Influence of irrigation, nitrogen and seed piece spacing on yields and tuber size distribution of seed potatoes

Abstract

This study examined the influence of irrigation, soil nitrogen (N) levels and seed piece spacing on the yields and tuber size distribution of Norland, Russet Burbank and Shepody potatoes over three seasons at two sites in central Saskatchewan. The crops were grown under standard irrigated conditions or on dryland with in-row spacings of 15, 23 or 30 cm and total N levels of 200 or 300 kg ha−1 as either preplant or split applications. Irrigation greatly enhanced yields of all tuber size categories in the drier years but had less effect if seasonal precipitation reached or exceeded normal levels. Smaller size tubers formed a greater proportion of the total yield in crops exposed to drought stress. Norland was less affected by drought than the later-maturing cultivars. Yield responses to N were limited to situations where soil moisture was abundant or crop demand for nutrients was increased by close in-row spacings. Close in-row spacing increased total yields in some cases, while in others it resulted in a reduction in tuber size with little effect on overall yields. Yields for the cultivar Norland were less affected by seed piece spacing than yields for Russet Burbank or Shepody. Key words: Solanum tuberosum, drop seed, spacing, fertility