Morphological characteristics and distribution patterns of lowland soils in the Philippines

Abstract Thirty lowland soils from six lowland rice areas were selected for the study. Among these soils, 13 were considered to be irrigation water aquic soils, while seven ground water aquic soils, based on the morphological characteristics. The irrigation water aquic soils showed cloud-like ferruginous mottles inside the matrix of grayed subsurface horizons, while the ground water aquic soils displayed ferruginous coatings and/or hypo-coatings of voids, corresponding to tubular or filmy mottles. Hence, the difference in ferruginous pedofeatures in the subsurface horizon between the two types of aquic soils was confirmed. By setting a value of 4 dry months per year was associated with increasing influence of irrigation water, while in Bicol with <2 dry months per year, with increasing in...