The Rice Soil Fertility Capability Classification System

Abstract

The Rice Soil Fertility Capability Classification (RSFCC) is based on FCC (Fertility Capability Classification) system, with some modifications. The system deals with soil morphology, physics, and chemistry characteristics. Most of the class limits of modifiers are borrowed from soil taxonomy, others could be from field observation, which consists of 4 categories and based on three soil layers. The upper layer coincides with the top 20 cm or Type (C for clay and L for Loamy). The soil below the upper layer from 20 to 50 cm is referred to the Substrata Type (C for Clay and L for Loamy), and from 50 to 100 cm is referred to Subsoil Type (C for Clay, L for Loamy, and S for Sandy). The condition modifiers, directly relevant to plant growth, include a, a^- c, c^-, e, f, f^-, g⁺, i, n^-, s, s^-, o, p. Some modifications and additions for classification are suggested, in which new modifiers of p (low P available), o (low organic carbon), c, c^- (actual acid sulfate), f, f^- (potential acid sulfate) are added, the former c condition modifier (sulfidic) divided into c (actual acid sulfate) and f (potential acid sulfate). Modifiers of a, i, n, s, are suggested with modifications from FCC system. The classes within each category and assigned modifiers for each soil type/substrata type/subsoil type are different, which is followed by modifiers presented.