Digging Deeper: Comparative Study Of Soil Properties In Allophanic And Non-Allophanic Horizons Of Volcanic Ash Soil In Kyushu, Japan
Hiroshi Takahashi Suzuki
Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori, Japan
Masako Yamamoto Tanaka
Aomori Prefectural Industrial Technology Research Center, Kuroishi, Aomori, Japan
Abstract
Andosols, volcanic ash-derived soils, play a vital role in upland farming in Japan, with distinct categorization into allophanic and non-allophanic types. Allophanic Andosols, constituting 69.9% of the total Andosol land area in Japan, are prevalent in regions with significant Holocene tephra deposition. In contrast, non-allophanic Andosols, accounting for 30.1% of the total Andosol area, occur in areas with minor tephra deposition. Both categories exhibit distinctive characteristics such as a thick black A-horizon, high phosphate fixation, superior water retention, and low bulk density. Despite similarities in morphology, chemistry, and physical attributes, non-allophanic Andosols possess unique features due to the presence of 2:1 minerals. Notably, non-allophanic Andosols, characterized by substantial exchangeable aluminum (represented by exchangeable acidity y1), pose a significant challenge by inducing severe aluminum toxicity in common agricultural crops. Hence, distinguishing between allophanic and non-allophanic Andosols is crucial for effective agricultural management