A system of classification of woody perennials based on their root activity patterns

A method of classifying woody perennials based on the 'effective foraging space' (EFS) is described. EFS of a plant is defined as the soil space which accounts for 80% or more of root activity. The lateral and vertical dimensions of EFS of a plant can be determined from the study of root activity pattern of the plant employing (3)2P-soil injection technique. Based on the dimensions of the EFS, the perennial plant species may be grouped into 16 classes ranging from plants with very compact-very shallow active root system (less than 100 cm lateral extension and less than 30 cm deep) to very extensive - very deep root system (more than 300 cm lateral spread and more than 90 cm deep). The soil and genetic factors which can influence root activity pattern of a plant can also alter its EFS. Nevertheless, given the soil type and the variety, the concept of EFS can be very fruitfully applied in several situations such as selection of plant species for a given land use system, spacing of the component species in agroforestry and other mixed production systems, deciding the planting geometry, developing the most efficient method of fertilizer application, choosing the most appropriate crop combinations for stratified exploitation of below-ground resources, etc. Although this classification system is primarily intended for woody perennials, it can be extended to other plant species as well.