Planting Depth Influences Potato Plant Morphology and Economic Value

The effects of planting depth on potato cultivars grown in the Columbia Basin of Washington State have gone unreported. The response of potato (Solanum tuberosum) cultivars 'Russet Burbank' and 'Umatilla Russet' to planting depth was evaluated during 2000, 2001, and 2002. The objectives were to determine how planting depth affected potato plant morphology, tuber greening, yield, and economic value in the Columbia Basin. Ten- and 20-cm planting depths were used all three years; 15- and 25-cm depths were added in 2002. Soil temperature extremes and heat-unit accumulation typically increased as seed pieces were planted closer to the soil surface. Plant emergence was occasionally delayed with an increase in planting depth for both cultivars. Node, stolon, and tuber number per stem increased as planting depth increased, but tuber number per plant did not. Russet Burbank stem number increased as seed pieces were planted closer to the soil surface; Umatilla stem number was not affected by planting depth. Despite differences in the emergence rate due to planting depth, total yield was not affected. However, marketable yield and gross income typically declined when seed pieces were planted shallow (10 cm). The largest impact to marketable yield and gross income came from green tubers. Tuber greening was reduced as seed pieces were planted deeper.