Areas which have ground water resources oasis are found there, with the help of springs and wells Palm trees etc are grown this is called dry farming.
Dry farming is not to be confused with rainfed agriculture. Rainfed agriculture refers to crop production that occurs during a rainy season. Dry farming, on the other hand, refers to crop production during a dry season, utilizing the residual moisture in the soil from the rainy season, usually in a region that receives 20” or more of annual rainfall. Dry farming works to conserve soil moisture during long dry periods primarily through a system of tillage, surface protection, and the use of drought-resistant varieties.
Dry farming has a very long history of use. Particularly in the Mediterranean region, crops such as olives and grapes have been dry farmed for thousands of years. Even today, vast swaths of Spain (e.g. Rioja and Andalucia), Greece, France, and Italy dry farm these crops, and in some regions of Europe it is illegal to irrigate wine grapes during the growing season, under the contention that the water will dilute the quality of the grapes.
The production of some of the finest wines and olive oils in the world is accomplished with dry-farmed fruit. The famous California wines that won the 1976 Paris Wine Tasting were all dry farmed. Today, California has dry-farmed vineyards all up and down the coast, from Mendocino in the north, Sonoma, Napa (estimated 1,000 acres), to San Benito, San Luis Obispo, and Santa Barbara on the central and south coast. There are a few old dry-farmed vineyards remaining in Lodi and the Sierra foothills, particularly Amador County. In addition to wine grapes and olives, a wide range of crops including tomatoes, pumpkins, watermelons, cantaloupes, winter squash, garbanzos, apricots, apples, grains, and potatoes are at times dry farmed in California.
Dry farming is not a yield maximization strategy; rather it allows nature to dictate the true sustainability of agricultural production in a region. David Little, a Sonoma vegetable grower who says he at times gets only a quarter of the yield of his competitors, describes dry farming as “a soil tillage technique, the art of working the soil; starting as early as possible when there is a lot of moisture in the soil, working the ground, creating a sponge-like environment so that the water comes from down below, up into the sponge. You press it down with a roller or some other implement to seal the top…so the water can’t evaporate and escape out.”
Dry farming is more than just the absence of irrigation. In the following example of wine grapes, there are five key elements: