bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of irrigation timing in autumn and spring on seed production of subterranean clover, and the change in permeability and rate of germination of seed
Authors: Kelly KB , Mason WK
Published: March 2005

The effects of time of initial irrigation in late summer-autumn and final irrigation in spring on the amount of seed present, seed burial, relative proportions of each cultivar and changes in seed permeability with time were studied in mixed cultivar swards (cvv. Clare, Woogenellup and Trikkala) of subterranean clover. Irrigation treatments were 3 times of initial irrigation (1 February, 1 March and 1 April) combined with 2 times of final irrigation (mid October and mid November) from 1982 to the autumn of 1985. Seed was sampled 3 times per year; in mid December, prior to initial irrigation and in late winter. The timing of the first irrigation in autumn had no effect on the number of seed present in December which averaged 55,57 and 78 seeds/dm2 in 1982, 1983 and 1984 respectively. Time of final irrigation in spring had a large influence on the number of seeds present in mid December, with a 3-year average of 42 seeds/dm2 for the mid October treatment and 85 seeds/dm2 for the mid November treatment. Rainfall in summer and early autumn reduced the number of seed present between December and the initial irrigation. Residual seed measured in late winter accounted for 18% of the seed present in the previous December and was mostly located below the ground. Without summer rainfall, the proportion of permeable seed averaged over all cultivars increased from approximately 20% in mid December to 40, 60 and 70% in February, March and April respectively. The rate of germination of permeable seed was influenced by time of sampling, temperature of germination test (15 and 30�C), the incidence of rainfall, and the type of cultivar. The limitations of current subterranean clover cultivars under irrigated conditions are discussed and an outline of the characteristics required by cultivars to be used under irrigation is presented, with particular reference to autumn feed production.
Yield and quality of irrigated summer fodder crops in northern Victoria
Authors: Pritchard KE
Published: March 2005

Dry matter (DM) yield, in vitro digestibility (DMD%), and nitrogen (N) concentration were determined for 28 cultivars of millet (Echinochloa utilis), hybrid forage sorghum (Sorghum spp.) and maize (Zea mays), under irrigation at Kyabram, Victoria. These summer fodder crops produced large amounts of digestible dry matter (DDM) under intensive irrigated management in northern Victoria, indicating their potential importance for animal production in irrigated warm temperate regions, where pasture dominates the present land use. Single harvest cultivars produced more DM and DDM than did multiple-cut types but with a lower N concentration and generally lower digestibility. Comparing the highest 3-year mean yields for each species, sweet sorghum cv. Honey drip produced more dry matter (273 t/ha) than did maize cv. XL77 (21.6 t/ha) but yields of DDM were similar (14.4 v. 14.0 t/ha). Both yielded more DM and DDM than grain sorghum cv. Pacific 303 (20.1 t DM/ha and 12.4 t DDM/ha). Maize had higher digestibility (65.0%) than grain sorghum (61.5%) or sweet sorghum (53.0% DMD) and higher N concentration (1.1%) than sweet sorghum (0.9%). All maize cultivars had similar dry matter yields but differed in grain yield. Echinochloa millet cv. Shirohie produced a similar amount of DM (16.3 t/ha) and DDM (10.8 t DM/ha) to sorghum x sudan grass hybrid cv. Sudax (17.1 t DM/ha and 10.7 t DDM/ha). This contrasts with their comparative performance at lower latitudes where sorghum hybrids have the higher yield. There was no difference in mean yield between cultivars of sorghum x sudan grass hybrid. Millet had a higher digestibility (65.9%) and nitrogen concentration (1.9%) than sorghum x sudan hybrids (63.3% DMD, 1.5% N). In this environment, maize and Echinochloa millet had similar DDM yield capacities to sorghum cultivars oftheir equivalent type but superior forage quality.
Influence of weed competition on autumn-sown lucerne in south-eastern Australia and the field comparison of herbicides and mowing for weed control
Authors: Taylor AJ
Published: March 2005

A field experiment in autumn-sown lucerne was conducted at Tatura to quantify the growth of winter weeds and the effects of weeds on lucerne seedling establishment, plant densities and hay production over the first year of cutting. In addition, mowing treatments and a range of herbicides were evaluated with respect to weed control. Weed growth rates in spring of up to 114 kg ha-l day-1 DM and high yields of annual winter weeds excluded lucerne (Medicago sativa L. cv. Delkalb 167) almost entirely from the first hay cut and significantly reduced seedling vigour and plant densities. The unsprayed control plots yielded 9.3 t ha-1 at the first hay cut and comprised 52% capeweed, 41% ryegrass and less than 1% lucerne. In other treatments where either capeweed or ryegrass remained uncontrolled, the proportion of lucerne in the hay was low. Weeds significantly reduced lucerne yields (P < 0.01) at the first and second hay cuts of 5 cuts taken in the first season. Combinations of herbicides gave the best weed control and highest lucerne yield at the first and second cuts and significantly higher total lucerne yield. The best herbicide combination was trifluralin and bromoxynil, which controlled all weed species on the site, reduced the weed yield at the first cut by 87% below that of the control and produced the highest total lucerne yield of 14 t ha-l. The hay composition of this treatment at the first cut comprised 59% lucerne, 27% ryegrass and 14% other weed species, while at the second hay cut lucerne comprised 95% of the DM. Lucerne was the highest yielding species in all treatments at the second cut. Lucerne plant densities were lowest on the unsprayed control plots, with 56% fewer plants than for the herbicide combination treatments. Mowing in August was effective in preventing the decline in lucerne plant density that occurred on the unsprayed control plots.
Lucerne seedling growth and first year productivity in south-eastern Australia as influenced by sowing date in autumn and early winter
Authors: Taylor AJ
Published: March 2005

A field experiment at Tatura, Vic., compared lucerne (Medicago sativa L.) seedling growth and first year productivity of 2 lucerne cultivars (cv. CUF101 and Dekalb 167) sown at monthly intervals from early autumn (March) to early winter (June). At the first hay cut in October, both delayed autumn sowing and the increased winter dormancy between cultivars resulted in significantly lower seedling DM and crop height. Total DM yield from 5 hay cuts during the first cutting season declined as sowing date was delayed. Yields were 18.5, 16.5, 14.5 and 13.1 t ha-1 for the March, April, May and June sowings, respectively. However, no differences in total yield occurred between cultivars despite better early growth of CUF101. During the first 20 weeks from each sowing, significant interactions occurred for seedling DM and crop height between sowing date and cultivar (P=0.05). At 20 weeks of age, seedling DM of the March sown CUF101 was significantly greater than for all other sowings at the same age. At 4 weeks, seedling DM of the June sowings were significantly lower than all others. However, at 20 weeks, seedling DM and crop height of the June sowings were significantly higher than for the April and May sowings. Seedlings of the May sowings remained small for the longest period. The greatest relative differences in seedling DM and crop height occurred at about 10 weeks after sowing where the March sown CUF101 and Dekalb 167 were 29 and 4 1 times greater than the May sown CUF101 and Dekalb 167 respectively. The comparison of seedling DM of the autumn sowings with spring (Sept. and Oct.) sown semi-winter-dormant lucerne (cv. Validor), showed that at 12 weeks of seedling age, seedling DM of the spring sowings was more than double that of the March sown Dekalb 167.
Effects of cincturing, defoliation and summer pruning on vegetative growth and flowering of custard apple (Annona cherimola x Annona squamosa) in subtropical Queensland
Authors: George AP , Nissen RJ
Published: March 2005

Trunk cincturing at monthly intervals from budbreak to mid January had no significant effects on vegetative flushing or flowering of 6-year-old custard apple trees (Annona cheriinola x Annona squamosa) cv. Pink's Mammoth in subtropical Queensland. In contrast, pre-budbreak defoliation with 1.0 g/L of 2- chloroethyi-phosphonic acid and 250 g/L of urea hastened, and post-budbreak defoliation and summer pruning delayed, shoot growth and flowering in 3-yearold custard apple trees, cv. African Pride. These responses were associated with a reduction in the number of flowers with defoliation and an increase after summer pruning. The main effect of summer pruning was to increase the number of subpetiolar buds which emerged on the new wood. There was no significant effect of treatments on the number of buds emerging from 1-year-old wood.
Effect of cattle tick (Boophilus microplus) infestation on performance of Bos indicus cross cows and their progeny
Authors: Holroyd RG , Dunster PJ , O'Rourke PK
Published: March 2005

The effects of cattle tick infestations on liveweight and fertility of Droughtmaster (1/2 Bos indicus) cows and on calf weaning weights were determined over 3 years. Tick populations on the control (non-dipped) group of cattle fluctuated, with mean annual tick counts/side being 9.5, 8.9 and 13.6 for years 1, 2 and 3 respectively, while the treated group of cattle, which were dipped every 21 days, were free of ticks. Tick counts were not related to fertility or liveweight change in pregnant-lactating cows or to calf growtb or weaning weights. Treatment for ticks significantly (P<0.05) affected liveweight change in pregnant-lactating cows on only a few occasions, and annual liveweight changes were not significantly influenced by treatment. When lactating cow pregnancy rates were low (< 30% for control cows), treatment for ticks increased the pregnancy rate by about 100% in 2 of the 3 years, these differences being significant only in the last year. Calves in the treated group were born significantly earlier in the first year and had significantly lighter birth weights in the third year. Treated calves grew faster to weaning and had higher weaning weights (mean difference 17.9 kg) than control calves but differences were significant in the first and third years only.
Effect on milk production of adding bentonite and reactive limestone to maize grain supplements for grazing cows
Authors: Hamilton BA , Carmichael AW , Kempton TJ
Published: March 2005

Sodium bentonite and 2 types of limestone differing in rate of reactivity were each used as additives to cracked maize grain in 2 experimental periods. In the first period, maize was fed individually to 32 grazing cows at a rate of 4 kg cow-1 day-1 for 3 weeks and then 6 kg cow-1 day-1 for 4 weeks in the second. The limestones and bentonite were added at rates of 3 and 33% (w/w) of the maize in the respective periods. In the first period, the control cows produced 20.2 kg milk day-1 containing 3.34% fat and 2.97% protein; in the second period, they produced 22.5 kg milk day-1 containing 3.41% fat and 3.21% protein. None of the additives had any significant effects on milk production, milk composition or liveweight change in either of the feeding periods.
Relationship between wax, suint and fleece rot: effect of sample preparation, time of sampling and fleece rot induction
Authors: Raadsma HW , Thornberry KJ
Published: March 2005

The major factors thought to affect the relationship between wax and suint and fleece rot susceptibility were examined. Time of sampling and fleece rot induction were the major factors which resulted in changes in wax and suint levels in the fleece and their relationship with fleece rot. Variation in staple portion used for extraction did alter the yields of wax and suint, but these yields were highly correlated to full staple values in the case of wax (r = 0.77-0.92) and lower in the case of suint (r = 0.23-0.77). Variation in length of staple used did not alter the relationship between wax and suint levels and fleece rot. We conclude that wax would be a more suitable indicator of fleece rot susceptibility than would suint because of its more stable relationship with fleece rot. Differences between sheep affected and unaffected with fleece rot in wax and suint values were small and consistent for the 15 Merino genotypes sampled. The evaluation of wax for indirect selection against fleece rot will depend on further evaluation of the required genetic parameters and a more cost-effective means of measurement.
Performance of fourteen Leucaena lines at five sites in Queensland
Authors: Bray RA , Cooksley DG , Hall TJ , Ratcliff D
Published: March 2005

Ten lines of Leucaena leticoceyhala, 1 of L. diversifolia and 3 L. leucocephalax L. pulrerulenta F1 hybrids were grown at 5 contrasting sites in Queensland. Harvests were taken over 3 growing seasons, and dry matter yields estimated. The F1 hybrids were outstanding in most environments, outyielding cv. Cunningham by an average of 45%; the L. Ieucocephala lines CPI 58396 and 61227 and cv. K8 consistently outyielded cv. Cunningham by an average of 24%. When 2 contrasting cutting intervals were compared at Lansdown, there was no effect on dry matter yields, although the longer cutting interval produced more wood. The range of mimosine concentrations in the L. Ieucocephala lines was 4.1-5.6%. CPI 6 1227 had significantly lower mimosine content than cv. Cunningham. The genotype x site interaction for total yield was significant (P< 0.01). However, ranking of lines of L. leucocephala was fairly consistent across environments.
Effect of depth of burial on the longevity of hard seeds of subterranean clover and annual medics
Authors: Taylor GB , Ewing MA
Published: March 2005

Burrs of 3 cultivars of subterranean clover (Trifolium subterraneum) and 1 cultivar each of burr medic (Medicago polymorpha) and barrel medic (M. truncatula), which had experienced 1 summer at the soil surface, were placed on the soil surface and at depths of 2, 6 and 10 cm in the soil. The numbers of residual hard seeds were determined each year for up to 4 years. There was a marked reduction in the rate of seed softening in all 3 clover cultivars with increasing depth of burial. Whereas <20% of the seeds of the hardest seeded clover cultivar, Nungarin, survived 3 years at the soil surface, there was no significant decline in seed numbers during 4 years of burial at 10 cm. Even with cv. Geraldton, in which only 5% of seeds remained after 1 year of placement at the soil surface, 75% of seeds survived 4 years of burial at 10 cm. Hard seeds of both medic varieties were considerably more resilient than clover seeds at the soil surface, particularly during the first summer following seed set. However, burial had much less effect on their longevity, with no significant effect of burial to 2 cm in either medic, or of burial to 6 cm in the case of barrel medic. These results support earlier findings which showed that tillage operations associated with crop establishment which result in the burial of substantial proportions of subterranean clover seeds can lead to useful soil seed reserves. The much lesser effect of burial on seed softening of the medics, compared with subterranean clover, suggests that tillage operations will be less advantageous to medic persistence in leys.
Residual effectiveness of superphosphate is greater than that of rock phosphate fertilisers for lateritic soils in south-western Australia
Authors: Bolland MDA , Weatherley AJ , Gilkes RJ
Published: March 2005

The residual values of granular reactive rock phosphate (highly carbonate-substituted apatite from North Carolina, USA.), partially powdered low-reactive Queensland rock phosphate (low carbonate-substituted apatite from the Duchess deposit), and granular triple superphosphate were measured in 3 experiments on different lateritic soils in different climatic regions of south-western Australia (Gibson, South Bodallin, West Dale). Finely powdered calcined crandallite-millisite rock phosphate from Christmas Island (Calciphos) was included in one of the experiments. The fertilisers were applied once only in May 1984 and their residual value measured over 3 years (1984-1986) using yield and phosphorus content of the following species each year: experiment 1 (Gibson), barley in years 1 and 2 and oats in the third year; experiment 2 (South Bodallin), triticale in all 3 years; experiment 3 (West Dale), subterranean clover in years I and 2 followed by oats in year 3. Relative to triple superphosphate (TSP) applied each year, the effectiveness of superphosphate in year 1 (year of application) in the experiment at Gibson decreased by about 40% between years 1 and 2, and by a further 5% between years 2 and 3. The corresponding values for the experiment at South Bodallin were 75% and 5%, and at West Dale 50% and 25%. All rock phosphates were much less effective than TSP in year 1, being 5-30% as effective as TSP. Effectiveness of rock phosphates remained low over the 3 years, being 5-20% as effective as newly applied TSP. Although the effectiveness of TSP decreased, it continued to be 50% as effective as newly applied TSP after 3 years. Residual TSP and both freshly applied and residual rock phosphates did not support the same maximum yield as freshly applied TSP despite well defined yield plateaux being obtained in each case. At each harvest, the relationship between yield and phosphorus content of plants was similar for all fertilisers so that the smaller maximum DM and grain yield and reduced effectiveness of the rock phosphates were largely due to less phosphorus being taken up by plants.
Yield and fruit quality responses of Ellendale mandarins to different nitrogen and potassium fertiliser rates
Authors: Lee LS , Chapman JC
Published: March 2005

Three rates of nitrogen fertiliser (88, 176 and 352 kg N ha-1 as ammonium nitrate) and 3 of potassium (0, 220 and 440 kg K ha-l as potassium sulfate) were applied to mature Ellendale mandarin trees, in the Central Burnett district, Qld. Optimum yield response occurred at the I76 kg N ha-1 nitrogen rate but potassium treatments did not significantly affect yield. Rind was thinner and fruit colour better at the lowest nitrogen and potassium rate. Whereas nitrogen produced no effect on internal fruit quality, the ratio of total soluble solids:acid was depressed by the highest potassium rate as a result of increased acid content. For Ellendale mandarins under Queensland conditions the lowest potassium treatment produced smaller fruit with thinner rind and earlier colour development. The results indicate that the optimum nitrogen fertiliser application rate is 160-180 kg N ha-1 and that potassium fertilisers can impair fruit quality.
The influence of shade on milk production of Holstein-Friesian cows in a tropical upland environment
Authors: Davison TM , Silver BA , Lisle AT , Orr WN
Published: March 2005

Sixteen Holstein-Friesian animals, comprising 8 multiparous cows and 8 first-lactation heifers, were divided into 2 equal groups which had access to either tree shade or no shade. All animals were in the first third of lactation and were subjected to treatment for 8 weeks in summer 1985. Average maximum monthly temperatures ranged from 26.2 to 28.22� over the experimental period. The provision of shade increased (P< 0.01) milk yield; however, there was a significant (P<0.05) interaction between response to shade and cow parity. Mean daily milk yields for multiparous cows were 19.2 and 17.2 kg/cow (P< 0.01) and 16.3 and 15.9 kg/cow (P> 0.05) for heifers in the shade and no shade groups respectively. Cows without shade incurred a significant decrease (P< 0.05) in solids-not fat yield, lactose percentage and lactose yield, and a significant increase ( P < 0.05) in somatic cell count. The composition of milk from heifers without shade was no different from that from heifers with shade. Rectal temperature was higher (P < 0.01) in animals without shade (mean 40.0�C) than in animals with shade (mean 39.4�C). The highest mean maximum rectal temperature of 41.6�C was recorded in the noshade group. It was concluded that shade is essential if milk yield and milk composition are to be maximised in this environment.
Responses of cattle to different space allowances, pen sizes and road conditions during transport
Authors: Eldridge GA , Winfield CG , Cahill DJ
Published: March 2005

Angus x Shorthorn heifers weighing about 350 kg were used to study the responses of heart rate and behaviour to different pen sizes, space allowances and road conditions during transport. In experiment 1, 6 groups of 9 heifers were transported at contrasting space allowances (0.9 and 1.1 m2/animal) on two 135- km journeys over a predetermined route of country, highway and suburban roads. Space allowance was varied by adjusting pen size. In experiment 2,4 groups of 8 heifers were used in a 2 (space allowances [0.8 and 1.0 m2/animal])x2 (pen sizes [8 and 16 m2]) factorial experiment to determine animal responses during a 31 km journey over sealed suburban roads. Space allowance was adjusted by adding non-experimental animals from the same herd. In experiment 3,6 groups of 7 animals were used to study the response of cattle to 2 space allowances (0.89 and 1.14 mVanima1) during a journey of 424 km. Space allowance was adjusted by using non-experimental animals from the same herd. In all experiments, animals transported at the lower space allowances had 3.9-6.7% lower heart rates (P < 0.05) and l27-260% lower movement scores (P < 0.05) than did animals transported at higher space allowances. In experiment 1, road type significantly affected heart rate (P<0.05) but not movement. In experiment 2, both heart rate and movement were significantly (P<0.01) less in small pens compared with large pens (heart rate 68.8 v. 71.7 bpm; number of movements 7.1 v. 15.8). There was a significant (P<0.05) interaction between space allowance and pen size on heart rate, but not on the amount of movement. In experiment 3, the stage of the journey did not affect the difference in heart rate between space allowance treatments. It is concluded that, within the ranges of the variables examined, road transport was less demanding on cattle in small pens with a small space allowance. It is suggested that space allowances can be more readily manipulated in transport vehicles with small pens and so minimise risks to animal welfare during rapid changes in vehicle motion.
Failure of antisomatostatin antibodies to stimulate the growth of crossbred lambs
Authors: Hoskinson RM , Djura P , Welch RJ , Harrison BE , Brown GH , Donnelly JB , Jones MR
Published: March 2005

The effect of antisomatostatin antibodies on the growth of crossbred female and wether lambs was studied over 8 months. The antibody response profile established in the immune lambs, following a sequence of 3 vaccinations with an immunogenic somatostatin-haemocyanin conjugate in Freund's complete adjuvant, reached a maximum mean antisomatostatin antibody titre of 1:11 400. There were no effects (P>0.05) of the treatment on liveweight or shoulder height of immune lambs. There were predictable overall effects due to sex but not to level of antibody titre within the immunisation treatment. These data indicate circumstances where immunological growth promotion does not result when antisomatostatin antibodies are raised in growing crossbred lambs that are typical of a commercial breed.
Do sows need straw for nest-building ?
Authors: Hutson GD
Published: March 2005

The motivation of sows to obtain straw was measured in 4 experiments using operant conditioning apparatus. In the first experiment there was no significant difference in the operant level of response when lifts on a lever produced access to an empty box or a box containing straw. None of the 6 sows, 4 about 10 weeks pregnant and 2 non-pregnant, showed any interest in the straw. In the second experiment variation in motivation to obtain straw was measured by testing pigs for 7 consecutive days every 2 weeks from mating to weaning. All pigs showed little change in lever lifting behaviour, although 2 gilts showed increased responsiveness to straw at farrowing time. In the third experiment 4 sows were allowed to farrow in the test pen with access to the lever and straw box. The sows showed an increase in activity prior to farrowing which coincided with increased manipulation of the lever. The response to straw was variable, although all pigs showed an increase in pawing behaviour. However, in a fourth experiment, 4 control pigs showed similar increases prior to farrowing in activity, lever manipulation, and pawing behaviour when the straw box was empty. The apparent low motivation of sows towards utilisation of straw is discussed in relation to its importance as a key stimulus for nesting behaviour and its role in thermal protection of the piglets, and also in relation to possible absence of appropriate nest-building stimuli, previous experience, genetic adaptation and animal welfare.
Incidence of Colletotrichum trifolii on lucerne in New South Wales, its host range and reaction of lucerne cultivars to inoculation
Authors: Stovold GE , Francis A
Published: March 2005

Colletotrichurn trifolii, the cause of stem anthracnose and crown rot of lucerne, was detected in all major lucerne growing areas of New South Wales. The disease was more common and more severe in regions north of latitude 33�S. Most outbreaks occurred from February to June. The highest concentrations of spores for inoculations were produced on lima bean agar. Carnation leaf-piece agar was also satisfactory and was used as a routine medium for spore production. Viability of spores declined rapidly in cultures older than 7 days. Isolates of C. trifolii from New South Wales were most virulent on lucerne. Less severe symptoms were produced on other Medicago spp. and some Trifolium spp. Several grain legumes were inoculated but only chickpea showed slight symptoms. Two methods were used to evaluate the reaction of a range of lucerne cultivars and breeder's lines to C. trifolii. The standard inoculation method used in experiments in other countries and in local experiments produced the most severe symptoms and the ratings obtained agreed generally with known field reactions. A germination-inoculation method resulted in less severe symptoms and the ratings were poor indicators of field performance. Several cultivars showed a significantly higher resistance (P< 0.05) to C. trifolii and should prove useful in areas where the disease is endemic.
Tillage practices and the growth and yield of wheat in southern New South Wales: Yanco, in a 425 mm rainfall region
Authors: Fischer RA , Mason IB , Howe GN
Published: March 2005

In a comparison of tillage treatments over a 3 year cropping phase (1982-84) following clover ley on a red-brown earth soil, long (9 months) and short (3 months) cultivated fallow gave the highest average wheat yields (2.80 t/ha). Cultivated fallow in year 1, followed by direct drill without fallow in years 2 and 3 yielded 2.66 t/ha, while direct drill without fallow every year averaged 2.43 t/ha (full disturbance at sowing) or 2.25 t/ha (minimum disturbance). Stubble retention when combined with direct drilling reduced yield further. Herbicide fallow followed by direct drilling gave the same yield as cultivated fallow in 1 year but a lower yield in another. Long fallow accumulated significantly more total soil water and mineral nitrogen in 2 years out of 3, while short fallow had no effect in any year. Plant population and early growth were reduced each year by the absence of fallow and by direct drilling, and also by residue retention; plant nitrogen and phosphorus status also tended to be reduced. In the absence of soil water differences at sowing and in the wetter 2 years, final grain yield differences, although always relatively smaller than early growth differences, were related to these differences in early growth which, it is concluded, reflect the main underlying cause of reduced yield with direct drilling. Reductions occurred even with a dry spring when direct drilled crops had clearly better soil and plant water status. In the driest year (1982) yield differences were small despite early growth differences. Sowing of all treatments was delayed in 2 years out of 3 because of top soil dryness in no-fallow plots. Some cultivated fallow crops showed a tendency to 'hay off' (i.e. markedly reduced harvest index and kernel weights) when the grain filling period was dry. The incidence of yellow leaf spot (Pyrenophora tritici repentis) and root diseases, although low, was greater in direct drilled crops, even after stubble burning.
Growth and yield of rice cultivars under sprinkler irrigation in south-eastern Queensland. 1. Effects of sowing time
Authors: Fukai S , Inthapan P
Published: March 2005

Rice crops were grown under sprinkler irrigation, on a free-draining soil, to examine the feasibility of growing rice without flooding in summer-rainfall regions of coastal Queensland. Three cultivars with different heading times were each sown on 3 different dates to determine the optimum time of planting in south-eastern Queensland. Dry grain yield was about 600 g m-2 for all 3 cultivars when sown in early summer. These early sown crops received a total of about 375 mm of irrigation water, all of which was applied during early stages of growth. Grain yield was much less in the later sowings, although total biomass production was relatively high. Low temperatures in autumn appear to have affected grain set of the late sown crops.
Growth and yield of rice cultivars under sprinkler irrigation in south-eastern Queensland. 2. Comparison with maize and grain sorghum under wet and dry conditions
Authors: Inthapan P , Fukai S
Published: March 2005

The performance of non-flooded rice was compared with that of the 2 major cereal crops grown in south-eastern Queensland. Three cultivars of rice and 1 cultivar each of sorghum and maize were grown either under weekly sprinkler irrigation or under non-irrigated conditions after establishment. Grain yield, total dry matter and light interception were measured to determine the responses of the cereal species to soil water deficits. Under weekly irrigation, the low grain yield (ovendry) of rice (680 g m-2 in the highest yielding cultivar compared with 1240 g m-2 for sorghum and 1060 g m-2 for maize) was mostly due to inefficient conversion of solar radiation to dry matter. Both total radiation interception and harvest index were similar among the 3 species. Under dry conditions, rice intercepted less radiation than did the 2 cereals. There was also a larger reduction in the efficiency of conversion of solar radiation to dry matter in rice, and hence total dry matter production was severely reduced. Grain yields under dry conditions were 52, 58 and < 10% of the corresponding yields in the wet trial in maize, sorghum and the 3 rice cultivars, respectively. In rice, dry conditions delayed heading, and consequently grain set was severely affected in the 2 quick maturing cultivars, while the long season cultivar (IR43) failed to head during the experimental period of 163 days. At maturity, the rice cultivar, Shinhakaburi, bred for upland conditions, produced a significantly higher biomass than the lowland cultivar, Labelle, or the upland cultivar IR43.
Effect on scald (Rhynchosporium secalis (Oud.) J. Davis) infection on yield response of Stirling barley to various sowing rates
Authors: Khan TN
Published: March 2005

The effect of a range of sowing rates on scald infection and yield in barley cv. Stirling was studied to investigate if increased plant density will lead to more ears/m2 and therefore compensate for yield losses due to scald. Increased sowing rate (50 v. 100 kg/ha) did not compensate for yield loss due to scald. However, significant yield increases (3.0 v. 4.0 t/ha) with increased sowing rates (25 v. 125 kg/ha) occurred when scald was controlled. Such yield in creases were accompanied by increases in the number of ears/m2 and number of grains/ha, but decreases in number of grains/ear and 100-grain weight. The severity of scald infection was not affected by sowing rates.
Insecticide-retentive carriers. 1. Methods of analysis
Authors: Desmarchelier JM , Paine C
Published: March 2005

Clay-based carriers of insecticides or 'dusts', e.g. talc or bentonite impregnated with fenitrothion, may either retain the protectant after admixture with wheat or release it into the surrounding grain. The amount of carrier was determined by mixing wheat with water or ethanol, subjecting to ultrasound, and determining absorbance of the supernatant at 580 nm. Swirling in water under ultrasound followed by decanting removed more than 90% of 9 tested carriers from water, was more efficient than sieving, and had no effect on fenitrothion levels in wheat that had previously been sprayed with an emulsifiable concentrate formulation. The amount of fenitrothion retained was measured by 3 methods, each duplicated, and was 0.5-5% for talc, 98-103% for Nuchart-Attaclay, 565-80% for Halloysite, and 96-97% for Steecoben.
Spatial distribution and sequential sampling of Nysius spp. (Hemiptera: Lygaeidae) on sunflowers
Authors: Allsopp PG , Iwao S , Taylor LR
Published: March 2005

Counts of adults of mixed populations of Nysius vinitor Bergroth and N. clevelandensis Evans on preflowering and postflowering sunflowers did not conform to the Poisson distribution because of overdispersion. Preflowering samples did not conform to the negative binomial model, but postflowering samples did with a common k of 3.78. Both sets of samples fitted significantly (P<0.01) Iwao's patchiness regression and Taylor's power law, but with significantly (P<0.01) different intercepts and slopes, respectively. Relationships to determine sample sizes for fixed levels of precision and fixed-precision-level stop lines are developed for both stages of crop development using Taylor's power law. Sequential decision plans based on Iwao's regression are developed for use in the management of Nysius spp. on preflowering and postflowering sunflowers.
Milk production of dairy cows grazing long or short kikuyu grass (Pennisetum clandestinum), and with access to forage lupins (Lupinus luteus)
Authors: Hughes RM , Royal AJE , Ayres JF
Published: March 2005

An experiment was undertaken at Wollongbar in subtropical New South Wales in which 48 dairy cows grazed long (1 200 kg/ha of dry green leaf) or short (800 kg/ha of dry green leaf) kikuyu (Pennisetum clandestinum) pasture and had access to forage lupins (Lupinus luteus cv. Weiko III) offered at 3 levels. There were 3 experimental periods in June, July-August and September, covering the dry winter-spring in successive years. Cows grazing long pasture produced more milk that was higher in protein content and lost less liveweight than did cows on short pasture (9.60 v. 8.01 L cow-1 day-l, 3.23 v. 3.09%, and -0.20 v. -0.75 kg cow-1 day-1 respectively). Cows with access to the highest rate of forage lupins produced an additional 1.4 L cow-1 day-1, the effect being greater in June (2.5 L cow-1 day-1) than in September (0.5 L cow-1 day-1). Access to lupins also improved liveweight maintenance through winter-spring. Pasture quality remained relatively constant throughout winter-spring but lupin quality declined from high nutritive value [70% in vitro digestibility (D). 48% cell wall constituents (CWC)] while vegetative in June, to low nutritive value (56% D, 56% CWC) at podding in September. The decline in milk production response in cows with access to lupins was associated with this progressive decline in lupin quality. It was concluded that lupins have high nutritive value at the vegetative stage and that when cows grazing kikuyu pasture are given access to it milk production can increase.
Effects of soil water supply and temperature on the photosynthesis of white clover and paspalum in irrigated pastures
Authors: Blaikie SJ , Martin FM , Mason WK , Connor DJ
Published: March 2005

Field canopy chambers were used to measure the effect of a range of soil water contents from surface ponding to very dry soil and the effect of high summer temperatures on the photosynthesis of irrigated white clover and paspalum pastures. Water was ponded for 5-12 days on swards of white clover and paspalum at full cover and on others that had been defoliated to a height of 50 mm. Photosynthetic rate was monitored each day and compared with a non-ponded control. In all cases there was little response in photosynthetic rate to ponding either with or without supplemental nitrogen fertiliser. Photosynthesis of full swards of white clover and paspalum was monitored during a drying cycle following irrigation and compared with the photosynthesis of a well-watered control. Soil water deficit was expressed in terms of cumulative evaporation minus rainfall (mm E - R) after irrigation. Water deficit stress reduced the maximum photosynthetic rate of white clover by 50% (from 0.8 mg CO2/m2.s at 25 mm E - R to 0.4 mg CO2/m2.s at 75 mm E - R), but the photosynthetic rate of paspalum did not decline until 70 mm E - R. At high irradiance, temperatures between 24 and 33�C had little effect on the photosynthetic rate of well-watered white clover, whereas the rate in paspalum was higher at temperatures between 29 and 38�C than at temperatures of 24-29�C. The slow surface drainage and subsequent rapid drying of the root-zone of flood irrigated soils, combined with the high temperatures experienced in northern Victoria during summer, favour paspalum and severely limit the productivity of white clover.
Effect of herbicides on black pigweed and sesbania pea, and yields of five grain sorghum cultivars in central Queensland
Authors: Walker SR , Hazard WH , Mich AF , Silver BA
Published: March 2005

Six experiments were conducted in central Queensland to compare the efficacy of some post-emergence herbicides and mixtures in controlling black pigweed (Trianthema portulacastrum) and sesbania pea (Sesbania cannabina). The herbicides tested were atrazine, 2,4-D, dicamba, picloram plus 2,4-D, and fluroxypyr and mixtures of atrazine with 2,4-D, dicamba, picloram plus 2,4-D, fluroxypyr or tridiphane. In addition, 4 experiments were conducted to assess the tolerance of 5 sorghum cultivars (Sorghum bicolor) to some of these individual herbicides and atrazine mixtures. Small black pigweed and sesbania pea (< 10 cm diameter) were controlled with atrazine at 1.0 kg a.i./ ha, while for larger black pigweed (up to 15 cm diameter) atrazine at 2.25 kg/ha and atrazine mixtures were effective and for sesbania pea (up to 12 cm high) atrazine at 2.25 kg/ha, picloram plus 2,4-D at 35 + 140 g a.i./ha, fluroxypyr at 0.3 kg a.i./ha and atrazine mixtures were effective. In general, control of both weeds by mixtures with atrazine at 1.0 kg/ha was as effective as atrazine at 2.25 kg/ha alone. In the tolerance experiments the treatments were applied at 18-20 days after planting when the number of sorghum leaves was 4-6. Spraying with 2,4-D, dicamba, MCPA, picloram plus 2,4-D and atrazine mixtures with 2,4-D, dicamba and picloram plus 2,4-D consistently caused injury symptoms, delayed flowering and sometimes reduced grain yield. However, the susceptibility of sorghum to these treatments varied with seasons and cultivars. Overall, yield reductions were less when 2,4-D, dicamba and MCPA were applied at lower rates in the atrazine mixtures than when applied alone. All sorghum cultivars were tolerant of atrazine at 4.5 kg/ha. For effective control of both weeds, for crop safety and for minimum atrazine residues after harvest, we recommend that the weeds black pigweed and sesbania pea be sprayed when less than 10 cm in diameter or height, respectively, with atrazine at 1.0 kg/ha.
Salinity tolerance in rice varieties at different growth stages
Authors: Heenan DP , Lewin LG , McCaffery DW
Published: March 2005

The salt tolerance of several Australian and overseas rice varieties was studied at germination, early vegetative growth, and reproductive development in a temperature controlled glasshouse to determine the reliability of screening at any particular stage. At all 3 stages, varieties differed in their degree of tolerance, but the order of tolerance varied considerably between stages. Of the varieties used, the Australian long grain variety Pelde was tolerant for germination but most intolerant during early vegetative growth and reproductive development. The Japanese variety Somewake was intolerant during germination and vegetative growth but most tolerant during reproductive development. Linear regressions showed inverse relationships (r2 = 0.97-0.73) between sodium concentration in the shoots during early growth and shoot dry weight for most varieties. For Pelde, dry matter production was most closely related to potassium concentration in the shoots (r2 = 0.92).
Response of soybeans to sowing date during the wet season in the Ord Irrigation Area, Western Australia
Authors: Beech DF , Garside AL , Wood IM
Published: March 2005

The responses of 3 soybean cultivars to sowing date during the wet season in the Ord Imgation Area (OIA) in northern Western Australia are described. The cultivars, Buchanan, Ross and Durack, are classified as early, medium and late maturity respectively, when grown during the wet season in the OIA. The cultivars were grown 10 times between 22 December and 18 April during 2 wet seasons and we investigated the patterns of phenology, growth and seed production. Sowing date had no significant effect (P> 0.05) on the time to flowering (26-36 days) with cv. Buchanan, but the duration of flowering was curtaiied so that the period from sowing to maturity declined from 120 to 95 days as sowing was delayed from December to April. In contrast the time to flowering of cv. Durack declined in response to photoperiod from about 70 to 40 days and the time from sowing to maturity declined from about 160 to 100 days. The responses of cv. Ross were intermediate between those of Buchanan and Durack. The phenological responses to sowing date were consistent with responses to photoperiod rather than to temperature. Sowing date also affected plant morphology and yields and quality of seed. Delay in sowing after December led to declines in above-ground dry matter yields at flowering, in number of nodes on the main stem at flowering, crop height at maturity and seed yields. Mean individual seed weights increased with delay in sowing. Oil concentrations in the seed declined (from 23 to 17%) and protein concentrations increased (from 32 to 45%) as the period of pod development occurred later in the season. Phenology is a major determinant of the suitability of a cultivar for specific cropping systems. The early maturing cultivar, Buchanan, most closely meets the requirements for a system of double cropping in which the wet season soybean crop is followed by a May sown dry season crop. The late maturing cultivar, Durack, is suitable for a system involving a single wet-season crop.
Effect of nitrogen on growth, fruit quality and nutrient uptake of tomatoes grown in sand culture
Authors: Huett DO , Dettmann EB
Published: March 2005

The effect of nitrogen (N) application level on fruit yield and quality, growth and nutrient uptake ofthe tomato cv. Flora-Dade was investigated in a sand culture experiment. Plants were harvested at regular intervals over a 16-week period and N levels (1.07, 5.36, 10.71 and 32.14 mmol L-1 of N as nitrate) were applied each day in a complete nutrient solution which was formulated to provide a stable and balanced nutrient supply. A response surface model fitted actual growth and nutrient uptake data quite precisely (R2> 0.96) over the range 1-32 mmol L-1 of N. From this model predicted growth and nutrient uptake rates were derived. At final harvest, increases in the level of applied N increased the number of fruit set and increased the dry weight of roots, leaf, stem and fruit. Fresh and dry weight of fruit responded to N up to 32 mmol L-I, whereas vegetative and root dry weight failed to respond beyond 11 mmol L-1 N. The firmest fruit with the highest dry matter content were grown at N levels of 11 and 32 mmol L-1. Fruit with the highest total soluble solids content were grown at N levels of 1 and 32 mmol L-1. Fruit dominated top growth over the last 6 weeks of the growth period, when the maximum predicted growth rate by tops of 151 g plant-1 week-1 was calculated to occur 10 weeks after transplanting at an N application level of 2 1 mmol L-1. Similar growth rates were predicted over the N range 18-32 mmol L-1, with rates increasing rapidly up to early fruit harvest and remaining high. Predicted nutrient uptake rates followed a similar response to growth rates. The maximum uptake rates (g plant-1 week-1) were 3.65 N, 6.19 potassium, 0.83 phosphorus, 2.03 calcium and 0.59 magnesium. We conclude that, in order to achieve optimum nutrition and hence maximum growth rates and quality of tomatoes under field conditions, the application of N and K fertilisers should be matched to the high demand which occurs over the fruit growth period.
Diagnostic nitrogen concentrations for tomatoes grown in sand culture
Authors: Huett DO , Rose G
Published: March 2005

The tomato cv. Flora-Dade was grown in sand culture with 4 nitrogen (N) levels of 1.07-32.14 mmol L-1 applied as nitrate each day in a complete nutrient solution. The youngest fully opened leaf (YFOL) and remaining (bulked) leaves were harvested at regular intervals over the 16-week growth period. Standard laboratory leaf total and nitrate N determinations were conducted in addition to rapid nitrate determinations on YFOL petiole sap. The relationships between plant growth and leaf N concentration, which were significantly affected by N application level, were used to derive diagnostic leaf N concentrations. Critical and adequate concentrations in petiole sap of nitrate-N, leaf nitrate-N and total N for the YFOL and bulked leaf N were determined from the relationship between growth rate relative to maximum at each sampling time and leaf N concentration. YFOL petiole sap nitrate-N concentration, which can be measured rapidly in the field by using commercial test strips, gave the most sensitive guide to plant N status. Critical values of 770-1 120 mg L-I were determined over the 10-week period after transplanting (first mature fruit). YFOL (leaf + petiole) total N concentration was the most consistent indicator of plant N status where critical values of4.45-4.90% were recorded over the 4- 12 week period after transplanting (early harvests at 12 weeks). This test was less sensitive but more precise than the petiole sap nitrate test. The concentrations of N, potassium, phosphorus, calcium and magnesium in YFOL and bulked leaf corresponding to the N treatments producing maximum growth rates are presented, because nutrient supply was close to optimum and the leaf nutrient concentrations can be considered as adequate levels.
Effect of fungicides applied after infection on the control of Mycosphaerella brassicicola on Brussels sprouts
Authors: Wicks TJ , Vogelzang B
Published: March 2005

Ringspot caused by Mycosphaerella brassicicola was controlled on brussels sprouts, by applying a mixture of 2.5 g a.i. penconazole and 120 g a.i. mancozeb per 100 L either every 10- 14 days or only after identified infection periods. Applications after either 24 or 72 h of leaf wetness (9 or 5 applications) were as effective as 13 protectant applications and resulted in 19, 14 and 16% of sprouts being infected, respectively, compared with 95% of sprouts infected in unsprayed plots. Exposing potted plants to naturally dispersed inoculum, and 48 h of leaf wetness before spraying, showed that the fungicide mixture controlled ringspot when applied at either 2, 5 or 7 days after inoculation. Even when applied 14 or 21 days after inoculation, the number of infected leaves per plant, number of lesions per leaf and size of lesions were reduced compared with unsprayed plants. This curative effect was due to the penconazole component of the mixture. Exposing potted plants to naturally dispersed inoculum and leaf wetness periods of 24, 48 and 72 h showed that infection occurred within 24 h. At a mean temperature of 8�C, the incubation period on cv. Victoria Long Island was 28 days.