bluuebunny/crossref_metadata_2025 huggingface dataset:
Survey of the incidence of whiteheads in wheat crops grown in northern New South Wales, 1976-1981
Authors: Klein TA , Burgess LW , Ellison FW
Published: March 2005

The incidence of whiteheads in wheat in the northern areas of the wheat belt in New South Wales was surveyed from 1976 to 1981. Whiteheads were associated with plants affected by crown rot and were common in wheat crops in the survey areas, although the incidence was low (<5%) in most crops. There was a high incidence of whiteheads (>5%) in a small number of crops in each year. The mean incidence of whiteheads was highest in 1977 and was generally higher in the western, lower rainfall areas than in the other areas each year. The predominant crown rot pathogen Fusarium graminearum Group 1 was isolated from 97% of 1450 stem bases collected from plants with whitehead symptoms. A fallow of 18 months was not always associated with a reduction in the incidence of whiteheads.
Influence of soil pH and climate on the tolerances of barley and wheat to chlorsulfuron
Authors: Lemerle D , Leys AR , Kidd CR , Cullis BR
Published: March 2005

The effects of soil pH and seasonal conditions on the responses of barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) to chlorsulfuron were investigated at 3 sites in southern New South Wales in 1986, 1987 and 1988. The sites varied in soil pH (4.3-6.2) and annual rainfall (360-560 mm). In addition to the variation in soil pH between sites, 2 surface pH levels were obtained at each site by the addition of lime. The effect of post-emergence applications of 7.5, 15.0, 22.5, 30.0 and 37.5 g a.i./ha chlorsulfuron on the yield of weed-free barley and wheat varied with season, site and the addition of lime. The yield reduction was greatest in 1986, and the extent of the reduction was always greater in barley than wheat. In 1986, a recommended rate of chlorsulfuron (15 g a.i./ha) significantly (P<0.05) reduced the grain yield of barley at all sites by up to 18% and of wheat by up to 13%. Therefore, the reduced tolerance of barley and wheat to chlorsulfuron in some seasons was not restricted to the acid soils. Significant lime x chlorsulfuron interactions occurred with barley in 3 of the 9 trials, but the interactions were not consistent. At Ariah Park in 1986, grain yield reductions were greatest in unamended soils, while at both Ariah Park and Goolgowi in 1987, grain yield reductions were greatest with the limed plots. There were no significant interactions for wheat. In pot trials the effect of chlorsulfuron on the shoot dry weight of barley varied with soil type. However, there was no direct relationship between soil pH and dry weight reduction. When the pH of an acid soil was amended by liming to give soils with pH of 4.1-7.3, there was a trend to more damage at pH values of 5-6. With 4 soils of different pH and texture, there was less damage in the barley grown in soils of pH 7.3 and 7.4 than in soils of pH 4.1 and 6.0. While these results suggest that soil pH affects the tolerance of barley to chlorsulfuron, it is likely that soil pH is of less importance than other edaphic or climatic factors.
Grain yield of wheat in rotation with pea, vetch or medic grown with three systems of management
Authors: Silsbury JH
Published: March 2005

Pea (Pisum sativum L. cv. Alma), vetch (Vicia sativa L. cv. Languedoc) and annual medic (Medicago truncatula Gaertn. cv. Paraggio) were grown at Brinkworth, South Australia, in 1987 in large (0.75 ha) plots and subjected to 3 systems of management: (i) ploughing in at flowering as a green manure crop, (ii) harvesting for grain and ploughing in the dry residues, and (iii) harvesting for grain and removing the residues. A wheat crop was sown over the whole area in the following season (1988) and the effects of type of legume and management on grain yield and grain protein content were measured. The management system imposed on the legume had a highly significant (P<0.01) effect on the grain yield of the following wheat crop, but there were no significant differences between the 3 legumes in their effects on wheat yield or on grain protein content. Ploughing in the legumes as a green manure crop at flowering added about 100 kg/ha more nitrogen (N) to the soil than allowing the legumes to mature, harvesting for seed, and removing residues. Incorporating the dry residues rather than removing them added about 26 kg N/ha. The green manure crop significantly increased subsequent wheat yield (by 49%; P<0.001) and protein content of the grain (by 13%; P<0.05) compared with the treatment in which the legumes were harvested for grain and all residues removed; incorporating the dry residues increased yield by 10%. It is concluded that the amount of N added during the legume phase in a rotation is more important than the kind of legume from which the N is derived. The occasional use of a dense legume crop as a green manure may rapidly add a large amount of N to a soil to be slowly exploited by following grain crops.
Injury levels for soil-dwelling insects in sunflower in the Central Highlands, Queensland
Authors: Murray DAH , Wicks R
Published: March 2005

Soil-dwelling insects cause poor establishment of summer crops, especially sunflower, in the Central Highlands of Queensland. Laboratory studies established that adults and nymphs of cockroaches, Calolampra spp., and Pterohelaeus alternatus beetles were most damaging to sunflower seedlings. Field trials were used to define an econonic injury level (EIL) for these insects in sunflower, but a comparison of yields from untreated and treated plots (where baits were used to control soil-dwelling insects) was inconclusive. However, based on seed costs alone, 1.34 insects/mound.night was established as an EIL. Injury equivalents were used to refine the EIL to account for multiple species attacking seedling crops. At the recommended baiting rate of 2.5 kg/ha, the EIL was 1.97 insect equivalents/mound.night.
Root distribution of lychee trees growing in acid soils of subtropical Queensland
Authors: Menzel CM , Aitken RL , Dowling AW , Simpson DR
Published: March 2005

A core sampling technique was used to investigate the vertical root distribution of 8-10-year-old lychee trees (Litchi chinensis cv. Tai So) growing on 5 acid soils in subtropical Queensland (lat. 27�s.). At each site, soil and roots were sampled at 10 cm depth intervals to 100 cm, the root density determined and a range of soil chemical and physical properties measured. Eighty percent of the feeder roots were located within the top 0-20 cm (1 site), 0 4 0 cm (2 sites) or 0-60 cm (2 sites). The depth of rooting was greatest in the fine textured soils, while the greatest total root density was recorded in the coarse textured soils. The data suggest that the placement of tensiometers for water scheduling needs to take into account the effective rooting depth of lychee because it may vary with soil type. At all sites, pH values were acidic (pH<6.0) and subsoil pH values were below 5.5, and exchangeable Ca decreased and exchangeable A1 increased with depth. Four of the 5 sites had subsoil with >30% Al saturation of the cation exchange capacity. Although root density (all sites) was correlated with a number of soil chemical properties, stepwise multiple linear regression showed that 62% of the variation in root density could be explained by a curvilinear function of depth. The intercorrelations between soil properties and the correlation of depth with some properties demonstrate the difficulties in separating the effects of depth per se from those of soil properties in reducing root growth.
Effect of boron and copper contaminants in poultry manure on the growth of the common mushroom, Agaricus bisporus
Authors: Cresswell GC , Nair NG , Evans JC
Published: March 2005

The toxicity of boron (B) and copper (Cu) to cultivated mushrooms was tested in 2 experiments. The growth of mushroom mycelium (Agaricus bisporus) on potato dextrose agar in vitro was inhibited by additions of B as H3BO3 and Cu as CuSO4.5H20. Boron was more inhibitory than Cu to mycelial growth. Addition of B to compost at spawning decreased sporophore (i.e. mushroom) production and increased B concentrations in the sporophore. Boron added at 35 mg/kg of fresh compost gave a 10% yield reduction and this was associated with a sphorophore tissue B concentration of 170 mg/kg dry weight. Addition of Cu to the compost had no effect on the final yield of mushrooms but increased Cu concentrations in the sporophores. Boron added at 5, 10 and 20 mg/kg and Cu at 10 mg/kg of fresh compost stimulated sporophore growth at first flush but this was not evident in total mushroom yield from all flushes. There was a significant negative linear effect of mushroom tissue B (r2=0.98) and Cu (r2=0.54) at harvest 1 (day 1) on the change in tissue B or Cu from harvest 1 to 6 (day 17). This suggested that tissue B was buffered around 7 mg/kg and Cu around 73 mg/kg. The results indicate that the levels of B and Cu which are normally contributed to mushroom compost from poultry litter are unlikely to cause significant losses in mushroom production.
Growth and carcass fatness of ewe, wether, ram and cryptorchid crossbred lambs reared at pasture: effects of weaning age
Authors: Lee GJ , Harris DC , Ferguson BD , Jelbart RA
Published: March 2005

The effects of weaning age and sex on growth, the carcass fatness and dressing percentage were studied in grazing Dorset x (Border Leicester x Merino) lambs. Entire male (ram and cryptorchid) lambs grew significantly (P<0.001) faster from marking to slaughter than did either wethers or ewes. They were also leaner than wethers, which were in turn leaner than ewes (mean � s.e. GR tissue depth: 11.4 � 0.16, 13.9 � 0.22 and 16.3 � 0.23 mm, respectively, at a carcass weight of 19.7 kg). Across all sex groups, the GR measurement increased 1.2 � 0.03 mm per kg increase in carcass weight. An earlier weaning (at 13-15 weeks of age) reduced (P<0.001) liveweight gains. There was also a small reduction (P<0.05) in the GR measurement associated with the earlier weaning, particularly in ewe and wether lambs. The dressing percentage of wethers increased with increasing liveweight over the entire range of weights. However, in ewes and entire males, there was little change in dressing percentage with increasing liveweight above 40 kg. An earlier weaning was associated with a small reduction in dressing percentage.
Distribution of field birth-sites of lambing ewes
Authors: Alexander G , Stevens D , Bradley LR
Published: March 2005

This paper reports on birth-site distribution of Merinos and some British breeds in 34 lambing paddocks in a major study over 5 lambing seasons at Armidale New South Wales, and in minor studies during single lambing seasons, 2 in New South Wales and 3 in the United Kingdom. The observed distribution of birth-sites is related to topographic and other environmental features of the paddocks. In level, or nearly level paddocks, Merinos tended to lamb in a random pattern, but in sloping paddocks their birth-sites were consistently aggregated in the areas of greatest elevation. British breeds (Suffolks and Cheviots in New South Wales, and Welsh Mountain, Scottish Blackface, North Country Cheviots and Greyface in the United Kingdom) showed a pronounced tendency to lamb near the margins of paddocks, and a less marked preference for an elevated site. It is suggested that lamb mortality could be significantly reduced by the use of paddocks that provide shelter at preferred elevated positions, or along and within the paddock margins.
Grazing management studies with Australian cashmere goats. 4. Cobalt supplementation and intestinal parasite burdens in sheep and goats in south-eastern Queensland
Authors: Norton BW , Cavaye JM , Hales JW
Published: March 2005

A flock of 32 weaner wether sheep (Border Leicester x Merino) and 32 weaner male goats (Australian cashmere) were grazed (37 animals/ha) on a common pasture of N-fertilised pangola grass from early March until June. One half of each group (16 animals) was supplemented with cobalt, and one half of each of these groups (8 animals) was dosed with approximately 500 infective helminth larvae at 2-week intervals throughout the trial. The final treatment was a drenching regime for one half (4 animals) of each of the above groups, levamisole (Nilverm) at 0, 2, 4 and 7 weeks and rafoxanide (Ranide) at 2-week intervals thereafter. There was no significant effect (P>0.05) of either cobalt supplementation or dosing with larvae on liveweight change, parasite egg concentrations in faeces or daily parasite egg excretion. Sheep gained significantly (P<0.05) more weight (50 g/day) than goats (31 g/day) in the first 7 weeks, and sheep also responded significantly (P<0.05) to drenching in this period whilst goats did not. In the second 8 week period, goats and sheep lost weight at a similar rate (-11 g/day), and both sheep and goats responded significantly (P<0.05) to drenching. The drenching program significantly (P<0.05) decreased faecal egg counts in sheep but not in goats. Undrenched sheep generally had higher concentrations of eggs in faeces than did undrenched goats, and with the exception of 1 sampling period, sheep also excreted significantly (P<0.05) more faecal eggs daily than goats. Undrenched sheep had significantly (P<0.05) lower haemoglobin concentrations in blood (82 gL) than drenched sheep (97 g/L). Undrenched goats also had lower blood haemoglobin concentrations (88 g/L) than did drenched goats (92 g/L). Cobalt supplementation did not exacerbate intestinal parasite burdens in either sheep or goats, and whilst goats did not appear to be more susceptible to intestinal parasites than sheep, the drenching strategies used for sheep were not effective in these goats.
Rooting depth of wheat in the Victorian Mallee
Authors: Incerti M , O'Leary GJ
Published: March 2005

In 1986 and 1987 wheat was sown in an experiment at the Mallee Research Station, Walpeup, at 2 times of sowing and with 3 rates of applied nitrogen. Soil cores were taken and trenches excavated to 1.5 m to measure wheat root growth and depth of rooting. Wheat roots penetrated to a maximum depth of 104 cm in crops sown in May, the optimum time of sowing for maximum yield, while delayed sowing reduced total root biomass and limited rooting depth to 73-83 cm. The application of nitrogen fertiliser did not affect either the rooting depth or growth and yield. Significant changes in total soil water content between sowing and harvest only occurred in 1987 with the early and late sown crops reducing the total soil water content by 47 and 99 mm respectively. In 1986, above average rainfall during the growing season caused the early sown crop to accumulate more water below 50 cm than the late sown crop. While total water use was increased only in 1986 with early sowing, crop water use efficiency and yield was greater in both years. The addition of nitrogen had no effect on crop water use or water use efficiency. A survey of wheat crops carried out in 1988 on 10 Mallee farms also found that shallow rooting is widespead. The field experiment and survey data show that, irrespective of sowing time, roots did not penetrate as far down the profile as might be expected, given reported rooting depths commonly in excess of 200 cm on similarly textured soils. This was shown to be associated with high soil pH and salt content. Poor rooting depth of wheat in this environment will restrict the use of stored water and accordingly, calls the practice of fallowing into question.
Response of seedlings of soybean, sunflower and sorghum to added mineral nutrients
Authors: Wood IM
Published: March 2005

The capacity of seed of soybean, sunflower and sorghum to sustain early growth was studied by growing seedlings from germination to day 15 at 25�C in growth cabinets in either aerated nutrient solution, aerated deionised water or rolled cotton towelling wetted with deionised water. Growth was markedly better in the nutrient solution and significant differences in growth and in content of nitrogen, phosphorus and potassium were observed 7-11 days after imbibition. By day 15 the dry weights of soybean, sunflower and sorghum seedlings grown in rolled towelling were only 38, 20 and 36%, respectively, of those grown in nutrient solution. Growth in deionised water was very poor and most seedlings were beginning to die by day 15. This was associated with a leakage of potassium from the seedlings to the growing medium, an effect consistent with impaired membrane permeability due to calcium deficiency. The marked effect of added mineral nutrients on the early growth of seedlings indicates that vigour tests which seek to measure the growth potential of a seed batch should be conducted under conditions providing adequate nutrition rather than in inert media. The growth of seedlings in aerated nutrient solution at optimum temperature for about 15 days can be taken as quantitative measures of potential growth and seed vigour. A comparison of growth of seedlings in aerated nutrient solution and an inert medium can be taken as a measure of the nutrient status of a seed lot.
Assessment of the nitrogen status of onions (Allium cepa L.) cv. Cream Gold by plant analysis
Authors: Maier NA , Dahlenburg AP , Twigden TK
Published: March 2005

Three field experiments were carried out during 1987-88 (1 site) and 1988-89 (2 sites) with Cream Gold onions grown on siliceous sands, to investigate the effect of nitrogen (N), at rates up to 475 kg N/ha on total-N, nitrate-N, potassium (K) and phosphorus (P) concentrations in youngest fully expanded blades (YFEB), bulked blades, necks and developing bulbs. The plant samples were collected when the largest bulbs were 25-30 mm in diameter. Nitrate-N concentrations were in the order WEB> bulked blades>necks = developing bulbs. For total-N the order was YFEB = bulked blades>necks> developing bulbs. Nitrate-N was more sensitive to variations in N supply than total-N in all tissues sampled. Potassium concentrations were in the order bulked blades > YFEB > necks > bulbs. At N rates <75 kg N/ha, P concentrations were in the order YFEB = bulked blades > bulbs > necks. Coefficients of determination (r2) for the relationships between nitrate-N and total-N concentrations and relative marketable yield of bulbs were in the range 0.73-0.98. At sites 1 and 3, the relationships between total-N and relative marketable yield were 'C-shaped' or showed the Piper-Steenbjerg effect. Critical concentrations (values at 90% relative marketable yield) for nitrate-N varied between plant parts (375-590 mg/kg) and sites (590-940 mg/kg for YFEB). Critical total-N concentrations also varied between the different plant parts (1.2-2.9%) but less so between sites (2.4-2.9% for YFEB) compared with nitrate-N. Based on sensitivity (as indicated by the range in tissue concentrations in response to variations in N supply) and on the correlations between nitrate-N and total-N concentrations and per cent relative marketable yield, we concluded that nitrate-N and total-N concentrations in YFEB were suitable indicators of the N status of onion plants. The YFEB is easily identified, and compared with bulked blades, necks or bulbs, samples of 50-100 can be collected without destroying plants and will also not result in excessive plant material to dry. Based on the variation in critical values between sites (reproducibility), total-N is preferred to nitrate-N. Correlations between nitrate-N and total-N concentrations in YFEB and bulb quality attributes (scale thickness, glucose concentration, fructose concentration, soluble solids and dry matter) were poor (72 values 10.48) and of little predictive value.
Prediction of conception rate in extensive beef herds in north-western Australia. 1. Seasonal mating and improved management
Authors: O'Rourke PK , Doogan VJ , McCosker TH , Eggington AR
Published: March 2005

Statistical models for conception rate were developed using data collected at a mid dry season (August-September) muster from a controlled-mated and supplemented herd of 900 Brahman cross cows at Mt Bundey from 1980-84. Average conception rates were 74% for maidens, 25% for first-lactation cows, 51 % for 4-10-year-old lactating cows, 54% for >10-year-old lactating cows and 96% for non-lactating cows. Although year effects dominated, they were partially explained by severity of the dry season and were consistent across levels of the other factors. Pregnant maiden heifers weighed 13 kg more than non-pregnant ones at the end of mating, after allowing for the weight of the fetus and gravid uterus. Conception rate of first-lactation cows was not affected by month of calving, adjusted mid dry season weight or condition score, possibly because of narrow ranges in these factors based on selection. For mature lactating cows the main effects on conception rate were month of calving (+11% for September to -16% for December or later), previous lactation (+6% for having reared a calf), adjusted mid dry season weight (-16% for <300 kg to +9% for >350 kg) and condition score (-17% for backward and store to +16% for good condition). Corresponding effects for aged lactating cows were +14% for September to -19% for December or later calving, +8% for previously rearing a calf, and -24% for backward store and store to +23% for good condition cows. The high conception rates for non-lactating cows corresponded with high liveweights and condition scores. A low cost, practical implementation of these models is based on previous lactation status and condition score in the mid dry season, with pregnancy diagnosis added at the next stage. Reproductive classes could be segregated on this basis for improved management and nutrition and to gain an economic return on capital invested in cattle control.
Effects of breed, season of lambing and fecundity level on production per ewe and per hectare
Authors: Obst JM , Thompson KF , Cayley JWD , Thompson RL , Saul GR , Brockhus MA , Cummins LJ , Wilson JM , Butler KL
Published: March 2005

Production per ewe and output per hectare were measured from the ewes of self-replacing, wool sheep flocks, stocked at 500 kg liveweight/ha on mixed annual-perennial pasture species in a temperate zone with 700 mm annual winter rainfall, near Hamilton in Victoria. Ewes of 2 breeds, a small body-sized, fine wool (20 pm) Merino and a larger body-sized, medium wool (23 pm) comeback, were compared at 2 lambing seasons (May or August) and at 2 levels of fecundity (natural or enhanced) from 1982 to 1985. Supplements were fed to prevent nutritional stress. Comeback ewes were about 10% heavier (P<0.01), produced 0.8 kg more (P<0.001) wool and reared more (P<0.01) lambs (0.93 v. 0.77) than Merinos, however, output per hectare was similar for both breeds. Ewes lambing in August required less (P<0.05) feed supplement than those lambing in May to produce similar wool and lamb output per hectare. Treatments to induce extra ovulations increased lambing rate in both ewe breeds. The mean change was from 1.06 to 1.23 lambs/ewe (P<0.01), but due to the high mortality of twins, lamb weaning rate and weight per hectare were not increased. When combined with the results from other studies, we conclude that the mean flock wool weight/ha is closely correlated to the mean ewe mating liveweight/ha across a range of wool sheep which differ in size and wool production because of either genotype or environment.
Sward growth of monocultures and binary mixtures of phalaris, lucerne, white clover and subterranean clover under two defoliation regimes
Authors: Hill MJ
Published: March 2005

Sirosa phalaris, WL5 15 lucerne, Haifa white clover and Seaton Park subterranean clover were grown in monocultures and binary mixtures on a cracking clay soil and cut at 4- and 8-week intervals over 3 growing seasons at Scone, New South Wales (32�S.). The plots were given supplementary irrigation between mid April and November to prevent water deficits. The deep-rooted perennials dominated mixtures under infrequent cutting, with cumulative dry matter yields for the growing season reaching 11 t/ha for lucerne-based mixtures. Frequent defoliation increased the contribution of the clovers in mixtures, and mixtures and monocultures containing clovers were more productive than other plots in winter, 1986. Frequent defoliation reduced the vigour and density of lucerne, resulting in balanced mixtures with phalaris and subterranean clover in the third year. Only lucerne plots contributed large amounts of dry matter yield (up to 4 t/ha) between December and April. Regeneration of subterranean clover from seedlings, and white clover from seedlings or stolons, was better in clover-only plots than in mixtures with phalaris. The growth of mixtures in response to mean daily air temperature in spring could be divided into 2 distinct patterns, with growth peaking at about 15�C for determinate (annual or dormant) mixtures, and at about 18�C for lucerne mixtures and pure white clover. In autumn, growth patterns were determined by the method of regeneration (i.e. by seedings or dormant crowns).
Effect of Kabatiella caulivora isolates and host growth stage on symptom expression and resistance in Trifolium subterraneum
Authors: Barbetti MJ , Gillespie DJ , Collins WJ
Published: March 2005

Occasional severe clover scorch disease outbreaks from Kabatiella caulivora have occurred in the 2 partially resistant Trifolium subterraneum cultivars, Karridale and Meteora. All K. caulivora isolates screened, including isolates taken from severely damaged field swards of Karridale and Meteora, were highly pathogenic, but there was variation in the pathogenicity of some isolates and there was a significant cultivar x isolate interaction in 1 of 2 studies. Plant age affected development of disease. Cultivars Karridale, Mt Barker and Woogenellup were least susceptible when inoculated 10 weeks from sowing, and there was a strong plant age x cultivar interaction. However, there was no suggestion that severe disease in Karridale was due to increased susceptibility at a particular plant growth stage. In resistance screening studies, the resistance rankings of subterranean clover varieties sometimes changed markedly depending upon the test isolate, and in 1 of 2 studies, there was a significant cultivar x isolate interaction. While there was significant overall correlation between glasshouse and field data, this only accounted for 49.9 and 20.5%, respectively, of the variation. Glasshouse screening was not suitable for replacing field screening but it was useful for confirming the field resistance of some highly resistant genotypes.
Using omethoate insecticide and legume inoculant on seed
Authors: Evans J , Seidel J , O'Connor GE , Watt J , Sutherland M
Published: March 2005

Omethoate, an organophosphorus insecticide used for early control of redlegged earth mite on legume seed, was toxic to some Rhizobium strains on direct contact when diffused through agar seeded with these bacteria or mixed in broth cultures containing the bacteria. Omethoate mixed with peat-based legume inoculant and applied to seed of subterranean clover or lucerne significantly (P<0.05) reduced the number of nodules formed over 3 weeks on seedlings grown in pots of sand, compared with inoculated controls. Most nodules were immature and located on lateral roots, and plant dry matter at 4 weeks was significantly (P<0.05) less for lucerne. Significantly (P<0.05) fewer rhizobia were recovered from seeds and seedlings of lucerne when seed was treated with omethoate. When subterranean clover seed was pretreated with omethoate 16 h before inoculation and sown into moist sand, there were no significant differences in the mean numbers of rhizobia, mean numbers of nodules or dry matter compared with inoculated controls. With lucerne, the number of nodules formed following omethoate pretreatment was significantly less than on inoculated controls at day 21 but not at day 30, and the dry matter at day 30 was not adversely affected. Rhizobia numbers were reduced less than by mixing omethoate and inoculant, so more taproot nodulation occurred and more of the nodules were functional (i.e. N2-fixing) at 3 weeks. In a field trial with pea, white clover and murex medic, seed pretreatment with omethoate before inoculation had no effect on nodule number 9-11 weeks after sowing, compared with inoculated controls.
Effect of split nitrogen applications on the yield and protein content of dryland wheat in northern New South Wales
Authors: Doyle AD , Shapland RA
Published: March 2005

Experiments were conducted with dryland wheat on a nitrogen (N) deficient site near Gunnedah, northern New South Wales, in 1987 and 1988 to compare post-sowing foliar applications of N with urea drilled between the rows at sowing. Post-sowing N was applied at tillering, booting or at both stages at rates of 20 or 40 kg N/ha while presowing applications ranged from 0-106 kg N/ha. Above ground dry weight and N uptake increased with increasing N application at sowing. Post-sowing N application increased dry weight and N uptake, with generally greater increases in N uptake than in dry weight. Dry weight and N uptake for post-sowing N application were invariably less than when an equivalent amount of N had been applied at sowing. Grain yield was increased by the application of up to 106 kg N/ha at sowing in 1987 and up to 80 kg N/ha in 1988 when a greater degree of moisture stress during grain filling restricted yield responses. Post-sowing N increased grain yield, but the yield response was lower than for the application of an equivalent amount of N at sowing. Grain yield responses were lower when N was applied at booting rather than tillering. Yield responses over the 2 years were 0.35-0.39 t/ha and 0.44-0.68 t/ha for 20 and 40 kg N/ha, respectively, applied at tillering and 0.26-0.4 t/ha and 0.26-0.48 t/ha for N application at booting. Post-sowing N application increased grain protein, with greater increases for booting than for tillering applications. There was an apparent recovery in the grain of 48-56% of N applied at sowing, but only 25-48% of N applied post-sowing.
Marginal responses over six years by sorghum and sunflower to broadcast and banded phosphorus on a low P Vertisol, and changes in extractable soil phosphorus
Authors: Hibberd DE , Want PS , Hunter MN , Standley J , Moody PW , Blight GW
Published: March 2005

At Emerald in central Queensland, dryland sorghum and sunflower were grown on a cracking clay soil (Vertisol) for 4 years and sorghum was grown in the sixth year, after an 18-month fallow. The initial bicarbonate-extractable soil phosphorus (P) concentration was 6 mg/kg in the 0-20 cm horizon. High analysis superphosphate (19.2% P) was broadcast at 0-180 kg P/ha in the first year, and banded rates of 0-20 kg P/ha were superimposed on the broadcast rates of 0-60 kg P/ha each year except in the fifth (fallow) year. Sorghum dry matter (DM) yields at anthesis, summed over 5 seasons, increased linearly (P<0.05) with both methods of P application, but significant (P<0.05) treatment differences occurred only after the 18 months of fallow. Total sorghum grain yields after 5 seasons fitted a quadratic reponse curve (P<0.05) with both application methods. Sunflower DM yields at anthesis increased significantly (P<0.05) with broadcast fertiliser in the first season only, but neither the rate nor the method of application of fertiliser affected seed yields over 4 seasons. Seed P concentrations for both crops were either unaffected or increased with increasing rates of fertiliser. Fertiliser P may not be needed for sunflower, but we recommend banding about 70 kg P/ha with sorghum at sowing over 5 years to ensure maximum yields. Based on extractable P values, the relative effectiveness of initial broadcast and incorporated P applications exceeding 40 kg/ha declined over the first 4 years, but then tended to remain steady at about 0.67. There was no consistent trend in relative effectiveness with time at the lower rates of P application.
Critical phosphorus concentrations in oilseed rape (Brassica napus) and Indian mustard (Brassica juncea) as affected by nitrogen and plant age
Authors: Pinkerton A
Published: March 2005

Oilseed rape and Indian mustard were grown in sand culture experiments in a glasshouse to derive values for a tissue test for the diagnosis of phosphorus (P) deficiency. Seven rates of P, combined factorially with 3 rates of nitrogen (N), were used to determine critical P concentrations. Suitable tissues to sample for a diagnostic test were the whole shoot of both species at any stage, or the youngest fully expanded leaf of rape and leaves 4-6 of mustard at the rosette stage. Critical P concentrations depended on both plant age and N supply. The critical values reported here for rape agreed closely with critical values found previously in tissues of field-grown crops of similar phenological age. Critical P levels in whole rape shoots adequately supplied with N decreased from 0.29% at the early rosette stage to 0.21% at the late rosette or yellow bud stage, while critical values in mustard fell from 0.25% at the early rosette stage to 0.18% at stem elongation to full flower. Critical P concentrations for prediction of seed yield were slightly higher (0.05% higher at the rosette stage). A nutrient supply with high P and high N reduced the seed oil concentration of both species; a low P and high N supply reduced the oil concentration in rape seed but increased it in mustard seed.
An evaluation of copper-containing soluble glass pellets, copper oxide particles and injectable copper as supplements for cattle and sheep
Authors: McFarlane JD , Judson GJ , Turnbull RK , Kempe BR
Published: March 2005

The efficacy of 3 copper (Cu) supplements in maintaining adequate Cu status in Shorthorn heifers and Merino wethers was investigated in 3 experiments on alkaline peat soils in the South East of South Australia. The Cu supplements used were: soluble glass pellets containing Cu; copper oxide particles (CuO); Cu as a subcutaneous injection. Pasture contained moderate to high concentrations of molybdenum (Mo) (2.9-12.3 mg/kg), moderate Cu (3.8-8.7 mg/kg) and adequate sulfur (>1.7 g/kg) to limit the absorption of dietary Cu in ruminants. Shorthom heifers with normal Cu status were given 1 of 6 treatments (no Cu; 2 glass pellets; CuO at 3 doses; Cu injection) and introduced to the pasture (experiment 1). There was no liveweight response to any supplement. Relative to untreated heifers, mean liver Cu concentrations were raised only in heifers receiving the glass pellets or the highest dosage of CuO (20 g). The glass pellets maintained an adequate mean liver Cu concentration for at least 44 weeks but the CuO was effective for less than 24 weeks. Hypocupraemic heifers given 1 of 3 treatments (2 glass pellets; CuO; Cu injection) were significantly heavier (P<0.05) than the untreated heifers after 30 weeks (experiment 2). Mean plasma Cu concentrations were adequate at 30 weeks in the glass pellet and CuO groups, but mean liver concentrations indicated severe deficiency in all groups at 30 weeks. There was considerable individual variability in response to the glass pellet and CuO particle treatments, possibly due to the partial regurgitation of some of these orally dosed supplements. Merino wethers with adequate plasma and liver Cu concentrations received 1 of 5 treatments (no Cu; 1 glass pellet; 2 glass pellets; CuO; Cu injection) and were then grazed on a peat soil for a period of 1 year. Plasma Cu concentrations in the control group only indicated hypocupraemia at week 42. Liver Cu concentrations were higher (P<0.001) in all supplemented groups from week 18 to after week 30. Under the conditions of the experiments, 20 g CuO (the suggested dose) for the glass pellets or a single Cu injection were not sufficient to maintain the Cu status of heifers for 1 year. Repeat treatments or higher dose rates were required. The recommended dose rates of the supplements were adequate for wethers.
Effects of pasture improvement with superphosphate on soil pH, nitrogen and carbon in a summer rainfall environment
Authors: Crocker GJ , Holford ICR
Published: March 2005

The effects of pasture improvement on soil pH, total nitrogen, organic carbon and extractable phosphorus (P) were determined by analysing adjacent soils from improved and unimproved pastures at 67 sites on the Northern Tablelands of New South Wales. Pasture improved sites contained at least 1 clover species, predominantly white clover, and had received at least 125 kg P/ha over periods of 15-45 years. The majority of pasture improved sites contained more soil nitrogen, carbon and phosphorus and were of lower soil pH than adjacent unimproved sites. However, the decreases in pH were not statistically significant and not usually related to the magnitude of the increases in other soil fertility parameters nor to the amounts of superphosphate applied or duration of fertiliser history. The largest decline in soil pH and largest increase in organic carbon were on granitic soils which had received more than 250 kg P/ha. The relatively small decreases in soil pH and lack of relationship with fertiliser history, compared with soils from southern New South Wales, were attributed to: (i) re-cycling of legume-fixed nitrogen by summer-growing grasses; (ii) the naturally lower pH, higher nitrogen content and higher buffering capacity of many northern soils. Soil acidification therefore seems to be much slower and less frequent in the perennial pasture systems of the Northern Tablelands of New South Wales.
Mineral nitrogen dynamics in a fallow grey clay
Authors: Rochester IJ , Constable GA , MacLeod DA
Published: March 2005

An annual cyclic pattern of nitrate accumulation and dissipation was identified in a fallow grey clay. The pattern was regular during the 3 years studied, with maximum values of nitrate nitrogen (N) (to 34 mg nitrate-N/kg) occurring in late autumn (May) and minimal values (to 7 mg nitrate-N/kg) in late winter (August). Ammonium levels were low throughout the 3 years, except for a short period following the incorporation of crop residues. The cycle of soil nitrate lagged behind the annual temperature cycle by about 3 months. Multiple regression using temperature and soil water deficit explained 68% of the variation in nitrate-N. The identification of this pattern of soil nitrate may now enable the prediction of September soil nitrate (currently used to estimate N fertiliser requirement for the forthcoming crop) from soil sampled up to 3 months earlier. Laboratory incubation studies confirmed temperature and soil water as highly significant in determining the soil's mineral N status. By applying the temperature and soil water deficits which prevailed during the field observations to the regression equation derived from the laboratory data, a similar fluctuating pattern of soil nitrate emerged. Incubation of intact field cores under low temperatures produced a net N immobilisation and high temperatures produced a net N mineralisation. Immobilisation and remineralisation of N by the soil biomass (rather than leaching or denitrification) were responsible for the oscillations in nitrate-N, and these processes were largely driven by temperature and soil water status.
Effect of copper application on take-all severity and grain yield of wheat in field experiments near Esperance, Western Australia
Authors: Brennan RF
Published: March 2005

The effect of copper (Cu) fertiliser on the incidence and severity of take-all of wheat was examined in 5 field experiments on soils naturally infested with Gaeumannomyces graminis var. tritici.Wheat (Triticum aestivum L.) was grown in soils at 5 levels of Cu fertiliser, ranging from nil to luxury levels of Cu (i.e. 5.0 kg Cuba) for wheat growth and grain yield. One soil was adequately supplied in Cu for wheat growth and yield. Copper-deficient wheat plants were more susceptible (P<0.05) to take-all than those plants with an adequate supply of Cu. The addition of Cu fertiliser beyond that required for maximum plant growth and grain yield had no effect (P<0.05) on the incidence and severity of take-all of wheat.
Effect of nitrogen and residual copper on the occurrence of Rhizoctonia bare patch in wheat grown near Esperance, Western Australia
Authors: Brennan RF
Published: March 2005

The area of rhizoctonia bare patch and the incidence and severity of rhizoctonia root rot (caused by Rhizoctonia solani Khnn) were reduced by the application of ammonium nitrate fertiliser. Residual copper (Cu) from a Cu fertiliser treatment in 1967 had no effect on the area of rhizoctonia bare patch or the incidence and severity of root rot. With no applied nitrogen (N), 17.6% (mean of residual Cu levels) of the plot was affected by patches while the area of plot affected by patches declined to 4.2% where 92 kg N/ha had been applied. The incidence and severity of rhizoctonia root rot declined from 45.9 and 27.0% to 32.7 and 9.1%, respectively, with the application of N fertiliser. The grain yield of wheat supplied with adequate Cu increased although the level of N fertiliser exceeded that considered adequate for plant nutrition. The response is explained by the control of rhizoctonia bare patch. The area of rhizoctonia patches and the incidence and severity of rhizoctonia root rot decreased with the application of N, and with adequate Cu fertiliser (2.2 kg Cu/ha), the grain yields increased. However, with marginal and deficient levels of applied Cu fertiliser, the application of N fertiliser induced Cu deficiency in wheat plants, and the grain yields declined although rhizoctonia patches were reduced.
Effect of nitrogen, phosphorus and potassium fertiliser rates on fruit yield, leaf mineral concentration and growth of young orange trees in the Sunraysia district
Authors: Sarooshi R , Weir RG , Coote BG
Published: March 2005

Fruit yield, leaf nutrient concentrations and growth response of young Valencia orange trees to 4 rates of nitrogen (N, 75-450 kg/ha), phosphorus (P, 0-180 kg/ha) and potassium (K, 0-360 kg/ha) were studied using 2 soil management systems (sod-sown and bare ground) and 2 rootstocks (Troyer Citrange and Sweet Orange). Eight-year-old Sweet Orange produced maximum yield at the higher rates of applied N and P and medium level of K, but at 12 years of age, highest yields occurred at the lowest rate of applied N, medium P and nil K. High N without P at year 12 strongly depressed yield especially on bare soil. Phosphorus application at high rates of N greatly increased yield but had no effect at lower rates of N. The effect of nutrients on yield was smaller on Troyer than on Sweet Orange rootstock. Leaf N concentration increased with amount of N applied and slightly increased with K applications but not with applied P. Leaf P concentrations increased with higher rates of applied P, especially in year 12 and at the lowest rate of applied N. Both rootstock and management affected leaf P concentration. Leaf K increased with amount of applied K. Highest concentrations of leaf K were from Troyer trees under bare soil management but this trend declined with time. The effects of fertilisers on tree size were small and varied with rootstock and management.
Influence of monensin on some metabolic responses of cattle fed a restricted intake of lucerne hay during heat exposure
Authors: O'Kelly JC
Published: March 2005

The effects of monensin supplement (33 mg/kg feed) on ruminal fermentation and body metabolism were studied in Brahman steers fed 5 kg lucerne hay daily at thermoneutral temperature (24�C) and after heat exposure [I day at 31�C (acute) or 5 days at 37�C (chronic)]. At 24�C, monensin lowered the concentrations of ammonia and protozoa in ruminal fluid and increased the plasma concentration of cholesterol but did not affect the circulating levels of urea, glucose, insulin, thyroxine (T4), triiodothyronine (T3), free T4 and free T3. Acute heat exposure lowered the plasma concentrations of thyroid hormones. Chronic heat exposure increased body temperature, the rate of dry matter digestion in the rumen and urinary nitrogen and allantoin excretion and lowered the plasma concentrations of cholesterol and differentially lowered the concentrations of the thyroid hormones. An increase in the concentration of ammonia in ruminal fluid was the only response to monensin at elevated body temperature that was uncharacteristic of its effects at normal body temperature. The results indicate that a monensin treatment of 33 mg/kg feed does not have any adverse effects on steers suffering metabolic derangement during hyperthermia.
Effects of sex and year on growth and live assessment of carcass characteristics of lambs grazing annual pastures
Authors: Thatcher LP , Warren B , Nicholls PJ
Published: March 2005

Lambs from the Poll Dorset x (Border Leicester x Merino) cross were raised from a late lambing in 1983 (a year when pastures grew unchecked and had high clover content) and 1984 (a year with intermittent dry periods and a low clover content in pastures). Multivariate repeated measures analyses were used to compare growth rates for rams, wethers and ewes within 2 periods of growth in 1983, and 4 in 1984. In all stages rams grew significantly faster than wethers and ewes, whereas wether growth rate exceeded that of ewes in only 3 stages. In general, when pasture availability and quality was high, rams grew faster than wethers by 0.3 kg/week and ewes by 0.5 kg/week. The rams grew 0.16 kg/week faster when pasture availability was limiting for a period in winter but lost significant (P<0.01) body condition, whilst ewes maintained both weight and condition. When good quality feed was again available, rams gained more weight than wethers, as did wethers compared with ewes, while rams and wethers gained more condition than ewes. Carcass weight and fatness, measured either as indicators of fat (GR measurement or fat score) or as total subcutaneous fat, could be predicted from assessments made on live lambs. Full liveweight, sex and year explained 41% of variation in GR, 48% in fat score and 79% in subcutaneous fat. Condition score, sex and year explained 45% of variation in GR, 52% in fat score and 57% in subcutaneous fat. Full liveweight, condition score, sex and year explained 80% of the variation in subcutaneous fat, 47% in GR and 57% in fat score. An interaction of sex with full liveweight in predicting carcass weight and subcutaneous fat indicated that as carcass size increased, the sex of the lamb became an increasingly important consideration when assessing characteristics important in describing lamb carcasses. Dressing percentage decreased by 0.08/kg as liveweight increased. This result was consistent over the 2 years, with opportunities for error being assessed and eliminated in the second year. Notwithstanding that this was an unimportant loss in real terms, published information showed an increase in dressing percentage with liveweight.
Assessing differences in pasture mass with an automated rising plate meter and a direct harvesting technique
Authors: Gourley CJP , McGowan AA
Published: March 2005

The ability of a rising plate meter and a direct plot-harvesting technique to detect differences in herbage mass was assessed on 3 occasions in an experiment comparing 2 different phosphorus fertilisers.Values of variance ratios (F-values) indicated that labour expended the techniques were similar in their ability to detect significant differences in herbage mass. The rising plate meter had considerable advantages in capital cost and time efficiency, allowing for at least a 47% reduction in