APPLICATION OF AGROECOLOGICAL CONCEPTS AND HIERARCHY THEORY IN THE DESIGN OF DATABASES FOR SPATIAL AND TEMPORAL CHARACTERIZATION OF LAND AND SOIL

A hierarchial system for integrating information on soil, climate, landscape and land use at various scales, is discussed. A series of nested data bases at various scales (1:5 million and larger) are prepared, according to the concepts of agro-ecological stratification in combination with the tenets of Hierarchy Theory. Each polygon at each scale is treated as a unique area with its own environmental envelope of integrated information. Transposition between scales and the scientific integrity of the data is accomplished through the nested databases, and by carefully matching the ''grain'' of the data to the scale of each database. The nested databases are ''matched'' with a collection of crop growth models and other procedures of data analyses, each of which is specific to a general scale of application, and compatible to one of the available databases. The crop growth models are arranged in increasing detail, as reflected in the structure of the subroutines and time steps, and describe a variety of purposes from estimating yield potential to defining yield variability and production risk. The system is supported by a geographic information system.