Features of Winter Soil Temperature on an Apple Orchard in a Cold Snowy Region

Abstract

In apple production in the cold snowy region, Aomori prefecture, changes of soil temperature in the snow-melting period are important for farm work and field conservation. So, we aimed to clarify the characteristics of soil temperature in an apple orchard in this period. We have been monitoring soil temperature of the orchard for 7 years, particularly during the winter seasons. The results are: 1) There was little fluctuation in soil temperature, which was maintained above 0℃, due to the fact that the accumulated snow functions as insulation. 2) During the investigated periods, two types of soil temperature profile were found. In the first type, the nearer the soil layer was from the surface, the lower the temperature was; we called this Type I. Meanwhile, there were 2 years in these periods in which the shallow layer (8cm) was maintained almost as warm as the middle layer (32cm) until the snow-melting. We called this Type II. 3) This feature of Type II was caused in years when air temperature was relatively high in the beginning of the winter, and when there was only a short time lag between the first snow fall and when we started to have lingering snow.