Effect of initial soil salinity and subirrigation water salinity on potatotuber yield and size

A field lysimeter study was conducted to investigate the effect of initial soil salinity and salinity level of brackish subirrigation water on tuber w eight and tuber size of three potato (Solanum tuberosum L.) cultivars (Kenn ebec, Norland and Russet Burbank) under simulated arid conditions. Both sal ine and non-saline initial soil conditions were simulated in a total of 36 lysimeters. Eighteen lysimeters were flushed with fresh water (0.2 dS/m), w hite the remaining 18 lysimeters were flushed with brackish water (2 dS/m). For each soil condition, two subirrigation water concentrations, 1 and 9 d S/m, were used in nine lysimeters each. For each subirrigation water treatm ent, three potato cultivars were grown. In all lysimeters, water table was maintained at 0.4 m from the soil surface. Arid conditions were simulated b y covering the lysimeter top with plastic mulch, allowing the potato shoots to grow through a cut in the mulch. The average root zone salinities (ECw) were found to be 1.2 and 1.5 dS/m in non-saline lysimeters subirrigated wi th 1 and 9 dS/m waters, respectively. The corresponding salinities were 3.2 and 3.7 dS/m in the saline lysimeters, Across cultivars, there was no sign ificant effect of either initial soil salinity or subirrigation water salin ity on total tuber weight. However, the weight of Grade A tubers was higher in non-saline soil than in saline soil. Kennebec and Russet Burbank Grade A tuber weights were not affected by the initial soil salinity. On the cont rary, a significant reduction in Grade A and total tuber weight under initi ally saline soil was evident for the Norland cultivar. (C) 2001 Elsevier Sc ience B.V. All rights reserved.