The morphology and development of Lotus uliginosus and Trifolium subterraneum under Pinus radiata canopy in southern Chile

Abstract

A split-plot experiment was conducted in southern Chile to study the effects of tree cover and level of fertilizer application at establishment on the morphology and development of the legumes Lotus uliginosus and Trifolium subterraneum, when sown in conjunction with Festuca arundinacea as the companion grass. Trees were 13-year-old Pinus radiata, spaced at 4 × 12.5 m intervals and with a mean canopy diameter of 4.8 m. At 150 days after sowing the total area of Lotus leaves and length of Lotus stems/plant were not affected by tree cover. Individual plants had fewer stems but they were longer. For Trifolium, despite large increases in individual petiole length and leaf area, total petiole length and leaf area/plant were reduced by tree cover because of a reduced number of petioles/plant. At 275 days after sowing, the number and weight of Lotus components/ha was not affected by tree cover, although companion grass development was reduced. By 640 days the number and weight of Lotus components/ha was reduced but only to the same degree as the companion grass. Trifolium plant development, and in particular seed yield, was affected by tree cover at 275 and 640 days and to a greater extent than Lotus or the companion grass. A high level of fertilizer application at establishment induced a greater development of both legumes at 275 days, but by 640 days the effects were much reduced. It is concluded that both Lotus uliginosus and Trifolium subterraneum respond to tree cover by increasing stem length and leaf area, but that in situations with low soil fertility, the development of Lotus is less affected by tree cover than Trifolium.