ALMANAC: a potential tool for simulating agroforestry yields and improving SWAT simulations of agroforestry watersheds.

摘要

The Soil and Water Assessment Tool (SWAT), a robust watershed scale hydrological model, would benefit from the improvement of its plant model subroutine. To be applicable to agroforestry, the process-oriented plant model needs to be capable of simulating interspecies light competition, as well the water balance and nutrient balance of interacting crops, grasses, and woody species. It must also be able to consider short and long term effects of various management and climate scenarios. Here we describe the usefulness of the general plant competition model Agricultural Land Management Alternatives with Numerical Assessment Criteria (ALMANAC) in this capacity. Further, we discuss a version of the model (ALMANAC_BF) that realistically simulates complex successional changes in mixed coniferous and deciduous boreal forest ecosystems. For application to agroforestry in a tropical context (ALAMANC_TF), plant physiological parameters need to be developed for relevant species and algorithms derived to describe particularities of management systems. Simulation scenarios could then be conducted and compared to forest inventory data to determine the accuracy of ALMANAC_TF in tropical systems. Current incorporation of ALMANAC into SWAT, including ALMANAC_BF capabilities, will improve the accuracy of watershed scale simulation of plant competition and agroforestry systems, and provide a basis for developing improved tropical systems routines. Accurate simulations will enable agroforesters and policy makers to adopt the most economically and ecologically sound management strategies at the farm and watershed scale.