bluuebunny/crossref_metadata_2025 huggingface dataset:
The timing of a moderate nutritional restriction in mid pregnancy and its effect on lamb birth weight and ewe gestation length
Authors: Holst PJ , Allan CJ
Published: March 2005

Lamb birth weight and ewe gestation length data were collected from a flock of 300-600 parous Border Leicester x Merino ewes over 4 years, as part of a study on nutritional restriction of pregnant ewes. One half of these ewes were nutritionally restricted for a 4-week period commencing 75-95 days post coitus, in order to achieve loss of maternal liveweight and reduction in body fat score to a minimum of 3. The remaining ewes with no nutritional restriction were >6 kg heavier and had a body fat score >0.8 higher at the end of the restriction period. Nutritional restriction affected (P<0.05) birth weight of lambs. With each day's delay in commencing restriction, from day 75 to day 95, gestation length was increased (P<0.001). For each additional day in utero, birth weight was increased by 40-50 g. Restriction and refeeding produced lambs of birth weights and weaning weights indistinguishable from the control ewes, and since there were no apparent disadvantages, mid pregnancy restriction is an alternative nutritional strategy for pregnant ewes.
On-farm methods for assessing zinc sulfate concentrations in footbaths
Authors: Ferrier GR , Bowditch LC , Makin TJ
Published: March 2005

An hydrometer and a titrimetric colour change method were compared as 2 on-farm tests for assessing the strength of zinc sulfate in footbaths used for the control of footrot in sheep. Contamination of zinc sulfate solutions with soil, water, and sheep faeces and urine reduced initial concentrations by up to 33%; however, zinc sulfate concentration could be still assessed by the 2 methods. The hydrometer was found to be the most practical method for on-farm use.
An evaluation of the production potential of six tropical grasses under grazing. 1. Yield and yield components, growth rates and phenology
Authors: Hacker JB , Evans TR
Published: March 2005

Fertilised pastures of 4 varieties of Setaria sphacelata (var. splendida and cvv. Nandi, Narok and Kazungula), pangola grass (Digitaria eriantha ssp. pentzii) and kikuyu grass (Pennisetum clandestinum cv. Whittet) were grazed rotationally over a 3-year period at Beerwah, south-eastern Queensland. Each variety was grazed on a 5-weekly rotation by 2 leaders for 7 days; a follower herd including 2 testers grazed the regrowth for 7 days. The numbers of followers were subjectively adjusted weekly, depending on feed available. The experiment was designed to provide adequate quantities of forage of maximum potential quality to the leaders throughout the year. There were large and frequently consistent differences between the grasses in yield and its various components, leafiness, leaf and forage density, rate of development of leaf dry matter, and time and intensity of flowering under the management system imposed. Of particular interest were the high leaf yield of Narok, high overall yield of Narok and var. splendida, low rate of development of leaf area index of pangola grass and kikuyu grass, and high forage density of kikuyu grass. These differences might be expected to have an effect on pasture quality, carrying capacity and optimal management strategy.
Differential tolerance of annual medics, Nungarin subterranean clover and hedge mustard to broadleaf herbicides
Authors: Young RR , Morthorpe KJ , Croft PH , Nicol H
Published: March 2005

The tolerance of 5 species of annual medics (Medicago spp.), Trifolium subterraneum cv. Nungarin, and hedge mustard (Sisymbrium orientale) to a range of post-emergence broadleaf herbicides was tested over 2 years. The least damaging to M. truncatula was 2,4-DB, which provided more consistent and effective control of hedge mustard than the other chemicals tested, including the less expensive tank mix of 2,4-DB + diuron. MCPA amine or sodium salt (300 g a.i./ha), bromoxynil (420 g a.i./ha), and tank mixes containing MCPA amine (150-175 g a.i./ha) severely damaged annual medics, particularly M. truncatula, with flowering delayed by up to 21 days, and dry matter and seed yields often significantly (P<0.05) reduced. Seed yields of most test plants indicated a degree of recovery from herbicide damage assessed visually after 10 days. Hedge mustard was not always as severely damaged by MCPA amine as was M. truncatula. Nungarin subterranean clover and M. aculeata SAD 2356 were more tolerant than the M. truncatula cultivars of MCPA amine, MCPA sodium salt, MCPA tank mixes, and bromoxynil, and less tolerant of 2,4-DB. Medicago littoralis, M. polymorpha and M. laciniata were severely damaged by bromoxynil but were more tolerant of MCPA than M. truncatula.
Competition between lupin (Lupinus angustifolius L.) and great brome (Bromus diandrus Roth.): development of leaf area, light interception and yields
Authors: Suspasilapa S , Steer BT , Milroy SP
Published: March 2005

Great brome (Bromus diandrus) is a common weed in wheat and can be expected as a weed in lupin crops (Lupinus angustifolius L.), particularly those in rotation with wheat. Although chemical control of brome in lupin is available, those plants escaping control compete with the lupin. This competition has been investigated by comparing the growth of lupin (cv. Yandee) in monoculture with its growth in the presence of 2 densities of brome, and with the growth of brome in monoculture. Each of the 4 treatments was grown with high and low fertiliser applications, to see how the competition was modified by nutrient availability. Water was not limiting. Daily measurements were made of lupin growth rates and the development of leaf area, and light interception and radiation use efficiencies were calculated (g DM assimilated per MJ intercepted photosynthetically active radiation). Radiation use efficiency changed with the phase of development of lupin, increasing to over 3 g/MJ at 95 days after sowing. It was higher in the high fertiliser treatments and in the presence of brome, particularly before 95 days after sowing. Changes in unit leaf rate (i.e. net assimilation rate) of lupin due to brome were small, but these, and changes in radiation use efficiencies, may have played a minor role in the depression of crop growth rates, more important during early lupin growth than later when leaf area indices had reached >15% of their maximum values. Depressions of the crop growth rate of lupin caused by the presence of brome were linearly related to changes in leaf area indices of lupin. The decrease in lupin seed yield per plant was due to a decrease in pod number per plant, not to a change in the number of seeds per pod or single seed weight. The number of pods was linearly related to the number of axes per plant (i.e. branches plus main stem).
Responses to protein plus energy supplements of pregnant ewes eating mature grass diets
Authors: Stephenson RGA , Bird AR
Published: March 2005

Three experiments were conducted with ewes during late gestation (last 4 weeks) to examine metabolic and lamb birth weight responses to supplements. In a metabolism experiment, 18 ewes were divided into 2 groups and offered 800 g chopped Rhodes grass (Chloris gayanu, 1.1% N) with or without a supplement of 150 g cottonseed meal + 50 g molasses, daily until parturition. Supplementation was associated with significant increases in intake of digestible dry matter (37%) and crude protein (121%). Supplemented ewes had significantly greater liveweight gain (173 v. 39 g/day), plasma glucose (2.9 v. 2.5 mmol/L), glucose entry rate (20.6 v. 12.3 mmol/h), udder measurements (e.g. circumference, 548 v. 443 mm), and milk yields (measured at day 2 post-partum, 1748 v. 627 mL/day), and had heavier lambs at birth (3.9 v. 2.9 kg). In a second experiment, 10 ewes were pen-fed chopped Rhodes grass ad libitum, and 5 received individually 150 g cottonseed meal + 100 g molasses administered daily. Supplemented ewes were significantly heavier (47.8 v. 45.0 kg) in the last week before parturition. Supplementation was associated with improved ewe liveweight change (48 v. -33 g/day) and lamb birth weight (3.4 v. 2.4 kg). In a third experiment, 42 ewes grazed a 80-ha paddock during a dry season and received daily 1 of 3 individually administered treatments: control (20 mL water drench); 7 g urea + 4 g sulfate of ammonia in a 20 mL drench; 100 g meat and bone meal + 100 g molasses + 3 g urea administered as a slurry in a single drench. Performance and metabolic parameters for the 3 groups were ewe liveweight gain (38, 80, 131 g/day), rumen ammonia concentration (7.1, 10.0, 8.6 mmol/L), plasma glucose (2.6, 2.6, 2.1 mmol/L), plasma hydroxybutyrate (0.6, 0.5, 0.4 mmol/L), and lamb birth weight (3.5, 3.7, 4.0 kg). Differences were significant between the protein-supplemented and control groups for all parameters except rumen ammonia concentration. The data support the conclusion that protein supplements provide a production response in pregnant ewes that is sufficient to improve lamb survival rates when the nutrition from grass diets is inadequate.
Effect of supplementing sheep with oat grain on their intake, digestion, and nitrogen balance when fed chopped carpet grass (Axonopus affinis Chase) hay
Authors: Lloyd CE , Davies HL , Lloyd Davies H
Published: March 2005

The effect of 0, 150, 300 and 450 g/day of oat grain on voluntary consumption, digestibility, and nitrogen balance in sheep offered chopped carpet grass(Axonopus affinis Chase) hay was studied.Carpet grass intake was significantly (P<0.05) decreased at the 2 higher levels of oat grain. The intake of unsupplemented hay was 606 g/day, compared with 410 g at the highest oat intake. Total dry matter intake increased linearly with level of oat supplementation, from 606 to 816 g/day. No associated effects were detected on the digestibility of the hay. Digestibility of the cell wall components decreased at the higher level of oat supplementation.
Influence of soil pH on the development of symbiosis in field-grown acid-sensitive and acid-tolerant annual medics
Authors: Young RR , Brockwell J
Published: March 2005

Relationships between soil pH, resident population of Rhizobium meliloti in the soil, rhizobial colonisation of the rhizosphere, and nodulation of annual species of Medicago were examined. Established swards of M. truncatula (acid-sensitive) and of M. murex and M. polymorpha (acid-tolerant) growing at 6 different locations in central and western New South Wales were sampled to measure soil pH, to enumerate the populations of R. meliloti resident in the soil and colonising plant rhizospheres, and to assess the extent of nodulation. Soil pH (0.01 mol CaCl2/L) varied from 4.70 to 7.25, soil populations from 3 to 100000 rhizobialg, and rhizosphere populations from 10 to >1 x 106 rhizobia/plant. Nodulation varied from poor to good, depending on growing period and location, but was consistently poorer on M. truncatula than on M. murex or M. polymorpha. Regression analysis showed a consistent and significant (P<0.01) relationship between rhizobial colonisation of the rhizosphere and extent of nodulation. There was also a significant (P<0.001) correlation over all 44 sampling sites between soil pH and the population of R. meliloti resident in the soil. The relationships between soil pH and rhizosphere colonisation, and between soil pH and nodulation, were significant for M. truncatula (P<0.01, P<0.02, respectively) but not for either M. murex or M. polymorpha. These data suggest that the range of soil pH at which M. truncatula was growing (4.80-7.25, but mainly 4.8-5.6) spanned the threshold at which unfavourable soil pH began to obstruct normal expression of its symbiosis, whereas, the critical soil pH levels for symbiotic development of M. murex and M. polymorpha were below this range.
Effect of nitrogen source and soil type on inorganic nitrogen concentrations and availability in field trials with wheat
Authors: Mason MG
Published: March 2005

Thirteen trials, each with 3 nitrogen (N) sources (urea, ammonium nitrate, and ammonium sulfate) and 2 N rates (25 and 75 kg N/ha), were carried out during 1987-89, to measure the rate of disappearance of ammonium-N on different soils. Six soil categories were examined, from very acid to calcareous light soils, and from medium to heavy textured soils. Plots were planted with wheat, and at the higher rate of N, fallow plots were included to distinguish plant uptake from other processes such as nitrification and immobilisation that cause the disappearance of ammonium N. Reduction in concentration of ammonium-N was rapid on high pH, light soils (2-3 weeks at Dongara 1988), and slower with decreasing soil pH (e.g. >19 weeks at Merredin 1987). Nitrate-N concentration increased on fertiliser-treated plots at all sites, indicating that nitrification was taking place. Ammonium-N decline was slower with ammonium sulfate supplied than with urea or ammonium nitrate, consistent with its greater acidifying effect in the soil. This difference did not occur on the alkaline light soils, where reduction in concentration of ammonium-N was rapid for all sources. In 1989, the rate of decline of ammonium-N was considerably slowed because the soil surface containing the ammonium-N was dried during a very dry spring with little effective rainfall in September and October.
The responses of sorghum and sunflowers to 2,4-D and dicamba residues in clay soils in central Queensland
Authors: Walker SR , Osten VA , Lack DW , Broom L
Published: March 2005

The residual phytotoxicity of 2,4-D mine and dicamba to sorghum (Sorghum bicolor L.) and sunflowers (Helianthus annuus L.) was investigated under central Queensland conditions of variable rainfall and high temperatures. Effects of soil water content, sowing depth, and leaching in clay soils were determined. Phytotoxicity, as measured by decreases in shoot dry matter in pots, increased with herbicide rate and decreased rapidly in moist soil (34% w/w) but was maintained for at least 14 days in dry soil (114% w/w). 2,4-D and dicamba were phytotoxic when leached into the soil but not when they remained on the soil surface. Seedling growth and yield were not affected by 2 kg 2,4-Dha applied at 7 or more days pre-sowing, or by 0.5 kg 2,4-D/ha and 0.14 kg dicamba/ha applied at 1 day pre-sowing, in 5 field environments. When either herbicide was applied at higher rates 1 day pre-sowing, seedling growth was reduced if 25 mm of irrigation was received within 4 days of sowing, and yields were reduced in the field environment that received 144 mm of rainfall within 14 days of sowing.
Surveys of spraying practices for banana leaf disease control in New South Wales, and an assessment of disease control based on leaf retention at harvest in July
Authors: Allen RN , Akehurst AA , Ireland G
Published: March 2005

Commercial 'Williams' banana plantations were surveyed at random on the North Coast of New South Wales during July 1990 and 1991, to determine spraying practices for leaf disease control and their efficacy in relation to leaf retention at harvest. A climatic index (CIP), based on temperature and wetness, indicated environmental conditions were conducive to leaf diseases caused by Mycosphaerella musicola and M. musae over summer and autumn 1990 but were less conducive in 1991, especially in autumn. In 1990, 5 of 44 plantations surveyed on the Mid North Coast (MNC) received no fungicide sprays; the remainder received 1-5 sprays of petroleum oil or oil mixed with propiconazole (mean 3.0 � 1.3) in December-May. Two plantations were sprayed using misting machines, the other 37 were aerially sprayed. The average numbers of leaves remaining on plants with mature bunches ranged from 0.3 to 8.3 (mean 4.7 � 2.2). A spray frequency model indicated that leaves per plant at harvest in July increased with numbers of sprays applied and decreased with increasing damage from wind and frost (r2 = 0.49; d.f. = 40; P<0.01). Another model based on the accumulated CIP from October to July (+CIP), adjusted for the timing and fungicidal effects of each spray, indicated that leaves per plant at harvest decreased with increasing +CIP, and wind and frost damage (r2 = 0.53; d.f. = 40; P<0.01). In 1991,4 of 38 plantations on the MNC and 3 of 32 on the Far North Coast (FNC) received no sprays; the remainder received 1-9 sprays of oil, oil + propiconazole, or oil + protectant fungicide mixtures. Fewer sprays were applied on the MNC in 1991 than 1990, but the timing of sprays remained unchanged. More sprays were applied on the FNC than MNC in 1991, and sprays were applied from December to July. Leaves per plant varied from 4.2 to 12.1 (mean 8.3 � 2.0). The spray frequency model from 1990 predicted leaves per plant in 1991 poorly (r2 = 0.17; d.f. = 68; P<0.01) and with substantial bias, whereas, the CIP model predicted leaves per plant for the MNC and FNC well (r2 = 0.41; d.f. = 68; P<0.01) and without bias. Observations in 1991 on the 70 surveyed plantations indicated that leaf retention also decreased with increasing damage by burrowing nematode (Radopholus similis) and banana weevil borer (Cosmopolites sordidus), increasing latitude of the plantation, and decreasing electrical conductivity of the soil solution. These variables accounted for a further 21% of the variation in leaves per plant observed in 1991. Leaf retention was not significantly (P>0.05) related to soil pH or to spraying method (aerial v. ground).
Response of carrots (Daucus carota L.) to applied phosphorus leaching on a Karrakatta sand, under two irrigation regimes
Authors: McPharlin IR , Aylmore PM , Jeffery RC
Published: March 2005

The response of carrots (Daucus carota L.) to applied phosphorus (P) (0-320 kg/ha) and P leaching was investigated on a Karrakatta sand under 2 irrigation regimes (140% of pan evaporation in 2 or 4 applications per day). There was no significant effect of frequency of irrigation on response of carrots to P. Phosphorus at 157 � 57 kg/ha was necessary for 99% of maximum yield (95 t/ha) of carrots, which corresponded to maximum economic yield. For 95% of maximum yield 102 � 10 kg/ha was necessary. Applied P at up to 20 kglha resulted in a significant increase in the yield of medium (25-50 mm crown diameter) and large carrots (>50 mm diameter), a decrease in the yield of small (10-25 mm diameter) and very small carrots (<I0 mm diameter), and an increase in root to shoot ratios. Rejects were a constant percentage (9%) of total yield at all rates of applied P. The P concentration (dry weight basis) in youngest mature leaves at midgrowth required for 99% of maximum yield was 0.38 � 0.02%. Visual symptoms were not useful for diagnosing P deficiency in carrots because symptoms such as purpling of older leaves were only apparent on severely deficient plants. Phosphorus uptake by both roots and shoots increased with increasing rate of applied P; however, efficiency of P uptake (i.e. P uptake by shoots � roots/P applied, in per cent) decreased with increasing application rate from 27% of applied P at 20 kg/ha to 14% at 320 kg/ha. Eighteen per cent of applied P was taken up by the crop at the rate of P necessary for maximum yield and profit. There was no evidence of soil P leaching below 30 cm except at the highest application rate, and there was no effect of frequency of irrigation on P leaching. This supports evidence that Karrakatta sands have moderate P retention capacity and present a low pollution risk to water systems on the Swan Coastal Plain.
Curing to prevent chilling injury during cold disinfestation and to improve the external and internal quality of lemons
Authors: Predebon S , Edwards M
Published: March 2005

In 1988, 2 experiments were undertaken to test the effect of curing on the external and internal quality of lemons. The experiments were designed to determine the optimum postharvest handling regime for protecting lemons from chilling injury during the cold disinfestation process that is necessary for entry into markets such as Japan. In experiment 1, a mixture of Eureka and Lisbon lemons was cured for 0, 2,4, 8, 16, or 32 days at ambient temperature, then cold disinfested at 1�C for 16 days and stored for 4, 8, or 16 weeks at 10�C. In experiment 2, a mixture of Eureka and Lisbon lemons was treated with either thiabendazole (TBZ) (500 mg a.i./L) or sodium ortho-phenyl phenate (SOPP) (200 mg a.i./L) by bulk dipping before processing, or by an in-line spray during processing. The fruit was then cured for 0, 2, 4, 8, 16, or 32 days, cold disinfested as above, and stored at 10�C for 28 days. Curing for 16 days reduced chilling injury symptoms in experiment 1 but increased oleocellosis in experiment 2. Curing for 16 days also reduced the incidence of fungal breakdown caused by Penicillium spp. and Geotrichum candidum Lk. ex. Pers. When used as a bulk dip for pretreating lemons prior to curing, TBZ was more effective at controlling fungal breakdown than when used as an in-line spray, and more effective than SOPP used as a bulk dip or in-line spray. Red spotting of the rind was also reduced by bulk dipping in TBZ. Curing for 4 or more days produced increases in extractable juice. Development of yellow colour occurred during curing for 16-32 days and was enhanced by storage at 10�C. Curing for at least 4 days, when used in conjunction with a bulk dip of TBZ (500 mg a.i./L), can be used to protect lemons against fungal breakdown and to increase juice. Curing for 16-32 days can be used to develop even yellow coloration of the fruit and to decrease chilling injury.
Yield, plant characteristics, and relative tolerance to bunch loss of four banana varieties (Musa AAA Group, Cavendish subgroup) in the semi-arid subtropics of Western Australia
Authors: Hill TR , Bissell ARJ , Burt JR
Published: March 2005

The yield, plant characteristics (pseudostem height and girth), and relative tolerance to bunch loss of 4 banana varieties (Musa AAA Group, Cavendish subgroup) were studied over 2 crops in the semi-arid subtropics at Carnarvon, Western Australia. The varieties were New Guinea Cavendish, Chinese Cavendish, Hsien.Jen Chiao, and the most widely grown Australian variety, Williams. The marketable yield of Williams was higher (P<0.05) than the mean of the other varieties in the parent crop (70.2 v. 50.7 t/ha) and ratoon 1 crop (65.8 v. 34.4 t/ha). This was the result of lower (P<0.05) bunch loss, about 41% less over the 2 crops, than for the other varieties. Resistance to bunch loss-pseudostem breakage and bunch peduncle snap was not associated with the shorter varieties (New Guinea Cavendish and Chinese Cavendish), but resistance to choke throat was associated with the taller varieties (Williams and Hsien Jen Chiao).
Boron deficiency and toxicity in potato cv. Sebago on an oxisol of the Atherton Tablelands, North Queensland
Authors: Pregno LM , Armour JD
Published: March 2005

A field experiment was established to determine whether excess boron (B) in a new, blended commercial fertiliser reduced growth of Sebago potatoes. Five rates of B as sodium borate (0, 2, 4, 8, and 12 kg B/ha) were mixed with superphosphate, potassium chloride, and ammonium sulfate and applied in bands, at planting, to an oxisol with a hot CaCl2-extractable B concentration of 0.7 mg/kg. At the common commercial rate of 1500 kg blended fertiliserba, 8 kg B/ha would be applied in the new blended fertiliser. Yield of grade 1 tubers was significantly (P<0.05) higher at 2 kg B/ha (27.2 t/ha) than without applied B (19.7 t/ha). Grade 1 tuber yield decreased with increasing B rate above 2 kg/ha, and the yields at 8 and 12 kg B/ha were significantly lower than the maximum yield. Plant height was not increased by low rates of B but was significantly (P<0.05) reduced by 8 and 12 kg B/ha, compared with nil B. Boron concentrations increased with increasing application rate. At 12 kg B/ha, whole shoots had 50 mg B/kg and youngest fully expanded leaves (YFEL) 31 mg/kg. Maximum tuber yield was obtained with 33 mg B/kg in whole shoots and 24 mg/kg in the YFEL. Tuber yield was significantly (P<0.05) reduced at >39 and 26 mg B/kg for whole shoots and YFEL, respectively. The sufficiency range for B in Sebago potatoes was 33-39 mg/kg for whole shoots and 24-26 mg/kg in YFEL. The threshold B concentrations for yield reduction in potatoes due to toxicity recorded in this study are much lower than those previously reported for other cultivars.
Maize silage for the pasture-fed dairy cow. 2. A comparison between two systems for feeding silage while grazing perennial pastures in the spring
Authors: Moran JB , Jones D
Published: March 2005

Dairy cows in early lactation grazed irrigated perennial pastures in early spring and were offered 7-8 kg maize silage DM/day, either in the morning or throughout the entire day and night. Another group of cows with rumen fistulae were pen-fed annual pasture of similar quality and offered maize silage, again, in the morning only or throughout the day and night. Rumen retention time, diet digestibility, and excretion of maize grains were measured during the pen-feeding trial, as well as the rate of disappearance of feed samples from nylon bags placed in the rumen of each cow. Diurnal variations in rumen pH, total volatile fatty acids, and ammonia concentrations were monitored every 2 h. Intakes of grazed pasture, and diurnal variations in rumen pH and ammonia, were measured in the grazing cows. Milk yield and milk composition, and changes in liveweight and body condition (in the grazing cows only), were also monitored. Although time of feeding maize silage influenced rumen fermentation patterns in both pen-fed and grazing cows, it had little effect on feed intake and utilisation, or on milk production. This was attributed to the low levels of rumen-degradable starch in the maize silage, which would have had minimal influence on rumen cellulolytic activity. Therefore, unlike supplements of cereal grains, for which twice-daily feeding is recommended, maize silage need only be offered once daily without adversely affecting the performance of cows grazing high quality spring perennial pastures.
Lambing potential and mortality in Merino sheep as ascertained by ultrasonography
Authors: Kilgour RJ
Published: March 2005

The results of commercial ultrasongraphic determination of fetal number in 47 648 autumn-joined and 7846 spring-joined Merino ewes on private properties in New South Wales were analysed to determine reproductive potential. Overall, about 12% of maiden ewes and 31% of adult ewes were diagnosed as carrying twins, with about 5% of ewes diagnosed as dry. Season of joining had no effect on these proportions, except for a slightly lower number of dry ewes among those spring-joined. This analysis indicates that the average flock gives birth to 121 lambs per 100 ewes joined, while the average number of lambs marked per 100 ewes is 80. This means that the State flock is achieving only two-thirds of its potential.
Effects of frequency and height of defoliation on the production of a Persian clover-annual ryegrass sward
Authors: Stockdale CR
Published: March 2005

An experiment established the effects of frequency and height of defoliation on the production of an irrigated Persian clover (Trifolium resupinatum)- annual ryegrass (Lolium rigidum) sward. Five intervals of defoliation (from 4 to 12 weeks) were superimposed on 2 heights of defoliation (to ground level and to 4 cm above ground level) in a split-plot design. Total harvested yields ranged from 7.52 to 11.94 t DM/ha and varied according to defoliation management. Except for the very short defoliation intervals, defoliating to the higher level was less productive than defoliating to ground level. There were wide seasonal variations in the effect of treatment. In general, quality of the harvested herbage was relatively constant for much of the year, but in spring the effects of frequency and height of defoliation were evident. At this time, all chemical characteristics indicated that herbage quality declined with maturity of the sward. Optimum defoliation management will depend on both the quantity and quality of herbage produced. This will depend on animal requirements.
Effect of management of previous cereal stubble on nitrogen fertiliser requirement of wheat
Authors: Mason MG
Published: March 2005

The effect of either burning stubble, or incorporating it in the soil, on the nitrogen (N) fertiliser requirement of the following wheat crop was examined over 10 years (1978-87) in a continuous wheat system at 2 sites (Wongan Hills and Nabawa), and in both continuous wheat and wheat-fallow systems at one site (Merredin). There were significant grain yield increases in response to N fertiliser in all years at Nabawa. At Wongan Hills there was no response in 1978 and 1985, a yield reduction in 1979, and a yield increase in all other years. At Merredin, there was no response in 1980, a yield decrease in 1984 and 1985, and an increase in all other years. In some years grain yield responses were small at Wongan Hills and Merredin. The only significant overall effects of stubble treatment were at Nabawa in 1978 (P<0.01) and 1985 (P<0.05). The interaction between stubble treatment and N rate was significant at Wongan Hills in 1980 and 1981 (P<0.05), and at Merredin in 1981 (P<0.001), 1983, and 1985 (both P<0.05). Response to N fertiliser was higher where the stubble was incorporated than where it was burnt. There was also a tendency for higher optimum economic rates of N fertiliser with stubble incorporated rather than burnt, but differences were not large. At Merredin, the overall yield increase with fallow was significant (P<0.001) in 1979 and 1983. The fallow x N fertiliser rate interaction was significant in all comparison years except 1987. Responses to N were greater in the non-fallow treatments. Soil organic carbon (C) levels were higher with stubble incorporation than where the stubble was burnt, and fallowing resulted in lower organic C. There was a downward trend with time, especially when fallowing was carried out. Effects on total N levels in the soil were similar to those for organic C but were less marked. The study indicates that at a level of stubble residues of 1-3 t/ha with continuous wheat in this winter rainfall environment in Western Australia, stubble treatment is unlikely to be a major factor in determining the rate of N fertiliser required for a wheat crop.
Effect of amount and quality of previous crop residues on the nitrogen fertiliser response of a wheat crop
Authors: Mason MG , Rowland IC
Published: March 2005

Burr medic (Medicago polymorpha cv. Circle Valley) at 3 sowing rates (3, 12, and 50 kg/ha), narrow leaf lupins (Lupinus angustifolius cv. Illyarrie) at 2 sowing rates (30 and 100 kg/ha, with the high rate sown early or late) and oats (Avena sativa cv. Winjardie) at 2 sowing rates (20 and 60 kg/ha, with the high rate sown early or late), were planted on a deep, infertile siliceous sand at Badgingarra in 1988, to produce residues of varying quantity and quality. Residues produced (minus seed) varied in quantity from 0.70 t/ha (medic 3 kg/ha) to 4.22 t/ha (lupins 100 kg/ha sown early) when measured in late summer. Carbon to nitrogen ratios (C/N) ranged from 37.3 to 58.5 (medic), 28.3 to 40.4 (lupins), and 78.6 to 112.0 (oats). Seed present in the residues ranged from 0.18 to 0.47 t/ha (medic) and from 0.32 to 0.57 t/ha (lupins). The ranges in C/N values were 8.3-9.3 (medic) and 9.4-10.0 (lupin). There was no grain in the oats residues. The residues were incorporated into the soil during the sowing operation of a wheat crop in 1989. Subplots of 6 rates of N as ammonium nitrate (0, 14, 27, 54, 82, and 163 kg N/ha) were included in each block. Wheat dry matter and grain yields were higher following lupins and medic than following oats, and although there were large responses to N fertiliser following all 1988 crops, the N application had little effect on the difference between oats and legumes. In the absence of N fertiliser, yields and N uptake by the 1989 wheat crop were higher following lupins than following medic, due to hardseededness of medic seeds. There were no significant differences within 1988 crop groups. There were good correlations between dry matter and grain yield of wheat without N fertiliser and C/N value of the residues. The correlations were better when seed was not included in the calculation (r2 = 0.86 and 0.80, respectively) than when the seed was included (r2 = 0.79 and 0.64). Similar correlations were obtained between dry matter and grain yields and total N content of the residues. Correlations were lower when seed was omitted (r2 = 0.64 and 0.75) than when it was included (r2 = 0.70 and 0.81). Yields decreased with increasing C/N and increased with total N content of the residues. Wheat grain N concentrations fell with the first increment of N fertiliser, which produced a large yield increase, but rose to high levels at high rates of N.
Variability in seedling elongation of wheat, and some factors associated with it
Authors: Addae PC , Pearson CJ
Published: March 2005

Coleoptile lengths of 22 cultivars of wheat (Triticum aestivum L.) were measured in darkness at 2 depths of sowing (2 and 6 cm) under minimal mechanical stress and at 4 cm depth under 0.76 kPa mechanical stress. The experiments were done to describe variability in elongation abilities and to develop a technique for genotypic screening for tolerance of high soil strength. Of the 8 cultivars with shortest coleoptiles, 6 had cv. Condor parentage. Lengths of coleoptiles of all cultivars were reduced by 18% on average, under 0.76 kPa mechanical stress. Lengths were correlated with time to median emergence (r = 0.72) and total emergence percentage by 20 days after sowing (r = 0.77). Some cultivars with shorter coleoptiles took an extra 2-3 days to reach median emergence and attained a poorer total emergence percentage than those with long coleoptiles. A doubling of seed weight resulted in an increase of only 9% in coleoptile lengths, with no effect on emergence. The results suggest that cultivars appropriate for emergence from particular soil types or under adverse conditions could be selected under minimum soil stress because their performance ranking was similar under mechanical stress.
Glyphosate residues in a sandy soil affect tomato transplants
Authors: Cornish PS
Published: March 2005

Glyphosate residues in a loamy sand soil were suspected of damaging transplanted tomatoes at Gosford in 1990. Field and glasshouse experiments were conducted to determine whether phytotoxic residues of glyphosate persist in this soil type and, if so, under what conditions. In the glasshouse experiment, visible symptoms of glyphosate toxicity occurred in tomato seedlings transplanted into soil that was sprayed 1, 5 or 15 days earlier with glyphosate (360 g a.i.L) at 4 L productha. Glyphosate also reduced plant dry weight (16 days after transplanting), but only where soil nutrient deficiencies were corrected after transplanting. In this case, seedlings transplanted 15 days after spraying suffered an average reduction in dry weight of 57%. Greater reductions in dry weight occurred where superphosphate (43 kg Pha) was mixed through soil before spraying (75 v, 35% reduction). In the field, glyphosate residues reduced plant dry weight 16 days after transplanting, even when transplanting followed spraying by up to 9 days, and possibly as many as 30. At 9 days, reductions of 50, 74 and 78% were recorded with glyphosate (360 g a.i./L) applied at 2, 4 and 8 L/ha, respectively. Effects of glyphosate on fruit yield were significant (P<0.05), but much smaller than effects on earlier plant dry weights. The phytotoxicity of glyphosate residues in this loamy sand appears to result from a combination of inherently low P sorption capacity and application of superphosphate, leading to low adsorption of glyphosate by soil. This may be exacerbated when dry conditions occur between application and planting. On the present evidence, a plant-back period of 3 weeks could be considered safe when transplanting tomatoes into this sandy soil, provided some mixing of soil occurs at transplanting. It is recommended that farmers perform a simple bioassay to confirm safety.
Ethylene-induced fruit ripening in arabica coffee (Coffea arabica L.)
Authors: Winston EC , Hoult M , Howitt CJ , Shepherd RK
Published: March 2005

The effects of ethephon on arabica coffee (Coffea arabica L.) were tested in experiments conducted over 2 years in North Queensland. Rates tested were 0, 125, 250, 500, 750, 1000, 1500, and 2000 mgkg, applied when 15-20% (early treatment) or 45-50% (late treatment) of fruit were coloured. Measurements were made on the degree of leaf and fruit abscission, berry ripening, and berry weight. Ethephon did not cause significant fruit abscission, but rates >500 mg/kg caused unacceptable leaf abscission. Rates of 250 mg/kg were marginally acceptable in terms of leaf abscission. Excessive defoliation led to dieback, which resulted in a reduced crop the following season. Ethephon concentrated berry ripening, significantly increased the number of red (mature) berries, and decreased the number of green (immature) berries. Rates of >500 mg/kg were effective in accelerating berry ripening, while 125 mg/kg had a limited effect. Maturity stage of the bean at time of application helped to determine the ethephon response; early application of ethephon had a more pronounced effect on berry ripening than late application. Ethephon applied early at rates of 1500 and 2000 mg/kg decreased fresh berry weight compared with all other treatments but parchment weight was unaffected. Selection of a suitable rate of ethephon from these data is difficult because berry ripening is offset by leaf drop. Variability of response was also observed.
Clonal selection within the apricot varieties Trevatt and Moorpark
Authors: Cirami RM , Hamilton R , Hodge D
Published: March 2005

Barossa Valley selections of 5 Trevatt and 4 Moorpark apricot varieties were compared over 3 seasons for their characteristics as drying apricots.Although there was a lack of significant differences between Trevatt clones, enough differences occurred in the Moorpark varieties to suggest that many quality attributes, particularly fruit weight, diameter, pH, and drying ratio, can be improved through rigorous selection from a wide and diverse population. The data suggest that different clones may be better suited to particular sites or management systems. A large experimental error was noted and attributed to the variability in seedling rootstock material and the unknown viral status of the scions and rootstocks.
Effect of timing of hand thinning on the cropping potential of Red Fuji apple trees
Authors: Jones KM , Bound SA , Koen TB , Oakford MJ
Published: March 2005

In a hand-thinning trial of 6-year-old Red Fuji apple trees on seedling rootstocks at the Grove Research Station in southern Tasmania, unthinned controls were compared with trees that were hand-thinned between full bloom and 56 days after full bloom. Trees were thinned to about 200 flowers or fruit per tree. The response of fruit size and weight to later thinning was negative and linear (R2=0.72). This regression was not significantly affected if adjusted for the varying fruit crop per tree. It is concluded that in Australia, Red Fuji is capable of producing larger fruit at higher crop loads than either Red Delicious or Golden Delicious and that thinning at blossom produces much larger fruit than later thinning. Because of the strong correlation between Red Fuji fruit size or weight and time of thinning, we conclude that it is preferable to thin at blossom time.
Productivity of Hereford, highgrade Simmental and Belmont Red beef herds in central Queensland. 3. Explanatory models for pregnancy rate
Authors: O'Rourke PK , Esdale CR , Howitt CJ , Rudder TH
Published: March 2005

Statistical models for pregnancy rate of Hereford, highgrade Simmental and Belmont Red cows were developed for brigalow pastures in central Queensland. Cows grazing improved pasture at 1 breeder/2 ha over 6 years, from 1979 to 1985, were mated to single sires for 78 days from early December each year and their calves weaned in May. Overall herd pregnancy rates were 74% Hereford, 69% highgrade Simmental and 86% Belmont Red. The 2-year-old maidens and non-lactating cows had higher rates than lactating cows for Hereford and highgrade Simmental. Mature, lactating and non-lactating cows had higher liveweights at the start of mating than first lactation cows and all were heavier than maidens. Pregnancy rate for maidens was not affected by liveweight, but 71% Hereford, 90% highgrade Simmental and 95% Belmont Red were above 300 kg at the start of mating. Response in pregnancy rate to liveweight at start of mating plateaued above 375 kg for first lactation Belmont Red and mature lactating Hereford; above 400 kg for mature lactating Belmont Red; and above 425 kg for mature lactating highgrade Simmental; but this liveweight was not important for first lactation Hereford and highgrade Simmental, nor for non-lactating cows. Mature cows calving in the first 6 weeks of the season had 13-30% higher pregnancy rates than those calving later. Previous lactation status did not affect pregnancy rate for highgrade Simmental and Belmont Red, but Hereford cows rearing a calf in the previous year had 14% higher pregnancy rates than those failing to rear a calf. Breed differences were apparent in the responses to the factors modelled. Pregnancy rates of lactating Belmont Red cows were sensitive to time of calving and liveweight at start of mating, even though these rates exceeded 80%. Mature, lactating highgrade Simmental were highly sensitive and Hereford intermediate, but first lactation and non-lactating Hereford and highgrade Simmental did not respond to these factors, even though pregnancy rates were low. Segregation of the breeding herd into high, intermediate and low expected fertility groups can be based on calving time and liveweight at start of mating. The high fertility group, consisting of cows calving in the first 6 weeks of the season and weighing greater than the plateau level, had advantages compared with the herd averages of 16 and 8% in fertility for first and mature lactating Belmont Red, respectively. Conversely, the low fertility group, consisting of late calving cows of low liveweight, had disadvantages of 30 and 18% for first and mature lactating Belmont Red. respectively.
Rearing dairy calves on irrigated tropical pastures. 1. Effect of protein level on liveweight gain and blood components
Authors: Moss RJ , Murray RM
Published: March 2005

Isoenergetic (12 MJ ME/kg DM) concentrate supplements of varying protein contents, were fed to dairy weaner calves grazing irrigated Setaria anceps cv. Kazungula pastures. Calves in each of the 5 treatment groups were given 1 kg concentratelday containing cracked maize and cottonseed meal in the proportions 1:0, 5:1, 4:2, 3:3 and 0:l. Acontrol group received no supplement. Two drafts of animals were used to measure the response during winter-spring (dry season) and summer (wet season). Without supplementation, calves gained 0.34 kg/day in spring and 0.20 kg/day during the wet season. Supplementation increased liveweight gains by 0.25 and 0.20 kg/calf.day in spring and summer, respectively. Substitution of cottonseed meal for maize did not consistently increase liveweight gain. Calves selected a pasture diet of 97% leaf, 16% crude protein and 66% in vitro dry matter digestibility (IVDMD). Mean daily rumen ammonia concentration was 134 mg NH3-N/L in unsupplemented calves, and 89 mg NH3-N/L in calves fed maize (P<0.05). Cottonseed meal was rapidly degraded in the rumen, with peak concentrations of rumen ammonia of 570 mg NH3-N/L 2 hours after feeding. Concentrations of rumen ammonia and plasma urea were closely correlated with supplemental protein intake (R2 = 0.98). Plasma total protein and albumin also increased with protein content of supplements (R2 = 0.73). Concentrations of plasma glucose and total volatile fatty acids in rumen liquor increased with supplementation, but were not influenced by the level of protein in the supplement. Correlations between liveweight gain and plasma glucose concentration were low (R2 = 0.65 spring; R2 = 0.20 summer). Digestible energy intake was the first limitation to liveweight gain of these calves grazing actively growing, tropical grass pastures. Although animals consistently selected leaf, the level of digestible energy intake was well below requirements, and increasing the level of protein in the diet was ineffective in increasing liveweight gain.
Rearing dairy calves on irrigated tropical pastures. 2. Effect of levels of maize and cottonseed meal on growth of weaner calves
Authors: Moss RJ , Goodchild IK
Published: March 2005

Fifty-two Australian Friesian Sahiwal (AFS) calves were weaned at 70 kg liveweight onto irrigated and fertilised couch (Cynodon dactylon)- pangola (Digitaria decumbens) pastures in North Queensland. They were offered supplements of maize (9.5% crude protein) or a mixture of 5 maize: 1 cottonseed meal (15% crude protein) fed at 1.0 or 1.5 kg/calf.day in a 2 x 2 factorial experiment. Calves entered the experiment after weaning and were removed when they exceeded 130 kg liveweight. More calves were reared in spring and summer than in autumn and winter, and stocking rate varied between 20 weaners/ha (summer) and 12.5 weaners/ha (winter). Additional supplementation with maize above 1 kg/calf.day did not increase liveweight gain in calves of up to 130 kg liveweight. Inclusion of cottonseed meal in the supplement increased calf growth at the higher level of supplementation (P<0.01) and calves reached 130 kg liveweight 2 weeks earlier than calves fed maize (P<0.05). The interaction of level of feeding with protein content of the supplement was significant at P = 0.058. Calves reared in the wet season gained less (0.47 kg/day) than calves reared in the dry season (0.60 kg/day) (P<0.01). Animal responses to supplementary feeding were similar in both seasons, but even at high levels of supplementation, and with added protein, calves reared in the wet season did not maintain desired growth rates over this period.
The performance of Merino ewes and lambs grazing two cultivars of Trifolium subterraneum at Kybybolite, South Australia
Authors: Craig AD
Published: March 2005

Two cultivars of subterranean clover, Trikkala and Mt Barker, were continuously grazed by Merino ewes and lambs at 3 stocking rates (8, 13, 18 ewes/ha) from 1976 to 1981. The sheep were assessed for liveweight, fleeceweight, fibre diameter, staple length, wool yield and lambing performance including lambing, marking and weaning percentage. From September 1978 onward, ewes grazing Trikkala pastures were consistently heavier than those grazing Mt Barker pastures, and they produced heavier fleeces in 1978 and 1980, with a 3 and 9% greater total wool production. The heavier fleeces of 1980 were associated with a larger fibre diameter. There were no cultivar differences in lambing performance. Cultivar treatment had no effect on lamb birthweight, but in 1980 the Trikkala lambs were, on average, 3.5 kg heavier at weaning. These lambs also produced heavier fleeces than lambs on the Mt Barker pastures. Higher stocking rates produced decreases in all of the animal performance variables measured. The results of this study suggest that improved livestock performance may only occur if animals are grazed on higher performing cultivars for at least 3 years.