Effects of nitrogen and irrigation management on seven potato cultivars.

摘要

This research was undertaken to compare patterns of growth and development of seven main-season potato cultivars and to test their response to preplant nitrogen fertility and in-season irrigation management.;Field trials were conducted in 1998 and 1999 to compare Russet Burbank, the standard russet cultivar, with Ranger Russet, three recently released cultivars Umatilla Russet, Bannock Russet, and Russet Legend, and NatureMark's ® genetically enhanced NewLeaf Russet Burbank and NewLeaf Plus Russet Burbank. Plants were subjected to two levels of irrigation: a standard level of irrigation with water replacement approximately equal to water lost through evapotranspiration, and a drier deficit treatment maintained with longer intervals between water application. Standard irrigation plots received approximately 12 cm more water per season than deficit irrigation plots. Two preplant nitrogen fertility levels were established each season: 225 and 330 kg N ha−1 in 1998, 112 and 225 kg N ha−1 in 1999. Plant growth and tuber development were evaluated at several dates during the growing season. Final harvest occurred 150 days after the planting date.;Results from these studies indicate cultivar differences in plant emergence, vine growth rate and vine senescence, petiole nitrate concentration and seasonal trend, timing of tuber initiation, tuber bulking rate with time, tuber grade, tuber specific gravity, and soil nitrate residual after harvest. The level of preplant available nitrogen influenced cultivars differently relative to early tuber development. Differences in the final yield and quality of tubers in response to preplant nitrogen levels were small. Deficit irrigation initially reduced rates of vine growth, but resulted in more vine growth later in the growing season. Petiole nitrate levels tended to be higher with deficit irrigation. The total tuber yield at 150 days after planting was not affected by irrigation treatments. Deficit irrigation reduced yield of U.S. no. 1 grade tubers in 1998 but not in 1999. Unusually high temperatures in July, August, and September of 1998 exacerbated the effects of the deficit irrigation treatment.