bluuebunny/crossref_metadata_2025 huggingface dataset:
Pasture production of two cultivars of Trifolium subterraneum at Kybybolite, South Australia
Authors: Craig AD
Published: March 2005

Two cultivars of subterranean clover, Trikkala and Mt Barker, were continuously grazed by Merino ewes and lambs at 3 stocking rates (8, 13, and 18 ewes/ha) from 1976 to 198 1. The pastures were assessed for clover seedling density, pasture availability and composition, seed reserves, and oestrogen content. Trikkala produced consistently higher seed yields than Mt Barker, with an average yield 3.36 times that of Mt Barker by January 1981 (1178 v. 350 kg/ka). The higher Trikkala seed yields resulted in improved clover seedling densities and increased amounts of clover in the pastures. At the last assessment (8 September 1980) there was an average of 3.15 times more clover in the Trikkala pastures than in the Mt Barker pastures (469 v. 149 kg/ha). Trikkala produced more total available pasture than Mt Barker, at several samplings, because the contribution of subterranean clover to total available pasture was greater after September 1978. The formononetin, genistein and biochanin A content of both cultivars decreased with increasing stocking rate. The most consistent effects were observed in genistein content, with reductions occurring in 7 of the 11 samplings.
Production of cultivars and native populations of Trifolium subterraneum L. in the south of France (Corsica)
Authors: Volaire F , Leliere F , Prosperi JM
Published: March 2005

On the northern Mediterranean island of Corsica, 28 populations of subterranean clover were tested during 3 years: 18 French native ecotypes, and 5 Australian and 5 Spanish cultivars. A principal component analysis showed that dry matter yields, seasonal growth rhythms, and maturity date were the most important factors in the observed variability. By cluster analysis, 6 groups of subterranean clover were defined from these factors. Seasonal and total yields were linked to annual rainfall, but with a specific coefficient for each group. For 100 mm of rainfall, we obtained a range of production from 0.4 t DM/ha for the least productive group to 1.1 t DM/ha for the highest yielding group. The Australian cultivar, Clare, and 9 native Corsican ecotypes were the most productive genotypes (up to 10 t DM/ha.year in a wet year, with 2 t DM/ha during the winter period). These highest yielding ecotypes could be exploited to breed new mid-to- late-maturing cultivars better adapted to northern Mediterranean environments. In the short term, Clare may be used on large scale, for establishment of improved pastures in this region.
Effects of stubble and sowing treatments on take-all of wheat in north-eastern Victoria
Authors: Boer RFde , Steed GR , Macauley BJ , De Boer RF
Published: March 2005

The effects of stubble management treatments on take-all (Gaeumannomyces graminis var. tritici) of wheat were examined in 2 field experiments in north-eastern Victoria. Wheat stubble from a preceding crop was left standing, mulched, burnt or incorporated into soil prior to sowing wheat. At Rutherglen in 1984, neither the incidence nor the severity of take-all was affected by these treatments. Although the severity of root symptoms on take-all affected plants at anthesis and the incidence of white heads were very low, sowing with a zero till, triple disc drill resulted in a small but significant (P<0.05) increase in both disease severity and white head incidence (2% tillers with white heads), compared with sowing with a conventional tine drill (0.6% tillers with white heads), regardless of the stubble treatment. At Wilby in 1985, the incidence and severity of take-all in wheat at early tillering was higher in plots in which wheat stubble was incorporated into soil prior to sowing (16% plants affected), than in plots where stubble was left standing, mulched or burnt (2, 3 and 4% plants affected, respectively). At anthesis, however, there were no significant differences in the incidence of affected plants between the 4 stubble treatments (average of 81 % plants affected).
Control of onion downy mildew in the presence of phenylamide-resistant strains of Peronospora destructor (Berk.) Caspary
Authors: O'Brien RG
Published: March 2005

Two isolates of Peronospora destructor differed in their sensitivities to phenylamide fungicides. An isolate (3014) from the Lockyer Valley did not respond to increasing concentrations of metalaxyl, benalaxyl and oxadixyl between 0.1 and 200 mg a.i./L. An isolate (2967) from Bundaberg was sensitive to these fungicides, with EC50 values (concentrations which reduce disease severity by 50%) of 1.6, 6.0 and 12.1 mg a.i./L, respectively. Isolates 3014 and 2967 were both sensitive to dimethomorph, with EC50 values of 4.3 and 1.4 mg a.i./L, respectively. Field trials compared the efficacy of fungicides for the control of onion downy mildew in the Lockyer Valley in 1989 and 1990. In both trials, treatments containing mancozeb gave the best control, resulting in yield increases of 60% in 1990. There was no difference from the check treatment in either disease severity or yield when metalaxyl was applied, suggesting that phenylamide-resistant strains were prevalent. Other fungicide treatments which did not significantly reduce the severity of downy mildew in the 1990 trial included copper hydroxide, chlorothalonil, fosetyl-Al, and propamocarb. The experimental compound dimethomorph, although less effective than mancozeb, significantly reduced disease severity and increased yield by 24%.
An evaluation of the production potential of six tropical grasses under grazing. 3. Responses to set stocking rates under continuous grazing
Authors: Evans TR , Hacker JB
Published: March 2005

The response of 3 setaria cultivars, the setaria variety splendida, kikuyu grass, and pangola grass to stocking rates of 4-6 steers/ha under continuous grazing was evaluated over a 3-year period. On a year-round basis, averaged over stocking rates, liveweight gain per ha ranged from 822 kg on Narok (164 kg/steer) to 568 kg on Kazungula (114 kg/steer). Narok produced the highest weight gains in summer and winter (142 and 23 kg/steer, respectively). The greatest winter weight loss was from steers grazing Nandi and Kazungula (both -15 kg/steer). Animal production in a year of above-average rainfall, in both summer and winter periods, was markedly reduced overall, even though the quantity of feed on offer was increased. The year x grass interaction was statistically significant in summer, but year x stocking rate and grass x stocking rate were not. Species response to stocking rate showed a linear relationship between stocking rate and liveweight gain per steer, declining with increasing stocking rate, except for Narok setaria where the reverse occurred over the range of 4-6 steers/ha. The results of this experiment support those previously published on these 6 grasses and demonstrate the species potential for good levels of animal production per ha and their ability to withstand high grazing pressures and to maintain weed-free pastures.
Comparison of locations used in cotton-breeding trials
Authors: Williams ER , Luckett DJ , Reid PE , Thomson NJ
Published: March 2005

Cotton-breeding trials are conducted annually throughout the commercial growing regions of eastern Australia. Accumulated yield data for the period 1974-85 were assembled into an incomplete cultivar x location x year table. This table was then analysed in order to compare test locations. The method involved analysing cultivar x location tables separately for each year, using symmetric joint regression analysis. Results were then collected into location x year tables and further analysed. Four criteria for comparing test locations were developed. The discrimination criterion is important when locations are evaluated in terms of their ability to display cultivar differences. The representation criterion measures the ability of a location to mirror the relative performance of cultivars over all locations. The other 2 criteria are concerned with the mean yield at test locations and the stability of location yields over years. Based on the 4 criteria, preferred test locations are recommended.
Effects of leaf rust on selected Australian barleys
Authors: Cotterill PJ , Rees RG , Platz GJ , Dill-Macky R
Published: March 2005

The effects of epidemics of leaf rust (Puccinia hordei Otth.) on grain size and yield of some commercial Australian barley cultivars were determined in 3 field experiments at or near Toowoomba in 1985, 1989 and 1990. Yield was reduced by 38% for the highly susceptible cultivar, Gus, in a mild to moderate epidemic in 1985; cvv. Prior, Schooner, Clipper, Lara and Stirling lost between 10 and 20% yield and cvv. Corvette and Grimmett were unaffected. In a mild to moderate epidemic in 1989, leaf rust reduced the yield of Gus by 40%, and of Grimmett and Clipper by 17 and 12%, respectively, while Prior and Corvette were unaffected. In a moderate to severe epidemic in 1990, yield losses were 62% in Gus, 26% in Grimmett, 31% in Skiff and 14% in the slow-rusting cultivar, Athos. No losses were detected for Corvette or the slow-rusting cultivar, Koru. Loss of yield was largely attributable to reduction in grain size.
Iron-phosphorus interactions in the nutrition of seedling macadamia in organic potting media
Authors: Handreck KA
Published: March 2005

Macadamia integrifolia cv. Keauhou seedlings were grown in an organic potting medium based on ground pine bark and peat and of pH 5.9. Interactive effects of iron (Fe) and phosphorus (P) on shoot growth and quality were studied by amending the medium with single superphosphate to provide 0-240 mg P/L, and either FeSO4.7H2O at 0-3 g/L or FeEDDHA at 0.1-0.4 g/L. Shoots of all seedlings, except those at the highest levels of ferrous sulfate with low P addition, were chlorotic, with symptoms typical of Fe deficiency. Shoot quality, as judged by degree of chlorosis, was correlated with Fe concentrations in unbuffered DTPA (1:1.5 by volume) and double acid (DA) (1:5 by volume) extracts of the media (r2 = 0.683 and 0.688), poorly correlated with P concentrations in these extracts (r2 = 0.284 and 0.289), and highly correlated with concentrations of both Fe and P in the regression equation (r2 = 0.845 and 0.865). Shoot quality was not as well correlated with Fe and P in ammonium acetate (NH4OAc) extracts. Optimum shoot quality was achieved in media (pH 5.9) whose DTPA, DA and NH4OAc extracts contained 2-9, 1.54 and 2-4 mg P/L and at least 60, 15 and 0.43 mg Fe/L, respectively. Leaf chlorosis did not occur if the Fe : P ratios of the extracts were >4.5, >1.7 and >0.02, respectively.
Farming duplex soils: a farmer's perspective
Authors: Edwards I
Published: March 2005

The methods we have employed to tackle the problems of farming duplex soils are being carried out by many farmers statewide to varying degrees. These methods also apply to soils other than duplex ones. In this paper I will give a brief description of the area that we farm and its soil types, and outline the problems with farming duplex soils, our solutions to them, and how we have implemented the solutions.To illustrate the differences that management and rotations can achieve in increasing yields, I will describe our previous management compared with our current management and outline what we will be attempting in the future to increase yields further. Finally, I will give some of my views on sustainability and neglected research areas.
Tile and mole drainage for control of waterlogging in duplex soils of south-eastern Australia
Authors: MacEwan RJ , Gardner WK , Ellington A , Hopkins DG , Bakker AC
Published: March 2005

Waterlogging is a major problem of dryland agriculture in many areas of Australia. Yellow duplex soils, especially those with bleached A2 horizons, are the soils most commonly associated with waterlogging. The problem is principally the development of perched watertables in the A horizons after rain, due to the restricted downward drainage of water caused by the low hydraulic conductivity of heavy clay subsoils. Pipe and mole drainage techniques are briefly reviewed, and experience with subsoil drainage in yellow duplex soils in Victoria is outlined.
Effects of heterogeneous nutrient supply on root growth and nutrient uptake in relation to nutrient supply on duplex soils
Authors: Robson AD , Longnecker NE , Osborne LD
Published: March 2005

Most duplex soils in Western Australia are characterised by multiple nutrient deficiencies. Applications of micronutrients, as well as the macronutrients phosphorus, potassium, nitrogen and sulfur, have been essential for crop and pasture production on these soils. Duplex soils are characterised by heterogeneity in the distribution of mineral nutrients with depth. Additionally, there is heterogeneity both vertically and horizontally in suitability of soil conditions for root growth. There are at least 2 consequences of this heterogeneity for the mineral nutrition of plants on duplex soils. First, there are important effects of localised nutrient supply on root growth and nutrient uptake. Second, identification of nutrient deficiencies by soil and plant analysis is complicated by variation in nutrient supply through time and with depth. These 2 consequences are examined.
Crop production on duplex soils in south-eastern Australia
Authors: Gardner WK , Fawcett RG , Steed GR , Pratley JE , Whitfield DM , Rees Hvan , Van Rees H
Published: March 2005

The environment, duplex soil types and trends in crop production in South Australia, southern New South Wales, north-eastern and north-central Victoria, the southern Wimmera and the Victorian Western District are reviewed. In the latter 2 regions, pastoral industries dominate and crop production is curtailed by regular and severe soil waterlogging, except for limited areas of lower rainfall. Subsurface drainage can eliminate waterlogging, but is feasible only for the Western District where subsoils are sufficiently stable. The other regions all have a long history of soil degradation due to cropping practices, but these effects can now be minimised with the use of direct drilling and stubble retention cropping methods. A vigorous pasture ley phase is still considered necessary to maintain nitrogen levels and to restore soil structure to adequate levels for sustainable farming. Future productivity improvements will require increased root growth in the subsoils. Deep ripping, 'slotting' of gypsum, and crop species capable of opening up subsoils are techniques which may hold promise in this regard. The inclusion of lucerne, a perennial species, in annual pastures and intercropping at intervals is a technique being pioneered in north-central and western Victoria and may provide the best opportunity to crop duplex soils successfully without associated land degradation.
Catchment issues in farming duplex soils
Authors: Morrell H
Published: March 2005

The Morbinning Gully Catchment is located in an area of predominantly yellow duplex soils. The catchment forms part of the Alcoa Landcare program and is the site of the East Beverley Research Annex on which a considerable part of the research reported in this special issue has been conducted. This paper describes the catchment planning and management that is being undertaken by farmers in the catchment in order to reduce land degradation. The principles underlying catchment planning, the various management options being undertaken and the monitoring of water levels in the catchment are all elaborated.
Pasture production and water use on duplex soils along a rainfall gradient
Authors: Bolger TP , Turner NC
Published: March 2005

No abstract available.
Limits to the productivity of Atriplex in salt-affected duplex soils
Authors: Davidson NJ , Galloway R , Lazarescu G
Published: March 2005

No abstract available.
Straightbred and crossbred weaner steers bred in north-eastern New South Wales and grown on Victorian foodlots and pastures
Authors: Doyle PW , Barlow R , Darnell RE
Published: March 2005

Weaner steers of 6 breed types were procured from 82 herds from the North Coast of New South Wales and grown in feedlots and on pastures in Victoria over a 3-year period. Growth and carcass traits were compared when adjusted to a common initial liveweight (204 kg), and breed type effects were tested using the between-herd (of origin) mean square as error. Steers comprised Hereford; first-cross Angus x Hereford (A x H); first-cross Brahman x Hereford (B X H); Braford; an outcross A x (B x H); and a backcross H x (B x H). Initial liveweight was significantly and positively correlated with final liveweight, carcass weight, dressing percentage, muscle score, subcutaneous fat depth [except for B x H and A x (B x H)], and eye muscle area [except for H x (B x H)]. There was no significant relationship between initial liveweight and daily gain. Feedlot steers grew faster than pasture steers (1159 v. 741 g/day) and were slaughtered earlier (after 144 v. 268 days) at similar carcass weights (202 kg) and subcutaneous fat depths at the 12-13th rib (6.6 mm). Muscle colour was significantly lighter for the younger feedlot steers, but all other fat and muscle measurements were unaffected by feed type. The A x H and B x H steers had the highest carcass weights (204 and 206 kg, respectively), while Braford and H x (B x H) steers had the lowest (both 199 kg). The A x H steers had the highest muscle score and greatest subcutaneous fat depth (5.6 units and 8.2 mm), while Braford steers ranked lowest for these measures (4.9 units and 5.5 mm) when adjusted to the same initial liveweight. Underlying these differences were significant breed effects on daily gain (range 71 g/day), final liveweight (range 10.8 kg), and dressing percentage (range 1.6%). There was a significant breed type x feed type interaction for muscle colour: on feedlot, A x (B x H) were significantly lighter than Hereford; and on pasture, H x (B x H) and A x H were lighter than B x H and A x (B x H), and Hereford were lighter than B x H. The range in producer effects (origin) on daily gain was 80-124% of the overall mean, with a repeatability of 0.47. Except for fat depth, breed differences were small, but first-cross steers were generally superior to progeny of first-cross cows. This indicates a conflict in the choice of breed type between that which performs best for rowers (first-cross cattle) and that which performs best for North Coast store weaner producers (calves from first-cross dams). There were large differences in growth rate between steers from different producers that could not be attributed to any 1 factor.
Productivity of Hereford, highgrade Simmental and Belmont Red beef herds in central Queensland. 4. Liveweight and age of heifers at puberty
Authors: Burns BM , Howitt CJ , Webber RJ , Rudder TH , Tierney TJ , O'Rourke PK
Published: March 2005

Liveweight and age at first and second oestrus of Hereford, highgrade Simmental, and Belmont Red heifers were measured over 4 cohorts born from 1979 to 1982. Heifers were observed for standing oestrus or chin-ball markings by vasectomised bulls from about 7 months of age (May) to about 26 months (December). During this period they grazed predominantly improved pastures growing on cleared brigalow country in a subtropical environment. Hereford heifers demonstrated first and second oestrus at lower (P<0.05) liveweights (277 and 301 kg) than Belmont Reds (293 and 319 kg), which were lighter (P<0.05) than highgrade Simmentals (322 and 345 kg). Belmont Red heifers were younger (P<0.05) at first oestrus (527 days) than either Hereford (565 days) or highgrade Simmental (550 days), which were not significantly different. There was a similar pattern for age at second oestrus, except that only Belmont Red (583 days) and Hereford (617 days) differed significantly (P<0.05). However, 13% of heifers did not record a second oestrus during the observation period, in addition to the 7% that failed to record first oestrus by the end of the experiment. There was no difference between cohorts for liveweight at which heifers expressed first oestrus, but the cohort born in 1981 had higher liveweights at second oestrus than the 1979 and 1980 cohorts. Average age ranged from 476 to 613 days at first oestrus and 542 to 620 days at second oestrus over the 4 cohorts. This variation was a reflection of seasonal conditions, particularly during the period May-October following weaning at about 7 months of age. Only 6% of Hereford, 19% of highgrade Simmental, and 16% of Belmont Red heifers had reached puberty in time for seasonal mating as yearlings (about 15 months), and 88% of these were from the 1982 cohort.
Productivity of Hereford, highgrade Simmental and Belmont Red beef herds in central Queensland 6. Whole herd income and gross margins
Authors: Rudder TH , Webber RJ , Knights PT , O'Rourke PK
Published: March 2005

Hereford, highgrade Simmental, and Belmont Red breeding and fattening herds were modelled using comparative productive traits established in a research program. These traits included survival and reproductive rates and liveweights of breeders grazing predominately improved pasture, and growth rates from weaning to sale under either pasture or pasture-plus-crop nutritional regimes. It was assumed that steers were targeted to the grass-fed Japanese market, which required carcass weights of 280-380 kg. Net income was estimated by developing a hypothetical property capable of supporting 1000 adult equivalents and using best-bet estimates of the variable and fixed costs of production for each herd. Belmont Red model herds produced higher net income ($A58 800) than Hereford ($19 000) or highgrade Simmental ($8 000) herds under the pastureonly regime. When surplus heifers and steers had access to summer and winter crops as well as pasture, net income was Belmont Red $60 600, Hereford $34 400, and highgrade Simmental$20 400. The lower earning capacity of the Hereford than the Belmont Red was due to lower herd output; higher variable costs, mainly due to higher costs for bulls and for tick and dystocia control; and lower prices, due to a smaller proportion of cattle meeting preferred fat scores. The difference between the Hereford and highgrade Simmental herds was mainly due to price reductions for the highgrade Simmental slaughter cattle because of failure to meet preferred fat scores. Their large mature size and, hence, fewer numbers to make up 1000 adult equivalents also contributed.
Liveweight gain and wool growth in sheep fed rations containing virginiamycin
Authors: Murray PJ , Rowe JB , Aitchison EM , Winslow SG
Published: March 2005

The feed additive virginiamycin was evaluated for its potential to improve wool growth and liveweight gain in Merino sheep in 2 experiments. In the first experiment 84 wethers (about 10 months old) were housed individually and fed ad libitum a pelleted diet based on lucerne chaff, lupin, and barley grain. Control sheep (28) were fed an unmedicated diet, and 14 in each of 4 groups were given diets containing 10, 20, 40, or 60 mg virginiamycin/kg pellets. Virginiamycin was found to reduce feed intake during the first 4-5 weeks of the experiment when included at levels 220 g/t. There was a dose-related reduction in liveweight gain. There was no significant effect of virginiamycin on wool growth. In the second experiment, weaners and adults from 2 locations in Western Australia, Mount Barker (relatively high rainfall) and Wongan Hills (relatively low rainfall and shorter pasture-growing period), were housed individually in a shed and fed a pelleted diet at rates equivalent to 3.5 and 3.1%, respectively, of liveweight for weaners and adults. The pelleted ration was based on wheat and lucerne chaff, lupin grain, and fishmeal. Virginiamycin was included at 20 mg/kg pellets for 16 of 40 sheep of each age and location. The remaining sheep were fed the unmedicated diet. Feed conversion and liveweight gain improved (P<0.05) in response to the inclusion of virginiamycin during the first 4 weeks of the trial, but wool growth was reduced over the same period. Virginiamycin had no effect on fibre diameter in sheep in either experiment.
Effect of treatment with melatonin implants in conjunction with teaser rams on the reproductive performances of Poll Dorset x Merino ewes joined in early summer in the south-west of Western Australia
Authors: Croker KP , Johns MA , Williams AH , McPhee SR , Staples LD
Published: March 2005

Melatonin pretreatment to improve the reproductive performance of first-cross Poll Dorset x Merino ewes joined in early summer was investigated in 2 experiments conducted in consecutive years. In experiment 1, melatonin pellets were administered subcutaneously to 1 of 3 groups of ewes; 14 days later they were joined with testosterone-primed wethers ('teasers'), followed after 15 days by entire rams (melatonin-teased group). The other groups were untreated and teased only. Experiment 2 consisted only of teased and melatonin-teased groups, with the ewes from experiment 1 being reallocated, as well as maiden ewes being joined for the first time. In this experiment melatonin pellets were inserted 38 days before the start of joining. Treatment with melatonin resulted in increased reproductive performances. The responses were characterised by an earlier (P<0.05) conception pattern in both experiments and higher (P<0.001) lambing percentages than controls in experiment 1. Up to 22% more lambs were born to melatonin-teased ewes than to teased ewes, and stimulatory effects were similar for ewes of different ages. In experiment 2, ewes that had received melatonin in both experiments tended (P>0.05) to have higher lambing percentages than teased ewes (up to 17% more lambs born), while ewes that had received melatonin in only experiment 1 tended (P>0.05) to have lower lambing percentages than ewes that were not treated with melatonin in either experiment (4-11%). The higher lambing performances of the melatonin-treated ewes were independent of ewe liveweights. Reproductive activity was also stimulated by the use of teasers alone in experiment 1. Conception patterns were advanced (P<0.01) and there was a trend for more (P>0.05) lambs to be born in the teased group than in the control group. The results show that both teasers and melatonin treatment will advance the conception patterns of first-cross Poll Dorset x Merino ewes joined in early summer, but the melatonin treatment also stimulated fecundity.
Subterranean clover pasture responses to lime application on the acid soils of southern New South Wales
Authors: Scott BJ , Cullis BR
Published: March 2005

The effects of soil amendment with shallow (0-10 cm) incorporated lime or dolomite were examined at 3 sites with acid soils over 6 years. Measurement was made of soil pH and exchangeable cations, and of subterranean clover dry matter production, seed set, and concentrations of calcium, magnesium, manganese, nitrogen and phosphorus. Application of lime or dolomite increased the production of dry matter, but not by the alleviation of molybdenum deficiency. Response in yield ranged from nil to 47%, with most responses in the range 20-35%. Such responses persisted for 5-6 seasons following lime or dolomite application. Differences in soil pH associated with liming were maintained for the 6 years of measurement, so that the benefits in pasture production from soil amendment are likely to accrue beyond the time span of this study. The analyses of plant dry matter indicated that manganese toxicity may have been a factor in the response to lime at 1 harvest, and that higher nitrogen concentration was associated with liming at another. Generally, the plant analyses did not indicate a clear mechanism for the plant responses to lime, although the soil analyses indicated the presence of exchangeable aluminium in the unamended plots at all 3 sites. The plant responses demonstrated that acidity constrained the yield of subterranean clover grown on these soils.
Comparison of the phosphate requirements of burr medic and yellow serradella with subterranean clover in the low rainfall wheatbelt of Western Australia
Authors: Paynter BH
Published: March 2005

Burr medic (Medicago polymorpha) and yellow serradella (Ornithopus compressus) were compared with subterranean clover (Trifolium subterraneum) in their response to freshly topdressed phosphate in the low rainfall wheatbelt of Western Australia. Species were compared on the amount of applied phosphorus (P) required for 90% maximum yield and the ratio of their curvature coefficients from the Mitscherlich relationship between P applied and absolute yield. On marginally acidic, medium-textured soils, burr medic had a higher external shoot requirement for applied P than subterranean clover. Relative differences between the species were affected by season, initial concentration of bicarbonate-extractable P in the soil (0-10 cm), and timing of plant harvest during the growing season. Burr medic generally achieved a higher absolute maximum yield at each harvest, a larger absolute yield response, and a larger percentage response to applied P than subterranean clover. There was no difference between burr medic and subterranean clover with respect to the internal efficiency of P use for shoot production. For seed production, the external requirements of burr medic and subterranean clover for applied P were similar according to the criterion of P required at 90% maximum yield, but burr medic had a higher requirement if curvature coefficient was the criterion for comparison. Burr medic also had a higher internal efficiency of P use for seed production than subterranean clover. On an acidic, light-textured soil, yellow serradella had a lower requirement for applied P than subterranean clover, according to both criteria for all harvests in 2 separate years.
Effect of nitrogen fertilizer on yield of perennial pastures irrigated with saline water
Authors: Mehanni AH , West DW
Published: March 2005

This study examines the interaction between salinity and nitrogen (N) fertiliser in perennial pastures growing in the Shepparton Irrigation Area of northern Victoria. In a greenhouse experiment, perennial ryegrass was irrigated with 5 concentrations of sodium chloride (100-6000 mg NaCl/L) and fertilised with 5 concentrations of N (25-800 mg/L). Nitrogen at 200 mg/L was optimum for dry matter yield; at N concentrations >200 mg/L, yield declined. Dry matter yield was greater at 750 mg NaCl/L than at 100 mg NaCl/L but was reduced with further increases in salinity. Significant interactions between salinity and N were recorded for dry matter, and for chloride, Na, potassium, and magnesium concentrations in perennial ryegrass. In a field experiment, the growth of mixed perennial ryegrass-white clover pastures irrigated with saline water [53000 mg/L of total dissolved solids (TDS)] also responded to N applications. With no added N, yield (2-year average) decreased from 16 630 to 11 277 kg DM/ha (32% decrease) with an increase in salinity from 100 to 3000 mg TDS/L. With 150 kg N/ha, the average yield was 17681 kg DM/ha at 100 mg TDSL and 14 123 kg DM/ha at 3000 mg TDS/L (20% decrease). Form of N (calcium nitrate, ammonium nitrate, or urea) had no significant effect on yield at 150 kg N/ha. Application of urea at 150 kg N/ha to pastures irrigated with water of salinity up to 3000 mg TDS/L would be economically justifiable.
Evaluation of a rapid mass-screening technique for measuring antibiosis to Helicoverpa spp. in cotton cultivars
Authors: McColl AL , Noble RM
Published: March 2005

A study of a variety of screening techniques was undertaken to determine their suitability for an antibiosis-enhancing cotton-breeding program. Techniques trialled included 9 different larval bioassays of varying durations on squares, leaves, and seedlings of cotton-using larvae of different ages. Chemical analyses of squares and seedlings, and a field trial to validate laboratory findings, were also conducted. The 'standard' measure of antibiosis in cotton plants, using long-term (8-day) bioassays based on larval weight gain, was found to be unsuitable for mass screening cotton plants for antibiosis to the cotton bollworm, Helicoverpa armigera (Hnbner), in Central Queensland. A 48-h technique using instar VI larvae proved as dependable as the standard, but faster and more energy-efficient, making it more suitable for mass screening. Chemical analyses supported previous findings that terpenoid aldehydes (i.e. gossypol) in cotton produce important antibiotic activity against H. armigera. Highly significant negative correlations were shown between gossypol content of ingested plant material and larval weight gains. In contrast, there was no relationship between condensed tannin content and larval weight gain. The relationships between larval bioassays and allelochemical content of cultivars were confirmed in a field trial.
A comparison of large white, landrace and hybrid pigs
Authors: Sheridan AK , MabeyA F , Gordon GNG
Published: March 2005

Large White, Landrace, and Hybrid breeding stock (and the crosses between them) account for most pigs produced in Australia. Performance information for these 3 breeds (obtained from the NSW Boar Performance Test Station) was analysed for a 5-year period (March 1986-June 1991). At the commencement of the comparison, Landrace boars were significantly slower growing than Hybrid boars, significantly fatter than Large White boars, and had a significantly poorer feed conversion ratio than both breeds. There were no differences by the end of the comparison. During the 5-year period, Landrace boars showed a significant improvement in the Test Index relative to the other 2 breeds, being equal to them in overall genetic merit at the end of the comparison. For all 3 breeds, the Test Index improved substantially over this period; however, this observation was made in the absence of control populations. Despite an increase in growth rate during the assessment period (40-90 kg liveweight), there was no decrease in age at 40 kg.
The adaptation of Medicago polymorpha to a range of edaphic and environmental conditions: effect of temperature on growth, and acidity stress on nodulation and nod gene induction
Authors: Loi A , Howieson JG , Cocks PS , Caredda S
Published: March 2005

Three experiments were conducted with Medicago polymorpha collected from a diverse range of sites in Sardinia, to investigate the relationship between edaphic and environmental conditions at collection sites, and the growth and nodulation of the genotype. Growth response to 2 temperature regimes (20/15�C, 11/9�C) was greater for genotypes collected from high altitude than for those from 1350 m. Shoot yield was more depressed by low temperature and more stimulated by high temperature in high altitude than low altitude genotypes. All genotypes nodulated when exposed to considerable acidity stress (pH 5.4) and 1 mmol Ca/L in solution culture. However, there were differences between genotypes in nodulation reduction caused by exposure to acidity. These differences were not well related to the soil pH at the site of collection, or to the effects of pH on the ability of root exudates from the genotypes to stimulate nod gene expression in Rhizobium meliloti.
A comparison of the potassium requirements during early growth of Lotus pedunculatus, Medicago murex, M. polymorpha, M. truncatula, Ornithopus compressus, Trifolium balansae, T. resupinatum, Pennisetum clandestinum, and Phalaris aquatica
Authors: Pinkerton A , Randall PJ
Published: March 2005

A comparison was made of 9 pasture species, some of which are coming into increasing use in Australia, for potassium (K) requirements and early growth. Plants were grown in sand culture in glasshouse experiments and were provided with nutrient solutions containing 7 rates of K (0-5 mmol/L), and nitrogen (12 mmol/L). Plants were sampled twice, the second sampling coinciding with flowering of most species. Symptoms indicating K deficiency were recorded, and diagnostic indices were derived for blades and petioles of the youngest open leaves (YOL), or for youngest expanded blades, and for whole shoots. Medicago murex and M. truncatula had the highest yield at the first sampling. Pennisetum clandestinum, Phalaris aquatica, and M. polymorpha had the highest yield at the second sampling and had a lower internal requirement for K than the remaining species, while Ornithopus compressus had the lowest yield. In all species except M. murex, critical K concentrations in whole shoots declined with plant age. Only in L. pedunculatus did the use of the YOL yield similar K concentrations at the 2 samplings. Ornithopus compressus was shown to have a low requirement for K and a high K efficiency, but it also showed poor scavenging ability. All plant parts sampled could be used to discriminate between K-deficient and K-sufficient plants. Critical K concentrations were higher in petioles than in blades of the YOL and, generally, were higher in whole shoots than in blades. The critical K concentrations derived for some species were similar to critical concentrations previously reported for other members of the same genera.
Survey of use and management of Lotus pedunculatus cv. Grasslands Maku in eastern Australia
Authors: Harris CA , Blumenthal MJ , Scott JM
Published: March 2005

A telephone survey of district agronomists and a postal survey of farmers known to have had experience with Lotus pedunculatus cv. Grasslands Maku were conducted in eastern Australia in 1990 with the objectives of determining the present use of Maku in eastern Australia, and documenting management practices and problems of Maku pastures. The data from the survey were used as an aid in identifying research needs relating to Maku, the results of which may overcome problems associated with Maku's wider adoption and use. Fourteen district agronomists were interviewed, and of the 100 questionnaires sent to farmers, 70 valid returns were received. The area sown to Maku along the coastal regions of eastern Australia increased from 100 ha in 1984 to 5500 ha in 1990. The main use of Maku was in beef enterprises; there was a lesser, but still substantial, use in the dairy sector. Maku was sown over a wide range of soil conditions. In the dairy sector it was most commonly reported to be sown on poorly drained, waterlogged soils (57% of respondents), followed by infertile and acidic soils. In beef systems it was sown into a combination of low pH and infertile soils (42%). The district agronomists were unsure of the feed value of Maku. However, there was a high level of satisfaction among the farmers, with 87% of beef farmers and 75% of dairy farmers reporting its feed value to be equal to, or better than, white clover. All beef farmers intended to establish larger areas over their properties, whereas 21% of dairy farmers surveyed did not intend to expand their sowing of Maku pastures. From the results of both surveys a number of areas requiring research have been identified. These include aspects of establishment, dry matter production, quality, persistence, and seed production.
A field comparison of three neutron moisture meters
Authors: O'Leary GJ , Incerti M
Published: March 2005

A study was undertaken to compare 3 neutron moisture meters (NMMs) over a range of counting times on 2 soil types in north-westem Victoria. The meters were a Pitman Wallingford 225 (WAL225), a Campbell Pacific Nuclear 503 (CPN503), and a Campbell Pacific Nuclear 501DR (CPN501). The soil types were a grey self-mulching clay and a solonised brown soil (sandy loam). The 3 NMMs exhibited different count rates in water, from 242 to 2645 counts per second. It was necessary to increase the counting time of CPN501 to 64 s to achieve a comparable performance to WAL225 at 16 s. Over the 15-month experiment, standard counts remained relatively constant for WAL225 and CPN501, but CPN503 showed pronounced variation. In field calibrations, the inclusion of depth (as a separate variable to account for neutron absorbing gradients in the soil profile) made significant improvement to the regression of all NMMs irrespective of counting time. No improvements in the calibration were achieved using density corrections from core samples for individual layers. On both soil types, WAL225 and CPN503 performed similarly to each other, with very similar residual mean squares and coefficients of determination. On the grey clay, WAL225 and CPN503 explained 77 and 88% of the variation in soil water content, respectively. CPN501 performed poorly, even with a 64 s counting time, and explained only 52% of the variation when depth was included. When depth was excluded this fell to 25%. On the sandy loam, WAL225 and CPN503 explained 76 and 74%, respectively, of the variation in soil water content. CPN501 again performed poorly with a 64 s counting time, accounting for 65% of the variation when depth was included and 33% with depth excluded. Examples of poor calibrations or none at all in water use studies are discussed and typical errors are demonstrated.
Effect of plant density on yield and rubber accumulation in guayule (Parthenium argentatum) in south-eastern Queensland
Authors: Ferraris R
Published: March 2005

Guayule (Parthenium argentatum) was grown as a rainfed and an irrigated crop on an oxisol in south-eastern Queensland for 36 months, to assess its potential as a source of rubber. The rainfed experiment consisted of 3 cultivars (N565, 11591, 11619) grown at 4 densities (0.9, 1.8, 3.6, 5.2 plants/m2). The irrigated experiment compared cultivars N565 and 11591 at densities of 1.8, 3.6, and 5.2 plants/m2. In both trials, harvests were taken at 4-monthintervals. Dry matter yields of stems and roots, and rubber concentration in stems and roots, showed a near linear increase with time. Stem dry matter yields at 36 months approached 8.0 t/ha, with a rubber concentration of 13%. Rubber concentration and rubber yield increased with plant density. Total rubber yield in stems plus roots after 36 months was about 1.2 t/ha. The low productivity of this crop was associated with poor root development in the soil profile, a low leaf area index, and subsequent low light interception. A main inhibitor to root growth was the high incidence of a Fusarium sp. root pathogen.
A comparison of visual and digital image-processing methods in quantifying the severity of coffee leaf rust (Hemileia vastatrix)
Authors: Price TV , Gross R , Ho Wey J , Osborne CF
Published: March 2005

Using disease diagrams, visual assessments of coffee leaf rust from Papua New Guinea overestimated severity by >2 times when >20% leaf area was rusted. Nevertheless, a significant linear relationship was established between visual and planimeter assessments of coffee rust severity. Colour image analysis, using a Matrox digitiser, was more accurate than visual estimates or black and white imaging systems in discriminating between rusted and healthy leaf tissues in colour transparency photographs of rusted coffee leaves. Electronic flash photography of rusted coffee leaves produced images with reflections from the waxy leaf surface which made it difficult to discriminate between healthy tissues and the background.
Influence of preseason weed management and in-crop treatments in two successive wheat crops 1. Weed seedling numbers and wheat grain yield
Authors: Dowling PM , Wong PTW
Published: March 2005

The effect of 5 preseason management treatments on seed set reduction of annual weed grasses and their regeneration in the following autumn was evaluated in a 2-year field experiment commencing at Orange in spring 1986. Preseason (spring) treatments were paraquat, glyphosate (2 rates), unsprayed heavy grazing, and unsprayed control. In the first of 2 successive wheat crops (planted 1987), 3 in-crop weed control treatments [control, chlorsulfuron (both sod-seeded), and trifluralin plus cultivation] were imposed. In 1988, the second wheat crop was sown into a cultivated seedbed or direct-drilled. The preseason treatments reduced potential annual grass regeneration by 91-99% compared with the control, with heavy grazing being the best treatment. For each preseason treatment compared with the control, the pattern of actual seedling emergence within the crop during 1987 was similar to that of potential emergence for each grass species (except Lolium rigidum), but numbers were lower and more variable (7-86% of potential numbers). The proportion of Bromus spp. and Vulpia spp. emerging within the crop declined from the first to the second crop, while L. rigidum increased to an average of 93% of the annual grass population in 1988. Trifluralin plus cultivation increased the control of annual grasses in 1987. In 1988, the 1987 in-crop treatments had little carryover effect on annual grass control; however, wheat grain yield was increased by both chlorsulfuron and trifluralin. Preseason management reduced seed set of annual grass weeds, and this control was maintained under cropping for at least 2 years (except for L. rigidum). Wheat grain yield responded to this control. Long-term control of L. rigidum where soil is disturbed appears difficult because of apparent long-lived seed in the soil.
Effect of different rates and timing of soil applications of paclobutrazol on the growth of sweet cherries (Prunus avium L.)
Authors: Granger AR , Traeger DRC
Published: March 2005

The response of sweet cherry trees (butt circumference, canopy volume, yield) to different rates of the growth-inhibiting chemical paclobutrazol applied at various times during each year was studied on red podsolic soils in the Mount Lofty Ranges of South Australia Two experiments were conducted: one used a regression design with 16 rates of paclobutrazol; the other was a randomised block experiment with paclobutrazol treatments applied in spring, autumn, or half in autumn and half in spring. Butt circumference growth of the variety Sam grafted on Mahaleb rootstocks tended to reduce with inceased rates of paclobutrazol in the first year of application. The lowest rate of paclobutrazol to reduce butt growth sigdicantly below that of control trees was 1.2 g a.i./tree. Canopy growth showed a delayed response in measurable growth inhibition in the season after treatment; however, no significant differences were measured for rate of canopy growth in any year for any treatment in the regression experiment. Despite this, final canopy volumes of trees treated with 1.6 g paclobutrazol in spring were half those of control canopies. Variability in butt growth response to the range of rates applied was attributed largely to localised differences in soil properties which influenced paclobutrazol movement and uptake. This variability was gradually reduced over the 3-year period with continued paclobutrazol applications. In 1987, crop level ratings made before harvest showed significantly higher levels of fruit on trees treated with 1.6 g paclobutrazol in spring, indicating that fruit numbers could be increased by applications of paclobutrazol.
Utilising the Western Australian soil profile database for research and land management
Authors: Peluso E , Mlodawski RG , Beeston GR
Published: March 2005

The analysis, design, implementation, and potential benefits of the Western Australian soil profile database are described. Entity-relationship modelling has been used in the data analysis phase to identify the relational schema. The database has been implemented using the ORACLE relational database management system.The database has the capacity to provide detailed land resource information in hard copy report format, and when integrated into a Geographic Information System, the data can be viewed and retrieved in a spatial context with other data sets. Such information is important for researchers and land managers involved in sustainable agricultural systems.