bluuebunny/crossref_metadata_2025 huggingface dataset:
Winter cereal production on the Darling Downs dash an 11 year study of fallowing practices
Authors: Marley JM , Littler JW
Published: March 2005

A long term field experiment to compare 4 methods of fallowing for annual winter cereal production on a Darling Downs Vertisol was started in 1968 on the Hermitage Research Station near Warwick, Queensland. Fallowing systems being investigated are (i) tined tillage with stubble burnt (TcSb); (ii) tined tillage with stubble retained (TcSr); (iii) zero tillage with stubble burnt (TzSb); and (iv) zero tillage with stubble retained (TzSr); each at 3 rates of nitrogen (N) fertiliser application. This paper reports the effect of these treatments on fallow water accumulation, fallow N mineralisation, crop growth and yield, for the period 1968-79. Average values for available soil water in the 0-150 cm zone at sowing were 195 mm for TcSb, 212 mm for TcSr, 225 mm for TzSb and 252 mm for TzSr, and for storage efficiency (percentage of fallow rainfall stored) were 18, 20, 25 and 27% respectively. The relatively greater water storage efficiency of Tz treatments occurred mainly in fallow seasons when initial storage was low.
Nitrogen mineralisation during fallows averaged 61 kg/ha and was depressed in some years by Sr. Carryover of available N in excess of crop requirements was shown at the higher rate of N fertilisation.
Grain yields averaged over 12 crops were similar for the 4 fallowing systems. The lack of grain yield response to the improved water storage under TzSr was probably caused by yellow spot disease (Pyrenophora tritici-repentis) and root lesion nematode (Pratylenchus thornei), which were most prevalent under this treatment in wheat crops. Poor early growth of barley under TzSr limited its water use and grain yield potential, however, the cause of the poor early growth of barley is not known. A reduction in grain yield of 232 kg/ha associated with Sr was overcome with the addition of 23 kg N/ha as urea.
Effect of tillage practice on grain sorghum production in northern New South Wales
Authors: Holland JF , Felton WL
Published: March 2005

Grain sorghum was sown at 5 sites in northern New South Wales to examine the response of this crop to no-tillage compared with cultivated fallows. The sites were at Duri and Tamworth in 1980-81, and Warialda, Croppa Creek and Burren Junction in 1982-83. Other treatments investigated were: rates of atrazine applied in the fallow at 4 sites, the gypsum x tillage interaction at 2 sites, and effect of stubble burning during the cultivated fallow at 2 sites.
An average of 31 mm more water was stored in the soil with a no-tillage fallow, and this was associated with a consistent grain yield advantage averaging 0.45 t/ha compared with cultivated, stubble retained fallows over all sites. At Warialda and Croppa Creek the stubble on the cultivated treatments from the 1981 wheat crop was either retained or burnt. Moisture accumulation and yield were substantially reduced in the stubble burnt treatment, particularly at Warialda. There was a yield advantage of the no-tillage treatment over the stubble burnt cultivated treatment of about 1.8 t/ha at Warialda, and 0.7 t/ha at Croppa Creek.
At Burren Junction, gypsum increased grain sorghum yield by 0.57 t/ha in both the cultivated and no-tillage treatments, indicating that it was not necessary to incorporate the gypsum to improve soil structure.
The results of this study indicate that no-tillage sorghum, using atrazine as the primary method of weed control, is an efficient method of production. Potential yield advantages of about 0.5 t/ha over cultivated fallows with stubble retained, and greater yield advantages in comparison with cultivated fallows with burnt stubble, are associated with improved moisture storage.
Residual effect of 2,4-D on the growth and yield of wheat and barley on alkaline clay soils in southern Queensland
Authors: Marley JM , Robinson GR
Published: March 2005

Pot and field experiments were conducted to investigate the residual phytotoxicity of 2,4-D to wheat (Triticum aestivum) and barley (Hordeum vulgare) on alkaline clay soils in southern Queensland during winter. Effects of soil moisture, 2,4-D formulation, application rate, crop species and cultivar were investigated.
With the exception of a 4% reduction in wheat grain yield in 1 field trial (considered commercially acceptable), grain yields of wheat and barley were not affected when seed was sown within 2 h of field application of 2,4-D dimethylamine or ethyl ester at rates of application up to 1 kg/ha.
No significant reduction in phytotoxicity (measured by shoot dry matter reduction of wheat) of 2,4-D dimethylamine occurred when exposed on dry soil for 4 weeks in pots, or of ethyl ester or dimethyl amine exposed for 16 days on dry soil in the field. In moist soil in pots, loss of phytotoxicity to wheat of 2,4-D dimethyl amine was complete within 4 weeks when the herbicide was applied at 2 kg/ha or 2 weeks when applied at 0.5 kg/ha.
An accurate and mobile weighing device for large pots
Authors: Hatfield PM , Wright GC , Tapsall WR
Published: March 2005

A device enabling fast and accurate weight measurements for large pots is described. It is manouverable and easy to operate. Large numbers of pots can be weighed with minimum effort and with little disturbance to pots.
Diagnostic nitrogen concentrations for cabbages grown in sand culture
Authors: Huett DO , Rose G
Published: March 2005

The cabbage cv. Rampo was grown in sand culture with 5 nitrogen (N) levels, between 2 and 43 mmol/L, applied as nitrate each day in a complete nutrient solution. The youngest fully opened leaf (YFOL), which became the wrapper leaf at heading, the youngest fully expanded leaf (YFEL) and the oldest green leaf (OL) were harvested at a minimum of 2-week intervals over a 12-week growth period. Standard laboratory leaf total N and nitrate-N determinations and rapid petiole sap nitrate-N determinations were conducted on YFOL, YFEL and OL. Total N was also determined in bulked leaves. The relationship between growth rate relative to the maximum at each sampling time and leaf N concentration was used to derive diagnostic petiole sap nitrate-N, leaf nitrate-N and total N in YFOL, YFEL and OL and bulked leaf total N concentrations. Critical concentration corresponded to 90% maximum growth rate and adequate concentration corresponded to 9 1-1 00% maximum growth rate. Petiole sap nitrate-N concentration, which can be measured rapidly in the field, and leaf nitrate-N concentration were very responsive to N application where positive growth responses were recorded. Critical N concentrations are presented for all leaves at most sampling times throughout the growth period. Critical total N concentrations in YFOL, YFEL and bulked leaves were higher during the pre-heading growth stage (weeks 2-6) than the post-heading growth stage (weeks 8-12). Critical N concentrations were inconsistent over the growth period and it was not possible to present single values to represent the full growth period, with 2 exceptions. A critical petiole sap nitrate-N concentration for OL of 3.0 g/L can be recommended for the full growth period because it represents a percentage of maximum growth rate range of 88-95%. Similarly, for YFEL, a critical total N concentration of 4.10% pre-heading (range 4.10-4.38%) represents a percentage maximum growth rate range of 62-90% and a post-heading critical total N concentration of 3.10% (range 3.10-3.50%) represents a percentage maximum growth rate range of 76-90%. The concentrations of potassium, phosphorus, calcium, magnesium and sulfur in YFOL, YFEL, OL and bulked leaf corresponding to N treatments producing maximum growth rates are also presented.
Field susceptibility of Japanese-type plums to Xanthomonas campestris pv. pruni
Authors: Topp BL , Heaton JB , Russell DM , Mayer R
Published: March 2005

Fifty-five cultivars and 9 breeding selections of Japanese-type plum (Prunus salicina and hybrids) were evaluated from 1985 to 1988 for their susceptibility in the field to Xanthomonas campestris pv. pruni in a cultivar screening trial at the Granite Belt Horticultural Research Station (GBHRS), Applethorpe, Queensland. Laroda, Friar and Beauty were the most susceptible cultivars and showed severe leaf shothole, summer twig cankers and twig death. October Purple, Eldorado, Santa Rosa and Blackamber were also susceptible, displaying leaf shothole and twig cankers in the worst years. The locally established cultivars Doris, Queensland Red Ace, Shiro and Santa Rosa have been considered our most susceptible cultivars but were not as susceptible as many of the recent Californian introductions. Californian cultivars were more susceptible to bacterial spot than the selections from the GBHRS plum breeding program. The incidence of bacterial spot was higher in the years of high summer rainfall. Seventeen genotypes including 5 GBHRS selections did not display symptoms of bacterial spot. Wilson (P. salicina x P. cerasifera) is considered a good source of bacterial spot resistance for use in breeding.
Milk production by dairy cows fed legume grains or barley grain with or without urea as supplements to a cereal hay based diet
Authors: Valentine SC , Bartsch BD
Published: March 2005

Milk production and composition was determined in Holstein-Friesian cows fed either 3.5 or 7.0 kg dry matter (DM) daily of lupin grain, pea grain, faba bean grain or barley grain with or without 1.5% added urea, as supplements to an oaten hay based diet. All the grains were hammermilled. Daily yields of milk (L), fat (kg) and protein (kg) were significantly (P<0.05) higher for cows fed lupin (20.0, 0.81, 0.57), pea (18.9, 0.80, 0.56) and faba bean (18.9, 0.79,0.55) grains compared with those of cows fed barley grain with (17.8, 0.73, 0.51) or without (18.0, 0.71, 0.52) urea. Yields of milk (L), fat (kg) and protein (kg) and milk protein content (g/kg) were significantly (P<0.05) higher when 7.0 kg DM (19.5, 0.80, 0.57, 29.6) compared with 3.5 kg DM (18.0,0.73,0.51,29.0) of grain was fed. There were no significant differences between treatments in hay DM intake by cows fed 3.5 kg DM of grain daily. A significantly (P<0.05) higher milk fat production per unit DM intake was recorded for cows fed legume compared with barley grain. There were generally higher returns above grain cost for cows fed legume compared with barley grain and for cows fed 4 kg compared to 8 kg daily of grain. It was concluded that it was more economical to feed 3.5 kg DM of legume grain compared with 3.5 kg DM of barley grain, with or without urea, as supplements for cows offered cereal hay in early lactation. However, the economics of feeding 7.0 kg DM of legume grain compared with 7.0 kg DM of barley grain and 7.0 kg DM compared with 3.5 kg DM of grain will depend on the costs of relative changes in hay intake associated with these practices.
Effect of pre-weaning farm environment on adult wool production of Merino sheep
Authors: Denney GD
Published: March 2005

The influence of pre-weaning environment on the adult productivity of medium Peppin Merino sheep has been examined in field experiments. In 1983 and 1984 groups of pregnant ewes and. subsequently, their lambs were run with breeding flocks on farms located over the Central Tablelands and Central Western Slopes of New South Wales. After weaning, each year's progeny grazed as a single flock at Condobolin on the Central Western Slopes, thus allowing the sheep equal nutritional opportunity in post-weaning and adult life. Differences in the progeny's liveweight and wool production could be attributed to the effects of the different environmental conditions experienced before they were weaned. Birth weight and lamb growth rates were affected (P<0.001) by early environment. At weaning, mean group liveweights covered a range of 6.9 kg in 1983 and 7.8 kg in 1984. In both years the proportion of the phenotypic variation of liveweight due to pre-weaning environment fell from approximately 0.35 at weaning to 0.15 (P<0.001) at 12 months of age, but the proportion was not significantly different from zero when the progeny were 24 and 36 months of age. Pre-weaning environment affected the production of greasy wool (P<0.001) over the progeny's first year of life. However, among the 1983 progeny no differences in wool production were observed at 24 and 36 months of age. With 1984 progeny no differences occurred at 24 months of age or, when the wool weights were adjusted to a common liveweight by covariance, at 36 months of age. Yield, fibre diameter and staple length were not affected by pie-weaning environment when measured at 24 and 36 months, and there were no differences between groups in the ratio of secondary to primary wool follicles or in wool follicle density at 36 months of age. It is concluded that the adult productivity of Merino sheep is unlikely to be permanently reduced by poor pre-weaning environmental conditions on farms but overall flock productivity will be reduced if fewer weaners survive.
Effects of pasture and supplement quality on the responses of lactating dairy cows to high energy supplements
Authors: Stockdale CR , Currie R , Trigg TE
Published: March 2005

An experiment was conducted in which 30 stall-fed dairy cows were fed a basal ration of either good or poor quality pasture (approx. 7 kg DM) and supplemented with varying amounts of either crushed wheat or a pelleted. high energy supplement (0, 4 kg/clay or ad libitum). The cows were in their third month of lactation and were fed their allotted rations for 5 weeks. Where no supplements were fed, the approximate 9% difference in digestibility between pasture types resulted in differences in daily production of 2.4 kg milk/cow, 0.07 kg milk fat/cow and 0.06 kg milk protein/cow, and a difference of 0.4 units of body condition over a 5-week period. Where supplements were fed, responses depended on the interaction between a supplement and basal ration. With good quality pasture as the basal ration, the type of supplement was not important; marginal returns of milk products to extra feeding were similar for both supplements, for example, 1.0 kg milk/cow.day was produced for each additional kg of concentrate consumed. There was a reduction in milk fat production when more than about 5-6 kg DM of supplement was fed. This was due to a depression in the fat content of the milk which was associated with low dietary fibre (<250 g/kg of dietary neutral detergent fibre). However. when pellets were fed to cows offered poor quality pasture. a reduction in milk fat yield did not occur. When wheat supplemented poor quality pasture, on the other hand, deficiencies other than fibre were implicated. While fibre was the most important limitation to productivity when good quality pasture was supplemented with concentrates, protein was the most likely nutrient to limit productivity first when poor quality pasture formed the basal ration. The potential exists for major imbalances of nutrients to occur unless the composition of dietary components is known.
Low effectiveness of Duchess rock phosphate on pastures in northern Queensland
Authors: Gilbert MA , Shaw KA , Armour JD , Teitzel JK , Standley J
Published: March 2005

Rock phosphate from Duchess, northeastern Australia, and superphosphate were compared as phosphorus (P) sources for pasture in glasshouse and field experiments in northern Queensland. Duchess rock phosphate was an inferior source of P for pastures, compared with superphosphate. The yield response to rock phosphate, however, varied between soils. On strongly acidic soils with high P sorption capacity, rock phosphate increased yield and bicarbonate-extractable P in the soil. On near neutral soils of low P sorption capacity, rock phosphate had little effect on yield. When the rate of rock phosphate was expressed as citrate-soluble P, its performance improved relative to superphosphate. Rates of coarse Duchess rock phosphate need to be at least 10 times those of superphosphate to produce a similar effect on pasture growth. In a glasshouse experiment, the fine rock phosphate was 1.6 times more effective than the coarse material.
The performance of short scrotum and wether lambs born in winter or spring and run at pasture in northern Tasmania
Authors: Hopkins DL , Gilbert KD , Saunders KL
Published: March 2005

Summary. The growth of short scrotum and wether lambs was studied in 3 experiments over 2 years, at the Elliott Research Station in northern Tasmania. Short scrotum lambs born in winter grew significantly (P<0.05) faster than wethers from birth to slaughter at 137 days of age. For spring born, short scrotum lambs, the growth advantage was less because of the quality and quantity of pasture available during summer and autumn. Wether lambs were fatter than short scrotum lambs in all experiments, with the slope of the relationship between GR and carcass weight being 0.57 � 0.02 I! 0.42 � 0.01 mmkg (experiment 1); 1.13 � 0.1 1 v. 0.68 � 0.09 mm/kg (experiment 2); and 0.91 � 0.16 v. 0.63 � 0.08 mm/kg (experiment 3) respectively. As carcass weight increased, the difference in carcass fatness increased. There was a shift in the distribution of carcasses according to fat score, with more wether carcasses being allocated high fat scores. Testes weight in the short scrotum lambs showed considerable variation within and between experiments and in all cases the testes were located in a subcutaneous position. There was a poor relationship between testes weight and growth rate. The level of testes development in a proportion of animals indicated that the animals could be fertile.
Influence of sex and year on carcass characteristics important in the marketing of second cross lambs
Authors: Thatcher LP , Maden JJL , Plant CL
Published: March 2005

The carcass characteristics important for the marketing of ewe, wether and ram lambs were examined for lambs grazing annual pastures in northeastern Victoria. The lambs were Poll Dorset x (Border Leicester x Merino). The lambs grew on abundant, high quality pastures after a spring lambing in 1983. The climate in 1984 was very dry and the lambs were born in autumn when pasture availability was low, and pasture clover content reduced. Apart from carcass weight and fat depth (GR) which are used in the AUS-MEAT lamb carcass description, it was found that sex also influenced the level of subcutaneous fat; and also the GR measurement and distribution of subcutaneous fat. Sex did not, however, affect primal joint size in a commercially important way. It was concluded that lamb sex should also be included to improve carcass description, and this would be more important as larger carcasses were used. The area of the M. longissimus dorsi at the 12th rib (EMA) was not affected by sex, but it was a significant (Pc0.01) inclusion with carcass weight in predicting hindleg muscle content. Year affected level and distribution of subcutaneous fat, EMA, and primal joint size even after GR and carcass weight were described. However, the major influence of year was not clear, because there were 2 times of lambing in 2 years when nutrition was vastly different.
Polysaccharide composition of Australian wheats and the digestibility of their starches in broiler chicken diets
Authors: Annison G
Published: March 2005

The polysaccharide compositions of 20 wheat varieties from New South Wales and Western Australia were determined. Mean pentosan and �-glucan contents ranged from 5.7 1 to 8.18% and from 0.61 to 0.87% respectively, on a dry matter basis. Starch contents ranged from 61.5 to 68.9% and the wheat starches were between 21.1 and 31.8% amylose. The starch digestibility of the wheats was found to be independent of the levels or composition of the polysaccharides when assayed using 5-week-old broiler chickens.
Soil acidification under subterranean clover (Trifolium subterraneum L.) pastures in north-eastern Victoria
Authors: Ridley AM , Helyar KR , Slattery WJ
Published: March 2005

Eleven paired soil samples to 60 cm depth were collected from grazing properties in north-eastern Victoria. Soils were naturally acid and most were red or yellow podsolics. At each site unfertilised soils (unimproved) and soils which had received regular superphosphate applications (improved) were sampled from either side of a fenceline. The percentage of organic carbon was higher on improved sites but pH was usually lower. Using pH and pH buffering capacity data, the rate of soil acidification under improved pasture, relative to unimproved pasture, was estimated. The improved pastures, on average, required 39 kg CaCO3ka.year to balance the net acid accumulated. The estimated rates of acidification are much lower than those reported previously for similar environments and soil types in New South Wales. There was a relationship between initial profile pH and net acid addition, lower measured net acid addition being associated with low initial soil pH. This paper demonstrates the need for both standardisation of soil pH buffer capacity measurements, and more direct assessment of the role of soil mineral dissolution processes in buffering the pH of strongly acid soils. Until such data exists it will be very difficult to provide convincing information to primary producers regarding the long term alkali input requirements needed for sustainable farming systems.
Establishment and production of lucerne on a salinised clay soil irrigated with moderately saline groundwater
Authors: Mehanni AH , Rengasamy P
Published: March 2005

Groundwater (ECw 3.8 dS/m, and a sodium adsorption ratio of 15.0) pumped from a shallow aquifer was used to irrigate a lucerne crop established in a salinised clay soil after initial leaching of salts. Pumping and irrigation with groundwater reduced the topsoil salinity (ECe) from 22.1 to 5.9 dS/m in the first 15 months and the pasture progressively displaced the weeds. Lucerne, a moderately salt tolerant crop, was then established and grown for 4 consecutive years (1982-86). Irrigation treatments during this period were saline irrigation (control) and saline irrigation plus gypsum, applied either in irrigation water (4 m.e./L) or on the soil surface (1 0 and 20 /tha). There were no significant differences in dry matter production of lucerne between the control and gypsum treatments during the 3 years after the year of establishment. Mean yields over all treatments were 18 143, 18 375 and 16 700 kg/ha. A decline in yield in 1985-86 was associated with leaf yellowing and brown necrosis and may have been caused by nutrient imbalance. Threshold concentrations of electrolytes were present in the soil whether gypsum was applied or not and, therefore, soil hydraulic conductivity was not affected by saline irrigation. This resulted in no beneficial effect of gypsum applied either in irrigation water or on the soil surface.
Effect of 2,4-D ester on the nitrate concentration of variegated thistle (Silybum marianum) (L.) Gaertn
Authors: Harradine AR
Published: March 2005

The effect of 2,4-D ester application on the nitrate concentration of variegated thistle (Silybum marianum) was investigated in pot and nutrient solution experiments. In general, the nitrate concentration of sprayed plants increased significantly 1-2 days after 2,4-D application. The effect lasted for up to 4 days before the nitrate concentration returned to the prespraying levels. In a pot experiment, this increase in plant nitrate concentration was only observed at the higher of 2 applied nitrate levels (i.e. 15 m.e./L). In a third experiment, the nitrate concentration of naturally occurring variegated thistles varied from 66 to 17152 �g/g. There was a strong correlation (r = 0.92) between thistle nitrate concentration and the nitrate level in the soil directly beneath the sampled plant. The results are discussed in relation to their implication for avoiding nitrate toxicity in livestock grazing variegated thistle, especially after the thistles have been treated with 2,4-D.
The influence of tillage, stubble management and crop rotation on the persistence of great brome (Bromus diandrus Roth)
Authors: Heenan DP , Taylor AC , Leys AR
Published: March 2005

Infestations of great brome, Bromus diandrus Roth, in a long-term tillage, stubble management and crop rotation trial were studied over 3 years at the Agricultural Research Institute, Wagga Wagga. Herbicides were effective in removing great brome from lupin but this did not prevent carryover to the following wheat crop. Over all years, in the wheat-lupin rotations, burning of stubble significantly reduced great brome infestation in the wheat phase by approximately 39%, while 3 cultivations prior to sowing reduced infestation by approximately 43%. The greatest infestation occurred where direct drilled wheat followed wheat with stubble retained. In a continuous wheat system, a combination of burning and 3 cultivations maintained great brome populations at a low level.
Nitrogen fertiliser response of wheat in lupin-wheat, subterranean clover-wheat and continuous wheat rotations
Authors: Mason MG , Rowland IC
Published: March 2005

Response of wheat to 7 rates of nitrogen (N) fertiliser was compared in clover-wheat (CW), lupin-wheat (LW) and continuous wheat (WW) rotations, in 4 alternate years on a grey gravelly sand over ironstone gravel at Badgingarra, during the period 1980-87. Nitrogen fertilisers significantly increased wheat grain yields in all assessment years (1981, 1983, 1985 and 1987). There were significant (P<0.05) interactions between rotation and N fertiliser in all years except 1983, with response to N fertiliser on wheat least in the LW rotation. The apparent average increases in N available in wheat dry matter, without added N, were 10.9 kg/ha from clover and 13 kg/ha from lupins. The contributions from clover and lupins in grain N were 10 and 12.3 kg/ha respectively. Organic carbon and total N levels in the soil were similar in the LW and WW rotations but were less than in the CW rotation. The levels of organic carbon in the LW and WW rotations decreased with time. Despite the difference in soil organic carbon and total N, grain yields were similar for the CW and LW rotations in the absence of N fertiliser but were higher than in the WW rotation. It was concluded that a LW rotation (in this environment) would be as effective, at least over a 6-year period, as a CW rotation in maintaining wheat yields due to the contribution of N from readily decomposible residues from the lupin crop. However, highest yields overall where obtained when N fertiliser was added to the CW rotation.
Effect of nitrogen on the growth, yield and grain protein content of barley (Hordeum vulgare)
Authors: Birch CJ , Long KE
Published: March 2005

Barley (Hordeurn vulgare) cvv. Grimmett, Galleon and Corvette were grown under irrigated conditions at The University of Queensland, Gatton College. to determine the effects of nitrogen (N) rates (0-200 kg N/ha) on plant growth, yield and grain protein content. Nitrogen delayed maturity in all cultivars, especially in Galleon. Total tiller number and fertile tiller number were increased by N and there was a significant cultivar x N rate interaction. Similar trends were evident in total dry matter at maturity and grain yield, with Galleon producing the highest yields. Fertile tiller percentage was reduced by increasing N rate. Grain protein content increased with the increasing N rate, with differences in the nature of the response between cultivars (i.e. linear in Corvette, quadratic in the other 2 cultivars). Total and fertile tiller numbers were explained by quadratic regressions, with maximum values at 150 kg N/ha (except fertile tillers in Grimmett, maximum value at 100 kg N/ha). The declines in fertile tiller percentage were explained by quadratic equations except in Grimmett, which showed a negatively linear response to increasing N rate. Dry matter yield and grain yield showed quadratic responses to N in Grimmett and Galleon (predicted maximum values near 200 kg N/ha) and linear responses in Corvette, over the experimental range of N rates. The response in grain protein content was explained by quadratic equations for Grimmett and Galleon, with minimum grain protein content occurring at close to 0 and 55 kg N/ha respectively. Corvette showed a linear increase in protein content in response to increasing N rate. It is concluded that plant breeding programs should consider variation in grain yield and protein content in response to N supply and select for efficiency of utilisation of N. Recommended N rates for irrigated barley could be 150-200 kg N/ha. Lower rates will promote strong yield responses, but protein content would remain low.
A review of the use of phosphate rocks as fertilizers for direct application in Australia and New Zealand.
Authors: Bolan NS , White RE , Hedley MJ
Published: March 2005

Field trials in New Zealand have shown that reactive phosphate rocks (RPRs) can be as effective as soluble P fertilisers, per kg of P applied, on permanent pastures that have a soil pH<6.0 (in water) and a mean annual rainfall >800 mm. Whereas RPRs such as North Carolina, Sechura, Gafsa and Chatham Rise have been evaluated on permanent pastures in New Zealand, most Australian field trials have examined unreactive PRs such as Christmas Island A and C grade, Nauru and Duchess, using annual plant species. Only in recent experiments has an RPR, North Carolina, been examined. Except on the highly leached sands in southern and south-western Australia, both reactive and unreactive PRs have shown a low effectiveness relative to superphosphate. In addition to chemical reactivity, other factors may contribute to the difference in the observed agronomic effectiveness of PRs in Australia and New Zealand. Generally, PRs have been evaluated on soils of lower pH, higher pH buffering capacity (as measured by titratable acidity) and higher P status in New Zealand than in Australia. Rainfall is more evenly distributed throughout the year on New Zealand pastures than in Australia where the soil surface dries out between rainfall events. Dry conditions reduce the rate at which soil acid diffuses to a PR granule and dissolution products diffuse away. Even when pH and soil moisture are favourable, the release of P from PR is slow and more suited to permanent pasture (i.e. the conditions usually used to evaluate PRs in New Zealand) than to the annual pastures or crops used in most Australian trials. Based on the criteria of soil pH<6.0 and mean annual rainfall >800 mm, it is estimated that the potentially suitable area for RPRs on pasture in New Zealand is about 8 million ha. Extending this analysis to Australia, but excluding the seasonal rainfall areas of northern and south-western Australia, the potentially suitable area is about 13 million ha. In New Zealand, many of the soils in the North and South Islands satisfy both the pH and rainfall criteria. However, suitable areas in Australia are confined mainly to the coastal and tableland areas of New South Wales and eastern Victoria, and within these areas the actual effectiveness of RPR will depend markedly on soil management and the distribution of annual rainfall. Further research on RPR use should be focused on these areas.
Effect of level of meat-and-bone meal and pasture type on milk yield and composition of cows grazing tropical pastures
Authors: Davison TM , Jarrett WD , Clark R
Published: March 2005

An experiment was conducted with Holstein-Friesian cows to determine the effect on milk yield and composition of feeding different amounts of meat-and-bone meal (MBM). Thirty-two cows grazed either tropical grass pastures fertilised with nitrogen (GN) or tropical grass-legume pasture (GL). Cows were offered 2.5 kg DM/day of a molasses supplement incorporating 1 of 4 levels of MBM: 0, 250, 500 or 750 g DM/day. The experiment was conducted over the first 160 days of lactation. With GN pastures, fat-corrected milk (FCM) yield (kg/cow.day) for days 1-160 of lactation was linearly related to the intake of MBM (kg DM/cow.day) and was described by the equation FCM = 14.0 + 1.84 MBM (P<0.01, R2 = 0.95). Most of this response occurred in the first 100 days of lactation, when significant I (P<0.05) relationships between milk yield, FCM yield and intake of MBM were found. Milk yield and FCM yield of cows grazing grass-legume pastures were increased by feeding MBM, but the FCM response was a mean of 32% less than with the nitrogen-fertilised pasture and non-significant at the 5% confidence level. The following mean values over 160 days were recorded for cows on GN and GL pastures, respectively: milk yield, 15.8 and 17.4 kg/day; FCM yield, 14.6 and 16.7 kg/day; butterfat, 3.54 and 3.69%; solids-not-fat, 8.40 and 8.59%; lactose, 4.91 and 4.95%. It was concluded that a MBM supplement will increase the milk yield for cows grazing nitrogen-fertilised pastures, but only during early lactation.
Comparative phosphate requirements of yellow serradella (Ornithopus compressus) burr medic (Medicago polymorpha var. brevispina) and subterranean clover (Trifolium subterraneum)
Authors: Paynter BH
Published: March 2005

The phosphate (P) requirements of burr medic (Medicago polymorpha) on marginally acidic, medium-textured soils and yellow serradella (Ornithopus compressus) on acidic, light-textured soils in the low rainfall (<400 mm) wheatbelt of Western Australia are not known. The hypothesis that yellow serradella, subterranean clover (Trifolium suhrerraneum) and burr medic have the same external requirement for applied P was tested in a glasshouse trial on 2 P-deficient soils. Species were compared on an equal total seed weight and similar maturity length basis. It was found that yellow serradella required less soil applied P to achieve 90% maximum shoot production or total plant (shoots + roots) growth and had a greater curvature co-efficient from fitted Mitscherlich functions than either subterranean clover or burr medic. Burr medic was the most responsive to applied P and had the largest external requirement for applied P. These differences in external P requirements were related to differences in ability of the 3 legumes to absorb P and to transport it to their shoots and were not due to differences in internal efficiency of the shoots. Yellow serradella was able to take up more P (total plant P content) per g roots than subterranean clover, and subterranean clover more than burr medic. The same relationship applied to the translocation of absorbed P from roots to shoots.
Seasonal changes in dry matter distribution and herbage quality of Urochloa species in north-eastern Queensland
Authors: McIvor JG
Published: March 2005

Seasonal changes in the dry matter distribution between green leaf, dry leaf, stem and infloresence, and the nitrogen and phosphorus concentrations and in vitro digestibility of these components, were measured in accessions of Urochloa mosambicensis and U. oligotricha growing at Lansdown, near Townsville, between 1979 and 1982. The grasses were grown in mixed stands with Stylosanthes cultivars and fertilised annually with superphosphate. U. oligotricha accessions were more leafy than U. mosambicensis accessions. In all accessions, the proportion of green leaf was high at the start of the growing season and then declined, usually to zero by the end of the dry season. The proportion of green leaf was closely related to water supply as indicated by a moisture index. The differences between accessions for chemical composition and digestibility were much smaller than the differences between sampling dates, and accessions did not differ markedly for herbage quality.
Acidification under grazed annual and perennial grass based pastures
Authors: Ridley AM , Slattery WJ , Helyar KR , Cowling A
Published: March 2005

Soil samples to a depth of 60 cm were collected from adjacent, 39-year-old, phalaris-based and annual pasture fields on an acid soil at Rutherglen, north-eastern Victoria. The fields had similar histories of fertiliser application and stock enterprise. Minimum net acid addition rates were determined under both pasture types, and the soil under annual pasture showed greater acidification. Carbon cycle acid addition contributed 1.3 1 and 1.36 kmol H+/ha.year to net acid addition on annual and phalaris pastures, respectively. Because slow alkaline soil reactions in the field contribute to buffering capacity on an acid soil and lead to underestimation of net acid addition rate and nitrate leaching, estimates of such reactions were made for both pasture types. If correct assumptions were used nitrate leaching was substantial under both pasture types but was reduced by 1.01 kmol H+/ha.year under phalaris pasture. This suggests that perennial grass based pastures can be used to reduce acidification on pastoral soils. Alkali addition to counteract net acidification may be necessary on acid soils to maintain management options for growing aluminium-sensitive species.
Effect of seed weight, and seed phosphorus and nitrogen concentrations on the early growth of wheat seedlings
Authors: Marco DGDe , De Marco DG
Published: March 2005

Wheat seeds of uniform weight selected from 3 batches of seed with phosphorus (P) concentrations of 0.14, 0.17 and 0.19% were sown in soil with a range of applied P treatments. Seedling emergence was more rapid the higher the seed P. By 25 days after sowing all plants grown at the highest concentration of applied P were similar in size, but with lower applied P, plants from seed with higher P concentrations had an advantage. A range of weight classes was selected from 2 batches of seed raised at low or high concentrations of P. There were 11 groups ranging in mean seed weight from 28 to 58 mg and in seed P from 0.13 to 0.37%. Seedlings from the high P batch had larger first leaves, a higher dry weight, and longer roots than those from the low P batch when grown in a highly P-deficient sand culture system. Within each batch, heavier seeds produced larger leaves, heavier plants and longer roots. The yield differences between batches were largely accounted for if the seed P content (�g P/seed) was considered rather than either percentage P or seed weight alone. Differences in seed nitrogen concentration or content did not consistently account for differences in seedling growth.
Prediction of zinc deficiency in navy beans (Phaseolus vulgaris) by soil and plant analyses
Authors: Armour JD , Robson AD , Ritchie GSP
Published: March 2005

Navy beans (Phaseolus vulgaris cv. Gallaroy) were grown with 7 rates of zinc (Zn) in a Zn-deficient gravelly sandy loam in a glasshouse experiment. The plant shoots were harvested 31 days after sowing and the Zn concentration in each of 4 plant parts (YL, young leaf; YOL, young open leaf; YFEL, youngest fully expanded leaf; and whole shoots) was related to the fresh weight of the shoots. The critical Zn concentrations (mgtkg) in the plant parts determined by the 2 intersecting straight lines model were 21.1 for YL (r2 = 0.66), 17.1 for YOL (r2 = 0.83), 10.6 for YFEL (r2 = 0.91) and 12.5 for the whole tops (r2 = 0.88). The YFEL was selected as an appropriate diagnostic tissue because it is readily identifiable in the field and had the highest 1.2 with fresh weight. In a second glasshouse experiment, the critical Zn concentration in the YFEL and 5 soil tests were evaluated for their ability to predict the Zn status of navy beans. There were 13 soils from sands to clays with a wide range of chemical properties. The soil tests were 0.1 mol/L HCl, DTPA, EDTA, dilute CaCl2 and soil solution Zn. The concentration of Zn in the YFEL correctly predicted Zn deficiency or adequacy in about 77% of samples. The results from both experiments showed that a critical Zn concentration of 10-11 mg/kg in the YFEL can be used to diagnose the Zn status of Gallaroy navy beans. It was not possible to recommend a single soil test for prediction of the relative yield of navy beans. A combination of quantity (HCl, EDTA, DTPA) and intensity (soil solution, 0.002 mol/L CaCl2, 0.01 mol/L CaCl2) parameters were able to explain most of the variation in the Zn concentration of the YFEL, a more sensitive measure of nutrient availability than relative yield. EDTA-Zn in combination with 0.01 mol/L CaCl2-Zn explained 90% of the variation in the Zn concentration in the YFEL, while HCl- or DTPA-Zn and 0.01 mol/L CaCl2 explained about 80% of the variation. As soil solution Zn was significantly correlated with 0.002 and 0.01 mol/L CaCl2-Zn (r = 0.75, P<0.01; r = 0.62, P<0.05, respectively), CaCl2-Zn may be used as a more convenient measure of Zn intensity than soil solution Zn.
Ethylene gas burn of Washington navel oranges - a form of anthracnose induced by degreening and controlled by brushing or applying fungicides
Authors: Wild BL
Published: March 2005

The effect of several postharvest treatments on rind damage to Washington navel oranges during ethylene degreening was assessed. Application of hot benomyl dips (500 mg/L) or washing the fruit on revolving brushes prevented rind damage for all fruit colours and ethylene concentrations (0-2000 �L/L) tested. Application of either of the fungicides benomyl (unheated) or prochloraz also reduced rind damage. Imazalil had less effect, while guazatine only slightly reduced rind damage. Rind damage was attributed to the development of anthracnose when dormancy of latent infections of Colletotrichum gloeosporioides was broken. It is recommended that when susceptible oranges are degreened, they are treated with benomyl, preferably at 50�C, or washed over revolving brushes. Ethylene concentrations should also be kept as low as practicable to reduce the risk of rind damage.
Effect of brief pre-marketing holding of bananas in nitrogen on time to ripen
Authors: Wills RBH , Klieber A , David R , Siridhata M
Published: March 2005

Bananas obtained from more than 20 plantations in 3 seasons and stored in nitrogen at 20�C for 3 days soon after harvest took about 27 days to ripen in subsequent air storage, compared with untreated fruit which ripened after about 19 days. However, skin injury was found on about 4% of fruit, with the affected areas principally being previously damaged areas. When nitrogen treatment was delayed, the inhibition of ripening was lost and skin injury became more severe. While there were some differences in chemical composition found between nitrogen treated and untreated fruit, taste tests showed that this had no noticeable effect on eating quality.
Metabolic effects of safflower oil given as a supplement for steers fed roughage diets at restricted intake
Authors: O'Kelly JC , Spiers WG
Published: March 2005

Supplements of safflower oil (300 mL/day) were given to groups of steers fed 4 different diets. Hereford steers were fed 6 kg/day lucerne hay (LH) or LH + 33 mg/kg monensin (LHM). Brahman steers were fed 4 kg/day low quality hay (DA) or DA + 1 kg sucrose + 60 g urea + 2.7 g sulfur (DAS). Metabolic measurements were made when the animals were fed an equal portion of the daily ration at hourly intervals. On all diets, safflower oil had no affect on rumen temperature, pH or the concentrations of volatile fatty acids in ruminal fluid. Safflower oil increased concentrations (mg/L) of microbial lipid in ruminal fluid (LH, 160.4 v. 317.1; LHM, 266 v. 541.7; DA, 194.6 v. 321.8; DAS, 172.8 v. 440.5) and increased plasma concentrations (�g/mL) of non-esterified fatty acids (LH, 117.2 v. 180.1; LHM, 101.1 v. 189.5; DA, 218.2 v 325.4; DAS, 197.4 v 311.4), especially 18:1 trans- 11 and polyunsaturated acids. In steers fed DA and DAS, safflower oil reduced protozoal numbers and increased the bacterial mass in ruminal fluid, and increased water intake and the daily amounts of urinary allantoin excreted. The addition of safflower oil to all diets depressed plasma urea concentrations (mg/L) (LH, 233 v. 203; LHM, 236 v. 191; DA, 74.6 v. 47.6; DAS, 96.6 v. 54). The excretion of daily amounts (mg/kg liveweight) of urinary urea increased in animals fed DA (3.5 v. 10.0) and DAS (6.2 v. 13.6) but decreased in those fed LH (208.8 v. 187.9) and LHM (188.8 v. 158.1). Safflower oil supplementation conserved body protein, accelerated liveweight gains in animals fed LH and LHM diets and retarded liveweight loss in those fed DA and DAS diets.
Acceptability of high fat grain mixtures offered to grazing dairy cows
Authors: King KR , Stockdale CR , Trigg TE
Published: March 2005

Levels of acceptance of mixtures of rolled oats and predominantly saturated, molten or free-flowing fatty acids were assessed with lactating dairy cows. Twenty cows grazed pasture and were offered rolled oats comprising 0, 2, 4, 8, 15, 25 or 40% (w/w) fatty acids. One kg/cow was offered twice daily to cows following milking. The acceptability of grain-fat mixtures was influenced by level of fatty acids. The fatty acid concentrations above which less than 95% of the supplement was consumed by animals ranged from 22 to 31%. Time spent eating the supplement was reduced by 2.4 s for every percentage unit increase in fatty acid concentration, while high air temperature increased (P<0.05) eating time.
Nitrogen rate and stocking rate effects on steer gains from grazed irrigated pangola grass in the Ord Valley, Western Australia
Authors: Jones RJ
Published: March 2005

Annual liveweight gain of steers grazing flood-irrigated, fertilised pangola grass in the Ord Valley, Western Australia, was modelled as a function of nitrogen rate (90-350 kg/ha) and stocking rate (5.2-12.6 steers/ha). Steer gains decreased linearly with increasing stocking rate (SR) at each nitrogen rate (NR). Increasing NR resulted in higher steer gains, particularly at the low levels of SR. The model predicted an increase in the slope (b values) of the linear relations between steer gains and SR with an increase in NR. As a consequence, SR for maximum gain/ha.year only varied between 6 and 7 steers/ha within the NR used. Responses to SR and NR for gains/ha were both quadratic, and the model predicted a maximum gain of 1266 kg/ha when SR was 6.2 steers/ha and NR was 420 kg/ha.year. Within the experimental range, maximum gain was 1233 kg/ha when SR was 6.6 steers/ha and NR was 350 kg/ha.year. Steer gain varied seasonally, even in this tropical, irrigated environment. Gains were highest in January-March and lowest in June-July. Increasing stocking rate had the greatest depressing effect on liveweight gain during the cool season with b values, for the relation between steer gain and stocking rate at the 220 kg N rate, varying from -1 g/day in November to -94 g/day per unit of SR in July.
Increasing wheat yields in a high rainfall area of Western Australia
Authors: Anderson WK , Smith WR
Published: March 2005

Average commercial wheat yields in the southern, high rainfall area of Western Australia have seldom exceeded 1.5 t/ha and wheat is not widely grown. However, the average annual rainfall and length of growing season (>400 mm and >6 months) are conducive to much larger yields. Thirteen factorial experiments with mid and long season cultivars (Aroona and Osprey), 2 levels of applied nitrogen (N) (40 and 80 kg N/ha), 2 seed rates (50 and 100 kg/ha) and with or without fungicide were conducted at 8 sites over 2 seasons. The experiment was done to investigate combinations of cultivar and agronomic practices suitable for increased wheat production in long season environments in Western Australia. Largest grain yields (>4 t/ha) were obtained where wheat followed a grass-free break crop, and the mid season cultivar was used with 80 kg N/ha and 100 kg/ha of seed. Increases due to cultivar and seed rate were more consistent than those due to N, and increases from application of fungicide were less consistent. It is suggested that the optimal wheat production 'package' will include sowing in May in rotation with a grass-free break crop, seed rate of about 100 kg/ha and, when all other factors are optimal, N rates of over 40 kg/ha. The greatest yield increases were associated with the sites where wheat followed a grass-free crop. Increases due to other factors were relatively smaller. Hectolitre weight and percentage of small grain (<2 mm) often reached levels that would have entailed downgrading in commercial deliveries. However, in the most productive crops where root and leaf diseases were minimal, these quality parameters were seldom deficient and grain protein contents exceeded 10% at yields of up to 4 t/ha.