No description available.

An Enzyme-Linked Immunosorbent Assay (ELISA) was developed which detected slug antigens in postmortem gut analysis of carabid beetles. The ELISA was used to identify beetles which fed on slugs in three fields of oilseed rape and winter wheat in the Tyne valley, Northumberland. Generalist species such as Harpalus rufipes, Pterostichus melanarius, Pterostichus nladidus, Anlara silnilata and Nebria brevicollis fed on slugs in the field. Molluscan specialists such as Carabus violaceus and Cychrus caraboides also fed on slugs in the field. Laboratory studies indicated that many large and medium sized carabids were able to predate small slugs. Some beetle species did not eat slugs but exposure to the beetles increased slug mortality. Therefore, postmortem investigations may underestimate the impact that carabids exert on slugs as they do not measure the number of slugs killed. Slug mucus affected the locomotory activity of generalist and specialist beetle species. Beetles foraged longer, covered greater distances, made more turns, walked slower and spent more time stationary on soil covered in slug mucus compared to control areas. Abax parallelepipedus, P.melanarius, Pterostichus niger and H.rufipes all reduced slug damage to a chinese cabbage crop in a miniplot experiment compared with unprotected plots. However, these differences were not significant. A.parallelepipedus was most effective at reducing slug damage to the chinese cabbage but was rare in arable land. H.rufipes was least effective at reducing slug damage but was abundant in arable land in both years of the study. A high proportion of H.rufipes beetles fed on slugs in the field. None of these four species occurred at densities in the field which reduced slug damage in the miniplot experiment.

No description available.

No description available.

The use of alfalfa (Medicago scitiva L.) for grazing is becoming more common. Alfalfa is the most widely planted legume, and is one of the most nutritional forage crops available. It is proposed that alfalfa was cultivated 4000 to 5000 years ago and produces the most protein per acre of any forage crop. Live weight gains for beef cattle grazing alfalfa average 230 to 360 kg ha-1. There is no cheaper way to harvest and utilize alfalfa than for the animal to harvest it directly. Most of the commercially available alfalfa varieties, however, were developed for hay production and thus do not always persist under grazing management. Recent advances in alfalfa breeding have provided "dual purpose" cultivars that are now available to producers. A grazing trial was conducted at the Western Kentucky University Agricultural Research and Education Complex in Bowling Green, Kentucky. Persistence and yield of six commercially available grazing-tolerant alfalfa varieties were evaluated to determine their response to rotational stocking by dairy cows. The varieties, Southern States Graze King, WL 324, Garst 645 II, WL 325 HQ, ABT 405, and Spredor III were established March 29, 2000 and harvested three times for hay throughout the year. Grazing was begun in April 2001 and ended in September 2001. Each plot was grazed when alfalfa reached a minimum height of 36 cm. Twelve dairy cows (nine Jerseys and three Holsteins) grazed each plot down to approximately 13 cm. Yield did not differ among varieties (P<0.05); however, there was a significant difference among varieties for stand count. The variety by harvest interaction was significant; when averaged across varieties, stand counts declined 48% during the whole season. Southern States Graze King with 8.8 plants 0.1m-2, was greater only than Spredor III with 6 plants 0.1 m-2.

The genus Dorycnium L. consists of a number of species of perennial leguminous shrubs known to be relatively drought tolerant. Low rainfall areas (i.e <600 mm annually) of Australia under agricultural use are subject to periods of feed shortage during summer and autumn, and hence animal production is limited at this time. Dorycnium spp. have been identified as having the potential to be integrated into Australian grazing systems as a source of forage when little or no other feed is available. This project was established to further investigate a number of key issues related to the agronomic and forage characteristics of this potentially important genus. Research was undertaken into Dorycnium spp. to examine three important factors associated with the evaluation of a legume, seed germination characteristics, the nutritional value of the forage, and rhizobial associations. Dorycnium hirsutum Ser. accessions TAS1002 and TAS2001 were subjected to a range of germination experiments examining the level of pod maturity, harvest season, and the effect of pre-germination treatments. The seed coat of D. hirsutum was found to influence germination behaviour, with the use of pre-germination scarification treatments improving germination behaviour by increasing the percentage germination (PG) and lowering the mean time to complete germination (MTG) and percentage hard seed. Mechanical scarification of TAS2001 for 20 seconds was found to increase (P<0.05) PG from 86 to 96 %, lower the MTG from 6.0 to 2.7 days, and reduce the percentage hard from 13.6 to 1.9 % in relation to untreated seed. Mechanical and chemical scarification techniques were found to be the most effective in promoting rapid and uniform germination, were simple to apply and were repeatable. In general, inherent differences in seed lot germination characteristics were believed to be associated with the influence of environmental factors and the natural characteristics of selected accessions with indeterminate flowering. Established plots of D. rectum Ser., D. hirsutum and D. pentaphyllum Scop. were sampled along with an area of lucerne (Medicago sativa L.) on a regular basis throughout the spring/summer period of 2001/2002. Samples were analysed using near infrared reflectance spectroscopy (NIRS) and wet chemistry for crude protein (CP), neutral detergent fibre (NDF) and dry matter digestibility (DMD) and metabolisable energy (ME). Over the course of the sampling period forage of Dorycnium spp. generally displayed decreases in CP, ME, DMD and increases in NDF. Typical CP values ranged from 4 - 18 % of dry matter (DM), NDF 21 - 72 % of DM, DMD 32 - 75 %, and ME 4.1 - 11.0 MJ/Kg/DM. The nutritive value of Dorycnium spp. forage appeared to be influenced by environmental and developmental characteristics, with the growth stage identified as a useful tool for predicting forage quality. Although Dorycnium plants were of lower forage value than lucerne, their forage can provide livestock with an important source of nutrition in areas of low rainfall and during periods where there are feed gaps. Experimental plots of Dorycnium spp. at three Tasmanian sites were sampled every six weeks throughout the spring/summer period of 2002/2003 and analysed using a modified butanol-HCl method for condensed tannins (CT). The CT content of D. hirsutum was found to fluctuate from 3.2 to 16.6 % of the DM. Dorycnium rectum and D. pentaphyllum were found to contain CT levels of at least 7.7 and 6.8 % of DM respectively during the sampling period. The CT levels observed were considered to be high in general, with only D. hirsutum containing levels that may be considered to be low and possibly beneficial at certain stages of development. Increases in CT levels were associated with the initiation of flowering, and interactions between the environment and species were observed, although no common factor was identified as influencing CT levels. A glasshouse experiment was undertaken to assess the nitrogen fixing ability of the commercial Lotus corniculatus L. inoculant SU343 with Dorycnium spp. against a range of alternative inoculants. The host/rhizobia interactions of Dorycnium spp. along with six important pasture legumes and a range of inoculants was assessed. Strains WSM1284, WSM2323 and WSM2338, along with SU343 were found to be suitable inoculants for Dorycnium spp. examined. However, negative interactions between these inoculants and important pasture legumes were identified. Inoculant strains, WSM1284, WSM2323, WSM2338 and SU343 were selected to undergo evaluation under Tasmanian field conditions with D. hirsutum and D. rectum. In the field all strains were found to fix adequate amounts of atmospheric nitrogen. Inoculant SU343 was confirmed to be a suitable inoculant for D. rectum in terms of performance and commercial viability, however, WSM2338 and WSM1284 were found to be equally suitable. The inoculation of Dorycnium hirsutum with the Tasmanian isolate WSM2323, was found to be a significantly (P<0.05) superior strain to SU343 in terms of nitrogen fixation. The inoculation of D. hirsutum did not affect (P>0.05) plant DM production in the field. The ability of the inoculants to compete with a background population of root nodule bacteria was found to be of concern, and may have serious implications for the long-term performance from a single inoculation event. It was proposed that a combination of rhizobial strains may be more effective as a commercial inoculant rather than relying on the single L. corniculatus inoculant SU343.

Thesis (Ph. D.)--University of Adelaide, Dept. of Soil Science, 1987. / 2 offprints in pocket. Includes bibliographical references (leaves 184-210).

Thesis (M. Ag. Sc.)--University of Adelaide, Dept. of Plant Science, 1995? / Includes bibliographical references (leaves 115-130).

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 197-227). Also available via the Internet.

Thesis (Ph.D) -- University of Adelaide, Depts. of Plant Science and Crop Protection, 1998. / Thesis (Ph.D.)--University of Adelaide, Depts. of Plant Science and Crop Protection, 1999? Bibliographical references: leaves 112-125.