Moisture stress in potato plants results in a significant increase in tuber NO3−N levels. Research plots with three irrigation treatments and four nitrogen fertilizer rates (0, 100, 200, and 500 lb N/A) (0, 112, 224, and 560 kg N/ha) were established to test the influence of soil moisture and nitrogen rate on tuber NO3−N content. Data from these plots showed that regardless of nitrogen rate, potato tubers from plants subjected to moisture stress had NO3−N levels approximately twice as high as tubers from plants under optimum or excessive irrigation. With low nitrogen fertilizer rates, tuber NO3−N levels were 78 to 80 ppm under optimum and excessive irrigation treatments as compared to 144 ppm under the deficient irrigation treatment. With excessive nitrogen fertilizer rates, tuber NO3−N levels were 151 to 154 ppm under optimum and excessive irrigation treatments compared to 370 ppm under deficient irrigation. Correlation between tuber NO3−N and petiole NO3−N levels suggest that moisture stressed plants have a different relationship between tuber and petiole than plants under proper to high soil moisture conditions.

Potassium fertilizer needs of potatoes were evaluated with a set of research plots established on coarse textured soils in southeastern Idaho. Over the seven-year period that these trials were conducted, tuber yields indicated no response to potassium fertilization. Specific gravity of tubers decreased with increasing rates of potassium fertilization, with greatest reduction in specific gravity resulting from the use of potassium chloride. Plots were established on land brought under cultivation for the first time in 1968. Under a potato-grain rotation, the plot area was planted to potatoes every other year beginning in 1968. At the conclusion of the trials in 1976, the check plots had not received any potassium fertilizer. Potassium fertilizer was applied to designated plots only in 1970 and 1974. Each plot received the same treatment in both of the years with rates of 150, 300, and 600 lb K2O/A (168, 335 and 670 kg/ha) using two different forms of fertilizer (KCl and K2SO4). Petiole samples were analyzed for levels of K. Soil K levels were determined annually from samples taken prior to planting the potato crop. Petiole K levels decreased as the season advanced. A petiole level of 6.5 to 7.5% K (45 to 75 days after planting) was sufficiently high for maximum yields. Soil test levels (sodium bicarbonate extraction) of 140 ppm K were sufficiently high for production of a 350 cwt/A (40 T/ha) yield.

A soil test value of 112 ppm K in the 0 to 8 in (0 to 20 cm) depth was sufficient to produce a 250 cwt/A (28 T/ha) yield with no response to K fertilization. With a 93 ppm soil test value, potassium fertilizer increased yields in all four varieties tested. These results were obtained from trials at two locations in a seed-growing area in eastern Idaho where soil tests indicated low potassium levels (90 to 100 ppm K). Russet Burbank, Targhee, Nampa, and Butte varieties were included in the study at one location and only Russet Burbank at the second location. Potassium fertilizer treatments included K2O rates of 0, 250, and 5001b/A (0, 280, and 560 kg/ha) for each of the two forms of potassium fertilizer (KC1 and K2SO4). At the time of tuber initiation, a petiole content of 7% K in Russet Burbank was sufficient to produce maximum yields while a petiole content less than 6% K was insufficient. Analysis of petiole samples taken during the season showed that the K content declined rapidly as the season progressed. Potassium chloride generally resulted in higher petiole K levels than did potassium sulfate. Varieties appeared to differ in petiole K levels.

A survey was undertaken to investigate the nitrate-nitrogen (NO3-N) content of potatoes grown on different soil types with different fertilizer and irrigation treatments. Tuber nitrate-N contents were determined immediately after harvest and after periods of storage of up to 210 days.

Plots of Russet Burbank, Nampa, Targhee, and A6371-2 received O, 250, and 500 lb of potash (K2O/A as KC1 or K2SO4). Tubers were bruised following harvest. Potash treatment had no significant effect in reducing blackspot development when there was no yield response to K fertilization. On soil that tested low for K, potash treatment significantly reduced blackspot development for all four cultivars. Tuber subsamples were bruised after 6 mo in storage at either 1.7 or 10 C. Differences in blackspot bruise development between low and high K were maintained for those tubers stored at 10 C; differences were not maintained and little discoloration developed in tubers stored at 1.7 C, due perhaps to less enzyme activity and less substrate. The Nampa cultivar was significantly more resistant to blackspot than the other three cultivars.

Journal of Food ScienceVolume 40, Issue 2 p. 415-416 ASCORBIC ACID CONTENT IN RUSSET BURBANK POTATOES JORG AUGUSTIN, JORG AUGUSTIN University of Idaho. Aberdeen and Twin Falls, IdahoSearch for more papers by this authorR. E. McDOLE, R. E. McDOLE University of Idaho. Aberdeen and Twin Falls, IdahoSearch for more papers by this authorG. M. McMASTER, G. M. McMASTER University of Idaho. Aberdeen and Twin Falls, Idaho Research & Extension Center, University of Idaho, Aberdeen, ID 83210Search for more papers by this authorC. G. PAINTER, C. G. PAINTER University of Idaho. Aberdeen and Twin Falls, Idaho Twin Falls Extension Center, Twin Falls, ID 83301Search for more papers by this authorW. C. SPARKS, W. C. SPARKS University of Idaho. Aberdeen and Twin Falls, IdahoSearch for more papers by this author JORG AUGUSTIN, JORG AUGUSTIN University of Idaho. Aberdeen and Twin Falls, IdahoSearch for more papers by this authorR. E. McDOLE, R. E. McDOLE University of Idaho. Aberdeen and Twin Falls, IdahoSearch for more papers by this authorG. M. McMASTER, G. M. McMASTER University of Idaho. Aberdeen and Twin Falls, Idaho Research & Extension Center, University of Idaho, Aberdeen, ID 83210Search for more papers by this authorC. G. PAINTER, C. G. PAINTER University of Idaho. Aberdeen and Twin Falls, Idaho Twin Falls Extension Center, Twin Falls, ID 83301Search for more papers by this authorW. C. SPARKS, W. C. SPARKS University of Idaho. Aberdeen and Twin Falls, IdahoSearch for more papers by this author First published: March 1975 https://doi.org/10.1111/j.1365-2621.1975.tb02216.xCitations: 23 Research Paper No. 7451 of the Idaho Experiment Station. The authors express their gratitude to the Idaho Potato Commission for their financial support and their appreciation to J.P. Rowe. C. Zimmerman and V.C. Hiebert for their technical assistance. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Reference AOAC. 1970". " Official Metho'ds of Analysis," 11th ed, p. 111. Association of Official Analytical Chemists, Washington , D.C. Bring, S.V. 1966. Total ascorbic acid of shoe string potatoes J. Amer. Dietet. Assoc. 48: 112. Bring, S.V. and Raab, F.P. 1964. Total ascorbic acid in potatoes—Raw, fresh mashed, and reconstituted granules. J. Amer. Dietet. Assoc. 45: 149. Bring, S.V., Grassl, C., Hofstrang, J.T. and Willard, M.J. 1963. Total ascorbic acid in potatoe—Raw, fresh mashed, and reconstituted flakes. Amer. J. Dietet. Assoc. 42: 320. Gebauer, H. 1968. Vitamins and plants. Qual. Plant. Matl. Veget. 3: 161. Hyde, R.B. 1962. Variety and location effects on_ ascorbic acid in potatoes. Food Res. 21: 373. Leichsenring, J.M., Norris, L.M. and Pilcher, H.L. 1957. The effect of storaee and of boiling on the ascorbic, dehydroascorbic and diketogulonic acid contents of potatoes. Food Res. 22: 31. Somogyi, J.C. and Schiele, K. 1966. Der Vitamin C GehaIt verschiedener Kartoffelsorten und seine Abnahne wahrend der Lanerung. Internatl. 2. Vitaminforsch. 36: 337. Sweeney, J.P., Hepner, P.H. and Libeck. S.T. 1969. Organic acid, amino acid and ascorbic acid as affected by storing conditions. Amer. Potato J. 46: 463. USDA. 1963". " Composition of Foods—Raw, Processed, Prepared," p. 50. Agric. Handbook No. 8. U.S. Dept. of Agric., Washington , D.C. Woodbury, G.W. and Weinheimer, W.H. 1965. Specific gravity-solids correlations in Russet Burbank with respect to point of origin and storage history. Amer. Potato J. 42: 98. Yamaguchi, M.J. 1957. Yamaguchi, M.J., Perdue, J. and MacGillivray, J. 1960. Nutrient composition of White Rose potatoes during growth and after storage. Amer. Potato J. 37: 75. Zilva, S.S. and Barker, J. 1939. The ascorbic acid content in potatoes. Rep. Food Invest. Bd. London, p. 199. Reported in Burton, W.G. 1966". " The Potato," p. 221. H. Veenman and Zonen N.V. Wageningen. The Netherlands. Citing Literature Volume40, Issue2March 1975Pages 415-416 ReferencesRelatedInformation

A potato cropping rotation study was initiated on coarse textured soils in 1969 to compare annual cropping to potatoes with potato-grain rotations. At the completion of the 1975 season, those treatments annually cropped to potatoes had been planted to potatoes for seven consecutive years. After this period of time, total yields were reduced by 14% or 55 cwt/acre (6 T/ha) when compared to yields from potato-grain rotation treatments. Soil fumigation with 30 gpa (285 1/ha) of soil fumigant (Shell D-D) resulted in no beneficial effects on tuber yield or quality.