bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitrogen-fertilised grass in a subtropical dairy system 3. Effect of stocking rate on the response to nitrogen fertiliser
Authors: Cowan RT , Lowe KF , Upton PC , Bowdler TM
Published: March 2005

Two stocking rates, one as practised on farms (2 cows/ha) and the other 50% higher, were assessed for effect on pasture and milk yield response to applied nitrogen (N) fertiliser (0-600 kg N/ha. year) for Holstein-~Friesian cows grazing Rhodes grass (Chloris gayana) cv. Callide pastures. Pastures were grazed in combination with grazing oats for winter, with overall farm stocking rates of 1.17 and 1.37 cows/ha for ' the 2 treatments. Cows were maintained on these areas for 3 years. Cracked grain was given at 0.8 t/cow. year, and hay or silage supplements were given when green grass yield was <0.5 t dry matter (DM)/ha. The incremental response (P<0.05) in milk yield to each kg increase in level of applied N was 4.93 kg/ha at 1.17 cows/ha and 1.64 kg/ha at 1.37 cows/ha. The amount of conserved forage fed at the high stocking rate increased (530 and 970 kg/ha. year at 1.17 and 1.37 cows/ha), and financial margins over costs were reduced at the high stocking rate. The low milk response at the high stocking rate was associated with a low response in pasture growth. At <2 t pasture DM/ha on offer, incremental response to applied N declined, and there may have been an excessive loss of N through volatilisation in heavily grazed pastures. Milk yield per cow was closely related to total pasture yield on offer (P<0.01), and to leaf and stem yields (P<0.05). Relationships were stronger in summer and autumn than in spring. Over the full year, milk yield increased by 1.24 kg/kg leaf DM or 0.24 kg/kg total pasture DM on offer. At the higher stocking rate, surface soil (0-10 cm) concentrations of phosphorus and nitrate were higher than at the lower stocking rate. We conclude that in areas of moderate rainfall (<1000 mm/year) in the subtropics, high stocking rates resulting in low pasture yields and exposed ground surface will be associated with low efficiency of use of applied N.
Consequences of reproduction on the liveweight, fat depth, wool growth, and intake of grazing Merino ewes in the short and long term
Authors: Lee GJ , Atkins KD
Published: March 2005

Effects of the current and previous year's reproductive performance on liveweight, fat depth, pasture intake, and wool growth were estimated in breeding Merino ewes in each of 2 years and in 4 seasons corresponding with stages of the annual reproductive cycle. Ewes bearing multiple lambs were heavier in early pregnancy (autumn, by 1.5 kg) and in late pregnancy (winter, by 2.5 kg) than single-bearing ewes, with both being heavier than nonpregnant (dry) ewes in winter (by 1.7-4.2 kg). Pregnancy had no effect on fat depth or intake in autumn or winter. Lactating ewes were leaner (by 1.0-1.7 mm), had lower liveweights (by 6.4-8.6 kg), and had substantially higher intakes [by 286-348 g digestible organic matter intake (DOMI)/day] than non-lactating ewes. From summer to winter, ewes that had previously reared a lamb, or lambs, to weaning weighed less, were leaner, and had higher intakes than ewes that were previously dry. Pregnant ewes grew significantly less clean wool and grew it less efficiently (g wool/kg DOMI) in autumn (7-9% less) and winter (11-18% less) than non-pregnant ewes. Similarly, lactating ewes grew less wool (by 23-30%) less efficiently than ewes not suckling, the effect being greater in ewes with multiple lambs. Post-weaning, however, ewes that had reared a lamb to weaning grew significantly more wool (by 6-15%) up to 4 months post-weaning, although efficiency of wool growth was still impaired. The effects of reproductive status on the fibre diameter of wool reflected those for wool growth. Effects of reproduction on productivity are long term and recovery may not be achieved before the next reproductive cycle.
Distribution and abundance of annual legume seeds in the wheatbelt of Western Australia
Authors: Fortune JA , Cocks PS , Macfarlane CK , Smith FP
Published: March 2005

The size and composition of pasture legume seedbanks were estimated from 2 surveys on a 460-km west-east transect of the wheatbelt of Western Australia. Survey 1 (in spring) sampled naturalised legumes, and survey 2 (in summer) measured the amount and botanical composition of legume seed from selected sites. Seedbanks were examined in greater detail on 2 farms in the higher rainfall part of the wheatbelt. Survey 2 revealed that mean seedbank size of the poorest 40% of sites (those with 5200 kg seed/ha) was 61 kg/ha, and that 72% of seeds were naturalised clovers. In contrast, the best 60% of sites (those with >200 kg seed/ha) averaged 533 kg seed/ha, of which only 35% was naturalised clover seed, the remainder in both surveys being mainly subterranean clover (Trifolium subterraneum). Mean seed bank size (kg/ha) varied from 359 (survey 2) to 587 (survey 1) and, in both surveys, was poorly correlated with long-term mean annual rainfall and a number of soil parameters. On the 2 farms, seedbank size ranged from 300 to 345 kg/ha (in spring) and from 650 to 740 kg/ha (in summer). Trifolium glomeratum (cluster clover) and subterranean clover were the most widespread species in both surveys. They were present at 35 and 30 of the 57 survey sites, respectively, and at both farms. Most of the subterranean clover collected was cv. Geraldton (22 of 30 sites), the next most frequent cultivar was Dwalganup (6 sites). The currently recommended cultivar, Dalkeith, was found at only 5 sites. Several other legumes including T. tomentosum (16 sites), T. suffocatum (8 sites), Medicago truncatula (7 sites), T. hirtum (4 sites), and M. minima (4 sites) were common, while M. littoralis, M. polymorpha, T. dubium, T. cernuum, T. cherleri, and T. carnpestre were found at single sites. With few exceptions, these are naturalised species and were characterised by flowering times about 20 days later than sown legume cultivars, and seed sizes < 1 mg. The value of these widespread annual legumes to agricultural productivity and sustainability needs to be quantified and their adaptation to wheatbelt farming systems assessed.
Effect of groundwater pump management on reclaiming salinised land in the Goulburn Valley, Victoria
Authors: Norman CP
Published: March 2005

In 1985, groundwater pumping from shallow aquifers, with off-farm disposal, began near Girgarre in the Goulburn Valley, Victoria, to provide salinity control to about 1000 ha of farming land. Two groundwater pumps (TI02 and T103) ran continuously for the first 5 years of the project before reverting to intermittent pumping. The operation of a third pump (T103) was based on the capacity for disposal into an evaporation basin. Following 3 years of groundwater pumping, significant reductions in root-zone (0-0.6 m) soil salinity levels were recorded in both annual and perennial pasture paddocks within 350 m of a pump. Yields of perennial pasture on all monitored paddocks showed a significant increase after commencement of the project. In a paddock 300 m from a groundwater pump, average dry matter production increased from 6.3 to 17.2 t/ha. year within 4 years of pumping. Reclamation was reduced by more than a year on paddocks not subjected to irrigation, or those located >800 m from a groundwater pump. Once reclamation was achieved from continuous pumping, the introduction of intermittent pumping continued to maintain optimum soil salinity and pasture production levels on the irrigated paddocks. However, on a dryland paddock and those located >800 m from a pump, increasing fluctuations in soil salinity and soil sodicity levels were measured under this management regime.
Effect of ripening temperature on quality and compositional changes of mango (Mangifera indica L.) cv. Kensington
Authors: O'Hare TJ
Published: March 2005

Preclimacteric mangoes (Mangifera indica L.)cv. Kensington were treated with ethylene (200 �L/L) for 36 h, then ripened under a range of temperatures from 13 to 30�C and under 2 diurnal temperature regimes (18/24�C in 12/12 h and 18/6 h cycles). Fruit were assessed for quality (skin colour, pulp colour, eating quality) and compositional changes over the ripening period. Fruit that was ripened at 18-22�C achieved the highest quality scores, with all quality parameters reaching a maximum within about 2 days of each other. Diurnal temperature cycling provided no advantage over non-cycled temperatures. Fruit ripened at 13 and 30�C had lower skin colour quality scores, related to poor carotenoid development and high chloropnyii retention, respectively. The poor carotenoid development at 13�C also resulted in lower pulp colour quality scores. Eating quality was significantly lower at 13 and 30�C, related to the slow decline in titratable acidity and poor flavour, respectively. Quality parameters became unsynchronised at 13 and 30�C, with skin colour quality reaching a maximum 5 days earlier than eating quality at 13�C, and 3 days later at 30�C.
Comparative study of vine morphology, growth, and canopy development in cane-pruned and minimal-pruned Sultana
Authors: Sommer KJ , Clingeleffer PR , Shulman Y
Published: March 2005

The seasonal development of vine canopy size and vine morphology of minimal- and cane-pruned Sultana was examined by destructive harvests during the 1982-83 growth period. Leaf canopies of minimal-pruned vines developed more quickly, grew larger, and filled sooner than those of cane-pruned vines. Minimal-pruned vines had 4 times the number of shoots and 3 times the number of nodes on current seasons's shoots at 34 days after budburst. This largely explains the more rapid canopy development and fill of minimal-pruned vines. Minimal pruning had a stunting effect on growth, resulting in shorter shoots, shorter internodes, and smaller leaves compared with cane pruning. Indirect optical measurements of the seasonal leaf canopy development of Sultana vines in the same experimental vineyard during the 1991-92 growth period confirmed the results obtained in 1982-83.
Alternative management strategies for maximising productivity in beef cattle in the subtropics
Authors: Peiris H , Elliott R , Hales JW , Norton BW
Published: March 2005

Two concurrent factorial experiments investigated the relative merits of the following management options to maximise liveweight gains in finishing cattle: breed [Hereford (Bos taurus) v. Belmont Red (B. taurus x B. indicus)]; implantation with zeranol; feed energy source (sorghum grain, molasses + urea, tropical grass pastures); feed protein source (sunflower meal, Leucaena leucocephala, tropical pasture legumes). These combinations of treatments were delivered by using nil, intermittent, or continuous grazing systems. Sixty steers of initial liveweight (� s.e) 321 � 3.6 kg were held on their respective treatments for 77 or 98 days, by which time all except those on pasture without supplement had attained at least 400 kg liveweight. Steers were slaughtered in a commercial abattoir and carcass characteristics recorded. Zeranol-implanted cattle grew faster than untreated (0.84 v. 0.66 kg/day), and there was a trend (P = 0.14) for Belmont Red cattle to grow faster than Herefords (0.83 v. 0.67 kg/day). In all systems, cattle given ad libitum sorghum grain grew significantly (P<0.05) better than those given molasses + urea (1.54-0.65 v. 0.72-0.45 kg/day). The poor performance of molasses-fed cattle was associated with low voluntary feed consumptions. The highest rates of gain (1.54 kg/day) were for penned cattle on a sorghum grain + sunflower ration. The provision of either supplement promoted better gains than that found for unsupplemented steers grazing tropical grass-legume pastures (-0.29 to +0.26 kg/day). However, cattle continuously grazing (10 steers/ha) leucaena-grass pastures and those given sunflower meal had significantly (P<0.05) higher rates of gain (0.82 and 0.91 kg/day, respectively) than cattle given molasses supplements or grazing alone. Cattle given sorghum had higher carcass weights and fat contents than those fed molasses or with grazing alone, although only those in the feedlot had acceptable fat cover at slaughter. There was no significant effect of treatments on the fatty acid composition of subcutaneous fat.
A comparison of buckwheat, oats, and wheat for the maintenance of liveweight and wool production in sheep
Authors: Mulholland JG , Preston GK
Published: March 2005

Merino wethers about 2 years old were confined in pens and fed, daily or weekly, maintenance rations of whole buckwheat, crushed buckwheat, whole wheat, or oats. All rations were supplemented with a small portion of pasture hay and minerals and were compared for acceptance, digestible energy (DE), and wool growth. The DE of the ration containing whole buckwheat was 13.1 MJ/kg DM and was 86.3% of the DE value of the wheat ration and 11% higher than that of oats, but the oats were below average Australian quality. Processing buckwheat increased faecal energy loss and reduced DE by 8%. During the first 10 days of feeding, the sheep fed weekly lost 75 day compared with a gain of 6 g/day for the daily-fed group, but thereafter liveweights remained fairly constant. This resulted in an overall difference (P<0.05) between weekly and daily feeding. Significantly (P<0.05) higher food refusals were obtained with weekly feeding, but there was no difference between grain types. Wool growth was similar for all grains and for daily and weekly feeding. It was concluded that buckwheat is a suitable grain for maintaining liveweight and wool production of sheep.
Dispersal of seeds of giant Sporobolus spp. after ingestion by grazing cattle
Authors: Andrews TS
Published: March 2005

Samples of fresh cattle faeces were taken from 2 grazing paddocks on the North Coast of New South Wales. One paddock was heavily infested with giant Parramatta grass (GPG, Sporobolus indicus var. major) and the other paddock had a medium-light infestation. Fifty-two and 14 viable GPG seeds/kg were recovered from the dung samples collected in May from these paddocks, respectively. Seeds of GPG and giant rat's tail grass (GRTG, S. pyramidalis) were fed to caged Friesian heifers in 2 experiments, and the time taken for all of the seeds to be excreted was measured: 4 days in experiment 1 and 7 days in experiment 2. Consequently, a 7-day withholding period is suggested for cattle grazing pastures infested with giant sporobolus. The number of viable seeds excreted was estimated as a proportion of seeds fed to each heifer using average viability of seeds recovered, concentration of viable seeds collected daily, and daily manure weights. Based on this, the number of seeds ingested by gazing stock was estimated to be 8300 and 2200 seeds/head.day for the paddocks with heavy and medium-light infestation, respectively. Manure collected 2 and 3 days after feeding had the highest concentrations of viable seeds. This manure was placed outdoors in styrofoam boxes and left for 7 months. No GPG seedlings or plants were present in the manure after this time, and further subsampling of the manure indicated that no viable seeds remained. Processes that disperse fresh manure, such as heavy rain or the hosing down of transport vehicles, may allow successful germination and emergence of giant sporobolus seeds. However, where dung pats are left intact for some months, establishment of giant sporobolus plants is unlikely. Adhesion to machinery and the hair of stock are likely to be more important causes of dispersal of giant sporobolus than ingestion by stock.
Field persistence of Bradyrhizobium sp. (Lupinus) inoculant for serradella (Ornithopus compressus L.)
Authors: Bowman AM , Hebb DM , Munnich D , Rummery GL , Brockwell J
Published: March 2005

Experiments were conducted, in situ in north-western New South Wales and in the laboratory, to evaluate the longevity of Bradyrhizobium sp. (Lupinus) inoculated as a peat culture onto seed of yellow serradella (Ornithopus compressus L.). Observations were made on the field persistence of the inoculant strain over 2 years. Two categories of seed were examined: seed encased in a segment of pod coat (hulled), and seed from which the pod coat had been removed (dehulled). The use of adhesive (methyl cellulose or gum arabic) ensured that the inoculant adhered to the seed. At a constant temperature of l8�C, inoculant applied to hulled seed survived for >8 months without loss of viability. Type of adhesive did not affect survival. At the 2 field sites, inoculated seed was sown into dry soil. Inoculant was sufficiently viable for 77-159 days to colonise the rhizospheres of young serradella and to form nodules on a significant (P<0.05) proportion of the plants. Rhizosphere colonisation and nodulation were better with hulled seed than with dehulled seed but were not affected by type of adhesive. Evidence is presented that the inoculant was able to establish in these soils as a permanent component of the soil microflora and to persist as a reservoir of inoculum for annually regenerating serradella.
Manganese toxicity in Trifolium balansae, T. resupinatum, T. subterraneum, Medicago murex, M. polymorpha, M. sativa, Lotus pedunculatus, and Ornithopus compressus: relative tolerance and critical toxicity concentrations
Authors: Marco DGDe , Li CB , Randall PJ , De Marco DG
Published: March 2005

This paper describes the tolerance to high concentrations of manganese (Mn) of pasture legumes that are suitable for the >500 mm rainfall zone in southern Australia. The legumes are lucerne (Medicago sativa), burr medic (M. polymorpha), murex medic (M. murex), balansa clover (Trifolium balansae), Persian clover (T. resupinatum), subterranean clover (T: subterraneum), greater lotus (Lotus pedunculatus), and seradella (Ornithopus compressus). Wheat (Triticum aestivum) cv. Egret and subterranean clover cvv. Mt Barker and Karridale were included to place the tolerance of the remaining species in the context of other studies.Symptoms of toxicity differed between species. Species ranking (in descending order) for Mn tolerance, and external threshold Mn concentrations (mmol/L), were subterranean clover (1.0), wheat (0.71), balansa clover (0.54), greater lotus (0.51), serradella (0.50), Persian clover (0.25), murex medic (0.24), burr medic (0.20), and lucerne (0.19). Critical toxicity concentrations derived from the relationships of yields to Mn concentrations in whole shoots for each species were as follows (mg Mn/kg DW): subterranean clover (2010), balansa clover (1330), serradella (1080), greater lotus (760), wheat (570), burr medic (440), murex medic (430), Persian clover (360), lucerne (190).
Nutrient sprays applied to the foliage of narrow-leafed lupins (Lupinus angustifolius L.) during flowering and podding do not increase seed yield
Authors: Seymour M , Brennan RF
Published: March 2005

Nitrogen (N), phosphorus (P), potassium (K), sulfur (S), manganese (Mn), magnesium (Mg), and boron (B) were applied as foliar sprays to narrow-leafed lupins (Lupinus angustifolius L. cv. Gungunu) grown in Esperance in 1991 and 1992. Applied individually, no nutrient increased the seed yield of lupins. In 1992, the application of 15 kg N/ha at 2 growth stages [flowering and 2 weeks after flowering (2WAF)I and 4 kg S/ha at 2WAF reduced the seed yield by about 10% (300 kg/ha), despite no evidence of damage to the foliage of the lupins. Nutrient mixes of N, P, K, S, and B were applied in both years at 3 growth stages (flowering, 2WAF, 6WAF), and no combination at any time of application increased the seed yield. In 1992, one combination treatment of (kg/ha) 15 N, 8 P, 12 K, 4 S, and 1 Mn applied 2 weeks before the start of flowering reduced yield by 14%. Where no foliar nutrients were applied, seed yields (t/ha) were 2.6 in 1991 and 3.2 in 1992. Foliar-applied nutrients sprayed during flowering and podding, in addition to some fertilisers applied to soil at seeding, are unlikely to increase the seed yield of lupin crops in the south coastal districts of Western Australia.
Agronomic effectiveness of partially acidulated phosphate rock fertilisers in selected New Zealand soils
Authors: Condron LM , Di HJ , Goh KM , Campbell AS , Harrison R
Published: March 2005

The agronomic performances of some longlife superphosphate (LSP) and partially acidulated phosphate rock (PAPR) fertilizers were compared with single superphosphate in glasshouse pot trials over 9-10 months using a range of New Zealand soils. The fertilizers used differed in the type (origin) of phosphate rock (PR), the acid to rock ratio used in the production of LSP, percentage acidulation of PAPR, and incorporation of elemental sulfur into LSP. The agronomic effectiveness of the fertilizers studied was primarily influenced by the type of PR and percentage acidulation of PAPR, but not by the acid to rock ratio. Variations in the agronomic effectiveness of LSP and PAPR fertilizers made from different PRs did not reflect the relative solubilities of the original PRs. This was mainly attributed to alterations in the chemistry and consequent solubility of PR which occurred during fertilizer manufacture. Plant phosphorus uptake was highly correlated with fertilizer solubility in 2% citric and 2% formic acids. The relative agronomic effectiveness of LSP and PAPR fertilizers was not significantly related to any single soil property.
Cadmium and lead content of lupin seed grown in Western Australia
Authors: Petterson DS , Harris DJ
Published: March 2005

The cadmium (Cd) concentration of 147 samples of commercial lupin (Lupinus angustifolius) seed from Western Australia ranged from <0.01 to 0.08 mg/kg as received. For 31 samples from Victoria and 25 samples from plant variety trials in South Australia and Western Australia the range was 0.01-0.06 mg Cd/kg. Only 12 samples contained >0.05 mg/kg, the maximum permitted by the National Food Authority for human consumption, and none contained >0.1 mg Cd/kg, the proposed Codex Alimentarius limit. The Cd concentration of 101 samples of various other grain legume seeds from around Australia ranged from <0.01 to 0.06 mg/kg, with 2 samples exceeding 0.05 mg/kg. There was no significant difference between lupins, field peas, and cereals in their concentration of Cd or lead (Pb) when grown at the same site. The Pb concentration of 143 samples of lupin seed from Western Australia, with a range of <0.01-0.25 mg/kg, was below the standard of 2.0 mg/kg for legume foods. This study indicates that problems are unlikely with Cd or Pb in lupin seed or other major grain legumes grown in Western Australia.
Changes in the composition of milk from healthy and mastitic dairy cows during the lactation cycle
Authors: Auldist MJ , Coats S , Rogers GL , McDowell GH
Published: March 2005

Variations in milk composition during lactation were studied in normal and mastitic dairy cows from 2 seasonally calving herds in northern Victoria. Milk yields, somatic cell counts (SCC), and concentrations of lactose, fat, total protein (TP), casein protein (CP), non-casein protein (NCP), sodium, potassium, and calcium varied considerably as lactation progressed. The basic patterns of change over lactation were similar whether cows were healthy or mastitic (SCC >3 x 105 cells/mL milk). Milk from mastitic cows had higher concentrations of TP, NCP, and sodium, but lower concentrations of fat, lactose, CP, and potassium, than milk from healthy cows, although differences were not consistently significant. The activity of the milk protease, plasmin, was positively correlated with log10SCC in both herds.
Meat quality, carcass fatness, and growth of short scrotum lambs grazing either forage rape or irrigated perennial pasture
Authors: Hopkins DL , Beattie AS , Pirlot KL
Published: March 2005

The growth of 136 short scrotum male crossbred lambs fed on either forage rape (Brassica napus) or irrigated perennial pasture was examined from December to April 1991-92, as was the effect on meat quality assessed by objective and subjective means. During the first 6 weeks the groups of lambs showed similar liveweight gains, but thereafter those on the irrigated pasture treatment had a slower growth rate until first slaughter. The first slaughter, of all lambs weighing >48 kg, took place when >50% of the rapefed lambs exceeded this liveweight, at which time they were significantly (P<0.001) heavier (49.3 � 0.82 kg) than the pasture-fed lambs (43.8 � 0.79 kg); consequently, significantly (P<0.001) more of them were slaughtered. Rape-fed lambs had significantly (P<0.001) higher fat scores (mean �s.e.) before the first slaughter than pasture-fed lambs (3.8 � 0.10 v. 2.9 � 0.09). The mean (�s.e.) GR tissue depths for the 2 groups were 15.2 � 0.36 and 12.3 � 0.36 mm, respectively, when adjusted to a common carcass weight of 21.4 kg. Carcasses from pasture-fed lambs had significantly (P<0.05) higher pH values. Meat from rape-fed lambs was significantly (P<0.05) lighter in colour; the M. semimembranosus (SM) from the pasture-fed lambs had significantly (P<0.05) higher a* values (indicating relative redness), but there was no significant difference for the M. longissimus thoracis et lumborum (LL). There was a tendency (P = 0.09) for the LL and SM muscles from the pasture-fed lambs to be tougher as indicated by shear values, but there was no significant difference between groups for cooking loss. For both the LL and M. biceps femoris (BF) from rape-fed lambs, flavour was considered significantly (P<0.05) stronger than for the same muscles from pasture-fed lambs, as was the aroma of the LL. Overall, the BF from pasture-fed lambs was significantly (P<0.05) more acceptable to panellists than BF from rape-fed lambs, with no difference for the LL. We conclude that provided a management procedure is in place to prevent overfatness, grazing entire male lambs on forage rape can produce heavy lean lambs over the summer period, whereas under normal dryland pasture conditions, the finishing time would be significantly longer. Based on objective assessments, the meat from entire lambs finished on forage rape will be of quality similar to that from lambs finished on perennial pasture and may have a more acceptable meat colour. From subjective assessments of quality, however, some Australian consumers may detect a stronger, less acceptable flavour from the meat of rapefed lambs. The importance of these flavour effects to consumers requires further study.
Effect of grain or silage supplementation on meat quality attributes of cryptorchid lambs grazing lucerne or annual grass-clover pastures
Authors: Hopkins DL , Holst PJ , Hall DG
Published: March 2005

Objective and subjective tests for quality were performed on the meat from 40 cryptorchid second-cross lambs fed lucerne only (L; n = 8), lucerne plus an oat grain supplement ad libitum (LO; n = lo), lucerne plus wilted lucerne silage ad libitum (LS; n = 11), or an oat-lupin grain (3:1) supplement at 90% of ad libitum while grazing dry summer annual pasture (OL; n = 11). All carcasses complied with the Elite lamb specification of weight >22 kg and GR measurement 6-15 mm. There was no significant difference between groups for hot carcass weight, the mean (� s.e) values being 25.1 0.43, 25.2 � 0.36,25.2 � 0.38, and 25.3 � 0.36 kg for L, LS, LO, and OL groups, respectively. When the GR and fat depth over the eye muscle at the 12th rib were adjusted to a common carcass weight of 25.2 kg there was no significant difference between groups. There was no significant difference between groups for pH, or the colour values a*, b*, and L* of the M. longissimus thoracis et lumborum (a* is relative redness, b* relative yellowness, and L* relative lightness). The shear force values for the loin muscle were significantly (P<0.05) greater for lambs from group OL than for those from group LO. Cooking loss for the loin muscle was significantly (P<0.05) greater for OL lambs than all other groups. A comparison of the mean values for aroma and flavour showed the lambs from group OL produced meat that was considered significantly (P<0.05) less desirable for these characteristics, with other groups being similar. Meat from OL-fed lambs was considered oilier and less meaty than meat from lambs fed the other diets. There was a significant (P<0.05) difference in absolute scores between panellists, but their ranking was not affected and there was no panellist x sample interaction. Because many producers use grain supplements such as oats and lupins for finishing lambs on dry forages, further study is recommended that focuses on the interaction between supplement and the base forage.
Differential tolerance of Trifolium subterraneum L. (subterranean clover) cultivars to broadleaf herbicides 1. Herbage yield
Authors: Dear BS , Sandral GA , Coombes NE
Published: March 2005

The differential tolerance of 7 Trifolium subterraneum (subterranean clover) cultivars to 5 broadleaf herbicide treatments applied at 2 rates was examined at 2 sites over 2 years. The herbicide treatments and the rate of active ingredient applied (kg a.i./ha) were 2,4-DB (0.8, 1.6), MCPA (0.5, 1.0), bromoxynil (0.28, 0.56), MCPA (0.15, 0.3) + terbutryn (0.275, 0.4125), and MCPA (0.25, 0.375) + diuron (0.25, 0.375). The herbage yield of all cultivars at 30 and 60 days after herbicide application (DAA) was suppressed by all herbicides except 2,4-DB at 60 DAA. There was marked variation in cultivar tolerance, with Trikkala being the most tolerant to all herbicides. Seaton Park was the most sensitive to MCPA + terbutryn, MCPA + diuron, and bromoxynil, while Karridale was the most sensitive to MCPA. Log10(sprayed yield) log10(unsprayed yield) was an appropriate measure of relative tolerance of cultivars to herbicide. While herbage yields and yield reduction due to the herbicides varied between sites and years, the effect of the herbicides and the relative responses of the cultivars were similar across years and sites. Herbage yield meaned over the 2 herbicide rates was reduced by 16-71% at 30 DAA depending on herbicide and cultivar, and by 445% at 60 DAA. A mixture of MCPA + terbutryn or MCPA + diuron caused the largest reduction in herbage (47-71%) at 30 DAA, while MCPA and 2,4-DB caused the smallest (16-56%) reduction. Neither the maturity ranking of the cultivar nor the cultivar vigour measured at 30 DAA influenced sensitivity to the herbicides. The rate of recovery (kg DM/ha.day) by the cultivars at 30-60 DAA was greatest in the MCPA, 2,4-DB, and bromoxynil treatments (80-120 kg DM/ha.day) and least in the MCPA + diuron treatment (71-84 kg DM/ha.day) and was not related to maturity ranking. Doubling the rate of herbicide increased herbage yield suppression and resulted in slower growth rates but did not affect seedling survival. The magnitude of the reduction in herbage yield has important implications for choice of herbicide and needs to be balanced against the likely loss due to weed competition. The identification of significant differential cultivar tolerance suggests that worthwhile improvements in tolerance can be achieved through plant breeding or selection.
Differential tolerance of Trifolium subterraneum L. (subterranean clover) cultivars to broadleaf herbicides. 2. Seed yield and quality
Authors: Sandral GA , Dear BS , Coombes NE
Published: March 2005

The effect of broadleaf herbicides on seed set by Trifolium subterraneum (subterranean clover) cultivars was examined at 2 sites (Wagga Wagga and Canowindra) over 2 years. Five commonly used herbicide treatments (bromoxynil, MCPA, 2,4-DB, MCPA + terbutryn, MCPA + diuron) were applied at 2 rates to 7 cultivars of subterranean clover. Significant site x cultivar x herbicide interactions were observed. Seed yields were either unaffected or depressed by up to 66% at the higher rainfall site (Canowindra), whereas at the lower rainfall site (Wagga Wagga) some herbicide x cultivar combinations showed increases in seed yield up to 115%. The increase in seed yield was greater at the lower herbicide rate. The variation in seed yield with herbicide treatment was largely a result of a change (P<0.001) in the number of seeds set (R = 0.94 at Wagga Wagga; R = 0.85 at Canowindra). Seed size was also correlated (P<0.001) with seed yield at both sites but explained less of the variation (R = 0.23 at Wagga Wagga; R = 0.47 at Canowindra). The reduction in herbage yield as a result of herbicide application was a poor indicator of the subsequent seed yield response at both sites. Cultivar Trikkala was consistently most tolerant to the herbicide treatments, showing either no change in seed yield at the wetter site or large increases in seed yield at the lower rainfall site. In contrast, the seed yield of Dalkeith was depressed by 2,4-DB at both sites in both years by 39-66%. Increases in seed yield, which were most pronounced in cultivars of midseason maturity (Trikkala, Junee, Seaton Park) and least in later maturing cultivars (Karridale, Clare) and in the very early flowering Dalkeith, were attributed in part to a water-saving effect of the herbicide treatments. Cultivar maturity ranking was negatively correlated (P<0.001) with seed yield (R=-0.73 at Wagga Wagga; R=-0.45 at Canowindra). The germination percentage of seed produced by the cultivars was unaffected by herbicide treatment, although the number of abnormal radicles formed by germinating seed was higher in the 2,4-DB and MCPA treatments.
Dry matter accumulation and partitioning and its relationship to grain yield in wheat
Authors: Flood RG , Martin PJ , Gardner WK
Published: March 2005

Total crop dry matter (DM) production and its components, remobilisation of stem reserves, and the relation of these to grain yield were studied in 10 wheat cultivars sown at Walpeup, Boort, and Horsham in the north-western Victorian wheatbelt. Between sites, all DM components decreased in the order Horsham > Boort > Walpeup. Differences between Boort and Walpeup were not always significant. Total DM at anthesis for Walpeu,p and Boort was in a similar range, and less than that for Horsham. Yields increased in the order Walpeup < Boort < Horsham. When data from the 3 sites were combined, leaf, stem (excluding cv. Argentine IX), and total DM were related to grain yield. Within sites, ear DM at anthesis was related to grain yield. Grain yield for all cultivars at Horsham and Walpeup and 5 cultivars at Boort was greater than the increases in crop DM from anthesis to maturity, indicating that pre-anthesis stored assimilates (stem reserves) were used for grain filling. Post-anthesis decrease in stem weight was inversely related to grain yield only at Horsham, which supports the view of utilisation of stem reserves for grain filling at this site. At Boort and Walpeup there was a similar negative trend, but values for 2 cultivars at each site were outliers, which weakened the trend. The wide adaptability of the Australian cultivars used in this study may be related to the differential remobilisation of stem reserves at each site. A measure of yield stability, however, was not related to stem weight loss during the grain-filling period.
Grain yields of field pea (Pisum sativum L.) in South Australia
Authors: McDonald GK
Published: March 2005

The grain yield of field pea (Pisum sativum L.) between 1959-60 and 1991-92 was examined in selected Hundreds in important peagrowing regions of South Australia. Over the 33 years, the rates of increase in grain yield have been substantial, ranging from 20 to 48 kg/ha.year. The rate of increase in the State average for the same period was 22 kg/ha. year. The largest rates of increase have occurred mainly in the Hundreds in the higher rainfall areas. Yields have increased irregularly. During the 1960s grain yields rose relatively slowly, but from the mid 1970s to the mid 1980s, large increases occurred. Since then, yields have increased relatively little or, in some Hundreds, declined. With one exception, grain yield was positively and significantly correlated with seasonal (April-October) rainfall in each Hundred, but there were few significant correlations with rainfall in individual months. Yield was often correlated with winter and autumn rainfall but not with spring rainfall. The efficiencies of seasonal water use in the Hundreds ranged from 2.7 to 4.8 kg/ha.mm; these were lower than the maximum values recorded for other winter grain legumes, suggesting that water use efficiencies can improve substantially.
Importance of seed-borne inoculum in the etiology of the Ascochyta blight complex of field peas (Pisum sativum L.) grown in Victoria
Authors: Bretag TW , Price TV , Keane PJ
Published: March 2005

Fungi associated with the ascochyta blight complex of field peas were isolated from 436 of 691 seedlots tested. Of the fungi detected, 94.8% of isolates were Mycosphaerella pinodes, 4.2% Phoma medicaginis, and 1.0% Ascochyta pisi. The levels of infestation of seed varied considerably from year to year and between seedlots, depending on the amount of rainfall between flowering and maturity. Within a particular pea-growing region, the level of seed-borne infection was often highest in seed from crops harvested latest. In addition, crops sown early were usually more severely affected by disease than late-sown crops, and this resulted in higher levels of seed infection. There was no correlation between the level of seed infestation by M. pinodes and the severity of ascochyta blight; however, where the level of seed infection was high (>11%) there was a significant reduction in emergence, which caused a reduction in grain yield. It may therefore be possible to use seed with high levels of seed-borne ascochyta blight fungi, provided the seeding rate is increased to compensate for poor emergence.
Effect of Ascochyta blight on the grain yield of field peas (Pisum sativum L.) grown in southern Australia
Authors: Bretag TW , Keane PJ , Price TV
Published: March 2005

Field experiments were conducted to determine the crop losses caused by ascochyta blight in different pea varieties grown in Victoria. For each variety, the reduction in yield associated with disease was determined by comparing grain yields in plots not sprayed with fungicide (disease present) and plots where the disease was controlled with fungicide sprays (no disease). There was considerable variation between pea varieties and lines in disease severity and crop losses. Individual varieties had different levels of tolerance to disease, and there were large differences between varieties in the percentage yield loss caused by the same level of disease. Disease severity was closely correlated with reductions in grain yield, and for most varieties there was a 5-6% reduction in grain yield for every 10% of stem area affected by disease (first 10 internodes on the main branch). Ascochyta blight caused substantial reductions in grain yield of all commercial pea varieties grown in Victoria but was usually most severe on the early-maturing varieties. For 15 varieties, empirical crop loss models to predict the relationship between disease severity and reduction in yield were developed. A disease survey of commercial crops was then conducted and estimates made of yield losses caused by ascochyta blight using the previously developed crop loss models. The estimated yield losses caused by ascochyta blight in commercial crops in Victoria in 1986 ranged from 3.1 to 26.4% and exceeded 15% in over three-quarters of crops surveyed. The results suggest that field pea production in Victoria is seriously retarded by ascochyta blight and that the development of effective strategies to control the disease should be given a high priority.
Influence of waterlogging on germination and survival of lupin seeds (Lupinus angustifolius L. cv. Gungurru) coated with calcium peroxide and streptomycin
Authors: Sarlistyaningsih L , Sivasithamparam K , Setter TL
Published: March 2005

Germination failed to occur in lupin seeds exposed to waterlogged soil, and survival was reduced to 0% after 4 days waterlogging. Coating seed with calcium peroxide (CaO2) increased germination and survival of lupin seeds for up to 4 days in waterlogged soils. This suggested that lack of O2 may limit growth of lupin seeds in waterlogged soil. Germination and hypocotyl elongation were also significantly increased on moist filter paper in Petri dishes when seeds were coated with CaO2. Adding streptomycin alone did not increase germination or survival of lupins under waterlogged conditions. Results are consistent with other data using sterilised soil or hypoxic solution cultures, that limited O2 supply is the primary factor limiting establishment of lupins in waterlogged soil.
Influence of soil-water matric potential on the control of Pythium root infection of wheat with metalaxyl in two contrasting soils of South Australia
Authors: Pankhurst CE , McDonald HJ , Hawke BG
Published: March 2005

Under prevailing climatic conditions, treatment of winter-sown wheat with metalaxyl (seed dressing, granule, or soil drench applications) significantly limited seed infection by Pythium species but did not give a significant yield response in separate field trials conducted on 2 contrasting soil types in South Australia. However, following irrigation of trial plots (which raised the soil-water matric potential from about -0.09 MPa to -0.02 MPa) during the first 3 weeks of wheat growth in 1989, metalaxyl granule treatment was effective in limiting seed and root infection by the 2 dominant Pythium species present, P. irregulare and P. echinulatum, and gave a significant increase in grain yield on both soil types. This effect of soil-water matric potential was confirmed in growth cabinet experiments in which metalaxyl was shown to be more effective in controlling infection of wheat by P. irregulare in both soil types when the soil-water matric potential was maintained at -0.02 MPa than at a soil-water matric potential of -0.1 MPa.
Residual benefits of limestone and superphosphate on barley yields and soil-water deficits on a krasnozem in north-western Tasmania
Authors: Rowe BA , Johnson DE
Published: March 2005

Twelve years after the last application of limestone, the residual benefits of 15 t/ha of surface applied limestone were measured on barley grown on a krasnozem [Gn4.11, pH 5.5 (1:5 soil:water)] at Elliott in north-western Tasmania. Liming increased grain yield by 77% (1.9 t/ha) when phosphorus (P), sulfur (S), potassium (K), and molybdenum (Mo) were non-limiting. An increase in the number of ears per m2 accounted for 73% of the yield increase, number of seeds per ear 20%, and slightly larger grains 7%. The soil-water deficit on the limed plots at the end of the growing season did not exceed that on the unlimed plots. We suggest that the crop responses to liming were due not to an increase in the potential soil-water available for extraction by the crop but to increased levels of available nitrogen on the limed plots, which increased tillering before the onset of water stress. Termination of superphosphate applications 20 years before reduced yield by 1.18 t/ha, to 59% of the yield obtained with superphosphate applied at 500 kg/ha.year. By comparison, the liming effect was 1.6 times larger. The barley crop responded equally to both the P and S components of the superphosphate, but did not respond to K or Mo fertilisers.
Growth of field pea on red-brown earth soils in a year with high rainfall
Authors: McDonald GK
Published: March 2005

A study of 4 commercial crops of peas was conducted in the Lower North of South Australia during 1992 to assess the importance of waterlogging on growth and yield. The area chosen for the survey has a high proportion of red-brown earth soils that slake and seal, have poor internal drainage, and are prone to transient waterlogging. Rainfall in the year of the survey was above average, particularly during September and October, and waterlogging and disease were common in pea crops throughout the region. Based on air-filled porosity and soil water tension, waterlogging occurred in each of the survey paddocks. Differences in vegetative growth and grain yields within and between paddocks could be related to the severity of waterlogging. There were differences between the 4 survey paddocks for concentrations of potassium, sodium, iron, and manganese in pea shoots, and these differences appeared to correspond to differences in the severity of waterlogging. Nutrient concentrations were, however, confounded by differences in soil pH and soil fertility. Despite adequate to high levels of available phosphorus (P) in each of the 4 paddocks, concentrations of P in shoots were generally low and, in 2 cases, indicated P deficiency. Phosphorus concentrations were not related to the concentration in the soil or to the severity of waterlogging. In field experiments conducted over 2 seasons (1991, 1992), peas were grown in raised hill plots to promote drainage around the upper root system. The method significantly increased plant establishment in both years, and in 1992, a year of record high rainfall, grain yields from the drained plots were 5-64 times greater than those from undrained plots. In 1991, a year with lower rainfall, drainage improved pod yield by 13%. Observations during the survey suggested that disease was worse in the paddocks that were severely affected by excess water.
Occurrence and distribution of races of Pseudomonas syringae pv. pisi in Australia and their specificity towards various field pea (Pisum sativum) cultivars
Authors: Hollaway GJ , Bretag TW
Published: March 2005

The occurrence of races among 65 Australian isolates of Pseudornonas syringae pv. pisi, the causal organism of bacterial blight of field peas, was investigated. Race 3 was most common in Victoria and New South Wales, while race 6 was most common in South Australia. Field pea cultivars were screened for their resistance or susceptibility toward the 7 races of P. syringae pv. pisi. The most common cultivars were susceptible to races 3 and 6, explaining the high incidence of these races in this survey. All cultivars tested were susceptible to race 6, which was identified in all 3 States.
Nutgrass (Cyperus rotundus L.) control in cotton (Gossypium hirsutum L.)
Authors: Charles GW
Published: March 2005

The effects on cotton lint yield and nutgrass tuber density of 12 treatment combinations were examined. Treatments included preplant norflurazon and benfuresate, in-crop cultivation, glyphosate and MSMA, and post-harvest glyphosate. The effects on tuber density of a further 14 treatment combinations of cultivation, MSMA, glyphosate, and norflurazon were examined in fallow. Under a traditional nutgrass control program of in-cotton cultivation and MSMA, nutgrass tuber density (no./m2) increased from 216 (0-0.15 m soil core) in 1990 to 1112 in 1992, with an average cotton yield of 1239 kg lint/ha. This result compared well with the untreated control, where the tuber density increased to 1641 tubers/m2 in 1992, with an average lint yield of 959 kg /ha. The best treatment was a combination of norflurazon, benfuresate, glyphosate, and cultivation, resulting in a tuber density of 220 tubers/m2 in 1992 and an average lint yield of 1217 kg/ha. Repeated applications of glyphosate in fallow effectively controlled nutgrass, with incremental improvements in control from additional glyphosate applications. Monthly glyphosate ap lications reduced the tuber density from 334 tubers/m in 1990 to 47 in 1992 at one site, and from 334 tubers/m2 in 1990 to 50 in 1992 on a second site. Overall, the results showed that traditional nutgrass control techniques were unsatisfactory, but repeated glyphosate applications gave effective nutgrass control both in cotton and in fallow.