bluuebunny/crossref_metadata_2025 huggingface dataset:
Scab (Sphaceloma batatas) a new disease of sweet potatoes in Australia: fungicide and cultivar evaluation
Authors: Ramsey MD , Vawdrey LL , Hardy J
Published: March 2005

Since 1982, stem and foliage scab caused by Sphaceloma batatas has occurred in crops of sweet potatoes cv. 'Porto Rico' on the Atherton Tableland in North Queensland. This is the first report of the occurrence of this disease in Australia. We developed a natural substrate agar suitable for sporulation of S. batatas and demonstrated that a suspension of conidia was pathogenic, producing lesions on the stem, petioles and leaf veins of sweet potatoes. Nine fungicides were tested for control of stem and foliage scab in a field experiment. Benomyl (400 g a.i./ ha), chlorothalonil (1300 g a.i./ha), captafol (1520 g a.i./ha), fentin hydroxide (300 g a.i./ha), copper oxychloride (1500 g a.i./ha) and mancozeb (1 500 g a.i./ha) reduced the disease at the earliest assessment, 55 days after planting (P= 0.05). However, at 82 days after planting, copper oxychloride and mancozeb were no longer controlling stem and foliage scab, and, at the third assessment (after 111 days) only benomyl and chlorothalonil reduced the disease (P = 0.05). A field rating after 195 days confirmed that benomyl provided significantly better disease control (P= 0.05) than any other treatment throughout the season. There was a negative correlation between yield and disease levels at 55 and 82 days (r= -0.39 and -0.36, P= 0.05), but not at 111 and 195 days (r= -0.23 and -0.10. n.s.). Twenty sweet potato cultivars were evaluated for disease resistance. Of the major commercial cultivars grown in Queensland, Centennial '83 was highly resistant, Beerwah Gold was moderately resistant, while Red Abundance, NC-3, Lo 323 and Porto Rico were susceptible to stem and foliage scab.
Effects of defaunation of the rumen and supplementation with amino acids on the wool production of housed Saxon Merinos. 2. Methionine and protected methionine
Authors: Cottle DJ
Published: March 2005

In experiment 1, 6 groups, each of 10 superfine Merino wethers, were individually penned indoors and hand-fed oats, wheat straw and whole lupins, either alone or with 2 g/day of DL-methionine or 6.6 g/day of fatty acid coated methionine (Ketionin) for 23 weeks. Following shearing the 6 groups were hand-fed lucerne-chopped hay in experiment 2 either alone or with hydroxymethyl-methionine (Mepron) or Ketionin for 23 weeks. In both experiments the rations were fed at maintenance level and were offered 3 times a week. Half of the sheep had no rumen ciliate protozoa following treatment in a previous trial. In experiment 1, defaunated sheep produced an additional 6.5%clean wool on the supplemented oats plus lupins rations. Inclusion of Ketionin in the ration of defaunated sheep resulted in an 11% increase in clean wool growth, without affecting wool quality. In experiment 2 defaunated sheep produced an additional 6% clean wool on the lucerne-chopped hay ration. No responses to defaunation occurred on the supplemented rations. Inclusion of both forms of protected methionine in the ration (providing 2 g methionine/sheep.day) resulted in 23% and 13% higher clean wool production in the faunated and defaunated sheep respectively. Fibre diameter of wool was increased by 0.7 pm in sheep receiving Mepron and 0-5 pm in sheep receiving Ketionin. The wool grown by suppiemented sheep remained suitable for the 'Sharlea' trade (< 17.5 �m). It is concluded that wool growth responds more to defaunation on high energy-low protein diets. Wool growth responses to supplementation with protected methionine were greater on 100% roughage diets than on high grain diets. Further study is needed before an optimal ration for superfine wool production is formulated.
Resistance to Phomopsis stem blight reduces the lupinosis toxicity of narrow-leafed lupin stems
Authors: Cowling WA , Allen JG , Wood PM
Published: March 2005

To determine if resistance to Phomopsis stem blight reduced the lupinosis toxicity of stems in sheep, we tested mature, dry stems of several selected lines of Lupinus angustifolius L. (narrow-leafed lupin). Resistance was defined as a significant reduction in Phomopsis stem blight symptoms on mature, dry stems compared with susceptible cultivars. Six experiments were conducted at 4 sites in Western Australia in 1983 and 1984. Mature, dry stems were collected from field plots of resistant and susceptible lines for assessment of the frequency of isolation of Phomopsis leptostromiformis (Knhn) Bubak from stem tissue and toxicity to sheep 0 and 14 weeks after the normal time for seed harvest. In both years, P. lepto-stromiformis was isolated with high frequency from susceptible cultivars but with reduced frequency from only some resistant lines. Similarly, toxicity was significantly reduced in some but not all resistant lines. The variation in toxicity among lines could not be fully explained by their relative resistance or frequency of isolation of P. leptostromiformis. Symptoms of Phomopsis stem blight, frequencies of isolation of P. leptostromiformis, and toxicity increased from 0 to 14 weeks after normal harvest time. New lupin lines resistant to Phomopsis stem blight will require testing in field grazing experiments at several sites and for many seasons to confirm their potential for reducing the occurrence of lupinosis.
Importance of mineral nitrogen in the subsoil to yield and uptake of nitrogen by wheat in southern New South Wales
Authors: Taylor AC , Lill WJ , McNeill AA
Published: March 2005

Dry matter and nitrogen uptake of wheat tops at flowering, dry matter and nitrogen of wheat grain at maturity, and soil mineral nitrogen (0-90 cm) at sowing and flowering, were measured at 68 sites (1 experiment per site in 5 Shires) in southern New South Wales to test the hypotheses that: (i) mineral nitrogen below 30 cm would improve the prediction of wheat yields, (ii) soil mineral nitrogen would be better indicated by wheat yields at flowering than those at maturity, and (iii) soil mineral nitrogen would be better indicated by nitrogen uptake by wheat than by dry matter yields. Mineral nitrogen concentrations in soil at depths greater than 30 cm did not improve the prediction of wheat attributes, but hypotheses (ii) and (iii) were validated. Curvilinear regressions, significant (P< 0.05) on 2 occasions, were not important in this study. The best regression of wheat dry matter at flowering against soil mineral nitrogen at sowing was a single straight line, but the best models for the other 3 wheat variables were all bilinear. The best of the latter related the uptake of nitrogen by wheat at flowering to mineral nitrogen in the soil at sowing as follows: FNUH = (31.6 � 5.9) + (0.892 � 0.110) TMNS30 and FNUL = (9.7 � 7.3) + (0.892 � 0.110) TMNS30 where FNUH is nitrogen uptake by wheat at flowering (kg/ha) in 1960, 1964 and 1966 (when Shire wheat yields were above the Shire's long term average), FNUL is nitrogen uptake by wheat at flowering (kg/ha) in 1961, 1965 and 1974 (when Shire wheat yields were below the Shire's long term average), and TMNS30 is total mineral nitrogen (0-30 cm) (kg/ha) at sowing.
A basis for improved soil and water management for irrigated pastures in northern Victoria
Authors: Blaikie SJ , Martin FM , Mason WK , Connor DJ
Published: March 2005

The water relations of white clover and paspalum as monocultures and components of a mixed pasture were studied on a normal and a modified soil profile during the interval between 2 successive irrigations. Responses of individual species were similar in monocultures and mixed pastures. On the normal profile white clover was the first species to react to soil water deficit when the rate of leaf elongation fell by 33% to about 10 mm/day after 30 mm of cumulative evaporation minus rainfall (E - R). This was followed by a reduction in dawn and midday leaf water potential at around 50 mm E - R. After 65 mm E - R, leaf elongation had ceased. In contrast, paspalum showed no signs of water shortage until 70-80 mm E - R. At this stage both the rate of leaf elongation and midday leaf water potential fell. After 90 mm E - R the dawn leaf water potential fell and by 120 mm E - R leaf elongation was negligible. Modification of the profile increased soil water availability by allowing more extraction of water at depth in the profile. This delayed the onset of water stress by about 40 mm E - R in both species. These observations show that the common irrigation interval of 60-90 mm E - R in northern Victoria is likely to restrict pasture yields because it causes a period of soil water deficit stress, especially for white clover, and the development of leaf area is impeded, increasing the time taken for canopies to recover maximum productivity after grazing. To overcome these limitations farmers will have to water more frequently or modify the soil profile to provide pastures with a better water supply.
Zinc, copper, iron, manganese and boron uptake by cotton on cracking clay soils of high pH
Authors: Constable GA , Rochester IJ , Cook JB
Published: March 2005

To determine the extent and timing of uptake of some micronutrients in cotton, 35 cotton crops were surveyed in 1 season and detailed sampling of whole plants and node segments at 1 site was done in 2 seasons. The soils were cracking clays of high pH. Meaned over all sites, iron was taken up in greatest amounts (600 g/ha), followed by manganese (450 g/ha), boron (200 g/ha), zinc (60 g/ha) and copper (20 g/ha). Based on critical values established elsewhere, none of the sites was judged to be primarily deficient or excessive in any of these micronutrients, but Zn status was the lowest in plant tissue and Mn the highest. At the levels found, there were poor relationships between soil tests and subsequent uptake of each micronutrient. Copper, boron and zinc were taken up throughout the season but Fe uptake was almost complete by flowering. It was calculated that continued uptake of Zn throughout the season was necessary, as redistribution from leaves was insufficient to sustain boll requirements. An analysis of fuzzy seed and lint indicated that 3 g of copper, 12 g manganese, 13g zinc, 21g boron and 66 g of iron are removed at harvest for each bale (225 kg) of lint.
Fungicide resistance in cucurbit powdery mildew (Sphaerotheca fuliginea) and its effect on field control
Authors: O'Brien RG , Vawdrey LL , Glass RJ
Published: March 2005

Decreased fungicidal control of powdery mildew (Sphaerotheca fuliginea (Schlecht: Fr.) Poll.) in commercial cucurbit crops led to an investigation to determine whether fungicide resistant strains were present. In field trials, fungicides such as bupirimate (100 mg a.i. L-I), dimethirimol (250 mg a.i. L-1), fenarimol (36 mg a.i. L-1), penconazole (40 mg a.i. L-l) and triadimefon (125 mg a.i. L-1) were less effective (P=0.01) in controlling the disease than oxythioquinox (100 mg a.i. L-1). This disagreed with earlier trial results and suggested that fungicide resistant strains may have developed. The sensitiyities of 6 isolates of S. fuliginea to 12 fungicides were determined using a leaf disc technique. Two isolates collected in fields where fungicides had been used intensively showed reduced sensitivity to fungicides from several chemical groups including the ergosterol biosynthesis inhibitors, hydroxypyrimidines, organophosphates and benzimidazoles. Several spraying strategies were compared. The S. fuliginea populations receiving spray schedules which included the protectant fungicide oxythioquinox alone, or in alternation with a systemic (triadimefon) developed a lower proportion (66-73%) of resistant strains than those treated with systemic fungicide alone (89%). These findings suggest that S. fuliginea can develop strains with low sensitivity to several fungicides against powdery mildew. To prolong their efficacy, systemic fungicides should not be used continuously but should be reserved for use during the latter part of crop growth when disease risk is highest. Alternating or tank mixing with an effective protectant fungicide is also recommended.
Response of 'Lambert' and 'Ron's Seedling' sweet cherries to fumigation with methyl bromide plus cold storage
Authors: Jessup AJ
Published: March 2005

Fumigation with methyl bromide followed by storage for 10 or 30 days at 1� retarded weight loss in 'Ron's Seedling' sweet cherries. Loss of skin colour was delayed in 'Lambert' sweet cherries fumigated with 32 dm3 methyl bromide when fumigated at 17�C, compared with fruit not fumigated and those treated with 48 g/m3 methyl bromide. Treatment with 32 dm3 increased the frequency of peduncle abscission in both varieties without serious phytotoxic effects on fruit quality.
Effect of seed position on fatty acid content in sunflower (Helianthus annuus L.)
Authors: George DL , McLeod CM , Simpson BW
Published: March 2005

Variation among F3 seeds from a single head for linoleic acid content was high (50.0-72.7%) and appeared unrelated to seed position. Fatty acid content of seeds within self-pollinated heads was not affected by unfilled, adjacent seeds. Thus single seed selections for linoleic acid content should not be biased. No general relationship between fatty acid level and seed position was evident from, analyses of bulk samples except that palmitic acid content of seeds from the upper half of heads (7.4%) was higher than from the lower half (6.5%). This may be related to the negative correlation (r = -0.45) between palmitic acid content and seed size. Fatty acid content and weight of seeds from the lower half of heads were less variable than from the upper half.
Effect of triazole coated superphosphate, applied at sowing, on take-all and yield of wheat
Authors: Ballinger DJ , Kollmorgen JF
Published: March 2005

Two fungicides, flutriafol and triadimefon, coated on superphosphate fertiliser and applied as an in-furrow treatment at 6 sites reduced the effects of take-all at all sites and also increased wheat yields at 3 sites by 12-44%. Each fungicide was applied at 3 rates (flutriafol at 125, 187 and 250 g ai/ha; triadimefon at 125, 250 and 500 g a.i./ha) but no rate effect was evident.
Use of a trickle irrigation system to distribute entomopathogenic nematodes (Nematoda: Heterorhabditidae) for the control of weevil pests (Coleoptera: Curculionidae) of strawberries
Authors: Curran J , Patel V
Published: March 2005

An established trickle irrigation system was used to distribute entomopathogenic nematodes for the control of Otiorhynchus sulcatus and Phlyctinus callosus in a commercial strawberry planting. This technique facilitated the rapid distribution of the nematodes to strawberry plants grown under plastic mulch. Variation in the distribution of nematodes was observed, both within the treatment area and on the soil surface immediately after application. Four weeks after the application of 48 000 and 80 000 infective stage Heterorhabditis heliothidis per plant, weevil survival (mean number of live larvae and pupae) was reduced by 59% and 25% compared with untreated plants.
Effects of defaunation of the rumen and supplementation with amino acids on the wool production of housed Saxon Merinos. 4. Cottonseed meal, analogues of methionine and avoparcin
Authors: Cottle DJ
Published: March 2005

Ten groups, each of 6 superfine Merino wethers were individually penned indoors and hand-fed at maintenance level a ration of 70% oats and 30% chopped lucerne hay (w/w). The groups of sheep were fed 3 different supplementary pellets rotationally during three 9-week periods. Each group received 3 of the following 7 pellets: (1) control, (2) cottonseed meal (CSM), (3) CSM plus hydroxymethyl-methionine (MEP), (4) CSM plus methionine hydroxy analogue (MHA), (5) CSM plus avoparcin (AV), (6) CSM plus MEP plus AV, and (7) CSM plus MHA plus AV. The rations were offered 3 times a week. Half of the sheep had no rumen ciliate protozoa. Wool production was measured during the 7-month period. Defaunation resulted in a 6.9% increase in greasy fleece weight and a 7.7% increase in clean wool production. Average wool fibre diameter increased by 0.6 pm in defaunated sheep. The clean wool growth responses compared with sheep fed the control pellets were 4, 5, 12, 0, 3 and 9% respectively for sheep fed pellets 2-7. The most cost-effective supplement was the CSM plus MHA pellet, which increased clean wool production by 0.5 glday compared with sheep fed the CSM pellet but did not significantly affect wool quality. It was concluded that supplements containing MHA could be economically fed to housed superfine Merino wethers ('Sharlea'), but MHA appears to be relatively inefficient in supplying methionine to the intestines.
Feed additives for attracting sheep to eat a pelleted diet during assembly for live export
Authors: McDonald CL , Rowe JB , Gittins SP , Smith JAW
Published: March 2005

The failure of some sheep to eat pelleted feed in feedlots prior to export may result in subsequent problems in their health and welfare. We investigated ways of improving feeding behaviour by adding chaffed hay or aromatic compounds to the pelleted feed. A control ration of pellets was compared with the same diet sprayed with solutions of butyric acid, aniseed oil or molasses, or fed with chaff (lucerne or oaten). Measurements of the number of sheep eating and total feed intake were made over a 10-day period. Merino wethers from 3 properties were mixed and allocated into 2 replicate groups of 39 animals per yard (1 3 m2/sheep) for each of the 6 treatments. The patterns of feed intake over time fell into 2 distinct groups. Over 70% of sheep fed pellets with either type of chaff visited the feed trough during the first 24 hours. When no chaff was fed, this level of feeding was achieved only after 4 days. All groups fed pellets without chaff showed the same pattern of feed intake, reaching a peak intake on day 3 or 4 before reducing intake until day 6 and then an increasing intake up to day 10. Little sign of this fluctuation was seen in the animals fed pellets with chaff, suggesting that, when only pellets were fed, an unstable pattern of rumen fermentation may have caused a build-up of lactic acid in the rumen and reduced feed intake. Molasses and aniseed reduced (P<0.01) the percentage of sheep per day visiting feed troughs to 5 1 and 53% respectively (6-day mean) compared with 63 and 62% for sheep on unsprayed pellets and pellets sprayed with butyric acid. Over the 10 days, intake of total feed per sheep putting its head in the trough was 1.10 kg/day for sheep fed pellets only while aniseed caused a reduction (P<0.01) to 0.85 kg/day and lucerne chaff resulted in an increase (P< 0.05) to 1.27 kg/day. There were significant differences in the eating pattern between different sources of sheep (P< 0.001) but there were no interactions between source and dietary treatments. We conclude that adding chaffed hay to the feed troughs can maximise the proportion of sheep eating from the first day in the feedlot. In addition, mixing chaffed hay with pellets on the first few days may assist the transition from roughage to cereal based diets. The use of aromatic compounds was not successful in attracting animals to the feed or in encouraging an increased intake.
Tolerance of grazed and ungrazed Phalaris aquatica to glyphosate, tetrapion and 2,2-DPA
Authors: Campbell MH , Ridings HI
Published: March 2005

In 3 experiments carried out near Orange, N.S.W., we assessed the tolerance of grazed and ungrazed Phalaris aquatica to glyphosate, tetrapion and 2,2-DPA each applied at 3 rates. P. aquatica, when maturing, or when dormant during summer, or at any time of the year after heavy grazing had removed almost all green leaves, was tolerant to glyphosate (0.54, 0.72, 1.08 kg/ha a.i.). At any time of the year, ungrazed P. aquatica tolerated low rates of tetrapion (1.5 and 2.25 kg/ha a.i.) or 2,2-DPA (4.4 and 11.1 kg/ha a.i.). It was most tolerant to the high rate of tetrapion (3.0 kg/ha a.i.) in winter and the high rate of 2,2-DPA (22.2 kg/ha a.i.) in spring, summer or autumn. Grazing before or after spraying did not improve the tolerance of P. aquatica to 2,2-DPA but grazing after spraying improved its tolerance to tetrapion. Maximum selective effect, on taking into account the optimum time for killing weeds and retaining pasture (P. aquatica and Trifolium subterraneum), could be achieved by applying: tetrapion to Nassella trichotoma, Eragrostis curvula or Sporobolus africanus in late spring or summer; 2,2-DPA to N. trichotoma in summer; and glyphosate to Poa labillardieri and heavily grazed pasture in summer, provided the weed was actively growing.
Effects of row spacing on growth and grain yield of early and late sorghum cultivars
Authors: Fukai S , Foale MA
Published: March 2005

The effects of row spacing on growth and yield of grain sorghum (Sorghum bicolor (L.) Moench.) were investigated at a constant population density using 5 cultivars of different duration to flowering under dryland conditions in south-eastern Queensland. The row spacings were narrow (0.33 m), standard (1.0 m), and wide-double (1.67 + 0.33 m). Rainfall was plentiful during the tillering and grain filling stages of growth, but a severe water deficit developed at the boot-anthesis stage. The water stress impaired heading and grain set, and grain dry weight was low (40-190 g m-2), with earlier flowering cultivars producing higher yields. There was a cultivar x row spacing interaction for yield; in the earliest flowering cultivar Texas (610SR), which headed before severe stress developed, there was no significant effect of row spacing while in the other cultivars the yield was highest in double row and least in narrow row. There was no detectable difference in soil water available to the plants at any time during growth, but a slightly higher plant water status and faster phenological development in the wider row plants. These responses are related to the fact that the tiller production was least in double row and therefore individual stems had more water available to them.
Crop development and leaf nitrogen in lychee in subtropical Queensland
Authors: Menzel CM , Carseldine ML , Simpson DR
Published: March 2005

Heaviest flowering of 6-9-year-old lychee trees (Litchi chinensis cv. Tai So) over 3 seasons in subtropical Queensland (lat. 27�S.) was associated with a growth check in the terminal shoots prior to panicle emergence (May-June). Leaf nitrogen was the main factor controlling the level of flushing before panicle emergence. Flushing was active (on >40% of terminal branches) when leaf nitrogen concentration exceeded 1.85% N in April. These results suggest that flowering of lychee in subtropical environments where heavy rain precedes panicle emergence in autumn can be promoted by restricting leaf nitrogen levels prior to panicle emergence below 1.75-1.85% N to reduce vegetative flushing. Studies on the seasonal pattern of leaf nitrogen showed that the period during flowering to just after fruit set was the most stable for sampling for leaf nitrogen.
Effect of gypsum on vertisols of the Gwydir Valley, New South Wales. 2. Ease of tillage
Authors: McKenzie DC , So HB
Published: March 2005

An experiment was carried out to deter- mine the effect of applied gypsum on the ease of tillage in 3 vertisols of the Gwydir Valley, New South Wales. The soils were classified as 'poor' and 'good' on the basis of past dryland wheat yields and structural of their surface aggregates.Where gypsum had been applied 22 months earlier at a rate of 7.5 t ha-1, tractor fuel consumption per centimetre of soil tilled was reduced by as much as 37% (0.85 v. 0.54 L ha-1 cm-1). The effect was most marked on the more sodic clays. The reduction in fuel consumption due to gypsum was associated with instability creased soil water content (0.127 v. 0.224 kg kg-1) and lower soil strength (330 v. 140 kPa).
Increases in wheat yield on limed soil after reduction of take-all by fungicide application and crop rotation
Authors: Coventry DR , Brooke HD , Kollmorgen JF , Ballinger DJ
Published: March 2005

The severity of take-all, caused by Gaeumannomyces graminis var. tritici, was measured with lime, rotation and flutriafol treatments in a long-term field experiment. The incidence of eyespot lesions caused by Pseudocercosporella herpotrichoides was also measured. Flutriafol reduced the number of plants with deadheads or no heads and resulted in 12-60% more grain yield. However flutriafol had no effect on the number of plants with eyespot lesions. The number of plants with deadheads or no heads was highest (50-53%) on the wheat which was a third consecutive crop and on soil which had been amended with 2.5 and 5.0 t/ha lime. Sowing wheat after a subterranean clover based pasture considerably reduced the number of deadheads. Control of annual grasses in the pasture by spray-topping further reduced deadheads and with this treatment and at nil and low lime there were 2-7% deadheads. The percentage of plants with eyespot lesions was higher with the continuous cropped wheat. Lime increased grain yield only where the disease incidence was low but had no effect on the percentage of eyespot lesions. This work demonstrates the importance of crop rotation for disease control, particularly where soils are limed to amend severe soil acidity; the value of controlling annual grasses in pasture in the year preceding wheat cropping; and the potential of fungicide treatment as a practical means for controlling take-all in field grown wheat.
Water use efficiency, nutrient uptake and productivity of micro-irragated citrus
Authors: Grieve AM
Published: March 2005

The comparative patterns of water and nutrient uptake, soil salinity and water use efficiency resulting from 2 irrigation systems were studied in a 20-year-old Valencia orange orchard in Sunraysia on the Murray River. A conventional full ground cover system with the sprinklers in the middle of the rows operated at 14 day intervals (peak water demand), was compared with a partial (60-65%) ground cover system using under-tree micro-sprinklers operated at 7-day intervals. Irrigation applications were calculated to replace water depleted from the soil (including a leaching fraction) and were scheduled using tensiometers. During the 4 years of the experiment, approx. 10% less water was applied using micro-sprinklers. The average measured values for the crop coefficients were 0.62 (micro-irrigated) and 0.64 (full ground cover) during midsummer. Measurement of soil water extraction patterns by plant roots showed that only 5% of water use occurred below 1.0 m in under-tree microsprinkler irrigated trees, whereas 17% of water was taken up below this depth by trees irrigated with the mid-row system. Water uptake was limited by water availability rather than root density and declined sharply in mid-row irrigated trees during the second half of the 14-day irrigation cycle, when lower values of soil matric potential and shoot water potential were observed. Root distribution reflected these water uptake patterns with the highest density of fine roots in the 30-60 cm layer. Fertiliser injection with the micro-sprinkler system significantly increased the efficiency of N and P uptake compared with surface application, whereas leaf K levels were lower under micro-irrigation. Soil and plant levels of Na and C1 were low and unaffected by irrigation system during the experiment indicating adequate leaching of salt occurred with both systems. Fruit yield averaged 12% (5 t/ha) higher from micro-irrigated trees due to higher fruit numbers in light crop years. Tree growth was depressed in micro-irrigated trees suggesting a change in the partitioning of photosynthetic energy from vegetative to reproductive growth. The net effect of micro-irrigation was to increase water use efficiency by 22%, from 3.56 to 4.34 t fruit per ML applied water. No adverse effects on orchard productivity were observed following conversion from full to partial wetting of the soil surface. Under-tree micro-irrigation can therefore be recommended as a practical and efficient system for citrus irrigation in the irrigation areas of the Murray River.
Effect of potassium and nitrogen supply on the distribution of minerals and organic acids and the composition of grape juice of Sultana vines
Authors: Ruhl EH
Published: March 2005

Fruiting Sultana vines grown under glasshouse conditions were supplied with 2 K+ levels (0.05 or 0.15 g K+/week) and fertilised with either NH4+ [as (NH4)2SO4] or NO3- [as Ca(NO3)2] as a nitrogen source. Enhanced K+ supply (0.15 g/week) increased K+ concentration in laminae by 1896, in petioles by 59% and in stems by 23%, and reduced Mg2+ of laminae and petioles by 18 and 24% respectively, while Ca2+ was not effected. K+ supply had no effect on tartrate or malate concentration in laminae, stem or roots. Use of NO3- instead of NH4+ as a nitrogen source led to 220% higher citrate and 168% higher malate concentrations in laminae. In roots NO3- supply caused 61% higher citrate, 41% higher tartrate and 26% higher malate concentrations. Higher K+ fertilisation (0.15 g/week) had no effect on fruit yield or sugar content, but increased grape juice pH from 3.95 to 4.08, malate concentration from 0.94 to 1.20 g/ L and K+ concentration from 46.8 to 56.8 mmol/L, thereby causing lower grape juice quality.
Reliability of three sites for measuring fat depth on the beef carcass
Authors: Hopkins DL
Published: March 2005

Over a 12-month period, damage at the P8 rump and 12thl13th rib sites was evaluated on 10 968 beef carcasses at 4 Tasmanian abattoirs. Damage at the 8th/9th rib site was monitored on 507 carcasses at 1 abattoir for 3 months. A biplot analysis showed a marked variation between and within abattoirs for the extent of damage at the P8 and 12th/ 13th rib sites. This demonstrated that the length of time over which evaluations were made was likely to influence subsequent interpretations. However, the percentage of carcasses measurable on one or other of the sides exceeded 90% for both the P8 and 12th/13th rib sites, with no evidence that 1 site was more reliable than the other. Factors such as worker technique influenced the extent of damage, demonstrating that conscientious management could reduce the problem. The method of mechanical hide removal was not found to have a bearing on the degree of damage. Under the conditions of this study, the extent of damage and difficulty of measurement precludes the use of the 8th/9th rib site as an alternative for measuring fat depth.
Effect of rotation and cultivation systems on establishment and persistence of annual medics
Authors: Crawford EJ , Nankivell BG
Published: March 2005

The persistence and annual and seasonal regeneration of 3 annual Medicago species, M. rugosa cv. Paragosa, M. scutellata cv. Robinson and M. truncatula cvv. Cyprus and Jemalong, were compared between 1978 and 1985 over 3 rotation systems, permanent pasture (R1); pasture, barley, pasture, barley repeated (R2) and pasture, fallow, wheat, barley, repeated (R3). Ploughing practices adopted for the various rotations affected persistence and regeneration. Not all ofthe seed that was produced in 1978 produced seedlings. A much lower proportion of the seed reserve of cv. Paragosa produced seedlings compared with cv. Robinson and cvv. Cyprus and Jemalong. The poorer re-establishment of cv. Paragosa could have been due to its more permeable seed compared with the other cultivars. Seed reserves persisted for a maximum of 7 years. Annual re-establishment was greater for all cultivars under the system of permanent pasture than under either the pasture, barley or the pasture, fallow, wheat, barley rotations which disturbed the soil. Unlike the other cultivars, germination and establishment rates of cv. Robinson were low following the first autumn rains in all years. Germination of this cultivar usually occurred from June to November following a delayed breakdown in hardseededness. It also responded to cultivation so that with the exception of R2 in 1980, the highest annual plant populations in R2 and R3 were in the cropping and/or fallowing phases rather than the pasture phases. Although cv. Paragosa produced the highest seed yield in the year of sowing, its reserves were exhausted by the third year in all rotations, whereas the harder seeded cultivars maintained adequate seed reserves to enable good plant re-establishment in the sixth year under all rotations, except in the continuous pasture rotation, where seed reserves of cv. Robinson were exhausted by the fifth year. Cultivation and consequent pod burial in the 2 cropping rotations preserved seeds longer than did the continuous pasture system. Jemalong maintained higher (P< 0.05) seed reserves than cvv. Cyprus and Robinson in the sixth year.
Selection for high linoleic acid content in sunflower (Helianthus annuus L.)
Authors: Simpson BW , McLeod CM , George DL
Published: March 2005

Inbred sunflower lines with high and stable levels of linoleic acid over a wide range of maturation temperatures have been produced. Normally linoleic acid (the polyunsaturated component of sunflower oil) is inversely proportional to temperature during seed maturation. During Queensland's hot summers, linoleic acid content may drop to <50%. Processors require a linoleic acid content of at least 62% of the total fatty acids in oil used for the production of polyunsaturated products, e.g. margarine. Four generations of breeding material (F2-F6 of Hysun 33xHysun 32) were grown and matured under hot summer conditions (approximately 30�C max., 18�C min.). The fatty acid composition of individual seeds was determined by non-destructive analysis, and sunflower breeding lines with up to 25% higher (actual) linoleic acid than the standard variety Hysun 32 (which averaged 48% linoleic acid when matured under hot summer conditions) have been produced.
Phytotoxicity of petroleum spray oils to Valencia orange, Citrus sinensis (L.) Osbeck, in New South Wales
Authors: Beattie GAC , Roberts EA , Rippon LE , Vanhoff CL
Published: March 2005

The phytotoxicity of petroleum oil sprays to Vakncia orange (Citrus sinensis (L.) Osbeck) on Poncirus trifoliata (L.) Raf. rootstocks was investigated at Kulnura and at Griffith, New South Wales. Four narrow-range petroleum oils, designated as 206, 212, 214 and 238 oils, were applied as high volume sprays in 3 consecutive years. Annual sprays were applied during the spring, summer and autumn months of November, February and April. Some treatments were sprayed once each year, others twice. The single spray per year treatments involved concentrations of 1.2 or 2% of each oil in February or 2% of the 212, 214 and 238 oils in November or in April. A total concentration of 3.2% oil per year of the 2 12,2 14 and 238 oils was applied in February (2%) and in November of the previous year (1.2%) or in April (1.2%) to the double spray treatments. The effect of the sprays on yield variables, percentage juice, �Brix (w/w sucrose), anhydrous citric acid, rind colour and oil content was studied. Rind colour was not affected by any treatment at either location. Significant (P< 0.05), though inconsistent, effects on other characteristics of fruit quality were found. Increase in 50% distillation temperature and rate of application of oils tended to decrease �Brix. The oils did not significantly affect yield at Kulnura. At Griffith, 2% sprays of 238 oil significantly reduced yield by reducing the number of fruit. At both locations, trees sprayed with 2% oil in April tended to have lower yields than those sprayed in November or February at the same rate. The effect of sprays with total concentrations of 3.2% was variable. The 238 oil was the only oil considered to be potentially phytotoxic. This type of oil should not be used at concentrations > 2% from March to November or in consecutive years at any time. They can be used from late spring to early autumn in consecutive years at 1.2%. Variation in the phytotoxicity of oils between locations in south-eastern Australia appears to be related to variation in night temperatures in summer and early autumn which affect flower initiation.
Fetal mortality from day 30 of pregnancy in Merino ewes offered different levels of nutrition
Authors: Kelly RW , Wilkins JF , Newnham JP
Published: March 2005

The effect of nutritional restriction during mid pregnancy on fetal mortality was examined in 3 experiments in which multiparous 3-6 year old Merino ewes were fed at maintenance (M) or 0.3M from about day 30 to 90 of pregnancy, followed by M or 2M for the remainder of gestation. Fetal wellbeing was determined by ultrasound examination at periodic intervals throughout pregnancy. Among 134 single borne fetuses, mortality was detected in only 3, between days 70-92 of pregnancy. There were no losses in 58 ewes bearing twins and fed at M. By comparison, 9 of 93 ewes bearing twins and fed at 0.3M lost 1 or both fetuses between days 30 and 95, and a further 3 of 66 remaining ewes had fetal losses between days 95 and 140. It was concluded that such losses in ewes bearing twins during periods of nutritional restriction may need to be considered when using scanning to predict the number of lambs born. Also it highlights the need to confirm the viability of each fetus during ultrasound examinations of multiple fetuses.
The contribution of nitrogen fertiliser to the nitrogen nutrition of rainfed wheat crops in Australia: a review
Authors: McDonald GK
Published: March 2005

Very little nitrogen (N) fertiliser is applied to wheat crops in Australia. Currently, about 105 t of N fertiliser (less than 20% of Australia's total consumption) are used annually at an average rate of 2-3 kg Nha. This scant use of N fertiliser over much of the Australian wheat belt N is because the N derived from a legume-dominant pasture ley is thought to provide a wheat crop's N requirement. However, trends in the grain protein content of Australian wheat and some other indices of soil fertility suggest that legume-based pastures have not always been able to supply all the N required for adequate nutrition of the wheat crop and that there has been some occasional need for extra N from applications of fertiliser. Recent declines in the productivity and quality of pastures has further increased the need for supplementary applications of N fertiliser. The increase in grain legume production also has been partly based on the presumption that grain legumes contribute to the N economy of the following wheat crop. Many experiments throughout the wheat belt show a yield advantage of wheat grown after a grain legume, but these rotation trials also show that the level of productivity of the grain legume has little effect on the yield of the following wheat crop. A review of these experiments suggests that grain legumes, directly, contribute little to the N nutrition of a following wheat crop and their benefit may be from the legume acting as a disease break or providing the opportunity to control grassy weeds.
Prediction of the commercial yield of beef from carcasses destined for the Japanese market by using measurements from the carcass and non-carcass parts
Authors: Johnson ER , Ball B
Published: March 2005

Yield of saleable beef was predicted in 4 genotypes of bullocks (Hereford, Brahman, Brahman x Hereford and Simmental x Hereford). Simple and multiple regression equations were used to determine how well 4 fat thickness measurements (12th rib and rump measurements SC3 SC5 and SC7) individually, with or without the inclusion of hot side weight, foreshanks weight and short cut tongue weight predicted the yields of saleable beef. Each of the 4 fat thickness measurements (alone) predicted percentage yield of saleable beef with low r.s.d.'s at the means. The regression coefficients for the 4 fat thickness measuring sites were negative and significant in the Hereford, Brahman and Brahman x Hereford groups. In the Simmental x Hereford cattle, the regression coefficients for the rump sites (SC3, SC5 and SC7) were positive but significant only in SC5 which had the lowest r.s.d. (1.56%) of all sites. Twelfth rib fat thickness, with a common regression coefficient for all 4 genotypes (P<0.01) and an r.s.d. of 1.81%, was the next most useful fat thickness measurement. The addition of hot side weight improved the prediction of percentage saleable beef yield at the SC3 and SC5 sites, but not in the pure-bred Brahman bullocks. For populations that include British, European and Bos indicus cattle and their crosses, SC5 fat thickness (alone) was the best determinant of percentage yield of saleable beef. Neither quadratic analyses nor the addition of foreshanks weight or short-cut tongue weight to the fat thickness measurements improved the accuracy of linear regression in any of the 4 genotypes. The errors in prediction of percentage yield of saleable beef (0.28-0.67%) attributable to incorrect rump site location (of up to 4.0 cm) are unlikely to jeopardise the commercial value of yield of saleable beef predicted from measurements made on the rump. Whilst the Brahman and Brahman x Hereford cattle produced high-yielding carcasses for the Japanese chilled beef market and the Simmental x Hereford cattle, by judicious management could equal this yield, carcass yields of the Hereford cattle were about 4-5% lower at all levels of fat thickness. The ability of Hereford cattle to satisfy this market, economically, is seriously questioned.
Residues of DDT and dieldrin in the subcutaneous fat and butterfat of cattle
Authors: Dingle JHP , Palmer WA , Black RR
Published: March 2005

Technical DDT or dieldrin was added to crushed wheat and fed to steers and dairy cows. Subcutaneous fat collected by biopsy and butterfat were examined for residues of DDT, DDD, DDE and dieldrin. Steers fed 6, 36 or 216 mg DDT/day for 10 weeks had total DDT residues (mean � s.e.) in subcutaneous fat of 0.38� 0.01, 2.72�0.37 and 24.5�6.9 mg/kg respectively. DDD was the major residue, comprising 80% of the total. When DDT was withdrawn from the diet, residues declined. Half-life for DDT was 11 weeks (range 8-14), and for DDD was 5 weeks (range 3.5-7.4). Half-life could not be determined for DDE. Steers fed 36 mg dieldrin/day for 10 weeks had 17.3�4.9 mg/kg dieldrin in the subcutaneous fat. The half-life for dieldrin was 5 weeks (range 2.5-10.0). Dairy cows fed 6, 36 or 216 mg DDT/day for 6 weeks had total DDT residues in butterfat of 0.31�0.05, 2.5�0.60 and 20.8�1.2 mg/kg respectively. DDD was again the major residue, comprising 65% of total residues. Half-lives of DDT, DDD and DDE in butterfat were 7.2 (range 6.3-7.7), 3 (range 2.2-3.0) and 5 weeks (range 3.5-8.0) respectively. When 36 mg dieldrin was fed to dairy cows for 6 weeks, residues of 17.3�4.6 mg/kg were found in the butterfat. The half-life for dieldrin in butterfat was 9 weeks (range 6-11.5).
Maternal interest in lambs smeared with polar and nonpolar substances
Authors: Alexander G , Goodrich BS , Stevens D , Bradley LR
Published: March 2005

Maternal interest in their own and alien lambs was examined in groups of 7-11 ewes before and after their lambs were coated with nonpolar substances (white soft paraffin or liquid paraffin), or more polar substances (polyethylene glycol, glycerol, silicone oil or diisooctylphthalate). Maternal interest in alien lambs was significantly increased by smearing lambs with the nonpolar material, but the effect was absent when lambs were washed before coating; more polar coatings had little or no effect. The coatings had little or no effect on the maternal interest in the ewe's own lambs. We suggest that coatings of polar materials, while dissolving polar components from the skin and wool, does not prevent the release of volatile nonpolar constituents which ewes employ to distinguish between lambs. We also suggest that nonpolar coatings dissolve and retard the release of lamb odour components of similar polarity, while permitting the release of other constituents which appear generally attractive to maternal ewes, and result in increased acceptance of alien lambs.
Field examination of temperature and oxygen relationships in mushroom composting stacks dash consideration of stack oxygenation based on utilisation and supply
Authors: Miller FC , Harper ER , Macauley BJ
Published: March 2005

Temperature and oxygen concentration in Phase I composting stacks were investigated in the field. that both determine and are consequences of biological Investigations focused on various physical factors activity. Data indicate that oxygen concentrations in Phase I stacks are affected by convection, gaseous diffusion and utilisation rates, but that these rates vary significantly spatially and temporally. When stack temperatures exceed 60�C, biological rates of activity, and therefore oxygen uptake, decrease, allowing oxygen to penetrate well into the centres of stacks. While natural convection is commonly used to explain stack oxygenation, this is an over simplification that does not adequately describe stack oxygen concentrations.
Tolerance of subterranean clover cultivars and balansa clover to selective herbicides in Tasmania
Authors: Evans PM , Smith RS , Carpenter JA , Koen TB
Published: March 2005

Fifteen cultivars of subterranean clover (Trifolium subterraneum L.) and 1 cultivar of balansa clover (Trifolium balansae Boiss.) were screened for tolerance to 2,4-DB, MCPA-Na salt, MCPA amine, bromoxynil and combinations of these herbicides. The clovers were sprayed at the 3-4 trifoliate leaf stage and dry matter production assessed in the following spring. All herbicides reduced clover dry matter production (DM). The least damaging herbicides to subterranean clover were bromoxynil (0.3 kg a.i./ha) and MCPA-Na salt (0.313 kg a.i./ha) which reduced DM production by 23 and 39% respectively. The most damaging were 2,4-DB (0.8 kg a.i./ha) and MCPA amine (0.313 kg a.i./ha) plus bromoxynil (0.3 kg a.i./ha) which reduced DM production by 62 and 56% respectively. The damage caused by MCPA-Na salt (0.5 kg a.i./ha) plus bromoxynil (0.3 kg a.i./ha) was intermediate, reducing clover production by 44%. Second year seedling regeneration was reduced across all herbicide treatments by 32%. Of the currently recommended cultivars, Trikkala was the most tolerant to herbicides, with an average reduction in DM of 37%. Bromoxynil was the herbicide tolerated best by cvv. Enfield, Karridale, Larisa, Mt Barker and Woogenellup. The most effective weed killing treatments were 2,4-DB plus bromoxynil and MCPA-Na salt (0.5 kg a.i./ha) plus bromoxynil(0.3 kg a.i./ha).