bluuebunny/crossref_metadata_2025 huggingface dataset:
Deep floodwater protects high-nitrogen rice crops from low-temperature damage
Authors: Williams RL , Angus JF
Published: March 2005

A field experiment was conducted to investigate the interaction of nitrogen (N) status, sowing date, and water depth on rice yield in the Murray Valley, New South Wales, where low minimum temperatures often lead to pollen sterility and low yield in high N status crops. The experiment combined 4 N rates (0, 75, 125, 250 kg N/ha) applied as urea just before permanent flood; 3 cultivars (Jarrah, early maturing; Amaroo and Doongara, midseason); 2 sowing dates (26 September, 31 October 1991); and 2 water depths (5, 20 cm) at the microspore stage. The early-sown crops and the later sown Jarrah crop encountered minimum air temperatures of 19�C at the cold-sensitive microspore stage, compared with 15�C for the other 2 later sown crops. Total dry matter production was little affected by either water depth or sowing date, but increased from 16 to 22 t/ha with N application. Shallow water depth and delayed sowing date affected yield through reduced harvest index. Grain yield response to N fertiliser was dependent on sowing date, water depth, and variety. For the early-sown crops grown in deep water, yields of Amaroo and Jarrah-increased from 7 to 13 t/ha with increasing N supply, while the yield response of Doongara plateaued at 9 t/ha. With shallow water, the yields of all varieties decreased from 7 to 3 t/ha with increasing N. For the later sowing date, Jarrah growing in deep water yielded up to 13 t/ha at high N, but yields of Amaroo and Doongara decreased from 7 to 2 t/ha with increasing N supply. For the later sowing date, yields of all varieties growing in shallow water decreased to <2 t/ha with applied N. In the deep water crops, developing microspores were submerged or partially submerged and so avoided low air minimum temperatures. In the early-sown crops, the microspore stage occurred during a period of relatively warm nights. Harvest index was successfully modelled using panicle temperature and N content at early pollen microspore. The experiment shows that high N applications can lead to high rice yields provided the microspores are protected from low temperatures by the use of deep water at the stage of microspore development. As a result, recommendations for N fertiliser application need to be adjusted for sowing date and expected water depth at early pollen microspore
Effect of sowing time and nitrogen on rice cultivars of differing growth duration in New South Wales. 1. Yield and yield components
Authors: Reinke RF , Lewin LG , Williams RL
Published: March 2005

New South Wales rice crops commonly take >180 days from sowing to harvest, and a reduction in crop duration is sought to increase the efficiency of rice production. The response of rice cultivars of differing growth duration to sowing time and N application was examined across 2 growing seasons. The highest yields were obtained at early sowing dates in each season. In season 2, the maximum yield of the short-duration cultivar M101 was not significantly different to the long-duration cultivars Calrose, Pelde, and M7, with yields >12 t/ha. However, yield of cv. M101 was significantly less than the long-duration cultivars at an early sowing date in season 1. Analysis of yield components did not clearly indicate the reason for reduced yield of the short duration cultivar. Damage by birds and mice before harvest, exacerbated by early maturity, is a possible cause.Later sowing reduced yields of all cultivars, with the short-duration cultivar-least affected. Optimum N application decreased with delay in sowing. At early sowings there was a positive yield response to increasing N, whereas at the latest sowings in each season the N response was negative for all cultivars. Where the yield response to applied N was positive, the yield component most associated with yield was the number of florets per unit area (r = 0.55). Where the yield response was negative, yield reductions were primarily caused by a reduction in the proportion of filled grains (r = 0.83). Minimum temperatures during the reproductive stage of each cultivar explained only a small amount of the variation in percentage of filled grain. Low minimum temperatures during the reproductive stage were not the sole cause of the reduction in proportion of filled grains of late-sown, high-N plots. The high yield potential of short-duration cultivars in The high yield potential of short-duration cultivars in the New South Wales rice-growing area is clearly demonstrated, as is the value of such cultivars where late sowing is unavoidable.
Effect of uneven emergence on rice yield, milling yield, and yield components
Authors: Gravois KA , Helms RS
Published: March 2005

Establishing a uniform rice (Oryza sativa L.) stand is an important beginning to managing a rice crop and attaining high yields. Most rice management practices in the United States are timed according to rice growth stages. Non-uniform rice stands, and subsequently non-uniform growth stages, present problems for the timely application of management practices for attaining high yields. Our objective was the determination of the effects of uneven emergence on rice yield, milling yield, and yield components. Experiments were conducted in 1988 and 1989 on a Hebert silt loam (Vertic Hapludoll) at the Southeast Branch Experiment Station near Rohwer, Arkansas. Uneven emergence was simulated by delayed (18 days from emergence) interseeding of rice to achieve 0, 20, 40, 60, and 80% uneven emergence. Each experiment was planted with the cultivars Lemont (semi-dwarf) and Tebonnet (tall) and was replicated 4 times. Rice yields for the uneven emergence treatment levels were significantly less than the rice yields seeded exclusively at PD1 (planting date 1), except for the uneven emergence levels 80-20 (80% planted at PD1 and 20% planted at PD2) and 60-40 for Tebonnet, and 60-40 in 1988 for Lemont. In 1989, there was a trend for head rice yields to decrease as uneven emergence levels increased. Average panicle density and number of grains per panicle for both Lemont and Tebonnet decreased with increasing uneven emergence, indicating a failure in the typical compensatory relationship between panicle density and grain per panicle. Lemont exhibited reduced average grain weights due to uneven emergence, especially at 80-20, 60-40, and 40-60 uneven emergence levels. Harvest indices were higher for PD1 than for PD2, except at 20-80 uneven emergence level. Essentially, the later emerging rice from the second planting acted much like a weed by competing against rather than contributing to rice yields. Late interseeding to enhance poor rice stands is unlikely to produce an economic return that could be expected from an adequate initial plant stand.
Pastures in temperate rice rotations of south-eastern Australia
Authors: Lattimore MAE
Published: March 2005

Legume-based pastures have long been an integral part of rice growing in the southern New South Wales irrigation areas and still offer potential to improve the productivity, profitability, and sustainability of the temperate rice-cropping system.This paper reviews both historical and current aspects of pastures in temperate rice rotations in southern New South Wales and highlights the importance of pastures in sustaining this cropping system as environmental pressures increase. Topics discussed include pasture species and rotations, their role in improving soil fertility and sustainability, the value of pastures in weed control, and their management for maximum profitability.
Effect of cropping sequences on soil nitrogen levels, rice growth, and grain yields
Authors: Beecher HG , Thompson JA , Bacon PE , Heenan DP
Published: March 2005

The effect of 7 different crop and pasture sequences and cereal stubble management on soil nitrogen (N) levels and growth and grain yield of 2 subsequent rice crops was studied over 6 years (1986-92) on a Birganbigil clay loam soil at Yanco Agricultural Institute. After harvest of an initial rice crop in 1987, the following crop sequences were imposed: continuous annual rice cropping; 2 triticale crops, 2 seasons of pasture; pasture for 4 seasons; a second rice crop, 3 seasons of pasture; a second and third rice crop, 2 seasons of pasture; winter cereals; double cropped (winter-summer) on raised beds. The growth and productivity of 2 subsequent rice crops (1990-91, 1991-92) was then evaluated. Stubble retention rather than burning was practiced on half of each plot. Half of each pasture plot was sown to annual pasture (Trifolium subterraneum), while the other half was sown to perennial pasture (Trifolium repens). All plots returned to rice in 1990-91 and N rates up to 400 kg N/ka were applied. No fertiliser was applied to the 1991-92 crop. Anaerobic incubation ammonium content of soil, sampled before sowing of the 1990-91 rice crop, ranged from 28 to 85 pg/g oven-dried soil. The 1990-91 rice crop reduced soil ammonium by 30 y g/g in all sequences except continuous annual rice cropping. These differences in soil ammonium content were significantly correlated with rice growth and yield. Dry matter at panicle initiation and at physiological maturity and grain yield all increased significantly with N fertiliser application for all crop sequences. This indicates the benefit of N fertiliser, even after a 4-year pasture phase. Modelled grain yield from the unfertilised 2-year subterranean clover pasture (10.4 t/ha) was equal to that from the continuous rice sequence receiving 212 kg N/ha. Applying 320 kg N/ha to continuous rice plots produced yields similar to that of the 2-year subterranean clover pasture sequence, which received 98 kg N/ha. This indicates that the major effect on grain yield of different crop sequences could be alleviated through high N applications. Stubble management had little effect on rice growth or grain yield. Sequences with pasture phases of 2, 3, and 4 years produced similar rice grain yields. Pasture phases still had a positive effect, compared with continuous ricegrowing, on the second rice crop; however, crop growth and grain yield were about half that obtained from the unfertilised plots of the first rice crop. We conclude that continuous, high-yielding, annual ricegrowing can be maintained provided the N supply is adequate, that highly productive legume-dominant pasture phases of 2, 3, or 4 years contribute eqivalent amounts of N to succeeding rice crops, and that stubble management technique or pasture type has little effect on grain yield.
Soil nitrogen supply to rice: crop sequence effects
Authors: Beecher HG , Thompson JA , Bacon PE , Dunn BW
Published: March 2005

The effect of cropping sequence on soil nitrogen (N) supply to a rice crop was investigated using an in situ incubation technique in a direct drill system on a red-brown earth soil in south-eastern Australia. The crop sequences were (i) a rice crop in each of the previous 4 summers, (ii) rice then 4 seasons of annual pasture (long pasture phase), (iii) rice, 2 winter cereal crops then 2 seasons of annual pasture (short pasture phase), and (iv) rice then 4 winter cereal crops. This study was undertaken in the fifth year of the crop sequence experiment, when all sequences had returned to rice. Within the rice crop, fertilised (160 kg N/ha) and unfertilised plots were established on the burnt stubble portion of the main crop sequence plots. Nitrogen uptake in unfertilised plots ranged from 79 kg N/ha in continuously cropped rice treatments to 165 kg N/ha in short pasture phase treatments. Application of 160 kg N/ha at permanent flood increased N uptake to 207 kg N/ha for the short pasture treatment. Crop biomass and tillering varied with cropping sequence and increased with fertiliser nitrogen application. Crop sequence had little effect on soil mineral N content during the growing season. However, total soil N mineralisation during the season varied with both crop sequence and fertiliser application. The continuous rice sequence mineralised 119 kg N/ha, whilst the long pasture phase sequence mineralised 246 kg N/ha. Fertiliser application increased mineralised N to 267 and 337 kg N/ha for continuous rice and short pasture phase treatments, respectively. Nitrogen mineralisation rate peaked (4 kg N/ha.day) some 40-50 days after permanent flood, coinciding with panicle initiation and the period of high N demand in the rice crop. Increased N availability after panicle initiation resulted in significantly higher grain yields. This work demonstrates that both the magnitude and timing of N supply affects the grain yield of the rice crop. Nitrogen supply is affected by the previous crop sequences. Practical implications are that pasture phase length of highly clover-dominant pastures could be reduced (from 4 to 2 years) and still provide similar contributions of N to succeeding rice crops; that continuous rice growing might achieve high yields similar to rice in rotation with legume pastures with the judicious application of fertiliser N; and that these N fertiliser applications may have to be quite high to achieve grain yields similar to rice in rotation with legume pastures.
Rice weed control: current technology and emerging issues in temperate rice
Authors: Hill JE , Smith RJ Jr , Bayer DE
Published: March 2005

Among temperate rice areas, the United States and Australia are most similar in climate and in the mechanisation of rice culture. Many weed problems, even weed species invading rice, are common to both countries; and the present technology for weed control as well as concern for the impact of these technologies to environmental quality, herbicide resistance, and other weed-related issues bear many similarities. Application of current, and any new, technologies to emerging issues in US rice weed control will therefore be directly relevant to rice production in Australia and all other temperate areas struggling with the same challenges. Weeds are a significant problem in temperate rice culture. In the United States, rice is mechanically direct-seeded, allowing weeds to germinate and establish with the crop. In the last 15 years weed growth and competition has been increased by the adoption of semi-dwarf cultivars, high N fertilisation, and, in water-seeded rice, shallow flooding. High rates, and often multiple applications, of herbicides have been necessary to maximise the yield potential of these cultural systems. Advances in cultural practices and herbicide technology have maintained, if not improved, weed control; but nearly 30 years of propanil use in the southern USA resulted in propanil-resistant barnyard grass Echinochloa crus-galli (L.) Beauv., and after 4 years of continuous use, bensulfuron resistance to 4 aquatic weed species was discovered in California. Although herbicides with different mechanisms of action are needed for alternation in resistance management strategies, fewer are likely to be available. Social and environmental concerns have slowed the development and registration of rice herbicides and increased the cost of controlling weeds. Water quality deterioration from ricefield tailwaters, drift to sensitive crops, the cost of renewing registration in aquatic systems, and weed resistance all forecast reduced herbicide use in rice. Neither cultural practices nor herbicides alone can solve weed problems in direct-seeded, mechanised rice culture. With fewer herbicides and a cultural system highly vulnerable to weed losses, integrated management strategies with better information on which to base weed control decisions will be needed to solve weed problems in temperate rice.
Pathogenicity of Rhynchosporium alismatis and its potential as a mycoherbicide on several weed species in the Alismataceae
Authors: Cother EJ , Gilbert RL
Published: March 2005

The inundative application of conidia of the plant pathogenic fungus, Rhynchosporium alismatis, to seedlings of Sagittaria pygmaea, S. guyanensis, and Alisma canaliculatum resulted in seedling death or significant growth suppression. In quarantine pot trials, inoculation of S. guyanensis seedlings caused reductions in average plant height of 60% and reduced leaf and root dry weights, by 89 and 84%, respectively. There was also high seedling mortality. Smaller, though significant, reductions in various growth parameters occurred in the other species when similarly inoculated. Alisma canaliculatum, Echinodorus rostratus, S. brevirostra, S. guyanensis, and S. pygmaea are recorded as new hosts of the fungus. The data indicate the potential use of this fungus as a mycoherbicide in temperate rice crops. Research is continuing on virulence and formulation to improve mycoherbicide efficacy.
Efficacy of a potential mycoherbicide for control of Alisma lanceolatum and Damasonium minus in Australian rice crops
Authors: Cother EJ , Gilbert RL
Published: March 2005

Alisma lanceolatum (Alisma) is becoming a problem weed in NSW rice crops because it is invasive and tolerant of currently used herbicides. Darnasonium minus (starfruit), a widespread native, is a serious competitive weed in rice. The endemic fungus Rhynchosporiurn alismatis, which causes necrotic lesions on leaves and scapes of Alisma and starfruit, is being studied for potential development as a biological control agent for these weeds. Spray application of a conidial suspension to Alisma seedlings in the field at the 2-3 leaf stage, in 2 seasons, resulted in significant suppression of plant growth and markedly retarded development. Lesions developed on emergent leaves and caused premature death. In 1993 assessment of treatments 53 days after inoculation showed that although total leaf number per plant was reduced by 20%, total leaf dry weight was reduced by 34%, and root dry weight by 32%. Inflorescence development was also markedly reduced in both years; inflorescence number was reduced by an average of 77% in 1992-93 and by 52% in 1993-94. In 1994, inoculation reduced the dry weight of healthy leaves at 63 days after treatment by 49%, although root dry weight was not significantly reduced. Competition from a developing rice crop would be expected to reduce plant size and vigour further. Inoculation of glasshouse-grown starfruit seedlings produced similar trends. Spray-inoculation of seedlings 33 days after sowing resulted in 45% reduction in total plant biomass (dry weight, measured 64 days after inoculation) compared with 19 and 25% reduction in biomass in seedlings sprayed 23 and 50 days, respectively, after sowing. Inoculation of starfruit seedlings in the field significantly reduced biomass production by 21% and increased 6-fold the number of necrotic inflorescences. These experiments indicate that R. alismatis has potential for development as a mycoherbicide and a possible role in integrated control of these weeds.
Effects of pesticides on soil and water microflora and mesofauna in wetland ricefields: a summary of current knowledge and extrapolation to temperate environments
Authors: Roger PA , Simpson I , Oficial R , Ardales S , Jimenez R
Published: March 2005

This review summarises information on the behaviour of pesticides and their impacts on microorganisms and non-target invertebrates that was collected in, or is applicable to, temperate wetland ricefields. An extensive bibliographic survey shows that current knowledge is fragmentary and partly outdated. Pesticides applied on soil at recommended levels rarely had a detrimental effect on microbial populations or their activities. They had more effect on invertebrate populations, inducing the blooming of individual species of floodwater zooplankton and reducing populations of aquatic oligochaetes in soil. Available information raises concerns regarding the long-term effects of pesticides on (i) microorganisms, primary producers, and invertebrates of importance to soil fertility, (ii) predators of rice pests and vectors, and (iii) microbial metabolism of pesticides.
Silage or hay based diets supplemented with different levels of grain for fattening cattle
Authors: Jacobs JL , Zorrilla-Rios J
Published: March 2005

Beef steers of liveweight (LW) 277kg were offered a basal ration of hay, untreated silage, or enzyme-treated silage supplemented with a barley + lupin + mineral (67:30: 3) concentrate at 0.5, 1.0, and 1.5% of LW for a maximum of 120 days. The quality of silage was significantly (P<0.001) higher than hay (in vitro DMD: 673.0 v. 609.2 g/kg DM), primarily due to a shorter ungrazed growing period before harvest. The enzyme additive did not improve the quality of the silage compared with untreated silage, as indicated by pH, lactic acid, and in vitro dry matter digestibility. Intake of silage was significantly (P<0.001) higher than that of hay (4.10 v. 3.68 kg DM/day). Final LW and LW gain of cattle fed silage were significantly (P<0.001) higher than of those fed hay (370 v. 345 kg; 1.03 v. 0.61 kg/day). As the level of grain increased there was a significant (P<0.001) increase in daily LW gain across all diets (0.63, 0.94, and 1.10 kg/day at 0.5, 1.0, and 1.5%). At slaughter, carcass weight was significantly (P<0.001) higher for cattle fed silage-based diets (207 v. 194 kg). When cattle were fed a higher quality conserved forage (silage), less grain (1.5 v. 4.5 kg/day) was required to achieve similar LW than with more traditional, forage (hay) based diets.
Pre-farrowing behaviour of sow and gilts with access to space for locomotion
Authors: Haskell MJ , Hutson GD
Published: March 2005

The expression of pre-farrowing behaviour in sows and gilts with access to space was investigated. Six multiparous sows and 6 gilts were observed in a test arena 6.5 by 7 m with a pen 2 by 2 m in 1 corner. No straw was provided in either pen. Observations commenced 4 days before farrowing. Each pig was observed from 0900 to 1700 hours, and the behaviour of the pig and her position in the pen and test arena were recorded. Pigs close to farrowing were also observed overnight. Both sows and gilts showed a highly significant (P<0.001) increase in the distance walked in the 11-4 h before farrowing compared with that in previous days. This restlessness was also reflected in other behaviour patterns performed by the pig. Nest building occurred in the 9 h before farrowing. There was no effect (P>0.05) of parity on the level of pre-farrowing locomotion, or on the amount of nest building performed. This indicates that pre-farrowing behaviour is largely unaffected by experience of farrowing and that it may be largely under internal control.
Diet quality affects the cashmere production and liveweight of Western Australian cashmere goats
Authors: Johnson TJ , Gherardi SG , Dhaliwal S
Published: March 2005

Young cashmere bucks (n = 113; offspring of mating of domesticated mainland feral does with commercial mainland, Bernier, and Faure Island bucks) were offered a high protein-high energy pelleted diet of lucerne chaff, lupin seed, and barley grain [crude protein, 202 kg; dry matter (DM) solubility, 75.0%] or a low protein-low energy diet of oaten chaff and oat grain (crude protein, 71 kg; DM solubility, 59.6%) ad libitum in groups (n = 4-8) from 14 January to 17 December 1987. Intakes and liveweight gains were measured for January-April, May-July, and August-December. Total fibre and cashmere production (weight, fibre diameter, yield) were recorded at shearing in June, October, and December. Faure bucks produced 34 and 64% more (P<0.05) cashmere on the high, than the low, quality diet at shearings in June and December, respectively; Bernier bucks produced twice as much (P<0.05) cashmere on the high quality diet at the October shearing. Mainland bucks produced similar amounts of cashmere on both diets at each shearing. The fibre produced on the high quality diet had a lower yield of cashmere and the cashmere had a greater diameter at shearings in June (26.0 v. 41.1% w/w, 16.7 v. 15.8 pm; both P<0.001) and December (22.1 v. 27.0% w/w, P<0.05; 16.9 v. 16.4 pm, P<0.01). The cashmere produced by Faure bucks was, on average, 1.0 pm coarser than that of the mainland and Bernier bucks at each shearing. Liveweights of bucks followed a seasonal pattern and increased at a faster rate in January-April and August-December than in May-July. Liveweight gains adjusted for body sizes were greater (P<0.001) for bucks on the high, than the low, quality diet in January-April (2.85 v. 1.71 g/kg LW0.75.day) and, conversely, lower (P<0.05) in August-December (1.49 v. 1.69 g/kg LW0.75.day) . Liveweight gains of all 3 genotypes adjusted for body sizes were markedly lower (P<0.05) in May-July, irrespective of diet (0.75 and 0.55 g/kg LW0.75.day for the high and low quality diet, respectively), with the exception of Bernier bucks on the high quality diet (1.67 g/kg LW0.75.day). The lower liveweight gains were not associated with decreases in the intakes of the diets. These results indicate that diet quality affects cashmere production and growth of Western Australian cashmere goats.
Field resistance in Trifolium subterraneum to Uromyces trifolii-repentis and Cercospora zebrina
Authors: Barbetti MJ , Nichols PGH
Published: March 2005

Advanced, early-midseason breeding lines and overseas introductions of Trifolium subterraneum var. subterraneum and var. yanninicum were screened for resistance to rust (Uromyces trifolii-repentis) and cercospora (Cercospora zebrina) diseases in field 'miniswards', and their performances compared with appropiate control varieties. The reaction to each disease varied between genotypes. The most rust-resistant within var. subterraneum were CPI 89848D, CPI 89840A, and 76S40-6, all with final incidence scores of <5.5 on a 0-10 scale (0, no disease; 10, >90% leaves affected). On the basis of rust-induced leaf collapse, CPI 89848D, 76840-6, CPI 89838G, CPI 89840A, Areces 1, and B x D 15A Black-8 were the most resistant of var. subterraneum, with scores of 0-0.5 on a 0-5 scale. Except for CPI 39314YB, var. yanninicum was very resistant to rust, with rust incidence scores of 0.6-3. Lines 76Y51-31, 76Y52-3, 76Y51-28.2, and 76Y51-25 had the best resistance, with end-of-season incidence scores of 0.6-1.4. Except for 76Y51-27, there was no leaf collapse from rust in var. yanninicum. For cercospora disease, the most resistant lines within var. subterraneum were CPI 89838G, 75811-7, 76340-6, and CPI 89841E, with final incidence scores 51.5 on a 0-10 scale. Except for CPI 39314YB, var. yanninicum showed excellent resistance to cercospora disease, with end-of-season incidence scores 0.1-1.
Improving the productivity of saline discharge areas: an assessment of the potential use of saltbush in the Murray-Darling Basin
Authors: Barson MM , Abraham B , Malcolm CV
Published: March 2005

Results of field trials testing the growth of Atriplex species on saline soils in Western Australia have been used with the PLANTGRO model to predict the success of 6 Atriplex species on 6 salinised soil types at 6 localities in the Murray-Darling Basin. The model's predictions that the productivity of all species would be severely limited on cracking clay soils due to poor aeration were tested by examining data from field trials. It was concluded that saltbush production will be very poor on heavy clay soils. Field trial data suggest that these limitations will be exacerbated by the interaction of aeration and soil salinity factors at mean salinities (ECe) >10 dS/m, and the planting of Atriplex on these sites is not recommended. Better results are expected on some duplex and gradational soils where larger sand fractions in the A horizon improve soil aeration characteristics. However, the model predicts that productivity will, at best, be low to moderate at all the Murray-Darling Basin sites examined.
Acidification rates in the central wheatbelt of Western Australia. 2. On a sandy duplex soil
Authors: Dolling PJ , Porter WM , Rowland IC
Published: March 2005

The rate and mechanisms of acidification were determined on a sandy duplex soil (depth of sand 30-45 cm) under a cereal-annual pasture rotation in Western Australia. We also evaluated the effect of rotation (intensity of cropping) on relative acidification of a sandy duplex soil. Rate of acidification was based on a linear regression analysis between soil pH and years since clearing. Sites were sampled to a depth of 50 cm in 10-cm increments and measurements included soil pH, pH buffering capacity, and bulk density. The effect of different rotations on the acidification rate was determined by soil sampling a rotation experiment which had been established for 25 years. Sampling and measurements were similar to the regression analysis. From regression, the rate of acidification for the profile was 0.15 kmol H+/ha.year, requiring 7.7 kg CaCO3 to neutralise. Most of the acidification could be accounted for by removal of alkaline products. Acidification was occurring to a depth of 30 cm, the acidification rate decreasing with depth. In the surface 20 cm the pH decline was 0.005-0.006 units/year. In the rotation experiment, the rate of acidification relative to continuous wheat without fertiliser nitrogen (N) ranged from 0.35 kmol H+/ha .year (17.5 kg CaCO3) for continuous wheat with fertiliser N to 0.92 kmol H+/ha. year (45.8 kg CaCO3) for continuous pasture. Between these rates was 1 year pasture-1 year cereal (0.41 kmol H+/ha. year, 20.5 kg CaCO3) and 2 years pasture-1 year cereal (0.82 kmol H+/ha . year, 41.2 kg CaCO3). Acidification was occurring to 60 cm depth in all rotations, mostly due to nitrate leaching, removal of alkaline products, and build-up of organic matter.
Effect of postharvest heat treatments on fruit quality, surface structure, and fungal disease in Valencia oranges
Authors: Williams MH , Brown MA , Vesk M , Brady C
Published: March 2005

The effect of prestorage heat treatments on the quality of Valencia oranges and on postharvest disease was investigated during a 6-week storage trial. Fruit receiving a hot water immersion regime (45�C core temperature for 42 min) designed to disinfest against Queensland fruit fly lost significantly less moisture and remained firmer during storage than unheated control fruit. Disinfestation treatment also significantly reduced fruit acidity and number of viable spores of Colletotrichum gloeosporioides, Penicillium digitatum, and P. italicum. The gradual heating process involved with disinfestation was more successful in maintaining fruit quality than surface sterilisation by hot water immersion (12 min at 53�C), or conditioning in air (24 h at 30�C and 90% relative humidity). Heat-treated fruit showed enhanced colour development. Light and electron microscopy studies showed that heating had little effect on the structure of surface waxes; however, collapsed oil glands were observed after cool storage. Prestorage heat treatments could be a favourable alternative to chemicals for control of pests.
Effect of Arachis pintoi groundcover on performance of bananas in northern New South Wales
Authors: Johns GG
Published: March 2005

Legume groundcovers have been promoted for controlling soil erosion in hillside banana plantations in northern New South Wales. An experiment was conducted at Alstonville to determine the effect of an Arachis pintoi (Pinto peanut) groundcover on banana productivity. The Arachis groundcover was slow to establish in the first year, but thereafter grew vigorously. While standing dry matter of groundcover was reduced at closer banana plant spacings, it was always more than adequate to control erosion. After 5.5 years many soil chemical parameters had been significantly affected by the presence of groundcover. Organic carbon concentrations to 30 cm depth were 5.6% greater on the groundcover plots (3.94 v. 3.71%), and total nitrogen was 8.5% greater (0.42 v. 0.39%). Other increases were exchangeable potassium 52%, calcium 26%, magnesium 43%, sodium 23%, electrical conductivity 24%, and pH 0.13 units. Banana leaf nutrient concentrations were not affected. Banana plants with groundcover produced 9% fewer bunches than their bare soil counterparts, with 4% fewer fingers per bunch. By the end of the experiment, fingers on the groundcover treatment were 9% lighter; consequently, the weight of marketable fruit (i.e. >120 g/finger) per bunch was reduced by 31% in the final year. The presence of groundcover reduced total fruit production over the whole trial by 16% and marketable fruit by 19%. In the last year of the experiment, total fruit production was reduced by 25%, and marketable fruit production by 40%. Over the whole trial, banana plants with groundcover produced 22% fewer suckers than the bare soil controls, with most of the effect occurring in the first 2 years. Soil temperatures at 20 cm under groundcover were as much as 0.7�C cooler than the controls in October-January, but similar for the rest of the year. This effect possibly contributed to decreased yields. Although the experiment was irrigated, the irrigation was possibly inadequate for the groundcover treatment, and competition for water between the Arachis and banana plants may also have been responsible for part of the yield depression. Rats fed on the buried Arachis seed each winter.
Investigation of flowering in Banksia baxteri R. Br. and B. hookeriana Meissner for improving pruning practices
Authors: Rohl LJ , Fuss AM , Dhaliwal JA , Webb MG , Lamont BB
Published: March 2005

Floral initiation and development in relation to time of flowering were investigated in Banksia baxteri and B. hookeriana with the aid of scanning electron microscopy. Floral initiation occurred in spring in B. baxteri and in early summer in B. hookeriana. Floral development was rapid in B. baxteri (3 months to reach anthesis in summer). In B. hookeriana, development took 5 months, with anthesis occurring in winter. Most B. hookeriana blooms were produced on 2-year-old shoots, while B. baxteri produced about half of its blooms on 2-year-old shoots and almost as many on 3-year-old shoots. In both species, shoots that flowered within 2 years were longer and thicker in their first year than other shoots. A critical minimum stem length was determined for the first year's growth, to be used as a criterion for determining which shoots to remove during pruning. Details are provided for the timing of pruning to achieve maximum bloom production in B. baxteri and B. hookeriana.
Growth and flower production of container-grown Geraldton wax cvv. Alba and Purple Pride at different levels of irrigation
Authors: Akilan K , Considine JA , Marshall JK
Published: March 2005

The effects of 3 levels of irrigation (25, 50, 75% pan replacement) on growth and flower production were studied on 2 container-grown Geraldton wax cultivars (Alba and Purple Pride) under field conditions. Water deficit during the vegetative phase reduced all vegetative growth components (shoot number, primary stem length, cumulative stem length, leaf number, crown area) and flower production in both cultivars. Primary stem length was reduced by 47% and shoot or flower number by >50% when irrigation was reduced from 75 to 25% pan replacement. The response to reduced irrigation was more severe in Purple Pride than in Alba. During the vegetative phase, 800-840 mm water or 60-63% pan evaporation is required to maximise marketable stems of 90 cm under the conditions studied.
Preweaning growth of Brahman, Braford, and Africander first-cross calves in the subtropics of New South Wales
Authors: Hearnshaw H , Arthur PF , Barlow R , Hoffman W
Published: March 2005

Preweaning growth of 435 first-cross Brahman x Hereford (BH), Braford x Hereford (BM) and Africander x Hereford (AM) calves was evaluated at Ballina in the subtropics of New South Wales. Thirty-five Brahman, 32 Braford, and 23 Africander sires were mated to Hereford females over 3 years to produce the calves. Mean gestation of BH calves (290 days) was 4 and 6 days longer than BfH and AfH calves, respectively. BH and AfH calves had more eyelid pigmentation (88 and 98%, respectively) than BM calves (59%). For males, birth weights of BH calves were higher than BfH, which, in turn, were heavier than AfH calves (38.6 v. 34.8 v. 31.5 kg). For females, birth weights of BH and BfH calves were not significantly different but were higher than those of AfH calves (33.3 and 32.6 v. 30.4 kg). BH calves had higher average daily gain (ADG) than BfH and AfH calves during the second half of the preweaning period, resulting in 200-day liveweights of 175.4, 167.5, and 167.3 kg for BH, BfH, and AfH calves. BH calves were taller and had larger girths than the other crosses at birth, but AM calves exhibited the greatest increase in height and body length from birth to weaning. For BH, BMI, and AfH calves, 34,6, and 94% were predominantly red, whereas 6, 94, and 5% were also red but had a Hereford coat colour pattern.
Implanting electronic identification transponders under the scutifon cartilage of beef cattle is inappropriate under Australian conditions
Authors: Hasker PJS , Bassingthwaighte J
Published: March 2005

Poor readout and recovery rates of electronic identification (EID) transponders at the slaughter of feedlot steers raise doubts about the suitability of the scutiform cartilage as a site for implanting EID transponders in commercial beef herds in Australia. At slaughter, a readout was obtained from73% of 4630 implanted steers that were scanned. Failure to give a readout was due to broken and lost transponders. Less than three-quarters of the transponders giving a readout at slaughter were recovered. These results could not be totally attributed to implanting procedure as they were similar for different feedlot-abattoir combinations and different operators.
Development of herbicide resistance in annual ryegrass populations (Lolium rigidum Gaud.) in the cropping belt of Western Australia
Authors: Gill GS
Published: March 2005

Annual ryegrass (Lolium rigidum) samples from the cropping belt of Western Australia were screened for herbicide resistance in 1992 and 1993. There was a strong relationship between the number of applications of a herbicide group and development of resistance in ryegrass populations. Resistance was detected in all populations that received >7 applications of aryloxyphenoxypropionate (AOPP) and cyclohexanedione (CHD) herbicides or >4 applications of sulfonylurea (SU) herbicides. Some AOPP-resistant populations had also developed crossresistance to SU herbicides, a group with a different mode of action. Inclusion of pasture in the rotation had little effect on the relationship between the number of applications of the AOPP and SU herbicides and development of resistance. A subset of 33 populations was chosen to determine the response of triasulfuron-resistant populations to sulfometuron, a nonselective SU herbicide which has been shown to be effective against metabolic-type resistance. All triasulfuron-resistant populations were found to be resistant to sulfometuron, possibly due to insensitive acetolactate synthase (ALS) in these ryegrass populations. Some of these SU-resistant populations were also resistant to the imidazolinone herbicide imazethapyr, another ALS inhibitor. However, there were several populations with a high level of SU resistance that were still susceptible to imazethapyr.
Resistance and associated yield losses from rust (Uromyces trifolii-repentis Liro) in midseason cultivars of Trifolium subterraneum L. var. subterraneum L. and var. yanninicum Katzn. et Morley
Authors: Barbetti MJ , Nichols PGH
Published: March 2005

A field study was conducted to quantify the effect of rust on the herbage production and seed yield of 4 new midseason cultivars of Trifolium subterraneum (Denmark, Gosse, Goulburn, Leura) and to compare their performance with 8 current commercial cultivars. Leura, Gosse, and Goulburn were all resistant to rust, with Leura most resistant. Denmark was not resistant to rust, but was much less susceptible than Green Range and marginally less susceptible than Mt Barker. By the end of the season, rust had reduced herbage yield in Green Range, Junee, Karridale, and Seaton Park (32, 23, 22, 18%, respectively) but did not affect any new cultivar. Rust reduced the seed yields of all cultivars except Goulburn, Larisa, and Leura. Seed yields of Green Range, Woogenellup, Mt Barker, Seaton Park, Denmark, Esperance, Karridale, Gosse, and Junee were reduced by 75, 70, 58, 55, 49, 47, 40, 40, and 38%, respectively. Rust also reduced the size of seed in all cultivars except Goulburn.
Wheat for fodder and grain on the Northern Tablelands of New South Wales
Authors: FitzGerald RD , Curll ML , Heap EW
Published: March 2005

Thirty varieties of wheat originating from Australia, UK, USA, Ukraine, and France were evaluated over 3 years as dual-purpose wheats for the high rainfall environment of the Northern Tablelands of New South Wales (mean annual rainfall 851 mm). Mean grain yields (1.9-4.3 t/ha) compared favourably with record yields in the traditional Australian wheatbelt, but were much poorer than average yields of 6.5 t/ha reported for UK crops. A 6-week delay in sowing time halved grain yield in 1983; cutting in spring reduced yield by 40% in 1986. Grazing during winter did not significantly reduce yields. Results indicate that the development of wheat varieties adapted to the higher rainfall tablelands and suited to Australian marketing requirements might help to provide a useful alternative enterprise for tableland livestock producers.
Rootstock, seasonal, and fruit size influences on the incidence and severity of albedo breakdown in Bellamy navel oranges
Authors: Treeby MT , Storey R , Bevington KB
Published: March 2005

The effect of stock and fruit size on the incidence and severity of albedo breakdown in fruit from Bellamy navel orange trees grafted onto 7 rootstocks was studied over 3 seasons. The rootstocks could be rated, from lowest to highest, according to the proportion of scion fruit showing some degree of albedo breakdown as follows: sweet orange < Cleopatra mandarin < trifoliate orange < Carrizo citrange = Troyer citrange < rough lemon < Rangpur lime. Rootstock strongly influenced fruit size distribution, and expression of albedo breakdown varied according to fruit size, but no fruit size x rootstock interaction occurred. Also, generally rootstock did not interact with year to affect the incidence and severity of albedo breakdown in Bellamy navel orange. Smaller fruit (<62 mm in diameter) had a lower incidence of albedo breakdown and the symptoms were less severe than for larger fruit. Very large fruit (>79 mm) had a lower incidence than medium (62-70 mm) and large fruit (71-79 mm). The proportion of fruit exhibiting symptoms of albedo breakdown was not positively related to crop load, and despite removal of the effect of crop load, season remained a strong influence on the appearance of albedo breakdown, indicating that seasonal factors, such as summer temperatures, may also be important in the development of albedo breakdown.
Nitrogen-fertilised grass in a subtropical dairy system. 1. Effect of level of nitrogen fertiliser on pasture yield and soil chemical characteristics
Authors: Cowan RT , Lowe KF , Ehrlich W , Upton PC , Bowdler TM
Published: March 2005

The effects of five levels of nitrogen (N) fertiliser on pasture yield and composition and soil chemical characteristics of Rhodes grass (Cholris gayana) cv. Pasture under grazing and cutting in a subtropical environment of 800 mm annual rainfall were studied over 6 years. Pasture received annual basal dressings of superphosphate (250 kg/ha) and potassium chloride (125 kg/ha for plots, 125 kg/ha . alternate year for grazed paddocks). Urea was applied in 3 equal dressings in September, December, and February, at rates equal to 0, 150, 300, 450, and 600 kg N/ha. year. Stocking rate was 2 Holstein-Friesian milking cows/ha throughout the year, and separate areas of grazing oats (0.4 ha/cow), cracked grain (0.8 t/cow.year), and hay or silage were used to supplement pasture. Under both cutting and grazing, pasture dry matter (DM) yield increased linearly with applied N to about 300 kg N/ha. year, with little further increase at higher levels. Under grazing there was evidence of a decrease in yield at 600 kg N/ha.year, due to total death of the pasture following frosting in winter and the need for regeneration from seedlings in spring; this regeneration was slowed by the large amount of surface litter. Grass N contents decreased and phosphorus and potassium contents decreased with increasing levels of applied N. All 3 nutrients increased from year 1 to 6. Leaf content of grazed pasture was highest during spring (>30% DM) and declined through to autumn (<20% DM), with no consistent effect of N level. Leaf content was consistently higher under cutting (>50%) but was not altered by level of applied N. Soil nitrate-N levels increased (P<0.05) with level of applied N, from 4 to 42 mg/L at 0 and 600 kg N/ha. year, respectively. After 6 years of fertilisation at 300 and 450 N/ha.year, nitrate-N levels were similar to those for 600 kg N/ha.year. Soil pH decreased (P<0.05) with applied N, by 0.15 and 0.28 units annually for 150 and 600 kg N/ha.year, respectively. We conclude that in this environment large responses in pasture growth occur under both cutting and grazing to levels of applied N to about 300 kg N/ha.year, with little response beyond this level.
Nitrogen-fertilised grass in a subtropical dairy system 2. Effect of level of nitrogen fertiliser on animal production
Authors: Cowan RT , Lowe KF , Ehrlich W , Upton PC , Bowdler TM
Published: March 2005

The response in yield of milk and milk components to level of nitrogen (N) fertiliser applied to a tropical grass pasture was measured over 6 years. Pasture (Chloris gayana cv. Callide) was stocked at 2 Holstein-Friesian cows/ha and received annual basal dressings of phosphorus (250 kg superphosphate/ha) and potassium (63 kg KCl/ha), and treatments of urea at 0, 150, 300, 450, and 600 kg N/ha. year. Fertiliser was applied in 3 equal applications in September, December, and February. Cows were maintained on the pasture throughout the year, and 0.4 ha grazing oats/cow (100 kg N/ha. year) and 0.8 t cracked grain/cow were given as supplements. Hay or silage supplements were given when green grass yield was <0.5 t dry matter (DM)/ha. The amount of hay and silage given annually averaged 755, 437, and 529 kg DM/cow at 0, 300, and 600 kg N/ha. Mean milk response over the 6 years was high (8 kg milk/kg N) for 0-150 kg applied N/ha. year. The difference between fertilised and unfertilised pastures increased with time, and this was associated with degradation of pasture, excessive liveweight loss during lactation, and premature drying off of cows at nil applied N. At 150-600 kg N/ha. year, response was consistent across years (4.5 kg milk/kg N. year). Yields of milkfat and lactose reflected changes in milk yield, although milk protein percentage decreased significantly (P<0.05) with increased level of applied N. Conception rate increased with rate of applied N, from 58 to 92% at 0 and 600 kg N/ha. year (P<0.01). The results suggest a maximum margin over feed costs at 334 kg applied N/ha over the total grazed area. We conclude that there will be a large milk response to applying about 150 kg N/ha.year; beyond that, the milk response would be consistently about 4.5 kg/kg N to at least 600 kg N/ha.year.