bluuebunny/crossref_metadata_2025 huggingface dataset:
Correction - The comparative yield method for estimating dry matter yield of pasture
Authors: Haydock KP , Shaw NH
Published: March 2005

This paper describes a new method for estimating pasture yield in which the yields of random quadrats are rated with respect to a set of reference quadrats preselected in the field to provide a scale which is available for reference throughout the sampling. Three alternative calibration procedures are described based either on the dry matter yields of the reference quadrats or on the yields of quadrats rated and cut either during or at the end of sampling. The second and third procedures are shown to have advantages over the first. When testing the method with four observers and two types of calibration scales, estimates of mean yield were generally within 4 per cent of the actual mean with a maximum difference of 8 per cent. Methods are given for calculating the number of samples required to obtain minimum variance for the estimate of mean yield for a given cost in terms cf time spent in the field.
Influence of a prolonged flowering period on the uniformity of an apple crop
Authors: Maggs DH
Published: March 2005

The flowering period of apples (Malus pumila) in the Murray Valley is prolonged because the mild winters afford insufficient chilling. A four-year examination of fruit weight in an orchard containing three cultivars showed that flowers opening between the fifth and the tenth day of flowering developed into the largest fruits. Fruits from later flowers were lighter at the rate of 2 g per day's delay in flowering. If this reduction in weight could be remedied by inducing the later flowers to open with the early flowers, the crop would average 5 per cent heavier and about one third of the fruit would grade one size larger. In some years the juice of Golden Delicious and Red Jonathan had a lower concentration of soluble solids in the later fruits. Asymmetry of Granny Smith fruits could not be related to flowering date or seed number.
Evaluating poultry feedstuffs in terms of their metabolizable energy content and chemical composition
Authors: Guirguis N
Published: March 2005

The metabolizable energy values (ME) of 16 feed ingredients available in Australia were determined with broiler chicks of both sexes. The chickens were fed test diets in which the feed ingredients replaced dextrose in a basal diet. The mean coefficient of variation was low in each determination of ME (range 0.78 to 1.20, mean 0.94 per cent). Sex had no significant effect on the ME value of most feedstuffs with the exception of oats, where ME values were significantly higher for female than for male chicks (P < 0.05). The ME values calculated from the chemical composition of feed ingredients by means of the equations of Sibbald et al; Carpenter and Clegg; and Bolton were considerably higher than that obtained by chick assay. On the other hand ME values of cereals predicted by means of Titus's equation were similar to those obtained in this experiment and to biologically determined values of ME published in the literature. ME values of protein concentrates varied considerably when estimated either by chick assay or by chemical composition. Titus's prediction equation was considered to provide a reasonably accurate estimate of the ME value of a ration where information is available only of the chemical composition of the feed ingredients.
Performance of temperate legumes and associated grasses on granitic soils of low fertility in the New England region of New South Wales
Authors: Thompson JA
Published: March 2005

A range of temperate annual and perennial legumes, naturalized or commonly sown in the area, was examined at three field sites in low fertility soils derived from granite on the south western slopes of the New England Region, New South Wales. They were compared over a four year period in terms of their persistence, dry matter and nitrogen production and their compatibility with associated temperate perennial grasses, The response of sown grass to nitrogen fertilizer application was also examined in the absence of legume. Ten legumes were examined at one site and six of these at the other two sites. In general, nitrogen yields were ranked similarly to total dry matter yields of all treatments, including grasses in the absence of legume. However, the legumes were ranked differently in terms of productivity of the legume component and productivity of associated grass. At all sites lucerne gave the highest yields of total dry matter and of legume and the lowest yield and persistence of associated grass-comparable to grass growing in the absence of legume or applied nitrogen. Subterranean clover was ranked second or third in total dry matter yield, depending on site, but provided the highest yield of associated grasscomparable to grass receiving high levels of applied nitrogen. Under this legume soil nitrogen levels tended to be highest. Rose clover, sown at one site only, yielded more legume dry matter than subterranean clover but grass yield was comparable to that with lucerne. The results suggest that subterranean clover is the superior legume for successful mixed sowings although inclusion of white clover could be justified. Lucerne appears to be best sown as a pure sward.
Chemical regulation of ripening of processing tomatoes in the field
Authors: Baqar MR , Edwards RA , Lee TH
Published: March 2005

In a three year field study, the effects of the plant growth regulant (2-chloroethyl)phosphonic acid (ethephon) were observed on transplanted and direct-seeded tomato plants of the Roma and Napoli cultivars in the Richmond, Mudgee, Wellington, and Narromine tomato growing areas of New South Wales. Ethephon increased the percentage yield of usable fruit from a single harvest when applied at a concentration of 300-1 000 mg l-1 to crops containg 0-38 per cent usable fruit. The optimum yield of Napoli fruit was obtained when ethephon was applied to a crop containing about 30 per cent usable fruit and the harvest made some 15-20 days later. The compound 2-(4-chlorophenylthio) ethyldiethylammonium chloride (CPTA), which induces the synthesis of lycopene in many plant tissues, did not increase the rate of accumulation of usable fruit when compared with untreated crop. When used in a combination treatment with ethephon, CPTA did not increase usable fruit accumulation compared with ethephon treatment.
Whole wheat grain feeding of Merino ewes. 3. Influence of level of wheat and vitamin A on wool growth in pregnancy and lactation
Authors: McManus WR , Reynolds JA
Published: March 2005

In experiment 1, ewes were fed three levels of wheat in pens, with or without vitamin A, from joining to weaning. The wheat levels ranged from 3.4 to 4.6 kg head-1 week-1. Control groups were run on native pasture. In experiment 2 three levels of wheat, which ranged from 3.9 to 7.1 kg head-1 week-1. were fed to ewes from joining to weaning. At each wheat level two groups were fed wheat in pens (wheat/ pen); another group was fed wheat in small paddocks (wheat/paddock). One of the wheat/pen groups received vitamin A. A control group was run at pasture. Vitamin A had no effect on wool traits except on wool yield in experiment 2. Clean wool weight and staple length increased linearly with increasing wheat intakes in both experiments. The relationship between fibre diameter and wheat level was linear in experiment 1 and curvilinear in experiment 2. In experiment 2 there were differences between wheat/pen and wheat/paddock groups in all the wool traits measured. In experiment 1, wool growth rate was reduced by 40 per cent in the wheat groups and by 44 per cent in the pasture groups during late pregnancy and lactation. In experiment 2, compared with early pregnancy, wool growth rate was reduced by 11 per cent and 31 per cent in the wheat groups during late pregnancy and lactation respectively.
Some relationships between wool production, nitrogen intake and digestible organic matter intake
Authors: Robards GE , Tribe DE , Thomas R
Published: March 2005

Two experiments are described in which the wool production of Merino wethers receiving roughage rations of varying quantity and average crude protein content was examined. The results support a hypothesis that wool growth response to supplementation of low quality roughage is more closely related to the total digestible organic matter intake than to the total nitrogen intake. The second experiment demonstrates that in the short term the efficiency with which dietary nutrients are used for wool production depends upon the direction of liveweight change of the sheep.
The digestibility of wheat, barley or oat grain fed either whole or rolled at restricted levels with hay to steers
Authors: Toland PC
Published: March 2005

The apparent digestibility of whole and dry-rolled grain was measured in separate experiments for oats, barley and wheat with six two-year-old steers fed rations of 4 kg of grain and 2 kg of hay in a cross-over design. Dry rolling oats, barley and wheat increased the mean digestibility of organic matter from 76.7 to 81.0 per cent, 52.5 to 85.2 per cent, and 62.9 to 87.7 per cent respectively. Whole grains recovered from the faeces was: oats 6.7 per cent, barley 48.2 per cent and wheat 39.8 per cent.
Effect of deferred autumn grazing and stocking rate of sheep on pasture production in a Mediterranean-type climate
Authors: Brown TH
Published: March 2005

The effect of deferred autumn grazing and stocking rate on an annual pasture was monitored for five years at Kybybolite Research Centre in the south-east of South Australia. Pasture availability, yearly production and botanical composition were measured under a series of eight stocking rates from 12.4 to 29.7 Merino wethers per hectare. Autumn deferment resulted in extra available pasture during the winter months of June, July and August. However, the continously grazed pastures reached the same level of availability as the deferred pastures in spring. By the third year of the experiment yearly pasture production irrespective of grazing management was greatly reduced at the higher stocking rates. This reduction was associated with an invasion of Poa annua and Juncus bufonius. Autumn deferment tended to favour the growth of Wimmera ryegrass at the lower stocking rates whereas continuous grazing tended to favour clover growth at these stocking rates.
Seed production of Stylosanthes guyanensis. 3. Effects of pre-harvest desiccation
Authors: Loch DS , Hopkinson JM , English BH
Published: March 2005

Strips within commercial crops of Stylosanthes guyanensis in the Mareeba district of north Queensland were sprayed with diquat 4, 6 and 10 days before harvest and compared with unsprayed strips. Pre-harvest desiccation made combine harvesting easier, but did not increase harvest yield. Where seed formation and maturation was still possible, desiccation prevented this without substantially increasing the loss of seed to the ground; increased harvest efficiency was thus offset by a diminished quantity of standing seed. However, where there was little or no further potential for seed development, diquat had virtually no effect on the quantity of standing seed or harvest efficiency. It was concluded that the results warranted neither recommendation nor further evaluation of preharvest desiccation of S. guyanensis seed crops.
Genetic improvement of meat sheep. 1. A comparison of different methods of correcting weaning weight for age of lamb
Authors: Gregory IP , Roberts EM , James JW
Published: March 2005

Several methods of correcting lamb weaning weight for age were compared. Lambs were weighed at birth, at 90 � 1 day of age, when the oldest and when the youngest lamb was 90 days and when the average age of lambs was 90 days. Weights were adjusted to 90 days by the methods of regression, regression pooled within sire groups, average daily gain with and without a standard birth weight and weight per day of age. All the correction methods examined gave similar results and there was no significant difference between methods. The correlations between the actual 90-day weight and the adjusted weights ranged from 0.922 to 0.960 and were highest when the weights taken when the average age of lambs was 90 days were used as the basis for adjustment. All adjusted weights were significantly biased as estimates of actual 90-day weight, but the bias was least for weights when average age was 90 days.
Influence of phosphorus content on feed intake and weight gain in sheep
Authors: Ozanne P , Purser DB , Howes KMW , Southey I
Published: March 2005

In two experiments penned sheep were fed the dry residues from subterranean clover based pastures. Phosphorus levels in the pelleted residues, produced by varying the rate of superphosphate application, ranged from 0.07 to 0.23 per cent. In addition, a high phosphorus ration was produced by the addition of inorganic phosphate salts. This supplement raised the phosphorus concentration from 0.07 to 0.30 per cent of dry matter. In both experiments, increasing the concentration of phosphorus in the dry feed by higher fertilizer rates resulted in: increased dry matter intake; increased percentage of dry matter digested (at least in one experiment) ; more phosphorus retained by the sheep (although on feed containing 0.1 1 per cent phosphorus or less, losses still exceeded gains) ; and increased body weight gains. Increasing the phosphorus content of the feed by use of an inorganic supplement gave: a smaller increase in dry matter intake; decreased digestibility; positive phosphorus balances; and an increase in body weight gain of about half that given by unsupplemented feed high in phosphorus. The results indicate that for maximum animal production, phosphorus concentrations needed in the dry feed are higher than those produced by fertilizing legume-based pastures at the lowest rate that gives maximum dry matter production. Near linear responses in body weight gains were obtained up to phosphate fertilizer rates of about three times those needed for maximum pasture yield.
The laying performance of hens fed Uniwhite lupin seed and supplementary DL-methionine
Authors: Hughes RJ , Orange KS
Published: March 2005

Hens, aged 34 weeks, were fed diets containing 0, 10 or 20 per cent lupin seed (cv. Uniwhite) and sufficient DL-methionine to raise the level to either 1.23 or 2 per cent of the protein. (1.23 per cent was the proportion of methionine in the control diet containing wheat, barley and meat-meal but no lupin seed.) The hens were fed for 24 weeks and each diet had the same metabolizable energy to nutrient ratio for each of the following: crude protein, calcium, phosphorus, sodium, and supplementary vitamins and trace elements. Egg number, egg weight, graded quality of eggs and mortality were recorded daily. Feed consumption was recorded midway and at the end of the experiment. An average peak rate of lay of 76 per cent was reached at 34 weeks and held until hens were 39 weeks of age. At the end of the study (hens aged 58 weeks), the average rate of lay was 57 per cent. Feed consumption increased significantly (P < 0.05) with increased proportions of lupin seed in the diet. There was a significant difference in mean egg weight (58.1 v 58.6 g) between factorial treatments containing methionine at 1.23 and 2 per cent of the protein. There were no significant differences between factorial treatments in any other of the measurements analyzed, namely, hen-day egg production, consumption of metabolizable energy or of protein, or the metabolizable energy or protein required per kg of egg. Uniwhite lupin seed supplemented with methionine was included in a laying diet at 10 and 20 per cent without a subsequent loss of laying performance.
Wild oat density and the duration of wild oat competition as it influences wheat growth and yield
Authors: McNamara DW
Published: March 2005

The effects of removing wild oats (Avena spp.) from wheat (cv. Gamut) at different stages of wheat growth were investigated in three replicated factorial field experiments at the Tamworth Agricultural Research Centre. In addition, two wild oat densities were compared in the first experiment, and handpulling wild oats was compared with cutting and a shielded paraquat spray in the second experiment. Wheat yield was linearly reduced by up to 1.025 g m-2 day-1 for the duration of wild oat competition. Reductions in tiller number and dry matter yield measured at maturity and the number of tillers per plant recorded at the 5-6 leaf stage were also proportional to the time wild oats were allowed to compete with the wheat. This competitive effect of wild oats increased with increasing weed density. Handpulling and cutting wild oats gave similar measured competitive effects whereas the paraquat spray applied at the 2-3 leaf stage of wheat reduced wheat density.
Foliar damage, residue levels and tuber yield in potato treated with various concentrations of 2,4-D at three stages of growth
Authors: Fung KH , Belcher RS , Downie WA
Published: March 2005

A field trial with potato plants treated with 0, 0.1, 1 and 10 p.p.m. 2,4-D at the emergence, flowering and flower drop stages was conducted. Symptoms of foliar damage were noted a month after the treatments. The susceptibility of the plants to 2,4-D damage decreased in the order of emergence, flowering and flower drop of the plants, irrespective of the concentration of the herbicide. There may be economic loss for producers of seed potatotes owing to the foliar 2,4-D damage. Residues of 2,4-D in both foliage and tubers were determined. The limit of detection was 0.005 p.p.m. The average recovery of 2,4-D amine and acid from fortified foliage and tubers was 81 to 87 per cent. Residue levels of 0.110 p.p.m. 2,4-D were found in the slightly damaged foliage following application at flower drop, but only 0.010 p.p.m. was found in severely damaged foliage following application at emergence. Traces of 2,4-D residue were found in the tubers after the plants had reached maturity. In general, tuber yield (numbers, weight and specific gravity) was not affected by the various concentrations of 2,4-D applied at the three stages of growth. However, it appeared possible that the yield of No. 1 grade tubers might be slightly reduced when plants are treated at emergence, irrespective of the concentration of the herbicide.
Factors associated with 'maturity bronzing' of banana fruit
Authors: Campbell SJ , Williams WT
Published: March 2005

Maturity bronzing', a severe skin blemishing of banana fruits of unknown cause, is of considerable economic importance in north Queensland. Two treatments were imposed on a set of 68 plants; these were bunch covering (aimed at influencing bunch microclimate) and removal of hands and leaves (aimed at influencing rate of filling). A series of observations was recorded from emergence to harvest; these were blemish details (13 attributes), morphological characters (15 attributes) and meteorological data (34 attributes). Numerical methods were used to relate severity of blemish to the other attributes. Imposed treatments were completely without effect. Morphological comparisons showed that severe bronzing was commoner in rapidly-filling fruit from plants with a reduced pseudostem girth and a small number of hands. The most striking associations were with meteorological conditions; severe blemishing is highly significantly associated with hot, humid, overcast conditions. The evidence is consistent with the hypothesis that bronzing is due to excessive turgor pressure, resulting from rapid water uptake when transpiration is low.
The evaluation of forage nutritive quality by microdigestion
Authors: Ayres JF , McManus WR , McFarlane JD
Published: March 2005

Ruminal microdigestion of test forage samples was run concurrently with conventional digestion trials in an experiment devised to evaluate microdigestion as a technique for assessing the nutritive quality of forages common to southern Australia. Microdigestion was found to be closely associated with in vivo digestibility. Significant variation in microdigestion estimates was attributed to basal diet, test forage, pouch fabric and individual sheep; microdigestion differences of the order of two to three units were detectable. It is suggested that the microdigestion technique offers potential scope for providing unbiased assessment of forage nutritive quality under field conditions.
Effects of initial clover seeding rate and length of ley on pasture production, soil nitrogen and crop yields in a ley farming system
Authors: Watson ER , Lapins P , Barron RJW
Published: March 2005

Several factors relating to the use of subterranean clover (Trifolium subterraneum) in a ley farming system were studied at Kojonup in the south-west of Western Australia viz; the effect of seeding rates of clover on the botanical composition and herbage production of a grazed pasture over five years; the build-up of soil nitrogen over this period, and the effect of 5, 8 and 11 years of clover on wheat yield and on subsequent regeneration of the pasture. In the final year (year 12) the effects of lime on mineralization of soil nitrogen and on crop yields were also studied. Seeding rates of clover in excess of 6 kg ha-1 affected botanical composition in the first year, and yield of pasture in the first two years only. Build-up of soil nitrogen over the first five years (when all plots were grazed) was significantly greater (P < 0.05) where clover had been sown at the higher rates (< 6 kg ha-1) but this did not result in increased wheat yields at the end of this period. In the 12th year, when all plots were cropped, there were no significant differences in grain yield between treatments cropped for the first time (after 11 years of clover) and those cropped either once or twice in the preceding six years. Cropping reduced pasture production in the early part of the post crop year but the proportion of clover in the pasture increased. The application of lime (in year 12) resulted in a significant increase in grain, and straw yields and nitrogen uptake on all treatments. The results suggest that crop yields can be sustained in short term rotations provided there is sufficient clover present in the pasture phase.
Plant nutrition studies on some yellow and red earth soils in northern Cape York Peninsula. 1. Soils and their nutrient status
Authors: Isbell RF , Jones RK , Gillman GP
Published: March 2005

Eleven complete profiles and an additional 112 surface soils of deep sandy yellow and red earths in the far northern part of Cape York Peninsula have been sampled for laboratory studies. Chemical analyses showed that these acid soils are very low in organic carbon, nitrogen, phosphorus, potassium, sulphur, copper, zinc, manganese, cobalt, exchangeable basic cations, and base saturation. They have relatively high contents of exchangeable aluminium. The variability of surface soil chemical properties is relatively low. Glasshouse experiments with Stylosanthes humilis cv. Gordon conducted on soils from the 11 profile sites showed responses to sulphur, potassium, zinc and lime on all soils and to copper on about half the sites. Considering the results of both the laboratory and glasshouse studies, it is suggested that responses to nitrogen, phosphorus, zinc and probably calcium and copper are likely in the field. Responses to sulphur may be transitory because of the presence of appreciable levels of phosphate-extractable sulphur at depth.
The response of lupins to waterlogging
Authors: Broue P , Marshall DR , Munday J
Published: March 2005

The growth response of species and lines of lupin (Lupinus spp.) to short-term flooding of the root system during vegetative growth was measured in glasshouse and controlled environments. L. luteus was consistently more flood tolerant than L. albus, L. angustifolius and L. mutabilis. Some data showed also that lines within species may vary in their response to flooding but the differences among lines were less marked than those among species.
Growing and fattening yearling steers on mature standing wheat and barley crops
Authors: Round MH , Stephens PC , Day HR
Published: March 2005

In three experiments, yearling steers grazed standing mature wheat and barley crops during February to April of three consecutive years in a Mediterranean environment in southern Australia. In one experiment, steers were grazed for 51 days on barley crop, which was either strip grazed or set stocked. The steers had mean daily liveweight gains of 0.92 and 0.74 kg respectively. In a second experiment, steers grazing a barley crop for 69 days with estimated rations of 3.2,5.0 and 6.8 kg of grain a day respectively consumed 72, 66 and 64 per cent of the total grain reserved, and had mean daily liveweight gains of 0.88, 0.83 and 0.96 kg. In the third experiment, steers grazing wheat and barley crops over 86 days ate an estimated 80 per cent of the available grain and had mean daily liveweight gains of 0.71 and 0.74 kg respectively. In all three experiments, mean fat cover of the steers at slaughter was less than optimal. In none of the experiments were differences in liveweight, carcase weight and fat cover between treatments significantly different. We conclude that the reserving of standing wheat and barley crops is a practicable management technique for growing and fattening steers. Further investigation is needed for the refining of the technique
DDT residues in poultry from rice hulls used as poultry litter
Authors: Gilbert WS , Singh G , Macindoe RN
Published: March 2005

The uptake of DDT into poultry tissues arising from the use of DDT contaminated rice hulls as poultry litter was assessed in trials conducted at the Poultry Research Station, Seven Hills. Litter treatments and periods of exposure were respectively 25, 50 and 100 mg kg-1 DDT and 22 weeks for laying hens and 50 mg kg-1 DDT and up to nine weeks for broiler chickens. Feed, eggs, body fat and litter were sampled at intervals for DDT residue and analysis. DDT uptake in egg yolk increased with the period and level of treatment, the highest residuesoccurring about two months after the start of the trial. Whole egg residues (0.29-1.45 mg kg-1) in some cases (1 00 mg kg-l treatment) exceeded the 0.5 mg kg-l Codex and 1 mg kg-l Australian recommended maximum residue limits and approached the 1.5 mg kg-1 actionable level of the United States Food and Drug Administration. The body fat residues of layers at 22 weeks (3.34-10.1 mg kg-1) varied with the treatment, the 50 mg kg-1 and the 100 mg kg-1 treatments producing levels approaching or exceeding the 7 mg kg-1 Australian and overseas limits. DDT uptake in the body fat of broilers increased with the period of exposure, highest residues occurring about six weeks after the start of the trial. Residues (19-133 mg kg-1) grossly exceeded the 7 mg kg-l limits
Germination characteristics of seven Stylosanthes species
Authors: McIvor JG
Published: March 2005

The germination response of dehulled, scarified seeds to a range of constant and alternating temperatures, and to moisture stress was measured in seven Stylosanthes species. Rates of water uptake and loss were also measured. With constant temperatures, both total germination and germination rate were greatest at 25�C for all species except for S. hamata which germinated faster at 30�C. Both higher and lower temperatures slowed and depressed germination. Constant and alternating temperatures produced similar results except at high temperatures where germination was less with the alternating regime. Moisture stress greatly reduced germination of S. guyanensis cv. Cook, S. scabra and S. viscosa but had little effect on S. fruticosa, S. guyanensis CPI 40294 and S. subsericea. Initial rate of water uptake was greatest for S. hamata and S. subsericea but moisture content was similar for all species by 18 hours. There were no differences between species in rate of water loss from imbibed seeds.
Liveweight changes of steers, ewes and lambs in relation to height of green annual pasture
Authors: Hamilton D , Ada ID , Maden JJL
Published: March 2005

Relationships were examined for weight (liveweight) changes of yearling steers and autumn lambing ewes and their lambs against height (median height) of green annual pasture. The sheep and steers grazed separately at five rates of stocking and together in seven ratios at one equivalent rate of stocking. Some aspects were examined in July in each of three years and others in winter and spring of one year. The lambs responded to an increase in pasture height up to at least 120 mm. The response was the same for the lambs 6 and 11 weeks old. The ewes lost weight about six weeks after lambing where the pasture was less than about 38 mm high and later responded to pasture height according to their earlier weight loss. The steers at the heavier rates of stocking lost weight on pasture below about 12 mm high, reached maximum rate of gain when it was about 120 to 140 mm, then gained weight at a slower rate on even taller pasture. The steers at the lightest rates of stocking did not respond to pasture height, although it was initially only 18 to 60 mm. The rate of weight gain of the lambs and steers in July increased in successive years on pasture of the same height. The year effect could have been partly due to differences in pasture density (lambs) and clover percentage (steers). At a given pasture height, the lambs generally grew faster with mixed than with separate stocking, but steer growth was the same for both methods of stocking.
Effects of nitrogen fertilizer applied in autumn and winter on milk production from a tropical grass-legume grazed at four stocking rates
Authors: Cowan RT , Stobbs TH
Published: March 2005

The effect of applying 50 kg N ha-I in autumn and winter each year on milk yield of Friesian cows and dry matter yield and botanical composition of a green panic (Panicum maximum var, trichog1ume)- glycine (Glycine wightii cv. Tinaroo) pasture was measured over two years on the Atherton Tableland, north Queensland. Pastures were grazed at 1.3, 1.6, 1.9 and 2.5 cows ha-1. Milk yield and pasture yield were increased by nitrogen fertilization, particularly at the high stocking rates (P < 0.05). Increases in milk yield from mid-autumn to spring almost totally accounted for increases in annual milk production. Nitrogen fertilizer did not decrease the yield of legume, but legume content of the pasture was reduced in the second year (P < 0.01). Response by non-leguminous species to nitrogen increased (P < 0.05) with stocking rate, a change associated with decreasing legume contents of the pastures. Average fat corrected milk (FCM) yield per cow from mid-autumn to spring was restricted by less than 1600 kg pasture D.M. on offer cow-I or 2500 kg D.M. ha-1. When compared at the same dry matter yields, FCM yield was always higher from nitrogen fertilized pastures than from pastures not recieving fertilizer nitrogen.
An evaluation of ammonium sulphate as a potential NPN source for ruminants
Authors: Graham CA , Warner RB , Jenkins SL
Published: March 2005

Experiments were undertaken to examine the comparative toxicity to sheep of ammonium sulphate and urea given as single doses and the value of ammonium sulphate fed alone or in combination with urea as a supplement to low nitrogen roughages. Ammonium sulphate dosing produced significantly lower mean blood ammonia levels than urea dosing. Fifteen grams of nitrogen as ammonium sulphate were tolerated as a single dose but the equivalent level of urea was toxic. lnappetance and ruminal stasis was noted when sheep fed a low nitrogen roughage (0.5 per cent nitrogen) received ammonium sulphate supplement as the sole non-protein nitrogen source. Ruminal stasis and inappetance may have been due to sulphide toxicity. Ammonium sulphate when used at lower levels in varying combinations with urea was well utilized as a nitrogen and sulphur source even when supplying 50 per cent of the supplemented nitrogen.
Symbiotic characteristics of Trifolium ambiguum seedlings grown in tube culture as affecting subsequent symbiotic vigour
Authors: Zorin M , Brockwell J , Muller WJ
Published: March 2005

A hexaploid line of Caucasian clover (Trifolium ambiguum), inoculated with two strains of Rhizobium trifolii, was grown in tubes of nitrogen-free medium under bacteriologically-controlled conditions. Observations were made on various symbiotic characteristics of the seedlings. After 30 days, they were transplanted into pots of sand and vermiculite watered with nutrient solution lacking nitrogen and grown for another 100 days. Uninoculated plants supplied with various levels of combined nitrogen were used for comparison. R, trifolii strain CC283b was classified as highly effective and was greatly superior in nitrogen-fixing ability to strain CC231a which had been used routinely in Australia for many years for inoculation of experimental sowings of Caucasian clover. In this line of T, ambiguum, the inherent plant-to-plant variation was accentuated in plants relying on symbiotically-fixed nitrogen. This effect was strong in plants inoculated with the intermediately-effective strain CC231 a but mild in plants inoculated with the highly-effective strain CC283b, i.e., a larger component of the variability amongst CC231a plants was due to the symbiosis than was the case for CC283b plants. Seedlings inoculated with the intermediately-effective strain and selected on the basis of 'within-tube' characteristics such as time to initial nodulation, symbiotic effectiveness rating, and nodule size produced more dry matter when grown in pots than the unselected population and were as productive as plants inoculated with the highly-effective strain. In contrast, with the highly-effective strain, selected plants grown in pots produced very little more dry matter than the unselected population. It was concluded that the use of 'within-tube' symbiotic characteristics as a means of selection for improved production will only be successful when a substantial component of the plant-to-plant variability is due to the symbiosis.
Transfer of nitrogen from three pasture legumes under periodic defoliation in a field environment
Authors: Simpson JR
Published: March 2005

Subterranean clover (Trifolium subterraneum), white clover (T. repens) and lucerne (Medicago sativa) were each grown in association with cocksfoot (Dactylis glomerata) for three years in field microplots with periodic removal of herbage. The three legumes produced quite different effects on the nitrogen uptake of the grass and the nitrogen content of the underlying soil. The total nitrogen input to the plant-soil system by subterranean clover was only about half that by either of the two perennial legumes. However, subterranean clover continually donated the most nitrogen to the grass. White clover also increased the nitrogen yield of the grass during the second year, but in the third year, severe competition caused a 45 per cent mortality of grass plants and nitrogen transfer was reduced. Both clovers released about 40 per cent of their apparent nitrogen inputs, distributed between the grass and the soil ; thus soil nitrogen under white clover increased by 160 kg N ha-1 year-1. Lucerne put the most nitrogen into the system but produced only transient increases in grass nitrogen yield. Twenty-one per cent of the apparent nitrogen input of lucerne was donated to the soil.
Correction - Use of a soil moisture model and risk analysis to predict the optimum time for the aerial sowing of pastures on the Northern Tablelands of New South Wales
Authors: Dowling PM , Smith RCG
Published: March 2005

The objective of this study was to determine the time of year that maximized establishment and . minimized the risk of failure in aerial sowing of pasture seed on the Northern Tablelands of New South Wales. This was achieved by relating a set of monthly measurements of establishment spanning two years to mean soil moisture, predicted by a water balance model for the six-week period following sowing. From this relationship, establishment was simulated for 61 years using historical rainfall data to estimate probability density functions of establishment for each week of the year. From these functions it was concluded that maximum establishment with minimum risk can be expected from sowing in the June-July period. For perennial species plant survival over the first summer is of more practical importance than per cent establishment. Our data on plant survival, although not presented, indicated a close relationship existed between establishment and survival and supported the conclusion that the optimal time for oversowing is June-July.
The effects of moisture stress on the germination of some Australian native grass seeds
Authors: Hagon MW , Chan CW
Published: March 2005

The effects of moisture stress on the germination of the native grasses Themeda australis, Bothriochloa macra, Danthonia spp. and Stipa bigeniculata and the introduced species Lolium perenne (ryegrass) were investigated under laboratory and glasshouse conditions. At osmotic potentials between -3 and -10 bars and soil water potentials between -4.5 and -10 bars, the level of germination of ryegrass was greater than that of the native grasses. Also, at any given soil water potential, the levels of germination of both ryegrass and the native grasses were greater in a clay soil than in a sandy one. When native grass seeds were sown on the surface of the soil in flats in a glasshouse there was no germination in the absence of added water, even though the initial soil moisture content was as high as 40 per cent in some cases and a straw mulch was applied. When flats were watered daily, Stipa had the highest percentage establishment and Themeda the least. Establishment of all species was reduced by a decline in soil moisture content.
Effect of sowing rate, grass competition and cutting frequency on persistence and productivity of two lucerne (Medicago sativa) cultivars at Biloela, Queensland
Authors: Bishop HG , Gramshaw D
Published: March 2005

Persistence and production of lucerne (Medicago sativa) cvv. Hunter River and Siro Peruvian were studied on alluvial soil under raingrown conditions in a factorial experiment examining effects of lucerne sowing rates (1.1 and 4.4 kg ha-1), competition from buffel grass (Cenchrus ciliaris cv. Biloela) and 3,6 and 9-weekly cutting frequencies. Lucerne populations at establishment from 1.1 and 4.4 kg ha-1seed averaged 18 and 60 plants m-2, which reduced to 4 and 7 plants m-2 respectively after three years. Population initially declined rapidly at the higher sowing rate and the presence of buffel grass accentuated this decline. Persistence of Siro Peruvian was inferior to that of Hunter River. Cutting frequency did not affect lucerne persistence. Sowing pure lucerne and cutting every six weeks produced highest lucerne yield, but total yield was greatest from the lucerne/buffel grass mixture cut either 6- or 9-weekly. Increasing lucerne sowing rate increased lucerne yield only slightly and lucerne cultivar had no effect on total lucerne yield.
Weeds in grain-lupins. 2. The response of narrow-leafed lupins to pre-emergence herbicides
Authors: Allen JM
Published: March 2005

Results are reported from 18 experiments in which pre-emergence herbicides were evaluated in narrow-leafed lupins, (Lupinus angustifolius). At all 11 sites south of Perth (latitudes 32�S to 35�S) there was a significant lupin grain yield response to herbicides (P<0.05). There was a significant yield increase at only one of the seven sites north of Perth (latitudes 28�S to 32�S). Significant yield increases were obtained on at least one occasion with alachlor 1.1, 2.2 kg a.i. ha-1; diuron 0.4, 0.8, 1.3 kg a.i. ha-1; linuron 1:1, 2.2 kg a.i. ha-1; simazine 1.1, 1.7, 2.4 kg a.i. ha-1 and trifluralin 0.5, 1.1 kg a.i. ha-1 (P<0.05). Diuron 0.8 kg a.i. ha-1; linuron 2.2 kg a.i. ha-1 and simazine 1.1, 1.7 kg a.i. ha-1 each resulted in a significant lupin yield reduction on one occasion (P<0.05).
Efficiency of wool production of grazing sheep. 4. Forage intake and its relationship to wool production
Authors: Langlands JP , Donald GE
Published: March 2005

Relationships between the quantity of forage consumed, and the wool growth of penned and grazing sheep, were examined in two experiments. Wool production was proportional to intake over the range of intakes examined.
An evaluation of the 'Scanogram' as an ultrasonic aid in assessing carcase composition of live sheep
Authors: Thompson JM , Pattie WA , Butterfield RM
Published: March 2005

An evaluation of the Scanogram as an aid in assessing carcase composition of live sheep was made using 23 Dorset Horn rams. Live animal measurements included tracings from Scanogram photographs taken at the 12th rib, tuber coxae and shoulder sites and an 18-hour fasted liveweight. Half carcases were dissected into fat, muscle, bone and connective tissue. Repeatability of photograph interpretation was of the order of 0.75 for fat depth at the 12th rib and tuber coxae sites and M. longissirnus area, but low for shoulder fat depth. Correlations between scan and carcase measurements made at the same site were of the order of 0.7 for 12th rib and tuber coxae fat depth and low and non-significant for shoulder fat depth and M. longissirnus area.Scanogram measurements of fat depth at the 12th rib and tuber coxae sites were the best predictors of percentage fat, and when considered in combination with liveweight provided the best estimate of total carcase fat weight. Liveweight was the best predictor of total muscle weight and the addition of Scanogram measurements to liveweight did not improve the accuracy of prediction. From examination of confidence intervals about predicted means it was concluded that the value of the Scanogram, as an aid to assessing carcase composition, was limited to differentiating between individual animals of widely differing carcase composition, or selecting groups of animals where confidence was required in the group mean.
Hybrid pennisetum in a warm temperature climate: regrowth and stand-over forage production
Authors: Muldoon DK , Pearson CJ
Published: March 2005

Dry matter, tillering and herbage quality changes were examined in hybrid pennisetum (Pennisetum americanum x P. purpureum) over 15 weeks of uninterrupted regrowth in summer and autumn, and in regrowth of differing ages throughout autumn until frosting. During uninterrupted regrowth above-ground dry matter accumulation was slow until internode elongation, at which time the apparent utilization of visible radiation was 10 per cent. Nitrogen and organic matter digestibility percentages declined with age except during internode elongation. The dry matter yield was high (12 t ha-1) but the quality of the forage poor after 12-13 weeks. When defoliated in summer and autumn the rate of regrowth decreased as defoliation was delayed. Nitrogen concentration decreased during autumn and fell rapidly after frosting; digestibility also decreased with time but increased with lateness of defoliation when forage was compared at the same age. Defoliation in mid-February was recommended to provide a reasonable yield of stand-over forage containing adequate concentrations of crude protein and digestible organic matter.
Growth and oil production of lemongrass (Cymbopogon citratus) in the Ord Irrigation Area, Western Australia
Authors: Beech DF
Published: March 2005

Experiments with irrigated lemongrass (Cymbopogon citratus) have shown that high oil yields can be obtained in the Ord Irrigation area, Western Australia. The highest oil yield of 419 1 ha-1 over a 360 day period was obtained when the plants were cut at 60 day intervals and at a height of 20 cm. Longer intervals and higher cutting heights gave lower oil yields, although in some cases, fresh and dry matter yields were increased. Studies on the effect of water stress showed that time between irrigations in the dry season should not be more than ten days if oil yields are to be maintained. Wilting of cut lemongrass in the dry season was shown to result in a loss of oil, with losses increasing with the duration of wilting up to 11 hours. Under irrigated conditions, lemongrass removed large quantities of nutrients, particularly potassium. Over the 360 day period, maximum amounts of N, P and K removed were 186, 26 and 384 kg ha-1 respectively.
Effects of photoperiod and temperature on flowering of twelve Stylosanthes species
Authors: Cameron DF , Mannetje L't , 't Mannetje L
Published: March 2005

The flowering of accessions from 12 Stylosanthes species was studied in two controlled environment experiments and a glasshouse experiment. In controlled environments photoperiod exerted a strong control over flowering with short day, day neutral and long day responses being recognized. High temperatures generally delayed flowering, increased the node of first flower and reduced the number of inflorescences, but acted as a modifier only of the basic control exerted by photoperiod. With natural photoperiods in the glasshouse, flowering responses were generally consistent with the photoperiod responses observed in controlled environments. The climatic adaptation of Stylosanthes species is discussed in relation to the alternative reproductive strategies of the photoperiod response types.
The assessment of seasonal yield using some Stylosanthes guyanensis accessions in humid tropical and sub-tropical environments
Authors: Edye LA , Williams WT , Burt RL , Grof B , Stillman SL , Winter WH
Published: March 2005

The seasonal growth patterns of some S. guyanensis accessions were compared in three humid environments at South Johnstone (extended rainfall tropics), 'Heathlands' (seasonally dry tropics) and Cooroy (humid sub-tropics). The accessions were selected mainly for their productivity in previously described small mown sward experiments over three years at each site. Previous methods of presenting seasonal growth patterns are reviewed, and a new, simpler method of presentation is defined. Growth was highly seasonal at all sites. There was no growth during July to November at 'Heathlands' and Cooroy due to moisture and temperature limitations respectively. At South Johnstone growth was continuous but depressed in August and December with limitations due to both soil moisture and temperature: the maximum growth rate was 22 times the minimum growth rate. The accessions differed markedly in their growth patterns at each site. In general, the yield differences between accessions were greater at the beginning and end of the growing season than during the peak growth period. The highest yielding accessions at each site had high growth rates spread over a long period. The yield distribution and persistence of Q8231 and 46589C seemed superior to existing cultivars in tropical and sub-tropical environments respectively
Insecticides for the control of dieldrin-resistant banana weevil borer, Cosmopolites sordidus Germar
Authors: Wright WE
Published: March 2005

Field trials were carried out in the Brunswick River district of New South Wales from 1971 to 1975 to evaluate insecticides against dieldrin-resistant banana weevil borer, Cosmopolites sordidus Germar. Effective control was obtained by spraying the bases of plants and surrounding soil to a radius of 30 cm in spring and autumn with pirimiphos-ethyl and chlorpyrifos emulsions at 2.24 kg active ingredient ha-1 (1.12g per plant) per application. Chlordecone dust, pirimiphos-ethyl granules and chlorpyrifos powder sprinkled by hand at 2.8 kg ha-1 a.i. (1.42 g per plant) per application also gave effective control and could be used where water is unavailable.
Studies of fruit shape in apples: response to gibberellin and cytokin sprays
Authors: Greenhalgh WJ , Godley GL , Menzies R
Published: March 2005

Results of experiments over two seasons at two locations in New South Wales and one in Western Australia have shown that 'typiness' of Red Delicious apples can be improved by the use of blossom applications of the plant growth regulators gibberellin (GA4/7) and N6benzyladenine (BA). Benzyladenine was the more effective of the two materials tested, and stimulated both an increase in the length : diameter ratio (L/D) of the fruit and development of the calyx lobes. The gibberellins were less consistent in their effect. Sprays combining both GA,/, and BA in equal proportions provided little additional benefit to that obtained with BA alone at the equivalent strength.