Detection of high NO 3 concentrations in domestic wells has led to concern about excessive fertilizer N use in crop production. A potato ( Solanum tuberosum L. cv. Russet Burbank) experiment was initiated to examine the effect of water and N on potato yield and quality, tuber N concentrations, petiole NO 3 concentrations, and N distribution in the soil. The field trial consisted of a line‐source irrigation system with six water rates (0.33, 0.66, 1.00, 1.10, 1.20, and 1.30 times crop evapotranspiration ET c ) each having six planting‐time N rates (0, 56, 112, 168, 224, and 448 kg ha −1 ) replicated four times with treatments applied to the same plots in two successive years on a Pittville sandy loam (fine‐loamy, mixed, mesic Typic Argixerolls). Yields were significantly increased with water, averaging 14.1 to 54.4 Mg ha −1 in 1992 and 20.8 to 46.5 in 1993. Nitrogen rate significantly increased yield in 1993, averaging 28.7 to 44.1 Mg ha −1 , but not in 1992. Residual soil profile NO 3 ‐N (1040 mg kg −1 ) present at planting time in the first cropping season was utilized, denitrified, or leached from the top 150 cm of soil by above‐normal winter rainfall before the beginning of the second season. At the end of the second season, low NO 3 −N concentrations were observed in soil profiles receiving 0, 112, and 224 kg N ha −1 , whereas a concentration of 1050 mg kg −1 was found in the 0‐ to 60‐cm depth of soil with the 448 kg N ha −1 rate. High residual soil N in 1992 resulted in N use efficiency (NUE) for tubers of >200 g kg −1 ; in the 1993 season, however, NUE was > 300 g kg −1 . Nearmaximum yields were obtained with 1.10 to ET c applied water and 0 to 56 kg N ha −1 in 1992 and with 1.10 to 1.30 ET c applied water and 168 to 224 kg N ha −1 in 1993.
No takes yet. Share an insight, caveat, or question.
Meyer et al. (1998) studied this question.