Ecology and Ecosystems

Biography

Biography: Andrew M Gordon

Abstract

Tree-based intercropping is a high-value, environmentally-beneficial agroforestry practice, well-suited to the climates and soils found in southern Ontario, Canada. Since 1984, researchers at the University of Guelph, Guelph, ON have been investigating ecological processes, crop responses and management protocols on a 30 ha intercropping research site, where a number of commercially-important tree species were intercropped at variable width with a variety of agricultural crops. This paper reports on the collective research conducted on-site over an approximately 30-year period. Results are presented for studies on row orientation, tree and crop physiology, tree-crop root interactions, economics and aspects of nutrient cycling and carbon-related processes. In addition, data is presented on the population dynamics of insects, birds, earthworms, mycorrhizae and crop weeds and diseases. Initially, the productivity of C3 agricultural crops intercropped with trees did not differ from those in corresponding sole-stand (conventional) systems of crops. But soil organic carbon content and bird and insect diversity increased in the intercropped area. The abundance and distribution of earthworms was higher closer to the tree rows indicating improved soil health. The C sequestration potential in tree-based intercropping systems varied from 2.5 to 3.7 times more than that reported for conventional agricultural fields in the region, depending upon the tree species. With reduced fertilizer use and more efficient N-cycling, tree intercropping could also lead to the reduction of nitrous oxide emissions from agricultural fields by about 0.7 kg ha−1 yr−1. With respect to water-quality enhancement, carbon sequestration, and biodiversity conservation, intercropping can be placed above conventional agriculture in terms of long term-productivity and sustainability.