Nitrogen fertilizer saps veggies' vitamin C.

Nitrogen fertilizer saps veggies' vitamin C 

Time was when chemical fertilizers cost little and farmers didn't worry about putting on too much. But recent research blames excessive nitrogen fertilizer for polluting water and diminishing methane uptake by soil microbes (SN: 9/30/89, p.213). Now a soil scientist has added vitamin C depletion to the list of drawbacks.

Excessive nitrogen fertilizer cut the vitamin C content of three green vegetables in experiments done by Sharon B. Hornick of the USDA's Agricultural Research Service in Beltsville, Md. Hornick set out to test whether organic fertilizers were better than inorganic ones at improving the nutritional quality of produce. As it turned out, too much nitrogen proved bad whatever its source, she says. Chard grown without fertilizers had 81.4 milligrams of vitamin C per 100 grams of leaves, compared with 54 milligrams for the same quantity of heavily fertilized plants. Hornick's work also pinpointed nitrogen as the cause of a vitamin C decline in green beans and kale. She says her findings, which she has submitted to the JOURNAL OF AGRICULTURE AND FOOD CHEMISTRY, support a proposed move toward agricultural methods that limit the use of fertilizers and herbicides (SN: 9/23/89, p.204).