vidalia because the low sulfur soil produces an extra valuable sweet onion. The Midwest soils support many kinds of crops because glaciers long ago deposited rich sub-soils. The local climate such as the annual moisture availability and temperatures also determine what can be grown. Sugar cane requires heat and high rainfall such as is found in southern Florida or areas even closer to the equator. Corn needs the long days found further north with winter cold to kill off pests and diseases. Labor for planting, cultivating and picking is a major expense. Lettuce and strawberries bring a high price but they are hand-picked, so the farmer needs a large expensive crew to harvest his crop. Other crops are highly mechanized and a ‘Combine’ picks, cleans, and packs the crop as the farmer works the field alone. Experience is a factor that traps the farmer into what he has grown before. If the farmer knows corn and has the equipment, then it is hard for him to switch to other crops that need different knowledge to grow them best and different equipment to work the fields. Inputs are the things the farmer must buy to get his crop to grow. He buys fertilizer, water, pesticides, and seed each year. Each type of crop needs different inputs and the price of those items change every year. The farmer needs a convenient market for his crop. If there aren’t enough buyers within a reasonable distance then the farmer wouldn’t be able to sell his product at a profit. Finally the farmer gambles every year on what he plants. If he has heard that corn is selling well to make ethanol he might plant more. But he must consider that all of his neighbors might be thinking the same thing. If they all plant corn then the market will be flooded and the price he gets for his corn will go down. Each year he risks his fortune on how much it will cost to earn his hoped for profit. Should he plant a high value, high risk crop, or should he stick with a low risk, low profit standby?
Farming is tough. Each year he must learn new techniques and new regulations. He must watch the weather and market predictions. Each year he has to decide whether to plant a crop, fallow the field or sell that valuable land to a bigger farmer (or a developer). A farm is a business, every year you ‘bet the farm’ and pray for good weather.
