Competitive exclusion ofCirsium arvensein pasture: a simulated neighbour grazing-height experiment

Abstract

The role of interspecific competition in regulating Cirsium arvense in newly sown pasture was investigated in two pot experiments in Canterbury, New Zealand, where it was grown in the presence and absence of Lolium perenne and Trifolium repens. In Experiment 1 (2006-07), where C. arvense was established as transplanted seedlings, it competitively excluded its neighbours when they were maintained between 20 and 60 mm in height. Coexistence occurred when the neighbour height was maintained between 100 and 150 mm, while competitive exclusion of C. arvense resulted when the neighbours were not trimmed. In Experiment 2 (2007-08), where C. arvense was established from small root cuttings, it was out-competed regardless of neighbour height. The results support the existence of a 'zone threshold' along a gradient of increasing pasture height (competitiveness) within which the weed and sown species can coexist, and below and above which the weed or the sown species exclude the other.

Californian thistle (Cirsium arvense): endophytes and Puccinia punctiformis

“…2 High-intensity/ high-frequency grazing generally leads to an increase in thistle populations as it removes competition from neighbouring plants. 21 Crop rotation has a similar effect as regular soil cultivation will enhance root fragmentation. 3 Hence, additional control methods are desirable.…”

“…These methods typically do not provide long‐term results and are not cost‐effective 2 . High‐intensity/high‐frequency grazing generally leads to an increase in thistle populations as it removes competition from neighbouring plants 21 . Crop rotation has a similar effect as regular soil cultivation will enhance root fragmentation 3 .…”

Impact of pasture height and herbage mass on suppression of variegated thistle in North Island East Coast hill country

“…Scop.) seedlings were transplanted into dense pasture swards in a pot study (Bourdôt et al 2015). The impact of pasture cover on variegated thistle establishment in glasshouse studies was investigated by Pook (1983) and Phung and Popay (1981), who found that increasing levels of shade (Pook 1983) and taller pastures (Phung & Popay 1981) severely reduced the growth of thistle seedlings.…”