Fruit viability on grubbed Nassella trichotoma (Nees) tussocks

2002 ◽  
Vol 42 (8) ◽  
pp. 1057 ◽  
Author(s):  
S. Lamoureaux ◽  
G. Bourdôt
Keyword(s):  
New Zealand ◽  
High Risk ◽  
Developmental Stage ◽  
Root System ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Leaf Sheath ◽  
Early Summer ◽  
Late Spring ◽  
Summer Fruit

An experiment was conducted to determine the influence of time of grubbing in the late spring–early summer, panicle developmental stage at grubbing, and the presence or absence of roots on grubbed plants, on the initial and post-senescent viability of fruits of Nassella trichotoma in North Canterbury, New Zealand. The percentage of fruits viable, following desiccation of panicles removed from plants grubbed in the field, increased from 1% for panicles just beginning to emerge from the leaf sheath, to 49% for panicles fully extended at the time of grubbing. Similarly, as grubbing date was delayed from late November (late spring) until late December (early summer), fruit viability increased from 0.3 to 47%. Overall, 36% of the fruits were viable on panicles at the time of grubbing, increasing slightly to 47 and 44%, respectively, after a period of desiccation with and without the panicles being attached to the grubbed plant's root system. It was concluded that if recruitment of fruits of N. trichotoma to the soil seed bank is to be prevented in North Canterbury, plants must be uprooted before panicle extension. Delaying grubbing to when panicles are fully extended, while possibly enabling a higher percentage of plants to be detected and therefore destroyed, carries with it a high risk of permitting the recruitment of viable fruits to the soil seed bank.

The role of soil temperature and seed dormancy in the creation and maintenance of persistent seed banks of Nassella trichotoma (serrated tussock) on the Northern Tablelands of New South Wales

2020 ◽  
Vol 42 (2) ◽  
pp. 85
Author(s):  
Annemieke Ruttledge ◽  
Ralph D. B. Whalley ◽  
Gregory Falzon ◽  
David Backhouse ◽  
Brian M. Sindel
Keyword(s):  
Seed Bank ◽  
New South ◽  
Soil Seed Bank ◽  
Seed Banks ◽  
Early Summer ◽  
Secondary Dormancy ◽  
South Wales ◽  
The Creation ◽  
Persistent Soil Seed Bank

A large and persistent soil seed bank characterises many important grass weeds, including Nassella trichotoma (Nees) Hack. ex Arechav. (serrated tussock), a major weed in Australia and other countries. In the present study we examined the effects of constant and alternating temperatures in regulating primary and secondary dormancy and the creation and maintenance of its soil seed bank in northern NSW, Australia. One-month-old seeds were stored at 4, 25°C, 40/10°C and 40°C, in a laboratory, and germination tests were conducted every two weeks. Few seeds germinated following storage at 4°C, compared with seeds stored at 25°C, 40/10°C and 40°C. Nylon bags containing freshly harvested seeds were buried among N. trichotoma stands in early summer, and germination tests conducted following exhumation after each season over the next 12 months. Seeds buried over summer and summer plus autumn had higher germination than seeds buried over summer plus autumn plus winter, but germination increased again in the subsequent spring. Seeds stored for zero, three, six and 12 months at laboratory temperatures were placed on a thermogradient plate with 81 temperature combinations, followed by incubation at constant 25°C of un-germinated seeds. Constant high or low temperatures prolonged primary dormancy or induced secondary dormancy whereas alternating temperatures tended to break dormancy. Few temperature combinations resulted in more than 80% germination.

Natural mortality of juvenile rabbits (Oryctolagus cuniculus ) in North Canterbury, New Zealand

1993 ◽  
Vol 20 (6) ◽  
pp. 815 ◽  
Author(s):  
DL Robson
Keyword(s):  
New Zealand ◽  
Soil Type ◽  
Oryctolagus Cuniculus ◽  
Early Summer ◽  
Late Spring ◽  
Natural Mortality ◽  
Marked Influence ◽  
Breeding Activity ◽  
Pasture Quality

Rabbit-breeding stops were monitored over 35ha of improved farmland, with relatively stable rabbit numbers, in North Canterbury, New Zealand. The number of stops dug varied seasonally, with most in spring, fewest in autumn. Pasture quality appeared to have a marked influence on breeding activity and productivity of the rabbits. Of the 427 breeding stops located, litters were found in 33%. Most (97%) of these stops were lined with grass and belly fur from the doe. Most juvenile rabbit mortality occurred prior to weaning. Of the 126 litters monitored, 38% were preyed upon, 29% drowned and 20% were either preyed upon or drowned prior to emergence. Young drowned when sufficient rainfall for a particular soil type caused flooding of stops. In all, 13% of litters were weaned and left the breeding stop, with late spring-early summer being the most favourable period for survival. Predator numbers were lowest during this period. Ferrets were the most numerous predator; cats and harriers were also present. Disease was not significant. Of those rabbits that emerged, approximately 50% survived to 14 weeks of age. Less-frequent drowning during a sequence of dry years may explain an increase in rabbit number observed in previous years. This may make it possible to predict the need for control.

A COMPARISON OF RYEGRASS CULTIVARS IN SOUTH CANTERBURY 2. Annual cultivars

1973 ◽  
pp. 219-223
Author(s):  
C.C. Mcleod
Keyword(s):  
New Zealand ◽  
Early Spring ◽  
Early Summer ◽  
Late Spring ◽  
Annual Ryegrass ◽  
Short Rotation

The results of three annual ryegrass cultivar trials showed that, of seven cultivars, the Dutch tetraploid Western Wolths Tewera Barenza established first and made good autumn growth. Three tetraploid Western Wolths cultivars including Grasslands Tama were observed to give the best early spring growth. In contrast, the two later maturing Dutch tetraploid Italian ryegrasses gave the highest late spring and early summer production, Poor maximum total yields, the tetraploid Western Wolths ryegrass Billion was the most consistent cultivar. In addition, the tetraploids, whether Italian or Western Wolths, tended to be more productive than the New Zealand diploid Grasslands Paroa (Ralian) or Gramlands Manawa (short-rotation) ryegrasses.

scholarly journals Productivity and composition of perennial lupin pastures in response to six sowing rates, lime application and lupin type at Glenmore Station, Lake Tekapo

2016 ◽  
Vol 78 ◽  
pp. 139-148
Author(s):  
K.M. Pollock ◽  
D.J. Moot
Keyword(s):  
New Zealand ◽  
Early Summer ◽  
Late Spring ◽  
Lime Application ◽  
Summer Grazing

This study aims to identify the sowing rate necessary to produce lupin dominant and productive pastures in the New Zealand high country under low-moderate fertility, and a regime of late spring/early summer grazing. Blue and Russell lupin were sown on 12 December 2012 at rates of 2, 4, 8, 12, 16 and 32 kg/ha with cocksfoot at 2 kg/ha, and ± 3 t/ha lime. Low lupin sowing rates (

scholarly journals Flight behaviour of the manuka chafers, Pyronota festiva (Fabricius) and Pyronota setosa (Given) (Coleoptera: Melolonthinae), on the flipped soils of Cape Foulwind on the West Coast of New Zealand

2018 ◽  
Vol 71 ◽  
pp. 255-261
Author(s):  
Richard J. Townsend ◽  
Jessica E. Dunbar ◽  
Trevor A. Jackson
Keyword(s):  
New Zealand ◽  
West Coast ◽  
Early Summer ◽  
Late Spring ◽  
Field Observations ◽  
The West ◽  
Flight Behaviour ◽  
Sweep Net

Some species in the genus Pyronota are known to be serious pests of pasture. The establishment of new dairy pastures on recently flipped soils on Cape Foulwind, Buller provided a unique opportunity to investigate the flight behaviour and biology of Pyronota festiva and P. setosa from 2008—2012. Flight behaviour was monitored by fixed-vane interruption traps and by field observations. Adults of both species flew through late spring/early summer (Nov—Dec) of each year and seasonal flight timing was consistent between years. Pyronota festiva flight timing and duration were similar to those previously reported in the literature and were slightly female dominated. Pyronota setosa flights started one to two weeks in advance of P. festiva and were dominated by males (>95%). Female P. setosa were rarely observed flying and were rarely caught in sweep-net sampling. Pyronota setosa beetles were never observed swarming or congregating and feeding on the foliage of mānuka. These differences in flight behaviour may help to explain the field observations that P. festiva can rapidly invade new pastures while P. setosa populations appear to spread more slowly.

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