bluuebunny/crossref_metadata_2025 huggingface dataset:
Critical potassium concentrations in Trifolium balansae, Medicago murex and Trifolium subterraneum as affected by sampling date
Authors: Pinkerton A , Randall PJ
Published: March 2005

Critical concentrations of potassium (K) for the diagnosis of K deficiency were derived for tissues of balansa clover (Trifolium balansae) cv. Paradana, murex medic (Medicago murex) cv. Zodiac, and subterranean clover (T. subterraneum) cv. Karridale. The legumes were grown for 2 seasons at 2 sites to which 7 rates of K fertiliser were applied in each season. Symptoms of K deficiency appeared on leaves of plants at both sites, where <50 kg K/ha had been applied. Diagnostic indices were obtained for K in the dry matter (DM) of blades and petioles of youngest open leaves (YOL) and of whole shoots, and for K in petiolar sap of the YOL. In all species, critical K concentrations in dry matter were initially high but decreased steadily as the season progressed. Critical values were highest for YOL petioles, and simllar for YOL blades and for whole shoots, with good discrimination between deficient and adequately supplied plants for K concentrations in these tissues. Critical concentrations (%) of K in DM of YOL laminae of balansa clover declined from 4.00 in May to 0.70 in November, of YOL petioles from 5.80 in May to 1.40 in October, and of whole shoots from 2.48 in July to 0.68 in November, while critical K concentration (�g/mL) in the YOL petiole sap declined from 1000 in May to 384 in November. The decline in critical K concentration (%) in DM of YOL laminae of murex medic was from 2.75 in May to 1.12 in September, of YOL petioles from 5.58 in May to 1.57 in September, and of whole shoots from 1.57 in July to 0.70 in November. Critical K concentrations (�g/mL) in murex medic petiole sap fell from 1000 in May to 471 in September. The decline in critical K concentrations in DM was related to date and was unaffected by rainfall before sampling, temperature, or sodium concentrations. Critical concentrations in DM of subterranean clover were similar to those in the literature for other cultivars. Critical concentrations in balansa clover agreed with those derived previously from glasshouse experiments. The test for K in petiolar sap was less satisfactory: the decline in critical concentration in sap was less consistent than that in DM, and the critical values for subterranean clover did not agree with published results.
Optimum plant population densities for lupin (Lupinus angustifolius L.) in the wheatbelt of Western Australia
Authors: French RJ , McCarthy K , Smart WL
Published: March 2005

Lupin (Lupinus angustifolius L.) seed yields at various plant population densities were studied in 33 separate experiments throughout the wheatbelt of Western Australia between 1987 and 1990. The experiments were designed to test the hypotheses that optimum plant population densities for lupins vary between environments and between cultivars. Another objective was the development of a framework for sowing rate recommendations from a large data set derived from sowing rate experiments. Two types of equation were fitted to each data set by nonlinear regression: one described an asymptotic response, the other a response where yield reached a maximum but declined at higher densities. The second type of equation was used to describe a data set if the residual mean square was significantly lower than for the asymptotic equation. In all, 122 individual responses were fitted, of these only 13 were not adequately described by the asymptotic model. Optimum density was chosen according to an economic criterion (when marginal revenue from an increase in plant population density equalled marginal cost). This was equivalent to choosing the point where the slope of the response curve was 0.004 t.m2/ha.plant (equivalent to 0.4 g/plant). Optimum density ranged from 14 to 138 plants/m2 and was linearly related to yield potential, which we defined as either the asymptotic yield value, or the maximum yield for responses that did not approach an asymptote. Yield potential ranged from 0.13 to 4.1 t/ha. The relationship between optimum density and yield potential was the same for cvv. Danja, Gungurru, and Yorrel, and for a reduced branching breeding line (75A/329). It was also the same on soils classified as good or poor for lupins. We suggest that the relationship between optimum density and yield potential will be useful in determining target plant densities for lupins under a wide range of conditions in Western Australia, and that the techniques should prove useful in producing recommendations from density experiments in other agricultural regions.
Effects of the herbicide metsulfuron-methyl on root length, nutrient levels, grain protein, and yield of barley
Authors: Pederson RN , Black ID , Dyson CB , Hannam RJ
Published: March 2005

In a series of 12 field experiments in 1990 and 1991, metsulfuron-methyl at rates of 2.1, 4.2, and8.4 g/ha (0.5, 1.0, 2.0 times the maximum recommended label rate of the commercial product) was applied at the early tillering stage to commercial barley crops in South Australia.At 4 sites, applications of 4.2 and 8.4 g/ha of metsulfuron-methyl resulted in a marked reduction in plant molybdenum concentrations for at least 6 weeks and grain yield reductions of about 10% resulted from applications of metsulfuron-methyl resulted in a temporary reduction in the concentrations of phosphorus and/or zinc for at least 4 weeks, followed by substantial recovery within 6 weeks. Temporary minor reductions in manganese, copper, sulfur, and potassium concentrations were also measured in the metsulfuron-methyl treatments at 3 sites. At harvest, no nutrient reduction due to chemical treatments was measured in grain samples from any site. Three weeks after the application of 4.2 and 8.4 g/ha of metsulfuron-methyl, marked decreases in total root length were measured in all diameter classes. We suggest these decreases are implicated in the plant these treatments. On these 4 sites and 5 others, nutrient reductions. Applications of metsulfuron-methyl at 4.2 and 8.4 g/ha resulted in grain protein increases of 0.3-0.4%, independent of yield.
Effect of form and rate of pig manure on the growth, nutrient uptake, and yield of barley (cv. Galleon)
Authors: Brechin J , McDonald GK
Published: March 2005

The effect of 2 rates of piggery waste on the growth, nutrient uptake and yield of barley (cv. Galleon) were compared with a fertiliser mixture of superphosphate and urea in the field. The piggery waste was either applied as a slurry (16 kL/ha or 32 kL/ha) or as a solid (0.5 t/ha or 1.5 t/ha). Both the fertiliser mix and the slurry significantly increased the growth and yield of barley while the dried manure failed to improve growth and yield. The effects of treatments on the nutrient concentration in plant tissue throughout the year were small and mainly not significant, while the increases in nitrogen and phosphorus content in the crop reflected the changes in dry matter production. The grain yield responses to fertiliser and to the slurry appeared due to an increase in nitrogen available to the crop rather than to the increase in the supply of phosphorus or other nutrients. The higher rate of the slurry reduced the boron concentration and increased the sodium concentration in the tissue but the concentrations of these elements were not great enough to affect plant growth adversely. However, the increase in sodium concentration following application of the slurry suggests that there may be some risk in the build up of sodium in the soil with the continued use of high rates of slurry, particularly in drier environments. The experiment indicates that the slurry was as effective as fertiliser in eliciting a response and was more effective, in the short term, than the dried form of manure.
Characterisation of Australian almond cultivars and comparison with Californian cultivars by isozyme polymorphism
Authors: Vezvaei A , Clarke GR , Jackson JF
Published: March 2005

Australian-derived almond cvv. Baxendale, Bruce, Chellaston, IXL Seedling, Johnston's Prolific, Keane's Seedling, Pethick's Wonder, Somerton, and White Brandis were identified by means of isozyme polymorphisms at 8 genetic loci: AAT- 1, GPI-2, LAP- 1, PGM-1, PGM-2, IDH, G6PD, and SKDH. The same genetic markers were used to compare Australian almond cultivars with commonly grown Californian cvv. Carmel, Davey, Drake, Fritz, Mission, Ne Plus Ultra, Nonpareil, Peerless, Price, and Thompson. The assignment of alleles at the various loci was aided by an examination of the inheritance of these markers by crossing Nonpareil with pollen from 17 Australian and Californian cultivars. This demonstrated, for the first time, null genes in Price at LAP- 1 and in Drake at AAT-1. The Australian cultivars differed from the Californian at several loci. These differences arise from the separate development in Australia of almond cultivars from what is believed to be largely Spanish 'Jordan' types, before a shift to larger irrigated orchards using Californian methods and Californian-Australian cultivars.
Effects of bait age on the number, sex, and age composition of Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae) in Western Australian blowfly traps
Authors: Vogt WG , Woodburn TL
Published: March 2005

Daily catches of the Australian sheep blowfly, Lucilia cuprina, in Western Australian blowfly traps were not significantly affected by exposing the baits in traps for up to 3 days in the field before trapping. Exposure of the baits for longer periods significantly increased the daily catch totals of both sexes. Baits with a mean exposure time before trapping of 7 days (old baits) returned significantly higher catches than baits with a zero exposure time (fresh baits): 5-fold and 3-fold increases, respectively, for males and females. Exposure of baits for only 1 day was sufficient to produce significant changes in the reproductive age composition of female catches; proportions of newly emerged females increased and proportions of gravid females decreased. Coefficients of variation for old bait/new bait catch ratios were small, 16.4% for males and 12.3% for females, which confirmed that both baits exhibited consistent levels of attractiveness on different trapping dates. Procedures are suggested for estimating population densities of L. cuprina based on trap catches using fresh and old baits.
The developing relationship between Stylosanthes and anthracnose after 14 years in a North Queensland pasture. 1. Field study
Authors: Davis RD , Boland RM , Howitt CJ
Published: March 2005

A 28.5 ha pasture sown in 1975 with a mixture of 7 different accessions of Stylosanthes provided information on anthracnose epidemics (caused by Colletotrichunz gloeosporioides) occurring under grazing in 1987 and 1989. The disease incidence varied throughout the area in response to the density patterns of Stylosanthes with dense populations recording more anthracnose than sections where there were fewer plants. Non-host pasture components did not influence disease incidence. The disease was present on 32% of the plants in the 1987 survey and on 65% of plants in 1989. This probably reflected different stages of epidemic development rather than an overall increase in epidemic severity. Several accessions which were sown in 1975 were not found in significant numbers, and the contribution of anthracnose to their demise is not known; however, in addition to the sown accessions, plants appearing to be S. scabra x S. hamata hybrids were commonly observed. The incidence of anthracnose on these largely infertile plants was not high. The pasture, 14 years after establishment, has persisted with a large host population sustaining varying amounts of anthracnose.
Residual effects of irrigated soybean on the growth and yield of irrigated grain sorghum
Authors: Garside AL , Lawn RJ , Byth DE
Published: March 2005

Irrigated grain sorghum was cropped immediately following irrigated soybean, to establish whether there were any residual effects on sorghum from the previous management of soybean. Results of experiment 1 showed that, where soybean residues were incorporated, sorghum DM accumulation and grain yields were greatest where soybean had been least frequently irrigated (after about 240 mm cumulative open pan evaporation), and least where the soybean had been grown with saturated soil culture (SSC). Extractable mineral nitrogen (N) at sowing of the sorghum was also least following the SSC soybean and greatest following the least-frequently irrigated soybean. The subsequent availability of N during sorghum growth appeared greater where the soybean was more frequently irrigated, although the release occurred too late to influence grain yield. In experiments 2 and 3 residual effects of conventional irrigation of soybean after 60 mm evaporation were compared with those of SSC. Where soybean stubble was uniformly removed (experiment 2), no significant effects of previous irrigation were observed. Where soybean stubble was either removed or incorporated (experiment 3), sorghum yields were lower following the SSC soybean. The incorporation of soybean stubble delayed the release of soil N, although this was not reflected in lower sorghum yields. Taken together, the studies suggested that, for a sorghum crop following soybean, more N fertiliser will be needed at sowing where the soybean stubble is incorporated; where the soybean had been well-irrigated; and the sooner after soybean harvest the sorghum is sown. Conversely, there were indications that more N may be available late in the growth of the sorghum crop where soybean had been well irrigated.
Reaction of Australian cultivars of oats and barley to infection by Fusarium graminearum Group 1
Authors: Nelson KE , Burgess LW
Published: March 2005

The incidence of infection by Fusarium graminearum Group 1 and the incidence of crown rot were compared for various cultivars of oats, wheat and barley in glasshouse and field experiments. In glasshouse studies, the incidence of infected plants was lower in oats than in wheat or barley at 6 weeks after sowing. Crown rot symptoms were not observed in oats of any cultivar. The incidence and severity of crown rot in barley was similar to that in wheat cv. Banks. Between 17 and 29 genotypes of oats, wheat and barley were assessed in field trials over 3 years. Stem browning, a symptom of crown rot, was common in wheat and barley but was not observed in any cultivar of oats. Among plants of wheat and barley, the effect of cultivar on incidence of crown rot was significant (P = 0.05) in 3 of 4 trials. Results suggest that oats are a symptomless host. This should be considered when growing oats in rotation to reduce crown rot inoculum. The barley cultivars assessed all developed moderate-severe crown rot symptoms and thus may incur yield limitations where crown rot is prevalent.
Field evaluation of plaster-based temephos pellets for residual control of midge larvae (Diptera: Chironomidae) in establishing rice crops
Authors: Stevens MM , Warren GN
Published: March 2005

A pelletised formulation of temephos (5% a.i.) was evaluated as a potential control agent for chironomid midge larvae in establishing rice crops. Four application rates between 0.03 and 0.53 mg a.i./L (42-732 g a.i./ha) were applied to 80 m2 experimental rice bays immediately after flooding. Water samples and soil core samples were taken at regular intervals until 29 days post-treatment. Larvae were extracted from core samples using magnesium sulfate (MgSO4) flotation, whilst laboratory-reared fourth instar Chironomus tepperi Skuse larvae were used in bioassays with field-collected water samples to determine pesticide activity in the water column. All treatments significantly suppressed C. tepperi-type larvae in the field for at least 13 days. Some suppression of non-C. tepperi-type larvae was obtained at 0.27 mg a.i./L, whilst at 0.53 mg a.i./L all chironomids were reduced to negligible levels for the full period of the trial. In bioassays, significant levels of water column toxicity to fourth instar C. tepperi larvae were only recorded for 2 days after treatment at the highest application rate. Our results indicate that plaster-based temephos pellets have the potential to provide effective, single application control of chironomid larvae in establishing rice crops without the risk of spray drift inherent in the aerial application of liquid insecticides.
Assessing Wiltshire Horn-Merino crosses. 2. Reproductive traits
Authors: Rathie KA , Tierney ML , Mulder JC
Published: March 2005

Wiltshire Horn-Merino (WH-M) crosses of 1/2, 5/8 and 31/4 Merino content were compared for various reproductive traits over an 8 year period. For 3 years pure Merinos were also included in the comparison. Merino ewes were of lower fertility and fecundity than the 1/2 Merino WH-M ewes. For example, numbers of ewes lambed per 2-year-old ewes joined were 2.6-15% lower for Merinos. For fecundity in 3-year-olds, litter sizes for Merino ewes averaged 0.33 lambs fewer than for 1/2 Merino WH-M. Among the WH-M ewes, fertility was uniformly high for all genotypes. Fecundity was considerably higher for 1/2 Merinos than for the 5/8 and 3/4 Merinos. There was no evidence of a difference in fertility or fecundity between F1 and later-generation 1/2 Merinos, and hence no evidence of heterosis. In 2 severe drought years the lambing percentages decreased most in the more productive ewes (1/2 Merinos and older ewes). Genotypes and age groups were more similar than in non-drought years, although a significant effect of genotype was still present in all years.
Effects of nitrogen fertiliser on canola production in north central Victoria
Authors: Ramsey BR , Callinan APL
Published: March 2005

Effects of nitrogen (N) fertiliser at sowing and at bud stage (terminal bud enlarged) on canola seed yield and oil and protein concentrations were studied at 6 sites in north-central Victoria during 1988-90. Rates of application (kg/ha) of nitrogen fertiliser were 0, 25, 50, and 100 at sowing, and 0, 25, 50, 100, and 200 topdressed at bud stage. Canola seed yields responded to N fertiliser applied at either sowing or bud stage, generally increasing with increased N. There was significant variation between years and sites. Maximum seed yields at any of the sites varied from 0.8 t/ha in 1990 to 2.66 t/ha at Charlton in 1989. No combination of N fertiliser treatments produced the highest yield at more than 2 sites. Percentage oil in seed generally decreased with increasing N. Oil concentrations were lowest in 1990, in response to a generally drier season, especially the spring. Maximum oil concentrations in 1988-89 ranged from 42.4 to 45.0%. Nitrogen fertiliser increased total seed protein by increasing seed yield and percentage protein in seeds. Highest seed protein was always obtained with highest application of N.
Triticum aestivum spp. vulgare (bread wheat) cv. Beulah
Authors: Martin PJ
Published: March 2005

Beulah, with the parentage Cook x 2/Millewa/TM56 (TM56 = AUS10894/4 x Condor), is a semi-dwarf, early flowering, spring wheat with moderately strong straw and reaching ear emergence 2 days later than Meering. In silo group A (Mallee region), Beulah yields equal to Meering and higher than Cocamba, and is similar to these cultivars in silo group C (Wimmera region). Beulah is resistant to cereal cyst nematode [Heterodera avenae], moderately resistant to stripe rust [Puccinia striiformis] and flag smut [Urocystis agropyri], and has the stem rust [P. graminis f.sp. tritici] resistance genes Sr30 and Sr36, giving it resistance to the current Australian races of stem rust. Average milling yields of this hard-grained cultivar are 2% higher than those of Meering. The flour has mixing properties similar to those of Meering, while the dough is more extensible (2.2 cm longer). Overall baking quality of Beulah is good. Beulah is acceptable for the Australian Standard White class in Victoria.
An economic assessment of rice breeding in New South Wales
Authors: Brennan JP , Lewin LG , Marshall GR , Reinke RF
Published: March 2005

An economic assessment is made of the rice-breeding program at Yanco, New South Wales. The achievements of the breeding program over the past 30 years are identified and quantified. The economic assessment considers current investment in the breeding program and analyses the likelihood of the program achieving sufficient gains through breeding to justify that investment on economic grounds. We estimate the rate of improvement in yield and quality that would give the required increase in the industry's value of production. Based on the contribution of new varieties to past gains, the future gains needed through breeding to accomplish satisfactory economic returns are achievable. However, the analysis highlights the need for focused breeding efforts to maximise the returns from the breeding program.
Identification of allelopathy in the USDA-ARS rice germplasm collection
Authors: Dilday RH , Lin J , Yan W
Published: March 2005

Field experiments in 1988 and 1989 identified rice accessions from the USDA-ARS rice germplasm collection for allelopathic effects to ducksalad [Heteranthera limosa (Sw.) Willd.]. About 10000 accessions were evaluated; 347 accessions had apparent allelopathic activity. Accessions that had demonstrated allelopathic activity to ducksalad in 1988 or 1989 were evaluated further for allelopathic activity in 1990 (67 accessions) and 1991 (47 accessions). In 1990, 12 accessions had a radius of activity of 0.18-0.20 m and 80-90% weed control within the area of activity. In 1991, 12 different accessions had a radius of activity of 0.13-0.18 m and 50-85% weed control in the area of activity.
Utilisation of anther culture in rice (Oryza sativa L.) breeding in Italy
Authors: Callegarin AM , Perfanov K , Dorotea G , Baldi G
Published: March 2005

Increasing market demand has led to efforts to select for non-sticky, long-grain rice varieties suited to the Italian environment. The variability of recombinant populations derived from crosses between Italian and USA genotypes was exploited. Together with the conventional breeding methods, in vitro anther culture was used to obtain homozygous lines from crosses more quickly. Moreover, hybrid lines were obtained from crosses otherwise impossible to exploit owing to sterility in the F, generation (namely those resulting from crosses involving semi-dwarf USA varieties). Plant regeneration was obtained from 6 F, hybrids whose parents were chosen for their grain quality or their suitability to the Italian environment. About 5500 plantlets were regenerated. Of these, 1000 were albino, and about 50% of the green ones died after transplanting into soil; 65% of the surviving plants were sterile, so about 1000 progeny were obtained (30-445 for each cross). Progeny with desirable characteristics were evaluated for agronomic traits. On the basis of these results, limits and possibilities of anther-culture breeding in rice are discussed.
Cold damage and development of rice: a conceptual model
Authors: Jacobs BC , Pearson CJ
Published: March 2005

Loss of yield in rice owing to exposure to suboptimal (<20�C) temperatures is a widespread phenomenon; in Australia there is circumstantial evidence that cold damage is substantial and that it can occur at any time during the growing season. Damage may take the form of reduced potential yield, abnormal spikelet development, and reduced spikelet fertility. In extreme cases plants may be completely infertile. We are using a conceptual model based on the daily cycle of temperature to quantify a cooling index and the impact of cold. The daily impact of cold varies with the phenology of the crop (i.e. some stages of development are particularly cold-sensitive), and the total or cumulative impact depends on the summation of thermal time below a critical minimum temperature for cold damage. We are in the process of quantifying the variables of the model for 2 cultivars of rice. This aims at prediction of yield loss in response to seasonal variation in temperature, and identifying the likely benefit which will arise from using particular parent lines in later breeding for cold tolerance.
A method to evaluate lodging potential in rice cultivars based on elastic stability theory
Authors: Moldenhauer PM , Moldenhauer KAK
Published: March 2005

Physical characteristics of rice which may be used to evaluate lodging resistance have been measured or calculated. The main characteristics considered were plant height, plant cross-section properties measured by the second moment of area, and the elastic behavior of the culm measured by the bending modulus of elasticity. A method for determining the modulus of elasticity is described. Plant height, modulus of elasticity, and relative straw strength scores were compared. The concept and application of natural stability was discussed in the context of Euler column theory. Euler column theory was applied to near-harvest rice. Predicted critical loads and the difference between predicted loads and average panicle weight were compared with relative straw strength scores.
Green manuring legume pasture for aerial-sown rice
Authors: Dunn BW , Beecher HG
Published: March 2005

The potential for suppling a portion of the required nitrogen (N) for aerial-sown rice crops by green manuring legume pasture was investigated in southern New South Wales. Green pasture material could be the source of up to 300 kg N/ha in the southern New South Wales ricegrowing systems. Three experiments were conducted over 2 seasons. Each included 3 land preparation treatments (fallow, pasture removed, pasture incorporated) split for 5 rates of N (0, 40, 80, 120, 160 kg N/ha) applied as urea immediately before flooding for aerial sowing. In all experiments fallow resulted in lower anaerobic incubation soil ammonium levels at flooding than the pasture-incorporated treatment. When the fallow was extended, N losses led to a decrease in grain yield. The incorporation of green manure resulted in an increase in grain yield at the nil N rate in experiment 1, where soil N levels were comparatively low and seasonal temperatures average. In experiment 2, where soil N levels were high and the temperatures before panicle initiation below average, the incorporation of green manure reduced total dry matter and increased per cent unfilled grain. Land preparation treatments did not affect total dry matter or grain yield in experiment 3, where a short season variety was grown and all treatments lodged severely. Grain yields in all experiments were affected by a season x soil fertility x variety interaction.
A preliminary study to predict net nitrogen mineralisation in a flooded rice soil using anaerobic incubation
Authors: Angus JF , Ohnishi M , Horie T , Williams RL
Published: March 2005

Complementary field and laboratory studies were conducted to determine whether laboratory measurements of net nitrogen (N) mineralisation under anaerobic conditions could be used to predict field rates in a flooded soil and N uptake by a rice crop. The laboratory experiment consisted of measurements of ammonium accumulation at 10, 20, 30, and 40�C for 7, 14, and 28 days of anaerobic incubation. There was no accumulation of ammonium at 10�C, but increasing ammonification rate at temperatures of 20�C was observed, except for a slower rate at 40�C after 14 days. Two models were tested on the data: a zero-order reaction in which rate of mineralisation was a linear function of temperature; a first-order reaction in which net N mineralisation rate was a proportion of a depleting pool of labile organic N. In the second model, the rate was also linearly related to temperature. Both models fitted the laboratory data well (R2 = 0.94 and 0.97, respectively), but the second model accounted better for mineralisation at 40�C for the 28-day incubation. These models were then run, using daily mean temperatures over a rice-growing season, to predict net mineralisation in the field. The predictions were compared with measured net N mineralisation in a flooded soil and N uptake by the crop measured throughout the season in the field from which the incubated soil was sampled. Net N mineralisation and crop uptake increased throughout the season, reaching maximum values of 115 and 111 kg N/ha at maturity. The zero-order and first-order models both predicted net N mineralisation accurately until the middle of the season, after which the zero-order model overestimated net N mineralisation but the first-order model predicted the reduction in the rate of net N mineralisation with reasonable accuracy. The close agreement between the laboratory incubations and field measurements of net mineralisation and crop N uptake suggest that incubation tests may provide useful information for including in a model to assist rice growers' decisions about N fertiliser.
Assessing the nitrogen requirements of rice crops with a chlorophyll meter
Authors: Turner FT , Jund MF
Published: March 2005

Soil and plant analyses to estimate nitrogen (N) fertiliser requirements of rice plants continues to be a research priority because of the major influence of N fertiliser on rice yield, production economics, and concerns regarding excess N in our soil, water, and air. Significant achievements have been made using a portable chlorophyll meter to determine the need for additional N fertiliser. This report summarises recent progress with the Minolta SPAD 502 chlorophyll meter in predicting the need for additional N. The meter does not measure N or chlorophyll concentration; rather it provides immediate, on-site, quantitative measurements of leaf greenness that have been correlated (r2 = 0.62) with rice plant N needs during the 10 days before and after the panicle differentiation growth stage. The SPAD meter measurements taken on the most recently matured leaf can range from 25 to 44 depending on N uptake and growth stage. At SPAD readings >40, additional N fertiliser has not increased yields. It is recognised that SPAD values are influenced by plant growth stage, cultivar, leaf thickness, plant population, and any soil or climate factor causing leaf chlorosis. Users should understand that SPAD values do not indicate how much N to apply, they only indicate the need for additional N. SPAD meter technology does not replace other proven N management practices. However, used in combination with other N management tools, the chlorophyll meter can improve N fertiliser practices for rice.
Management of fertiliser nitrogen in dry-seeded, delayed-flood rice
Authors: Bollich PK , Lindau CW , Norman RJ
Published: March 2005

Approaches taken in management of fertiliser nitrogen (N) in dry-seeded, delayed-flood rice (Oryza sativa L.) in the United States of America vary considerably. A 2-year study was conducted in Louisiana to evaluate N fertiliser efficiency and accumulation when applied in single or multiple applications. The cultivars Lemont and Tebonnet, representing semi-dwarf and conventional tall plant types, respectively, were grown on a Crowley silt loam (Typic Albaqualfs soil). Urea N was applied using 1 of 3 strategies: in a single (1-way) preflood (PF) application of 134 kg Nlha; in a 2-way split consisting of 100 kg N/ha PF and 34 kg N/ha at panicle initiation (PI); or in a 3-way split consisting of 66 kg N/ha PF, 34 kg N/ha at PI, and 34 kg N/ha at panicle differentiation. Microplots were established within each whole plot and fertilised with 2 atom% 15N urea. Fertiliser N application time had no influence on plant accumulation of 15N urea or biomass production. Plant accumulation of 15N urea was significant across year and cultivar. Tebonnet accumulated more 15N urea than Lemont. Accumulation was also significantly higher in 1992. Method of application of fertiliser N significantly affected grain yields. The highest average grain yield of 7905 kg/ha occurred with a single PF application. Yields were reduced by 378 kg/ha with a 2-way split application and by 1074 kg/ha with a 3-way split application. Method of application of main crop fertiliser N had no effect on ratoon crop yields. Total grain yield (main + ratoon) was significantly reduced with the 3-way split. This study demonstrates the importance of supplying adequate N to the rice plant before permanent flood establishment. It also suggests that midseason N applied at specific growth stages is less efficiently utilised, especially when insufficient N is applied at PF.
Presowing nitrogen fertiliser management for aerial-sown rice on puddled soil
Authors: Kealey LM , Humphreys E , Black AS , Muirhead WA
Published: March 2005

Presowing nitrogen (N) fertiliser management for aerial-sown rice was investigated for 2 soil cultivation methods, conventional cultivation and puddling, in the Coleambally Irrigation Area of New South Wales. Two N sources, urea and anhydrous ammonia (NH3, ColdFlo), were used. Urea was applied at 3 depths (0,7, 17 cm) and NH3 at 2 depths (7, 17 cm). These 5 treatments were compared with an unfertilised control and with a novel method of applying NH3 in the same operation as puddling. Urea was applied at 60 kg N/ha; the application rate of NH3 appeared to be higher than the intended rate of 60 kg N/ha. The site was responsive to N: agronomic efficiency of the urea-fertilised treatments averaged 39 kg grain yield increase/kg applied N. Dry matter yield, N uptake, and grain yield were similar on conventionally cultivated and puddled soil. There were no significant interactions between cultivation and N treatments in their effects on crop growth or N uptake. Application depth of fertiliser also had no significant effect on crop performance. Applying NH3 in the same operation as puddling was as effective as other methods of applying N, with the advantage of allowing soil preparation and fertiliser application to be completed in 1 pass. Urea labelled with 15N was applied at depths of 0, 5, and 15 cm to microplots at a rate of 60 kg N/ha. Recoveries of 15N in plants and soil were similar for both methods of soil cultivation and for different N application depths, consistent with results from the large plots described above. There was no interaction between soil cultivation and urea application depth treatments. Recovery of applied 14N averaged 32% in the plant shoots and 24% in the top 30 cm of the soil. Recoveries of 15N from presowing urea application have not previously been reported for aerial-sown rice in New South Wales. The results suggest that puddling can be readily integrated into the rice management system without changing current fertiliser practices. However, soil N uptake was very high, accounting for around 90% of the plant N uptake in the urea-fertilised treatments. Therefore, extrapolation of the results of the treatment comparisons to other sites with lower available N should only be done with caution.
Emergence phenology of Chironomus tepperi Skuse and Procladius paludicola Skuse (Diptera: Chironomidae) during rice crop establishment in southern New South Wales
Authors: Stevens MM
Published: March 2005

Midge emergence from untreated rice bays was monitored with conical traps during crop establishment. Chironomus tepperi Skuse was the numerically dominant species in all 3 seasons of the study, and generally had only 1 generation, although there was some evidence of a minor, non-overlapping second generation in the 1992 season. Emergence of first generation C. tepperi was highly synchronised, with peaks occurring 16-17 days after flooding. Procladius paludicola Skuse became the dominant species in trap collections after C. tepperi emergence declined, and had multiple overlapping generations. Members of the genus Procladius are predacious rather than phytophagous. Chironomus tepperi and P. paludicola together comprised 45.6-80.4% (mean 68.1%) of midges emerging during the first 48 days after flooding. More than 30 midge species were recorded from the trial site, but C. tepperi was the only phytophagous species recorded in sufficient numbers to warrant individually targeted control. Although C. tepperi has, in a practical sense, only 1 generation in establishing rice bays, growers have consistently reported that multiple chemical treatments are necessary to prevent crop damage. There are several possible explanations for this apparent anomaly. Chemical seed treatments may be failing to disperse sufficiently to control the first C. tepperi generation. Also, the elimination of chironomid larvae through the use of seed treatments may be making fields receptive to reinfestation by C. tepperi if oviposition is being regulated by the presence of larval populations. A third possibility is that phytophagous species other than C. tepperi, although poorly represented individually, may sometimes be abundant enough collectively to cause significant crop damage.
Estimation of evapotranspiration from rice in southern New South Wales: a review
Authors: Humphreys E , Meyer WS , Prathapar SA , Smith DJ
Published: March 2005

This paper reviews field measurements of evapotranspiration from rice (ET rice) in the Murrumbidgee Valley of southern New South Wales. The results are compared with US Class A open pan evaporation (E pan) at CSIRO Griffith, and with reference evapotranspiration (ETo) calculated using a locally calibrated Penman equation. Both methods (+ETrice = +Epan or +ETrice = +ETo) give good estimates of total evapotranspiration from flooded rice over the ponded season of about 5 months, from October to February. Variation between seasons in total ETo, rainfall, and ETo minus rainfall is large. Over 32 years, total seasonal ETo varied by a factor of 1.5, while rainfall varied >10-fold. The irrigation water requirement for rice +(ETo - rainfall) varied from 685 mm in 1992-93 to 1350 mm in 1990-91. This large variation highlights the need to adjust the rice water use limit (16 ML/ha or 1600 mm) on a seasonal basis, to detect and eliminate high water use paddocks where percolation to the groundwater or surface runoff is excessive (>2 ML/ha). On average, an irrigation requirement of 10.5 ML/ha is needed to replace net evaporative loss +(ETo - rainfall) for rice flooded for 5 months, October-February. Monthly totals of ETo are compared for several locations within the rice-growing areas of southern New South Wales, and differences between locations are found to be small and not significant. This reflects the strong dependence of evaporation on radiant energy, which is unlikely to vary spatially to a significant extent across the region. ETo calculated from meteorological data collected at CSIRO Griffith therefore provides a definitive basis for estimating evapotranspiration from rice in southern New South Wales. Furthermore, CSIRO Griffith has a computerised meteorological data base going back to the 1930s. Current meteorological data and historical records are readily available by contacting the Metdata Manager. Therefore, the case is made for using CSIRO Griffith ETo as the reference for estimating evapotranspiration from rice in southern New South Wales. This study provides farmers, Land and Water Management Plan groups, and policy makers with a tool that can be used, on a yearly basis, to evaluate rice paddock water use efficiency. It should be adopted to confine rice growing to the least permeable soils.
An inexpensive and effective basis for monitoring rice areas using GIS and remote sensing
Authors: Barrs HD , Prathapar SA
Published: March 2005

To ensure orderly, planned rice production, and to meet environmental constraints on the location of rice in the landscape, there is a need to locate and measure the area of rice plantings by paddock and by farm. Traditionally, rice areas have been estimated from manual measurements taken from aerial photography: overall, an expensive and time-consuming approach. In a pilot study covering 5 seasons on an area of 6 by 6.25 km containing 160 paddocks in 22 farms, we have found that it is possible to locate rice areas accurately, to determine their size, and to classify the vigour of the crop. Information is transferred into a geographic information system from classified satellite imagery using Landsat Thematic Mapper bands 3, 4, and 5 and then processed with a simple rule to distinguish rice rapidly from other crops. Furthermore, the classification categorises rice within each paddock into 3 statistically distinct groups of poor, medium, or good crop vigour. Total rice area and area of each rice class are computed for each rice paddock. Paddock data are combined to give corresponding values for each farm and for the entire study area. This information could be useful for forecasting rice yields in the current season and for the management of paddocks for more uniform and higher yields in subsequent seasons. The procedures used require inexpensive software and are largely automated since they include unsupervised clustering. The need for special skills is thereby minimised, making the transfer of the technology to interested parties quite straightforward. Over the 5 seasons, all paddocks growing rice were correctly identified and only 2 non-rice paddocks wrongly identified as growing rice.
Germinable soil seed banks in native pastures in north-eastern Australia
Authors: McIvor JG , Gardener CJ
Published: March 2005

Germinable soil seed banks were determined in 20 native pasture communities of widely varying composition (dominated by native tussock grasses, Bothriochloa pertusa, or forbs) near Collinsville (20�34'S, 147�51'E). Samples of surface soil (0-10 cm) were taken during the late dry season, seeds were germinated in a shadehouse, and seedlings were identified and counted. Over all pastures there were seeds of 100 species in the seed banks, including 29 grasses (14 perennial), 11 legumes, 8 sedges, and 52 forbs. Total seed numbers varied among pastures from 210 to 9770/m2. Forbs were the most numerous component, followed in order by sedges, perennial grasses, annual grasses, and legumes. Of the 790 seeds/m2 of perennial grasses, the naturalised species B. pertusa contributed 620/m2. Even though the native perennial grasses were prominent in these pastures, they had few seeds in the soil, especially when the pastures had been heavily grazed. To maintain these grasses in pastures, management should aim to prevent excessive mortality of the perennial plants as seedling regeneration could be limited by the small seed numbers available.
Studies on Phytophthora clandestina, the cause of taproot rot in subterranean clover. 1. Evidence for physiological specialisation in Phytophthora clandestina
Authors: Flett SP
Published: March 2005

Root rot caused by Phytophthora clandestina Taylor, Pascoe & Greenhalgh is a serious disease of subterranean clover (Trifolium subterraneum), an important leguminous component of Australia's temperate pastures. Previous reports have shown that P. clandestina causes severe taproot rot in cv. Woogenellup, while cvv. Larisa and Trikkala remain highly resistant. In this study, 3 greenhouse experiments were conducted to determine the effects of P. clandestina isolates collected between 1983 and 1990 on different subterranean clover cultivars. Woogenellup was consistently susceptible while Meteora was less affected by all isolates tested. Trikkala, a previously known root rot resistant cultivar, was as susceptible as Woogenellup when tested with a recently collected isolate from Katamatite, northern Victoria. This study provides the first evidence for variation in virulence between isolates of P. clandestina and for physiological specialisation in this species.
Identification of navy bean varieties using a random amplification of polymorphic DNA
Authors: Graham GC , Henry RJ , Redden RJ
Published: March 2005

Random amplification of polymorphic DNA (RAPD-PCR) was applied to the identification of Australian navy bean varieties. A total of 296 markers were generated from 29 primers. Three new navy bean varieties that were difficult to distinguish by visual characteristics could be uniquely identified by RAPDPCR. The varieties were distinguished from their parents and from 3 commercially available varieties. The overall level of polymorphism between all varieties was low (about 15%). However, 3 lines (Campbell-11, CH33-8D, Spearfelt) were more distinct genetically from the other genotypes (e.g. similarity of only 75%). Analysis using RAPD-PCR molecular markers may allow distinction of varieties for plant variety rights and will provide information on the genetic relationships of these varieties for breeding purposes.
The role of nematodes, fungi, bacteria, and abiotic factors in the etiology of apple replant problems in the Granite Belt of Queensland
Authors: Dullahide SR , Stirling GR , Nikulin A , Stirling AM
Published: March 2005

Investigations of apple replant failure in the Granite Belt suggested that the problem had a complex etiology. Soil fertility was an important factor because apple seedlings grew best in replant soils with high levels of nitrogen, phosphorus, and potassium. Consistent improvements in the growth of apple seedlings were obtained when typical orchard soils were treated with fenamiphos, confirming that lesion nematode was also an important component of the disease complex. Pratylenchus penetrans had been recognised as a pathogen of apples, and pathogenicity tests showed that P. jordanensis, another species widely distributed in the Granite Belt, had similar effects. Growth responses of apple seedlings were greater when soil was pasteurised than when it was treated with fenamiphos, suggesting that root pathogens other than nematodes were involved in apple replant failure. However, the primary cause probably differed between orchards because soils did not respond in the same manner to pasteurisation and nematicide treatments. Pathogenicity tests with 14 bacteria associated with apple roots showed no effect on the growth of apple seedlings. However, Fusarium tricinctum, Cylindrocarpon destructans, and Pythium sp. were implicated in the problem because they were consistently recovered from discoloured roots. In a factorial experiment involving nematodes and fungi in pots, P. jordanensis, P. penetrans, E. tricinctum, and C. destructans reduced the dry weight of apple roots but there was no interaction between nematodes and fungi.
Evaluation of fungicides and cultivars for control of gummy stem blight of rockmelon caused by Didymella bryoniae
Authors: Vawdrey LL
Published: March 2005

Ten fungicides were evaluated in 2 experiments with rockmelons for control of gummy stem blight caused by Didymella bryoniae. The fungicides (g a.i./ha) tebuconazole (100 and 160), fentin hydroxide (226), prochloraz Mn (231 and 370), benomyl (400), benomyl (400, 500) plus white oil (2 L/ha), propiconazole (100), mancozeb (1600), mancozeb plus phosphonic acid (1600 + 1000), myclobutanil (237), and chlorothalonil (1600) significantly (P<0.05) reduced the incidence and severity of gummy stem blight compared with an unsprayed treatment. Total weight of fruit and number and weight of marketable fruit in plots treated with fungicides were increased (P<0.05) by as much as 55% compared with untreated plots. Premature fruit ripening was reduced where there was effective disease control. Tebuconazole was the superior chemical but was phytotoxic when applied at 160 g a.i./ha. Fentin hydroxide caused burn on old foliage. Two accessions of Cucumis melo obtained from the United States Department of Agriculture (PI 266934, PI 266935) and 5 commercial cultivars were evaluated for resistance to gummy stem blight in a field experiment. PI 266934 and PI 266935 were highly resistant and the commercial cultivars were susceptible.
Aerial dispersal of first- and second-instar longtailed mealybug, Pseudococcus longispinus (Targioni Tozzetti) (Pseudococcidae: Hemiptera)
Authors: Barrass IC , Jerie P , Ward SA
Published: March 2005

First- and second-instar Pseudococcus longispinus (Targioni Tozzetti) were found in sticky plate traps erected around a commercial Josephine pear block. Of those trapped, 89% were first instars and11% second instars. Adult males are winged and capable of weak flight but were caught on only 2 of the76 days of trapping. It is unlikely that the winged males use the wind to assist them in dispersing to new locations. Numbers of instars found in the traps were positively related (P<0.05) to wind speed and to the square of the daily maximum temperature. Aerial dispersal could be important in the colonisation of new areas or in the spread of resistance genes.