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....