Effect of Fertilizer and Irrigation on Nitrate‐Nitrogen and Total Nitrogen in Potato Tubers¹

Abstract

This study was conducted to determine the effect of N fertilizer and irrigation management on potato (Sotanum tuberosum L,) tuber N0,-N levels and the relationship to the potential health hazard created by high nitrate levels in food products.Russet Burbank' potatoes grown using different N fertilizer rates, methods of application, and irrigation levels were analyzed for N0,-N concentration. The NO,-N concentration in the tubers on a wet weight basis varied from 36 to 131, 34 to 75, and 25 to 50 ppm in the 3 years of this study. The NO,-N concentration for each year of study was found to be directly related to the level of applied N fertilizer. The initial concentration and increase in N0,•N due to N fertilizer varied with the season. The addition of manure did not increase the N0,-N level above those to be expected from similar quantities of inorganic sources of N. Phosphorus fertilizer did not increase the N0,-N level. The N0,-N concentration in the tubers where more water was applied at each irrigation was less than on the lower level of applied water at each N rate. These data indicate that greater NO,-N levels in the tubers will result by increasing N fertilization rates. The levels of N0,•N obtained in this study were not expected to contribute substantially to the methemoglobinemia health hazard. There is considerable concern that use of these high nitrate containing vegetables could cause methemoglobinemia, especially in infants. Although nitrites are the toxic principle which may be formed prior to ingestion or during digestion and absorption of food, nitrates may be considered as the index or precursor to the amount of nitrite which may be formed. If foods contain high levels of nitrate, the potential hazard may be increased if conditions during storage or processing are conducive to conversion to nitrite (11). In spite of the appreciable nitrate content of some vegetables such as beets and spinach, no authenticated cases are known for nitrate poisoning of human adults. However, several cases of methemoglobinemia and one death have been reported recently when children, aged 2 to 10 months, were fed spinach purchased as a fresh vegetable and held under questionable storage conditions (1).In recent years, there has been a steady increase in the use of nitrogeh fertilizer to achieve maximum potato production. Also, an increasingly common practice is to add N to the irrigation water 1 Contribution from the Western Region, Agricultural Research Service, USDA; Idaho Agricultural Experiment Station cooperating. Received Aug. 13, 1973. 'Soil Scientist and Physcial Science Technician, respectively, Snake River Conservation Research Center, Rimberly, ID 83341.Mention of trade names or companies is for the benefit of the reader and does not imply endorsement by the USDA. throughout the season, The abundance and low cost of N fertilizer has encouraged the use of high fertilization rates in attempts to obtain maximum tuber yields. No reported cases could be found in the literature where high nitrate level...

Free and Total Amino Acid Composition of Edible Parts of Beans, Kale, Spinach, Cauliflower and Potatoes as Influenced by Nitrogen Fertilisation and Phosphorus and Potassium Deficiency

“…Both P-and Kdeficiency greatly reduced DM yield but increased total-N concentration, when compared with the same N-level (12 g N) without nutrient deficiency. Nitrate-N contents were only of significance at very high N-levels, and even then amounted to only 5-6% of total-N, * Total-N without NO,-N. which is in agreement with other investigations (Carter and Bosma 1974). At normal, moderate N-levels, NO,-N represents only 1% of total-N or less.…”

Simulation of nitrogen uptake from soil and partitioning in potato plants: model description and sensitivity analysis

“…The simulated nitrate concentration in leaves as a function of time (not presented) were similar to data published by Biemond and Vos (1992). It is noted that according to the model assumptions, nitrate concentration in leaves is proportional to the concentration in tubers, as was observed by Carter and Bosma (1974). The simulated fluctuations in nitrate concentration in tubers on DOY 113-114 and 126 stemmed from extreme evaporation on those days -14 and 11 mm1d, respectively.…”

Effect of Cultivar and Harvest Date on Nitrate (NO3) and Nitrite (NO2) Content of Selected Vegetables Grown Under Open Field and Greenhouse Conditions in Jordan

“…Growth-depressing temperatures also encourage nitrate accumulation (Habben, 1973). High levels of organic matter in soil encourage nitrate accumulation in plant, while increasing irrigation of growing plants can have an opposite e!ect (Carter and Bosma, 1974). The e!ect of cultivar on nitrate and nitrite accumulation in vegetables is controversial: while Lorenz (1978) reported that di!erences among lettuce cultivars were small and inconsistent, Cantli!e (1992) reported signi"cant di!erences in the nitrate content between smooth and savoyedleafed varieties of spinach.…”