Effects of Long-term Storage of One-year-old Rootstocks in Snow Mound on the Sugar Contents of Storage Roots and White Spear Yield of Asparagus

Abstract

The possibility of summer harvest of white spears from asparagus ( Asparagus officinalis L.) rootstocks stored in snow cover or a snow mound was examined over two seasons, in 2008–2009 and 2009–2010 experiments, respectively. One-year-old rootstocks were dug up on November 6 and November 12 in 2008 and 2009, respectively. Medium-sized rootstocks were put into the soil in containers and stored under natural snow cover or a snow mound for about 7 months. After snow storage, sugar content of the storage root was measured and containers with rootstocks were transferred to a dark room at 20 ° C to examine white spear yield. Rootstocks were stably stored at 0–1 ° C when they were fully covered with an adequate amount of snow. In both years, the total sugar contents in storage roots of rootstocks tended to decrease as the storage duration increased. Spear yield in summer harvest after more than 6 months of storage under snow tended to be lower than in winter harvest after 0 or 1.5 months of storage. Total sugar contents in storage roots during storage might greatly affect the spear yield of rootstocks. The marketable spear yield from one-year-old rootstocks with about 900 g fresh weight stored for more than 6.5 months under a snow mound was more than 190 g per rootstock in both years. Such a spear yield suggests that white asparagus spears can be commercially produced in summer from one-year-old rootstocks stored under a snow mound, a simple and low carbon system.