LAND EVALUATION SYSTEMS ORIGINATING SINCE THE FRAMEWORK
The Framework for land evaluation has influenced many land evaluation methodologies
developed since 1976. Most of these have an agro-ecological basis; there are hardly any
published economic land evaluations, even though the fourth principle of the 1976
Framework did emphasize the importance of economic land evaluation.
Soil survey and crop yield interpretations
The Fertility Capability Classification (FCC) is a technical soil classification system
that focuses quantitatively on the physical and chemical properties of the soil that are
important to fertility management (Sanchez et al., 1982). Information required by the
system is obtained from soil profile descriptions and associated field data, laboratory
analysis data, and soil classification (Soil Taxonomy). The system does not rank soil,
but rather it states the soil properties important to management decisions, which will
differ by crop type and management system. The system is applicable to upland and
wetland rice crops, pasture, forestry, and agroforestry needs under high- or low-input
systems. The system provides management statements for the classified soil and lists
the general adaptability of various crops. A recent paper advocates the use of FCC for
soil quality assessment in tropical regions (Sanchez et al., 2003).
Productivity indices are mostly multiplicative indices tied to soil properties and
are used as a relative ranking of soils with respect to yield. Soil properties important
to favourable rooting depth and available water capacity are the prime choice. Some
productivity indices rely on a few critical soil properties such as pH and bulk density
to rate soils (Pierce et al., 1983; Kiniry et al., 1983). Sys et al., (1991b) express the effects
of unfavourable land characteristics on the land production potential using a soil index.
The soil index is calculated by multiplying numerical rating values attributed to each
characteristic, after matching the collected or measured data with the requirements for
the cultivation of a specific crop (Laya et al., 1998).
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