Nassella trichotoma – plant growth rates and effects of timing of grubbing on populations in North Canterbury grassland. Issue 2 (3rd April 2019)

• Record Type: Journal Article
• Authors: Bourdôt, Graeme W.; Saville, David J.
• Is Part Of: New Zealand journal of agricultural research. Volume 62:Issue 2(2019)
• Page Start: 224
• Page End: 245
• Publication Date: 2019-04-03
• Subjects: Serrated tussock -- nassella tussock -- population model -- grubbing -- weed control; Agriculture -- Periodicals; Agriculture -- New Zealand -- Periodicals; Animal culture -- Periodicals; Animal culture -- New Zealand -- Periodicals; 630.99305
• DOI: 10.1080/00288233.2018.1483954
• Languages: English
• ISSNs: 0028-8233

Abstract

ABSTRACT: To quantify plant growth rates, responses to fertiliser and population responses to timing of grubbing (manual removal of plants) in a grassland population of Nassella trichotoma, three experiments were conducted. In Experiment 1, plant diameter growth, measured on 25 farms for up to 6 years, was unaffected by fertiliser and averaged 24 mm year −1, enabling a rapid increase in seed output. In Experiment 2, autumn and spring grubbing, compared on six 5-ha plots on four farms over six years, gave reductions in population size of 71% and 83%, respectively. In Experiment 3, effects of time of grubbing and pasture disturbance in spring/summer on recruitment were measured and combined with published demographic process rates in a simple population model. The model predicts population stability when 33.75% of plants are removed (the current mean grubbing rate) before mid-November with 3% pasture disturbance, and also for later grubbing with higher grubbing rate or lower pasture disturbance.