Science: Salt Farming

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Irrigation water is generally considered dubious if it contains more than 1,400 parts of salt per million. Plant Physiologist Gordon T. Nightingale of Hawaii regretted this limit, because the Hawaiian Islands have a lot of arid land underlain by abundant water that is considerably more brackish. So he undertook to find out whether the salt limit could be exceeded under Hawaiian conditions.

Dr. Nightingale started planting vegetables on arid land and irrigating them from shallow wells whose water carried 1,620 parts of salt per million. To his surprise, a long list of test crops— cucumbers, carrots, lima beans, broccoli, corn, cabbage, etc.— seemed to grow better than with purer water. On another test plot, he irrigated alfalfa and forage grasses with water containing 4,100 parts per million of salt. The crops grew vigorously.

Dr. Nightingale does not use normal irrigation methods. He flushes dried salt out of the soil, and he plants his crops on the sides of furrows so that their roots will avoid concentrations of salt. He expects that his salt irrigation system will add considerably to the food production of Hawaii's islands.