bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of cultivar and season on the response of Trifolium subterraneum to simazine
Authors: Dear BS , Conlan DJ , Richards MF , Coombes NE
Published: March 2005

The tolerance of 6 cultivars of Trifolium subterraneum (subterranean clover) to simazine applied at 0.63 and 1.25 kg a.i./ha was determined under weedfree conditions in the field by measuring herbage and seed yields. Large herbage yield losses occurred as a result of the simazine in spring in the 2 years of the experiments. In 1989, spring herbage yield losses of the cultivars at the 0.63 and 1.25 kg/ha simazine rates averaged 56 and 82%, respectively. In 1990 the spring herbage yield losses were 27 and 51%. Significant variation in tolerance was observed between cultivars in both years, with Trikkala being the most tolerant and Karridale the most susceptible cultivar. Rate of herbicide had the greatest effect on herbage yield, with cultivar having a smaller effect. In 1989, with relatively favourable spring conditions, clover seed yields were depressed by simazine, but in 1990 when drier conditions prevailed during flowering and seed set, seed yields were unaffected or slightly increased by simazine in all cultivars except the early-flowering cultivar Dalkeith. Seed yields of simazine-treated swards were 196-1480 kg/ha in 1989 and 359-686 kg/ha in 1990. The seed yield response in 1990 suggests that herbicides which retard growth in winter help to conserve soil water and, therefore, may benefit seed filling later in the season. The presence of Lolium rigidum at spraying did not reduce the effect of the herbicide on clover herbage yield and had no effect on seed set. Although simazine may reduce herbage yields and, in some cases, seed yields, its use may be justified for the control of annual grasses when other factors such as disease control, pasture quality, and level of weed competition are considered.
Seasonal variation of pH, aluminium, and manganese in acid soils from north-eastern Victoria
Authors: Slattery WJ , Ronnfeldt GR
Published: March 2005

Seasonal variation in pH (measured in H2O or 0.01 mol CaCl2/L) and in Al and Mn extracted by 0.01 mol CaCl2/L are reported for north-eastern Victoria. Seasonal variation in pH(H2O) was significantly (P<0.05) greater than either the spatial variation or laboratory error. There was no significant (P<0.05) seasonal variation in pH(CaCl2). For pH (H2O), values were observed to increase after the autumn break, to peak at or near midwinter, and to decrease slowly over the spring and summer months to lowest values in late summer. Seasonal changes for pH(H2O) were significantly (P<0.05) related to the ionic strength of the 1 : 5 soil : water extract. Significant seasonal variations (P<0.05) occurred for extractable Al and Mn in a podsolised red earth and a red podsolic. Seasonal effects were a significant (P<0.05) source of variation for the methods used in this study and should, therefore, be considered in any comparative or predictive studies using these methods.
Nitrogen dynamics of oats, sorghum, black gram, green panic and lucerne on a clay soil in south-eastern Queensland
Authors: Catchpole VR
Published: March 2005

Changes in the distribution of nitrate-nitrogen (N) in a clay soil (Pellustert) under oats (Avena sativa cv. Minhafer), sorghum (Sorghum bicolor cv. E57), black gram (Vigna mungo cv. Regur), green panic (Panicum maximum cv. Petrie), and lucerne (Medicago sativa cv. Hunter River), and the uptake of N into plant shoots, were measured at Narayen on the brigalow (Acacia harpophylla) lands of south-eastem Queensland over each cropping season in 1975-85. Nitrate-N accumulated in the subsoil (30-150 cm) under sorghum and black gram, but not under oats. Green panic depleted nitrate-N after 2 years, and lucerne after 1 year. Losses of nitrate-N during 2 wet years reached 300 kg/ha under sorghum and black gram, and 57 kg/ha under oats, but were negligible under green panic and lucerne. Leaching to below 150 cm in the soil was the probable cause. The supply of soil N to oats, sorghum, and black gram was adequate during the 10 years, but the N yield of green panic decreased from 239 kg/ha to 150 kg/ha after 5 years. Accumulation of nitrate-N under sorghum and black gram could be utilised by rotating these crops with green panic or lucerne. This would also improve the productivity of green panic pastures. Rotating the summer crops with oats (winter crop) or with deeprooted crops (e.g. sunflowers) should also be tested. Alternatively, reduction of production of nitrate-N in the soil could be attempted. Zero or reduced tillage could do this, but it may also increase leaching by increasing the entry and movement of water in the soil.
Host range and physiologic specialisation of Macrophomina phaseolina isolated from field peas in South Australia
Authors: Ali SM , Dennis J
Published: March 2005

Macrophomina phaseolina is reported as a pathogen of field peas, causing leaf, stem, and petiole lesions characteristic of ascochyta infection. Alternative hosts were found to include Vigna mungo, Medicago littoralis, Medicago scutellata, and Lens culinaris. Twenty-one isolates of M. phaseolina were differentiated into 15 pathotypes. Adequate sources of resistance were identified against all pathotypes. Breeding for specific resistance to M. phaseolina in field peas is discussed.
Fresh brewer's yeast slurry as a supplementary nitrogen source for cattle given native pasture hay or grain-based diets
Authors: Hennessy DW , Williamson PJ
Published: March 2005

Two experiments evaluated brewer's yeast slurry [mean (� s.d.) dry matter (DM) 9.7 � 3.8% and nitrogen (N) content 45.6 � 19.5 gkg DM] as a source of dietary protein for steers on a low N hay diet (experiment 1) and as a low cost supply of protein in a feedlot diet (experiment 2). Experiment 1 was an attempt to improve the N supply to rumen microflora, and total protein to the intestine. There was no improvement in liveweight gain of steers, or in their feed conversion efficiency (FCE), when up to 4.4 kg of yeast slurry (i.e. 423 g DM) was added to the basal diet. Mean (� s.e.) liveweight gain of non-supplemented steers was 402 f 13 1 g/day, with a mean (� s.e.m.) FCE of 12.2 � 1.9 kg DM intake/kg liveweight gain. There was a significant (P<0.05) improvement in liveweight gain (714 g/day) and FCE (7.8 kg DM intake/kg liveweight gain) when cottonseed meal, included as a positive control treatment, was added to the hay diet; however, N intake was higher in this diet (97.7 g/day) than in those based on yeast slurry (range 43.6-62.3 g/day). Experiment 2 was designed to assess the suitability of yeast slurry for replacing cottonseed meal and lucerne chaff as a protein source in grain-based feedlot diets. Yeast slurry did not significantly increase liveweight gain of steers, but when 1 diet with 61% yeast slurry (percentage fed, range 0-71.4%) was excluded from the evaluation, increased dietary proportions of yeast were associated with increased liveweight gains (r = 0.99) and carcass yield (r = 0.89). The range in slurry DM contents (4.8-15.6%) required close monitoring, with daily changes made to the amounts of slurry offered to maintain dietary N and protein levels in the experiments. This range would make it difficult for commercial feed compounders to produce a diet of consistent quality.
Effects of abomasal supplements of methionine on wool growth of grazing sheep
Authors: Pickering FS , Reis PJ
Published: March 2005

Seven experiments are reported in which methionine supplements were given directly into the abomasum of Merino wethers grazing either improved or native pasture at Armidale, New South Wales. In 4 experiments where initial wool growth was 0.4-0.8 mg/cm2.day of clean dry wool, significant increases in wool growth (at 2.4 g methionine/day in 3 experiments and 0.6-4.8 g/day in the fourth) and fibre diameter were obtained when methionine was given once daily in capsules. In the fourth experiment the response to methionine was quadratic, with a maximum at 2.4 g/day. In the remaining 3 experiments, where initial wool growth was >1.1 mg/cm2.day, no significant response to methionine was obtained, whether it was given once daily or infused continuously.
Storage of inoculated and omethoate-treated medic seed reduces effectiveness of rhizobial inoculant
Authors: Evans J , Dobrowolski N , Wallace C
Published: March 2005

The effectiveness of medic inoculation with Rhizobium meliloti was significantly reduced when inoculant was applied to seed pretreated with the organophosphorous insecticide omethoate and stored for 5 days until seeding. Average nodule number and shoot weight per plant were reduced to 6 and 22% of a nil omethoate treatment. When medic seed that was not stored before sowing was seeded into moist soil, its pretreatment with omethoate had no significant effect on nodulation and increased plant weights.
Prediction of nitrogen fertiliser requirements of maize in subtropical Queensland
Authors: Dickson T , Aitken RL , Dwyer JC
Published: March 2005

Sixteen field experiments were conducted at 9 sites in the South Burnett region of subtropical Queensland, to determine grain yield response of maize to fertiliser nitrogen (N) and to assess soil mineral N levels at sowing for predicting N requirement. At 6 sites, areas were either winter-cropped or bare-allowed, resulting in different cropping histories immediately prior to summer maize. In each experiment, 4 rates of N (0, 38, 76, and 152 kg/ha) were applied, with an additional rate (304 kg/ha) at 3 sites that received supplementary irrigation. Immediately prior to sowing, soil samples for mineral N and moisture were taken from each 10-cm increment to a depth of 120 cm. Soil nitrate-N levels (0-120 cm) before sowing were 16-100 kg N/ha (winter-cropped) and 65-167 kg N/ha (bare-fallowed). Application of N significantly (P<.05) increased grain yield in 14 of the 16 experiments. Maximum grain yields in non-irrigated experiments ranged from 2.08 to 5.61 t/ha and reflected profile available water at sowing and rainfall during the growing season. Maximum yields in irrigated experiments ranged from 4.44 to 6.95 t/ha. The magnitude of the response was greater at winter-cropped sites (relative yields 33-89%) than at fallow sites (82-100%). Relative grain yield was well correlated with nitrate-N in the 0-60 cm profile ( R2 = 0.74). There was also a good relationship between relative grain yield and nitrate-N at 0-10 cm depth ( R2= 0.64).
Sampling for the potato moth (Phthorimaea operculella) and its parasitoids
Authors: Horne PA
Published: March 2005

Numbers of potato moth (Phthorimaea operculella) collected by weekly samples using3 methods (random and selected leaf samples, and pheromone traps) were compared. An efficient method of sampling for P. operculella and its hymenopterous parasitoids is described. Pheromone traps for P. operculella and selected leaf samples for the parasitoids were used. Random sampling of leaves did not always give adequate estimates of either P. operculella or parasitoids, as particular life stages were either overestimated or excluded from samples. Selected sampling to obtain hosts after larvae were exposed to parasitoids, but before adult emergence, was more effective.
Starch-iodine staining patterns in petals of cut roses
Authors: Shellabear MA , Joyce DC , Cake MH
Published: March 2005

The starch distribution pattern and decline in starch content of Sonia rose petals were examined by starch-iodine staining. Flowers were harvested and held in 150 mg/L of sodium dichloroisocyanurate (DICA) or 150 mg DICA/L + 2% (w/v) sucrose, or were left on the plant. Starch was degraded initially from the outer margins of petals, then from the interveinal area nearest the petal margins, and finally towards the petal bases. Starch was first lost from the outermost petal and then sequentially towards the innermost petals. The rate of starch degradation was slowest in flowers left on the plant, intermediate in flowers harvested and kept in DICA + sucrose, and most rapid in flowers harvested and held in DICA. Preharvest treatments applied in an attempt to vary starch deposition (i.e. shading, leaf removal, and leaf removal with girdling) did not alter the normal starch-iodine staining pattern, reduce starch concentrations, or reduce vase life. However, flower pigmentation was less intense, abnormal flower development occurred, and dry weight and starch contents were reduced, suggesting that carbohydrate supply to the developing bud was affected. Thus, starch-iodine staining of cleared petals of mature Sonia roses was not useful for identifying flowers that developed under conditions of restricted carbon supply. In petals of flowers that had been harvested and held in cool storage (0-3�C) for 7 days, starch was degraded evenly from all parts across the petal. This diffuse pattern of starch degradation was sufficiently distinctive that it may prove a useful test for determining whether flowers have been cool-stored.
Storage characteristics and quality of foru broccoki (Brassica oleracea var. italica) cultivars
Authors: Tan SC , Bandarage A , Haynes Y , Phillips D
Published: March 2005

The t r i a l was designed to study the effectiveness of folded, high density polyethylene bags and sealed, high density polyethylene bags for maintaining the freshness of broccoli in waxed cartons and extending shelf life for exports. Four broccoli cultivars (cvv. Green Belt, Marathon, Skiff, and Shogun) were stored at 1�C for 3 weeks in folded, high density polyethylene bags. After storage, they were still green, compact, and marketable. After exposure to 26�C for another 2 days, most of the heads turned yellow and were unmarketable. Colour score and market quality were poorer in cv. Skiff than in the other 3 cultivars. Storage of broccoli in sealed, high density polyethylene bags retarded the yellowing after exposure to 26�C for 2 days and, hence, improved the market quality.
An alternative method of nutrient supplementation in the cultivation of the common mushroom Agaricus bisporus
Authors: Nair NG , Cho KY , Mitchell F
Published: March 2005

Addition of cottonseed meal to the casing material, rather than to the compost, was examined as an alternative method of nutrient supplementation in the cultivation of the common mushroom Agaricus bisporus. Formaldehyde and calcium sulfate were used independently to prepare delayed release supplement. Casing supplementation significantly (Pv0.05) increased mushroom production (by 0.5-52% in the different trials) and required significantly less nutrient than compost supplementation. It did not result in the increased compost temperature from microbial thermogenesis that is associated with compost supplementation. A supplementation rate of 6 or 8% (on a fresh weight basis) could be recommended. Increases in mushroom yield from the use of formaldehyde and calcium sulfate were not significantly different but calcium sulfate treatment is quicker and less hazardous than formaldehyde treatment.
The performance of Brahman-Shorthorn and Sahiwal-Shorthorn beef cattle in the dry tropics of northern Queensland. 3. Birth weights and growth to weaning
Authors: Fordyce G , James TA , Holroyd RG , Beaman NJ , Mayer RJ , O'Rourke PK
Published: March 2005

The birth weights and weaning weights of Bos indicus cross calves from 4 inter se mated herd groups in a dry tropical environment were studied. The calving season commenced in late October, about 2 weeks before the start of the pasture-growing season. Second and subsequent generations of 1/2 Brahman and 1/2 Sahiwal crosses and first backcross, and later generations of 3/4 Brahman and 3/4 Sahiwal crosses, were represented. The Bos taurus component of the crosses was primarily Beef Shorthorn. In general, Brahman crosses were heavier at birth and grew faster to weaning than Sahiwal crosses (P<0.05), with consequent advantages in weaning weights of 11 and 6 kg in first backcross and late generation crosses, respectively. There was a birth weight advantage (P<0.05) of 1/2 crosses over 3/4 crosses, which was eroded by the time of weaning. Superior growth rates of 3/4 crosses were primarily expressed in years with greater nutritional stress and appeared to be due to better adaptation to environmental stresses by the calf. The only difference between filial generations was the growth rate advantage (P<0.05) of F2 1/2 crosses over F3 1/2 crosses, apparently due to suckling of F1 and F2 dams, respectively. Males exhibited an 8% average advantage (P<0.05) over females for all weight and growth traits in late generation calves. Calves with mature dams were 1.8 kg heavier (P<0.05) at birth. This, along with their higher (P<0.05) preweaning growth rate (19-49 g/day), resulted in calves with mature dams being 4-10 kg heavier (P<0.05) at weaning than calves of young cows. Differences between years in birth weights and preweaning growth rates were <25% (P<0.05). Birth weight was affected by nutrition of the dam in late pregnancy (early calves were generally about 1 kg lighter than late calves), and growth of calves was higher in years when the pasture growing season commenced earlier.
Factors affecting subcutaneous fat depth at two sites on beef carcasses
Authors: Hopkins DL , Brooks AA , Johnston AR
Published: March 2005

Over a 12-month period, fat depths at the P8 rump and 12-13th rib sites were measured on 10968 beef carcasses at 4 Tasmanian abattoirs. All cattle were assigned to 1 of 5 breed types: British beef, dairy, dairy-beef cross, beef cross, and European and European cross. Dairy-beef cross and European breeds were excluded from the analysis because of small numbers. Sex and age (dentition) were recorded. As the data set was unbalanced and no single relationship between P8 rump and 12-13th rib sites applied, models describing the relationship between fat depths at the 2 sites were developed for subsets of the data. These showed that breed type, sex, age, season, and carcass weight all affected the relationship between fat depths at the 2 sites. In general, British beef and beef cross cattle could be considered as 1 group, but dairy cattle were different. In the former group, for the no-teeth age class a seasonal and sex effect was evident, giving rise to 4 models, 1 for each of the steer and heifer groups in winter-spring and summer-autumn. For the no-teeth dairy cattle there was no sex effect and all seasons were pooled to form an overall model. For older cattle (2, 4, and 8 teeth) there was significant monthly variation, and few overall models could be developed. In addition, the relationship between fat depths at the 2 sites was generally independent of carcass weight in older cattle. The analysis revealed that within the subcutaneous fat depot the relationship between sites for fat depth can be influenced by a range of variables.
Comparison of the phosphate requirements of burr medic and yellow serradella with that of wheat in the low rainfall wheatbelt of Western Australia
Authors: Paynter BH , Bolland MDA
Published: March 2005

The responses of burr medic (Medicago polymorpha) and yellow serradella (Ornithopus compressus) to topdressed phosphate were compared with the response of wheat (Triticum aestivum) to drilled phosphate on a range of soils in the low rainfall wheatbelt of Western Australia. Species were compared firstly on the amount of applied phosphorus (P) required for 90% maximum yield at 3 harvests, and secondly on the ratio of their curvature coefficients from the Mitscherlich relationship between absolute yield and P applied. On 7 marginally acidic, medium-textured soils, the comparative requirements of burr medic (cvv. Serena or Santiago) and wheat (cv. Gutha) for applied P changed with harvest. At harvest 1 152-55 days after sowing (DAS)], burr medic generally had a larger curvature coefficient and required less applied P for 90% maximum yield than wheat. At harvest 2 (107-111 DAS) and for harvest 3 (seed yields), the curvature coefficients for burr medic were smaller than those for wheat, and burr medic generally required more applied P at 90% maximum yield. The average P requirement at 90% maximum yield of burr medic was 14 kg P/ha at harvest 1, 22 kg P/ha at harvest 2, and 19 kg P/ha for seed production. The average P requirement of wheat was 28 kg P/ha at harvest 1,11 kg P/ha at harvest 2, and 15 kg P/ha for seed production. On 3 acidic, light-textured soils, yellow serradella (cv. Madeira) generally had a lower requirement for applied P at 90% maximum yield, and a larger curvature coefficient, than wheat (cv. Gutha) at all harvests in each experiment. The requirements of yellow serradella and wheat also varied between harvests. The average P requirement at 90% maximum yield of yellow serradella was 16 kg P/ha at harvest 1 (52-55 DAS), 21 kg P/ha at harvest 2 (105-110 DAS), and close to 26 kg P/ha for seed production. The average P requirement of wheat was 29 kg P/ha at harvest 1,25 kg P/ha at harvest 2, and >33 kg P/ha for seed production. In most experiments burr medic had a larger absolute response to applied P at harvests 1 and 2 and a lower absolute response for seed production than wheat. Yellow serradella had a smaller absolute yield response to applied P than wheat over all 3 harvests. When converted to a percentage of maximum yield, burr medic and yellow serradella had a lower percentage response to applied P at harvest 1, and a higher percentage response at harvest 2 and for seed production than wheat.
Effect of crop rotation, tillage practice, and herbicides on the population dynamics of wild oats in wheat
Authors: Martin RJ , Felton WL
Published: March 2005

The effects of crop rotation, tillage practice, and herbicide use on the population dynamics of wild oats (Avena fatua and A. sterilis ssp. ludoviciana) were studied in a field experiment in northern New South Wales. In the third and fourth years of a continuous wheat rotation, cultivated fallow using tines increased wild oat density and reduced grain yield compared with a no-tillage fallow. Tillage did not affect the vertical distribution of wild oat seeds in the soil, and about 80% of wild oat seeds were in the top 5 cm of soil in both tillage treatments. The seed reservoir at the end of the experiment was smaller under a no-tillage fallow regime. The half-life of wild oat seeds in the soil was about 6 months, and rotation of wheat with sorghum was the most effective means of reducing the wild oat seed reservoir. Rotational strategies for weed control are also likely to be effective in delaying or minimising the development of herbicide resistance, particularly where the average seed bank life time, as shown for wild oats in this study, is short. Annual use of either tri-allate or flamprop-methyl in 4 successive wheat crops did not prevent a massive build-up of wild oat seed. The poor performance of herbicides was partly attributed to below-average rainfall in autumn and early winter in 1985 and 1986. However, wild oats are well adapted to continuous cropping with wheat, where recruitment of 34% of the soil seed reservoir maintained the population despite the use of selective herbicides. The results of this experiment indicate that a continuous wheat rotation using herbicides to control wild oats is likely to be much less effective in reducing the wild oat seed reservoir.
Influence of preseason weed management and in-crop treatments on two successive wheat crops. 2. Take-all severity and incidence of Rhizoctonia root rot
Authors: Wong PTW , Dowling PM , Tesoriero LA , Nicol HI
Published: March 2005

The effects of cultivation and herbicide use to control weeds in wheat on wheat growth, the severity of take-all, and the incidence of rhizoctonia root rot were studied for 2 seasons. Preseason treatments were no weed control, paraquat (0.20 kg a.i./ha), glyphosate (0.18 kg a.i./ha or 4 applications of 0.72 kg a.i./ha), and heavy grazing. In-crop treatments were cultivation plus trifluralin, direct drilling plus chlorsulfuron, and direct drilling alone. At the site, take-all was the main disease while rhizoctonia root rot was relatively minor. Glyphosate applied 4 times at 0.72 kg a.i./ha over the previous spring and summer led to greater wheat dry matter (DM) production, significantly (P<0.05) less severe take-all, and a lower incidence of rhizoctonia root rot in the first year than the other preseason treatments. Spraytopping with glyphosate (0.18 kg a.i./ha) or paraquat (0.20 kg a.i./ha) and heavy grazing reduced take-all severity but not the incidence of rhizoctonia root rot. Conventional cultivation resulted in more wheat DM, significantly less severe take-all, and a lower incidence of rhizoctonia root rot than direct drilling. Grain yields reflected the trends of the DM production despite severe yield loss due to head frosting. Plots were split for cultivation and direct drilling in the second year. The highest wheat DM and grain yields were in the cultivated treatments but the effects of cultivation on take-all did not carry over from the first year. In both years, take-all was most severe in the control treatment and least severe in the treatment with the high rate of glyphosate (P<0.05). In the second wheat crop, however, take-all severity was similar in the 2 glyphosate, paraquat, and grazed treatments. The effect of a weed-free fallow obtained by use of a high rate of glyphosate was nullified in the second wheat crop because of a high carryover of volunteer wheat seedlings during the intervening wet summer. There was also a greater incidence of rhizoctonia root rot in the control than in the other treatments, and cultivation again reduced disease incidence compared with direct drilling.
Use of reflectance measurements to estimate early cereal biomass production on sandplain soils
Authors: Elliott GA , Regan KL
Published: March 2005

High early biomass production has been suggested as a useful selection criterion for improving cereal yields in mediterranean environments. Current methods for measuring biomass production in cereal plots involves destructive sampling which is not suitable for routine use by plant breeders where large numbers of samples are to be screened. The measurement of spectral reflectance using ground-based remote sensing techniques has the potential to provide a nondestructive estimate of plant biomass production. This field study investigated the relationship between spectral reflectance and early biomass production in barley and wheat and assessed the feasibility of using spectral reflectance techniques in cereal-breeding programs. Spectral reflectance measurements (0.40-2.5 �m wavelengths) were made before stem elongation for barley and wheat grown in separate experiments at Wongan Hills, Western Australia. Cereal biomass was closely associated with spectral reflectance in the visible (0.44-0.66 �m) and mid infrared (1.50-1.80 �m and 2.00-2.40 �m) regions, but not in the near infrared (0.71-1.10 �m). The poor correlation between reflectance in the near infrared region and biomass production was due to the low amounts of biomass present and the high reflectivity of the sandplain soils at these wavelengths. The close associations in the visible and mid infrared regions provides promise for use in estimation of cereal biomass, but further research is required to refine the technique for use in large scale breeding programs.
Variation among sorghum hybrids in the plant density required to maximise grain yield over environments
Authors: Wade LJ , Douglas ACL , Bell KL
Published: March 2005

In circumstances of limited water supply, the stability of grain yield in sorghum may be improved by manipulating the interaction between plant spacing and crop maturity. The plant density which maximises grain yield over environments may also be influenced by differences in compensatory capacity among hybrids of the same maturity category. Consequently, variation among 8 sorghum hybrids in the response of grain yield to plant density was examined at 5 locations. When number was used as a covariate, the interaction between hybrid, density, and site was significant (P<0.05) for grain yield. Hybrids differed in the plant density which maximised grain yield, even among hybrids of similar maturity. For the medium maturity hybrids, Hylan 4x8 required a higher plant density than Goldmine to maximise its grain yield at each of the 5 sites, while for the quick hybrids, Pride required a higher density than Nugget II at 4 sites. Among the slow and very slow hybrids, the plant density which maximised grain yield did not differ consistently. Because discrimination among hybrids in the plant density required to maximise grain yield was much greater in low yielding environments, some advantage may be obtained by reducing the target plant density for hybrids of greater compensatory capacity, when drier than normal conditions are expected.
Population dynamics of plant parasitic nematodes in Queensland pineapple fields and the effects of these nematodes on pineapple production
Authors: Stirling GR , Nikulin A
Published: March 2005

Twelve pineapple fields with various densities of root-knot nematode were selected during a ratoon crop. Nematode populations were monitored regularly after the crop was ploughed out. Regardless of the original population density, rootknot nematodes were almost nondetectable at the end of the subsequent 3-6-month fallow intercycle period. In the absence of nematicide treatment there were marked differences between sites in the manner in which rootknot nematodes increased in the newly planted crop. At some sites, they were detectable 9-15 months after planting, whereas at other sites, nematodes were not observed at 15 months. Increases in ratoon crop yield following application of ethylene dibromide or fenamiphos were related to root-knot nematode population density. Significant increases in yield were not obtained at sites where the nematode was not detectable at 15 months. The results suggest that some pineapple growers are needlessly applying nematicides and that nematode diagnostic services should be developed to provide growers with advice on their nematode management programs.
Fertiliser nitrogen and potassium studies with Flora-Dade tomatoes grown with trickle irrigation and polyethylene mulch covered beds on krasnozem soils
Authors: Huett DO
Published: March 2005

Field experiments were conducted with Flora-Dade tomatoes on krasnozem soils during 1985-86 (site I), 1986-87 (site 2), and 1987-88 (site 3) to examine the effect of nitrogen (N, 5420 kg/ha) and of potassium (K, 1120 kg/ha) on fruit yield and quality and leaf nutrient composition. Nitrogen and K were applied either pre-planting to first fruit set, or at increasing weekly increments from 1 week after transplanting to mid fruit harvest. At each site, one rate of N and one of K were based on a commercial soil chemical analysis. The yield and quality of fruit at all sites was not affected (P>0.05) by N or K fertiliser rate or by method and timing of application. Marketable yield was 83-1 18 t/ha and fruit firmness (compression) was 0.97-1.27 mm. At site 3, which had the lowest exchangeable K concentration [0.3 cmol(+)/kg], the addition of 90 kg K/ha increased the yield of large fruit. At all sites, and with the nil-N treatment (site 3), the youngest fully opened leaf (YFOL) petiole sap nitrate-N concentrations exceeded critical values (Coltman 1987, 1988; Huett and Rose 1988) at all sampling times. YFOL concentrations were highest at 2-6 weeks after transplanting, then declined over the growth period. The highest concentration recorded at site 1 was 5.6 g/L, and at site 2, 3.2 g/L. These concentrations were not affected (P>0.05) by N fertiliser rate, indicating greater mineralisation of organic N at sites 1 and 2 than at site 3, where the highest petiole sap nitrate-N concentration was 1.8 g/L. The pre-plant soil nitrate concentrations (0-15 cm depth) at sites 1 and 3 were similar (14 and 16 mg/kg), and when measured 6 weeks after transplanting at site 3, the concentrations in the nil and 120 kg N/ha treatments were 31 and 66 mgkg, respectively. Neither pre-planting soil test (N or K) accurately predicted fertiliser response by tomatoes. The application of supra-optimal rates of N and K to semi-determinate fresh market tomatoes of Flora-Dade type will not be detrimental to yield, composition, and firmness of fruit. For a 70 t/ha crop, 130 kg N/ha and 208 kg K/ha are equivalent to removal by fruit.
Nitrogen accumulation and remobilisation in wheat of sup 15N-urea applied to a duplex soil at seeding
Authors: Palta JA , Fillery IR
Published: March 2005

Accumulation and remobilisation of 15N-labelled urea by wheat grown on a duplex soil at East Beverley, Western Australia, was investigated. 15N-urea was applied to microplots in a field experiment at 5.2 g N/m2 at seeding. The microplots were sampled at tillering, stem elongation, anthesis, and maturity. A maximum of 10.6 g N/m2 was accumulated by anthesis and no additional N was accumulated to maturity. Most N uptake occurred between tillering and stem elongation when plant N increased by 7 g/m2. Nitrogen loss of about 1.2 g/m2 occurred after anthesis. Post-anthesis remobilisation from the vegetative plant parts accounted for 69% of the N measured in the heads. Remobilisation from the straw of the mainstem and tiller 1, respectively, was 68 and 71% of the N measured in the heads. The balance of about 0.7 and 0.4 g N/m2for the mainstem and tiller 1 was presumably obtained from tiller 2 and 3, from which losses were 0.4 and 0.6 g N/m2, respectively. Recovery of 15N-labelled urea in the plant was 39% and the apparent efficiency of utilisation of the N fertiliser applied at seeding was 50%. These low recoveries in the plant indicate a need to improve N utilisation by wheat in duplex soils.
Persistence and water use efficiency of a tropical grass and lucerne on a solodic soil on the Far North-West Slopes of New South Wales
Authors: Tow PG
Published: March 2005

The persistence and water use efficiency of Digitaria eriantha spp. eriantha and Hunter river lucerne were compared on red solodic soil with a hardsetting surface and poor internal drainage, on the North- West Slopes of New South Wales. After prolonged watering, the profile was wet to a depth of 48 � 1.5 cm, with an available moisture store of 90 mm. Over 3 years, persistence of digitaria was excellent. The population of lucerne was reduced following flooding at summer temperatures, Dry matter production of nitrogen (N) fertilised digitaria per mm warm season rainfall was similar to that of tropical grasses adapted to comparable rainfall environments in subtropical Queensland. Lucerne dry matter per mm rainfall was only about half that of digitaria (3.2 v. 6.3 kg). Lucerne grew well in mixture with digitaria except under prolonged wet soil conditions in summer. Artificial solodic profiles were constructed in the glasshouse to compare digitaria and lucerne in monoculture and mixture under varying temperature, moisture, and N regimes. Lucerne showed sensitivity to both high and low moisture levels at summer temperatures but performed very well at spring temperatures and moderate moisture levels where the mean evapotranspiration ratio was 400 g water per g dry matter. Water use efficiency was higher in digitaria than in lucerne, except at spring temperatures without added N. Water use efficiency of the mixture was always similar to that of the most efficient monoculture of the particular treatment.
Use of whole cotton seed as a dietary supplement for grazing dairy cows
Authors: Ehrlich WK , Cowan RT , Reid A
Published: March 2005

In a 2-part preliminary experiment, groups of 6 and 9 Holstein-Friesian cows in early t o mid lactation were unsupplemented or supplemented with either 3 kg cracked sorghum grain or 3 kg whole cotton seed on a base pasture of irrigated pangola grass for 12 weeks or oats for 12 weeks. The stocking rate was 5 cows/ha. Supplementation did not affect milk yield or composition. In a second experiment a group of 20 Holstein- Friesian cows in early to mid lactation grazed on a base pasture of subterranean clover at a stocking rate of 4 or 6 cows/ha a n d w e r e either unsupplemented or supplemented with 3 kg of whole cotton seed (WCS) over 12 weeks. Milk yield averaged 20.3 kg/cow.day and there were no significant effects on milk yield or composition. We suggest the lack of a significant milk yield response was due to a high substitution rate of WCS for pasture, associated with an oil content in the diet of 7.1 % of dry matter.
Evaluation of pasture legumes sown into a prepared seedbed at Tamworth, New South Wales. 1. Dry matter yield
Authors: Lodge GM , Cullis BR , Welsby SM
Published: March 2005

The potential dry matter production in autumn, winter, and spring of 15 annual and 7 perennial pasture legumes was assessed in ungrazed plots at Tamworth on the Northern Slopes of New South Wales. Seed was sown into a prepared seedbed, and dry matter yield was estimated on 24 occasions from August 1983 to November 1987. The presence of green material at each sampling time. and the actual and total dry matters, were examined. Among the annual legumes, the highest proportion of plots presenting dry matter at all sampling times, and the highest total yields, were found for Trifolium hirtum cv. Hykon (rose clover), T. subterraneum var. subterraneum cvv. Seaton Park and Woogenellup, T. subterraneum var. brachycalycinum cv. Clare (subterranean clovers), and Medicago aculeata (CPI No. 19416). The highest proportion of bare plots and the lowest dry matter yields were found for local ecotypes of the naturalised legumes T. glomeratum, M. minima and M. polymorpha, Astragalus hamosus cv. Ioman (milk vetch), and T. subterraneum var. subterraneum cv. Nungarin. After October (day 300) in 1983-87 the proportions of plots with >10 kg/ha of dry matter present as green material were Clare 85%; Hykon 78%; Woogenellup 74%; M. aculeata, Seaton Park, and Vicia villosa var. dasycalpa cv. Namoi (woolly pod vetch) 67%; M. scutellata cv. Sava (snail medic) 56%; and M. truncatula cv. Sephi (barrel medic) 52%. Total annual yields of Nungarin were often lower than those of the other subterranean clovers, with Clare having the highest yield in each year. Cumulative yields of Namoi declined markedly after 1985, while those of T. lairtum cv. Hykon increased. Little or no linear relationship was found between maturity grading and the relative yield of the annual legumes, although 4 of the 6 highest yielding legumes were late maturing. Among the perennials, yields of M. sativa cv. Pioneer 581 (lucerne) were above average in 1984-87. Lucerne cv. Pioneer 581 produced more dry matter over 5 years than Onobrychis viciifolia cv. Eski (sainfoin), but about the same amount as O. viciifolia cvv. Othello and Remont. Sainfoin production was high in the first 2 years of the experiment, but lower towards the end. The poor performance of T. repens cvv. Haifa and Huia (white clover) was attributed to high temperatures and low effective rainfall in summer. From these data, 5 annuals (Seaton Park, Woogenellup, Clare, Hykon, and M. aculeata) and lucerne show the most potential for sowing as ley pasture in the low elevation, summer rainfall environments of the Northern Slopes of New South Wales.
Relative importance of soil phosphorus to the growth of wiregrass (Aristida armata) compared with other grasses common to the mulga shrublands of Queensland
Authors: Armstrong RD , Helyar KR
Published: March 2005

The influence of phosphorus (P) applied to mulga topsoil on the growth of Aristida amata, Cenclirus ciliaris, Digitaria ammophila, and Thyridolepis mitchelliana was examined in2 glasshouse trials, to test the hypothesis that the invasion of A. amata into mulga shrublands may result from a superior ability to exploit and utilise soil P compared to the other grasses.Growth of all grasses was poor without added P, and all grasses produced large growth responses to added P. In contrast to the other native grasses, A. armata required as much added P as the exotic C. ciliaris to achieve maximum growth. The ability of the grasses to grow without added P was related more to an ability to absorb P than to differences in internal requirements. With no P added, T. mitchelliana had the highest P absorption rate (�g P/g root.day), followed by A. amata, C. ciliaris, and D. ammophila. Adding P reversed this order. Cenchrus ciliaris and D. ammophila had the highest relative growth rates of shoots during early growth stages, especially with P added. Although A amata had a greater ability than C. ciliaris to access and utilise soil P at low P concentrations, there was no evidence that it was superior to the other native grasses.
Effects of defoliation on dryland wheat production in central Queensland
Authors: Asghar M , Ingram BF
Published: March 2005

The effect of insect defoliation on grain yield, nitrogen (N) content, and gross value of dryland wheat was simulated by removing blades from the flag leaf, top 2 leaves (flag leaf plus the one below it), and all leaves, 100 days after planting the crop. When blades were removed from the top 2 leaves and all leaves, respectively, significant (P<0.05) reductions of 13.5 and 17.3% in grain yield, 9.2 and 11.9% in head weight, and 7.6 and 13.2% in 1000-grain weight were recorded. Defoliation did not significantly decrease grain number/m2. When blades were removed from the flag leaf, top 2 leaves, and all leaves, respectively, significant (P<0.05) reductions of 9.5, 17.3, and 14.0% in grain N concentration, and 14.2, 28.4, and 28.8% in grain N yield (g/m2), occurred. Gross values of the yields from different treatments were ranked (differences at P = 0.05) control > flag leaf blade removed > top 2 leaves removed = all leaves removed.
Phytotoxicity to transplanted lettuce (Lactuca sativa) of three pre-emergence herbicides: metolachlor, pendimethalin, and propachlor
Authors: Henderson CWL , Webber MJ
Published: March 2005

The phytotoxicity of the pre-emergence herbicides metolachlor, pendimethalin, and propachlor to heading lettuce was investigated in 5 experiments conducted in southern Queensland during 1990-91. Metolachlor was applied before transplanting lettuce seedlings in 2 experiments. On a krasnozem soil at Toowoomba, spraying >1.75 kg a.i./ha reduced lettuce growth and the number of marketable lettuce heads. When applied on a black earth at Gatton, 1.44 kg a.i./ha stunted the lettuce and reduced the number of marketable heads by 30% compared with hand-weeded treatments. On both soils, 2.2-2.9 kg a.i./ha of metolachlor is recommended for broadleaf weed control in other crops. The risks of phytotoxicity from such rates preclude its use in transplanted lettuce in this environment. Lettuce were severely stunted from application of 1 kg a.i./ha of pendimethalin after transplanting. Spraying at the same rate before transplanting initially reduced lettuce width in 1 of 4 experiments, but the lettuce recovered. Lettuce yields from areas treated with 1 kg a.i./ha before transplanting were unaffected. The number and size of harvested heads tended to decline where >1.3 kg a.i./ha was applied. Higher rates (up to 1.5 kg a.i./ha) may be acceptable on krasnozem soils. Use of pendimethalin at 1-1.3 kg a.i./ha would control or suppress many important broadleaf weeds in lettuce, as well as a range of grasses. Propachlor was less phytotoxic when applied immediately after transplanting the lettuce seedlings than when sprayed before transplanting. Yields were unaffected from application of 2-2.5 kg a.i./ha after transplanting on black earth and sandy soils. When sprayed before transplanting, >2 kg a.i./ha caused significant yield reductions in several experiments, although lettuce grown on a krasnozem soil appeared more tolerant. Use of 2 kg a.i./ha of propachlor would give a suppressive effect against several broadleaf weeds, but another herbicide would also be required to achieve effective weed control. A spraying strategy involving pendimethalin and propachlor herbicides in transplanted lettuce has the potential to reduce weed control costs by up to 80%.
Micropropagation of some Myrtaceae species which show potential as 'new' ornamental plants
Authors: Speer SS
Published: March 2005

Eleven species of Australian Myrtaceae were evaluated for their ability to be cultured in vitro. Ten species produced axillary shoots (microcuttings) suitable for inducing roots in vitro. Microcuttings of 9 species successfully developed roots and were transferred to soil culture in a glasshouse, where plants grew normally. Nodal explants were grown on a modified Murashige and Skoog (MS) medium supplemented with varying concentrations of 6-benzylaminopurine (BAP), to study shoot proliferation. Beaufortia heterophylla Turcz. explants did not respond to BAP, and all explants eventually died. The rate of shoot proliferation for the other species varied according to BAP concentration. Microcuttings of 10 species were grown on a modified half-strength MS medium supplemented with varying concentrations of the auxins indole-3-butyric acid (IBA) and naphthaleneacetic acid (NAA), to induce root formation. An increase in root number and an associated decrease in root length was observed as the concentration of IBA and NAA was increased. Verticordia muelleriana E. Pritzel did not develop roots in any treatment. Chamelaucium uncinatum Schauer cv. Purple Pride, Kunzea parvifolia Schauer, K. pulchella (Lindl.) A. S. George, Leptospermum rotundifolium (Maiden & Betche) F. Rodway ex Cheel, Verticordia drunzmondii Schauer, V. graizdis J. L. Drumm., V. hughanii F. Muell., V. nzonaclelpha Turcz., and V. roeii Endl. microcuttings developed roots both with and without added auxins. Roots that formed on microcuttings at higher auxin concentrations were generally thicker and slower in growth.
Supplementation of young Merino sheep grazing annual pastures with lupin, barley grain, or silage
Authors: Gardner JJ , Doyle PT , Rowe JB , Hetherington R , Spicer P , McQuade N , Crowhurst M
Published: March 2005

We examined the effects on liveweight change and wool production of supplements of lupin, barley grain, or silage given to Merino weaners (age 5-7 months; starting weight about 30 kg) grazing dry annual pastures. In experiment 1, each supplement was offered at 5 rates (g/sheep.day): lupin, air-dry, 75-450; barley, air-dry, 80-480; silage, fresh, 430-2580. Sheep on all treatments gained weight in the first 29 days of supplementary feeding, with no effect of rate of supplementation (lupin 97 g/day; barley 57 g/day; silage 74 g/day). Those receiving no supplement also gained weight (40 g/day). Different supplements were not compared because the energy levels of lupin and barley were not measured. Over the next 48 days, liveweight changes increased (P<0.001) linearly with rate of feeding of lupin (25 � 2.1 g/100 g) and barley (12 � 0.8 g/100 g). The trend with silage (11 � 5.0 g/kg) was not significant. Taken over the 77 days, liveweight changes increased (P<0.01) linearly with rate of feeding for lupin (20 �. 1.8 g/100 g), barley (8 �. 1.7 g/100 g), and silage (10 �. 2 g/kg). There were no significant (P>0.05) differences associated with the rate of supplementation for annual clean fleece weight (lupin 3.43 kg, barley 3.37 kg, silage 3.30 kg) or mean fibre diameter of the 12-month fleece (lupin 22.2 �m, barley 22.6 �m, silage 22.1 �m). In experiment 2, sheep were given no supplement, lupin, barley, or lupin and barley mixtures (metabolisable energy ratio, 1:3,1:1,3:1). All supplements increased liveweight change (P<0.01) and clean wool growth rates (P<0.05) compared with no supplement. There was also a trend towards an increase in total wool grown by supplemented sheep (3.8 - 4.00 v. 3.73 kg). Liveweight change during the first 71 days of feeding increased (P<0.01) as the proportion of lupin in the supplement increased, with no effects in the final 70 days of supplementation. During supplementation, clean wool growth rate increased (P<0.05) as the proportion of lupin in the mixture increased, but there was no significant effect on the total amount of wool grown over 12 months or on mean fibre diameter. Supplements resulted in increased (P<0.001) staple strength when compared with controls (21-25 v. 14 N/ktex).