Some aspeets of the seed and seedling biology of Bromus diandrus Roth, were investigated with the aim of formulating non-ehemical control methods. B. diandrus seeds remained viable for at least 2 years when dormaney was enforced by environmental conditions, although 95% of seed was capable of germinating within 27 days of shedding from the parent plant when conditions were favourable. Seeds buried at 50 or 150 mm depth in field soil germinated or lost viability within 6 months. Seedling establishment was greatest and most rapid from seeds buried at 50 mm with 97% of total seedling emergence occurring within 1 month of burial. Less than 1% of seeds buried at 150 mm produeed seedlings. Establishment of seedlings from surface-sown seed occurred over 18 months. The prevention of seeding by the application of paraquat to flowering plants of B. diandrus in the field led to a significant reduction in the population in the following year. Control methods based on these results are suggested. Longevite des graines et installation des jeunes plants de Bromus diandrus Roth.Certains aspects de la biologie des graines et des jeunes plants de Bromus diandrus Roth, ont fait l'objet d'une etude dans le but de formuler des methodes de lutte non-chimique. Les graines de B. diandrus sont restees viables pendant au moins 2 ans lorsque la dormance resultaient des conditions ambientales, bien que 95% des graines ait ete eapables de germer dans un delai de 27 jours a partir de la separation de la plante mere, etant donne des conditions favorables. Des graines enfouies a une profondeur de 50 ou 150 mm dans le champ ont perdu leur viabilitie au bout de six mois. L'installation la plus importante et la plus rapide de jeunes plants a eu lieu a partir de graines enfouies a 50 mm, 97% de la levee globale se produisant dans un mois apres enfouissement. Moins de 1% des graines enfouies a 150 mm n'a produit de jeunes plants. L'installation de jeunes plants a partir de graines semees sur la surface du sol a continue pendant 18 mois. L'applieation de paraquat lors de la floraison de plantes de B. diandrus, pour empecher la chute des graines dans le champ, a amene une baisse significative dans la population de l'annee suivante. A base de ces resultats, l'auteur propose des methodes de lutte contre cette espece. Lebensdauer und Keimung der Samen vonBromus diandrus Roth. Im Hinblick auf die Bekampfung dieser Trespe auch ohne Herbizide wurde die Keimungsbiologie in einigen Aspekten untersucht. Unter kuhlen und trockenen Bedingungen blieben die Samen im Lager nach einer Keimruhe mindestens 2 Jahre keimfahig, aber unter gunstigen Bedingungen keimten 95% der Samen innerhalb von 27 Tagen unmittelbar nach dem Abreifen. Von ganz fiach ausgesaten Samen wurden uber 18 Monate hin Keimpflanzen gebildet. Am besten keimten die Samen aus 5 cm Tiefe (97% innerhalb eines Monats). Aus 15 cm Tiefe keimten jedoch weniger als 1%. Die Verhinderung der Samenbildung durch Applikation von Paraquat auf die biuhenden Pflanzen verringerte die Population im Folgejahr signifika...

The reproductive development and seedling recruitment of Aristida rarnosa R.Br. \vas studied under field conditions at six sites on the Northern Tablelands and Northwestern Slopes of New South Wales. A. rarnosu is an undesirable species in pastures because of its low palatability and the propensity of its seeds for causing fleece contamination and mechanical injury to stock. All tillers ofA. vanlosa plants appear to be potentially reproductive and the extensive tiller branching means that each tiller has a high probability of completing the reproductive cycle. Individual plants, therefore, have a high potential for seed production. 'The majority of the seed production occurred in March averaged over all sis sites. Seedlings appeared in each one of the 20 months of observation when the results from all sites were added together, with the majority of seedlings appearing in the spring and autumn. Autumn seedlings had the greatest chance of becoming established at the lower, more western sites while spring seedlings survived best on the Tablelands. The results are discussed with respect to devising pasture management strategies aimed at reducing the abundance of A. wrnosa.

Summary: The rhizome biology of Pennisetum macrourum was studied in a series of field and glasshouse experiments. The total available carbohydrate content of rhizomes remained between 15 and 22% of dry weight throughout the year, with fluctuations, related to the seasonal growth pattern. The percentage regeneration or rhizome fragments of one, two and four nodes buried at 15 cm was 13, 33 and 57, respectively. Thirty percent of 4‐node rhizome fragments regenerated from a depth of 25 cm. In 11 desiecation experiment, regeneration of 3‐node rhizome fragments occurred until rhizome moisture content was reduced to 14%, The time taken to reach this moisture content varied from 4 to 10 days depending on the temperature. The significance of these results for the control of P. macrourum is discussed.

Angora wethers were evaluated for the control of gorse regrowth (Ulex europaeus) after burning. Unreplicated plots containing approximately 0.5 ha gorse and 0.5 ha perennial ryegrass (Lolium perenne) dominant pasture were stocked with A, 6 goats/ha; B, 10 goats/ha; C, 5 goats + 4 sheep (Polwarth wethers)/ha; or D, 5 sheep/ha in June 1981. After 2 years, percentage gorse control was estimated to be 82, 96, 92 and 56%, and percentage gorse ground cover was 36, 16, 13 and 47% for treatments A, B, C and D, respectively. Between spring 198 1 and spring 1982, when gorse was freely available for browsing, pasture consumption by goats averaged 15% (A) and 40% (B) of available pasture. Where goats were present, pastures contained a greater proportion of perennial ryegrass and less barley grass (Hordeurn sp.) and slender thistle (Carduus pycnocephalus) than where only sheep were grazing. Mean mohair production per goat from October 1982 to September 1983 was 3.2,2.3 and 2.4 kg for treatments A, B and C, respectively. Gross fleece values ($/ha) for the same period were $143 (A), $173 (B), $135 (C) and $92 (D).The preferential browsing of gorse and the acceptable mohair yields indicate that Angora goats could be used in a complementary grazing relationship with sheep for gorse control and product diversification in the Tasmanian Midlands.

Establishing plants of Aristida ramosa R.Br. and Danthonia linkii Kunth grown in root observation tubes differed markedly in their root growth and root morphology. Radicle extension of A. ramosa proceeded far more rapidly than that of D. linkii, and root branching occurred earlier and to a much greater extent in D. linkii. From 2 months after germination onwards, the maximum rooting depth of A. vamosa was greater than that of D. linkii, although total root dry weights for the two species were not significantly different. At 25 weeks from germination, 48 % of the root dry weight of D. linkii was present in the 0-10 cm level of the soil profile, while the corresponding figure for A. ramosa was 33 %. Root weight and rooting depth of both species were severely reduced by foliage clipping at weekly or monthly intervals, with roots being more sensitive to clipping than shoots. Clipping led to a concentration of root mass in the 0-10 cm level. The rapidly establishing seedling root system of A. vamosa would give it a competitive advantage over D. linkii in the environment of the north-western slopes of New South Wales. The results of the clipping trial suggest that grazing management may be manipulated to alter the relative abundance of A. ramosa and D. linkii in native pastures.