Soybean (Glycine max L.) root disease, canopy microclimate, growth, and yield in a tree-based intercrop and in an adjacent monoculture.

摘要

Tree-based intercropping is an agricultural system where trees are established in rows, creating alleys that allow the mechanized production of crops. In 2004--05, soybean root disease and yield were studied at the Agroforestry Research Site (established 1987--88, in Ontario, Canada) an intercrop with ten tree species. Soybean patches with symptoms of root rot and interveinal chlorosis were observed close to black walnut trees only. Symptoms resembled sudden death syndrome and were caused by Fuserium solani. In a hydroponic study, plants challenged with juglone, a black walnut allelopathic compound, and F. solani were more diseased than plants challenged with F. solani only. Soybean intercropped with poplar showed no disease patches, but the crop canopy water vapour pressure was 0.23 kPa lower than in monoculture because of tree competition. Moreover, yield of healthy soybean in intercrop with black walnut or pecan was not different from monoculture but with poplar or silver maple yield was 65% lower than in monoculture.