• Physical Environment (Climate, Soil, etc.);
• Land Use System (trees, crops, inputs, outputs, management);
• Initial Soil Conditions;
• Initial Rates of Plant Growth;
• Rates of Operation of Soil-Plant Processes;
• Feeback Effects of Soil Changes on Plant Growth.

The primary basis for description of the land use system is the proportions of trees and crops in each year. Also taken into account are additions (fertilizer, etc.), harvest, and prunings. A cutyear, when the tree component is wholly or partly removed, can be included. Values of all variables are displayed to the user; there is a set of default values for each environment, which can be replaced by values from field trials.

The model simulates and outputs changes in soil conditions (carbon, nitrogen, phosphorus), rates of erosion, and the effects of these on plant growth and harvest. It can be used to investigate erosion, land degradation, nutrient cycling (including competition between trees and crops), carbon sequestration (plant and soil), and sustainability.

SCUAF can be used in research and in education. In reseach, an important application is to explore the results of different scenarios for land management. In education, it teaches an understanding of soil-plant systems, nutrient cycling, and the effects of erosion.

A major advantage of SCUAF is its ease of operation. A training course is not needed! Anyone familiar with soil-plant systems can operate it.

SCUAF was originally developed by ICRAF (now the World Agroforestry Centre). Version 5 was programmed by Oscar Cacho of the University of New England, with support from ACIAR. The program can be downloaded from the linked University of New England site.

Download SCUAF5

Note - if this site is unavailable, a ZIP file containing SCUAF can be obtained here