Abstract
Precision agriculture (PA) holds promise in achieving uniform crop growth. However, it tends to focus on site-specific fertilizer application based on the non-uniformity of surface chemical properties. It does not consider the influence of soil physical properties on crop growth. This research aims to clarify the relationship between soil physical properties and the moisture content of wheat grain in Memuro Town, Tokachi District, using large-scale soil maps, elevation, the order of wheat harvest and field surveys.
It was found that the harvest is delayed in high elevation areas and areas of mainly Wet Andosols.
To understand which factors influence the moisture content of wheat grain, multiple regression analysis by the stepwise method was conducted. Response variables were elevation, sowing date and soil physical properties. The moisture content of wheat grain was found to be explained 70% by elevation and minimum gravitational water porosity in the effective layer. A regression equation indicated that the lower the minimum gravitational water porosity in the effective layer, the higher the moisture content of the wheat grain.
Wet Andosols are characterized by low gravitational water porosity. A large-scale soil map indicates that soil distribution in the areas of mainly Wet Andosols is non-uniform within a field.
Therefore, if PA is introduced to the studied area, it will be necessary to practice site-specific soil modification of Wet Andosols based on large-scale soil maps.
