Effects of saturated hydraulic conductivity on volunteer potato (Solanum tuberosum L.) tuber survival

Abstract

In situ observations were conducted at eight fields in the Tokachi region of the northernmost island of Japan to assess the effects of soil physical conditions on the survival of volunteer potato (Solanum tuberosum L.) tubers. Statistical analyses revealed a positive correlation between the survival rate and the lowest value of saturated hydraulic conductivity to a depth of 0.5 m, except for data from one field where potato tubers were killed by low temperatures below –3°C during winter and from another field with poor drainage despite high soil permeability to 0.5 m in depth. Incubation experiments indicated that potato tubers survived in saturated soil at 0 and 6°C, which respectively matched soil temperatures during the snowmelt period and 1 week thereafter. This result suggests that potato tubers can survive prolonged exposure to moist surface soil caused by large amounts of snowmelt water during the spring snowmelt period. The incubation experiment results also indicated that potato tubers were killed in saturated soil at 15°C. This temperature was almost equal to the average air temperature during the period when volunteer potato tubers were sprouting in the field. Therefore, this result implies that the potato tubers will be killed after a substantial amount of rainfall during the subsequent warm period at poorly drained fields.