bluuebunny/crossref_metadata_2025 huggingface dataset:
Possibility of using caustic residue from bauxite for improving the chemical and physical properties of sandy soils
Authors: Barrow NJ
Published: November 2004

Large quantities of alkaline red mud are produced as a waste product from the extraction of alumina from bauxite. Its chemical and physical properties and the way that it could be modified to produce good growth of plants were investigated. The cation exchange capacity of the red mud increased with pH, the adsorption of phosphate decreased, and the adsorption of cadmium increased. A pH of just above eight seemed to provide a good combination of desirable properties. This could be achieved by exposing the red mud to air and mixing it with gypsum - also available as a waste product. Carbon dioxide was absorbed by alkaIi in the red mud, and then precipitated by the gypsum as calcium carbonate. This released sodium sulfate which could be leached from the mud. Medic species could then be grown, provided that phosphate, potassium and manganese were supplied. Residual sodium sulfate from incomplete leaching seemed to limit the growth of other species. There seemed to be a potential to use the amended red mud to improve the waterholding properties and the chemical properties of sandy soils of the Western Australian coastal plain.
The effects on sheep urinary and plasma electrolytes of 4 weeks' exposure to different ambient temperatures and humidities
Authors: Guerrini VH , Berchinger H , Koster N
Published: November 2004

Urinary electrolyte output and plasma electrolyte concentration were determined in six Letelle wethers exposed to hot-humid, hot-dry, cool-humid and cool-dry environments. Urinary Na+ output increased during the first week of exposure to both hot environments, decreased after the third week of hot-humid exposure, and declined during the first 2 weeks of the cool-humid exposure. Changes in urinary Na+ output were accompanied by major changes in the opposite direction of urinary K+ and Cl- output. The changes in urinary electrolyte output were accompanied by lesser changes in plasma Na+, K+, and Cl- concentration. Increases in the temperature-humidity index were correlated with increased urine Na+ concentration, decreased urine K+ and Cl- concentration, decreased urine and plasma osmolality, decreased plasma Na+ concentration, and increased plasma Cl- concentration. Changes in urine volume, feed intake, total plasma protein concentration, and plasma cortisol were related to changes in urinary electrolyte output, especially after prolonged heat exposure. The results provide convincing evidence that changes in ambient temperature and humidity were related to major changes in urinary electrolyte output during the first weeks of exposure. More prolonged changes in ambient temperature and humidity were associated with major changes in urine output and feed intake which, in turn, were related to major changes in urinary electrolyte output and minor changes in plasma electrolyte concentration.
Interaction between lateral branch growth and pod set in primary inflorescences of lupin
Authors: Porter NG
Published: November 2004

In Lupinus angustifolius, L. luteus and L. mutabilis, flower formation and pod set were largely independent of the basal lateral branches. Partial or complete removal of lateral branches near the primary inflorescence increased the number of flowers formed and pods set. Flower formation was unaffected by most of the experimental treatments and was most closely correlated with the main-stem leaf area in L. angustifolius and L, mutabilis. Loss of leaf area from the main stem reduced flower formation and pod set more in L. mutabilis than in L. angustifolius. Leaves on lateral branches did not contribute significantly to flower formation or pod set in the presence of main-stem leaves, but could compensate for losses of main-stem leaves in L. mutabilis, especially when the upper lateral branches were intact and actively growing. Removal of all growing points from the upper lateral branches enhanced pod set. These findings suggest that crop management can increase pod set on primary inflorescences in lupin crops that have limited water in early summer, by bringing about a temporary restriction in upper lateral branch growth during the pod-setting process. It is concluded that the effect of lateral branch growth is more significant in the control of pod set in lupin species than the autonomous control by abscisic acid.
Zinc in subterranean clover (Trifolium subterraneum L. cv. Seaton Park). II. Effects of phosphorus supply on the relationship between zinc concentrations in plant parts and yield
Authors: Reuter DJ , Loneragan JF , Robson AD , Plaskett D
Published: November 2004

The effect of phosphorus on the relationship of zinc concentrations in various plant parts to yield of Seaton Park subterranean clover was examined. Plants were grown in a glasshouse at three levels of phosphorus (39, 65 and 130 mg phosphorus/pot; denoted P1, P2 and P3 respectively) and six levels of zinc added in factorial combination to a sand deficient in both phosphorus and zinc. At the lowest three levels of zinc supply, plants were severely to moderately deficient in zinc: in them, increasing levels of phosphorus depressed growth and induced high concentrations of phosphorus (> 1 % DM) in several plant parts and symptoms of phosphorus toxicity in leaves. At the highest three levels of zinc supply, plants at P1 were phosphorus deficient: application of P2 and P3 increased growth and induced zinc deficiency primarily by diluting the available zinc. In addition, P3 appeared to depress slightly the zinc content of plant tops by another mechanism. In severely zinc-deficient plants, phosphorus supply changed the relationships between zinc concentrations in various plant parts and yield of whole tops, probably as the result of phosphorus toxicity. In the youngest open leaf blades, an asymptotic relationship at P1 changed at P2 and P3 to sigmoidal and to 'Piper-Steenbjerg' relationships respectively. These changes would not have invalidated the use of plant analysis for diagnosing zinc deficiency. In moderately zinc-deficient plants, phosphorus supply had little or no effect on the relationships of zinc concentration in plant parts to yield of shoots. As a result, critical concentrations in plant parts generally remained constant over the whole range of phosphorus supply. The data refute suggestions that high levels of phosphorus in plant parts inactivate the zinc within them, thus removing a potential problem in the use of plant analysis for diagnosing zinc deficiency in subterranean clover. The results confirm the previous suggestion that a concentration range of 12-14 �g zinc/g in the youngest, open leaf blade is critical for diagnosis of zinc deficiency in subterranean clover.
Genetic variation within a natural Stylosanthes guianensis, Colletotrichum gloeosporioides host-pathogen population
Authors: Miles JW , Lenne JM
Published: November 2004

Sixteen first-generation selfed (S1) progenies from Stylosanthes guianensis plants collected from a natural population were inoculated with each of 16 Colletotrichum gloeosporioides isolates in a replicated glasshouse experiment. Both host and pathogen collections were obtained from a single site in the Department of Valle, Colombia (76� 25'W.; 3�55'N.; altitude 1720 m). Genetic differences among S1 progenies were detected based on differential disease reaction and on phenotypic differences in two morphological characters. No evidence of major resistance gene effects among or within S1 progenies was found. Both quantitative and qualitative differences among C. gloeosporioides isolates were detected: one isolate type was uniformly pathogenic across the S1 progenies, while a second type elicited large differences in resistance among the progenies. Cultural characteristics of the isolates also differed. Segregation within some S1 progenies for stipule hairiness and for disease reaction suggests that at least some natural outcrossing was occurring in the sampled S. guianensis population. The implications of the results with respect to the design of a disease control strategy for S. guianensis cultivars are discussed.
Factors affecting diet selection by sheep. 1. Potential intake rate and acceptability of feed
Authors: Kenney PA , Black JL
Published: November 2004

In experiment 1, potential intake rates of several dried forages, varying widely in nutritive value, were measured by offering each alone to six hungry sheep for eight, separate 1-min periods. Intake rates ranged from 5.5 to 26.1 g/min, but, within each forage, it varied little between sheep (c.v. 13%) or between measurements with the same sheep (c.v. 8%). The forages were then offered in pairs in separate containers and preference for one forage was defined as the percentage of total intake derived from that forage. With the exception of a dried clover pasture, preference for a forage was strongly related to the rate at which it could be eaten. Reducing the length of wheaten straw particles from 30 to 10 mm increased intake rate from 5.5 to 12.4 g/min and resulted in an absolute preference for the short material. The mean preference for a forage over all comparisons was more strongly correlated with intake rate of the forage (r2 = 0.87) than with in vitro digestibility of organic matter (r2 = 0.30). In experiment 2, two wheaten straws and two wheaten hays were each chopped to two lengths and, within each forage, mixed (w/w) in the short : long ratios of 0 : 1, 1 : 2, 2 : 1 and 1 : 0. Mean intake rates were 7.3 and 12.5 g/min for the two straws and 15.7 and 23.2 g/min for the two hays. Within each forage, all mixtures were offered in pairs to establish preference. The slopes of regression equations relating preference (%) to intake rate (g/min) were 21.4, 17.0, 5.9 and 2.7 (%.min/g) for the four forages as mean intake rate increased from 7.3 to 23 2 g/min, which indicates that discrimination between forages with the same difference in intake rate was greater when mean intake rate was low. In experiment 3, finely ground clover pasture, lucerne hay, wheaten hay or wheaten straw were added to a base diet of either chopped lucerne or wheaten straw in the ratio 1 : 10. Although the additive had little effect on intake rate, sheep preferred lucerne to clover pasture and wheaten hay to wheaten straw. Equations developed from the results of experiment 2 to predict the preference for one forage over another on the basis of their relative intake rates, showed fair agreement with observations from experiment 1, particularly when the effects of acceptability factors such as taste, odour or feel were translated into differences in potential intake rate.
Water use, foliage temperature and yield of irrigated wheat in south-eastern Australia
Authors: Steiner JL , Smith RCG , Meyer WS , Adeney JA
Published: November 2004

Quantification of the relationship between evapotranspiration (Et) and yield is important for the analysis of irrigation practices. Wheat (Triticum aestivum cv. Avocet) was grown at the CSIRO Centre for Irrigation Research, Griffith, N.S.W., in 1982 with treatments of no irrigation and irrigation at 40, 70, and 90% depletion of plant available soil water. Irrigation significantly affected total dry matter, grain yield, and the yield components of number of heads per m2, number of grains per head, mass of individual grains, and harvest index. Plot grain yields, varying from 1.7 to 8.3 t ha-1, were closely related to dry matter at anthesis (r = 0.94) and number of grains per m2 (r = 0.99), indicating the importance of early growth on final yield. Regression analysis showed a significant (P < 0.01) linear relationship between Et and total or grain dry matter. The relationship of Et (mm) to grain yield (Y) (t ha-1) was described by Y = -2.010 + 0.016Et. Foliage temperatures were monitored at noon and showed promise as plant stress indicators. The mean differential between foliage and air temperature from jointing to late grain fill showed a strong negative linear relationship to grain numbers per unit soil area (r2 = 0.88) and to final yield (r2 = 0.86).
A model of changes in the composition of binary mixtures of subterranean clover strains
Authors: Rossiter RC , Maller RA , Pakes AG
Published: November 2004

A relatively simple deterministic model is presented which predicts the long-term changes in plant densities of subterranean clover strains when grown as binary mixtures in continuously grazed swards. The model combines life-cycle parameters, based on measurements in monocultures, together with the 'k' parameters of the de Wit replacement series model for mixtures during the seed production phase. Field data, for the most part under grazing conditions, were collected from the CSIRO Experiment Station at Bakers Hill, W.A. The principal strain pairs of clover were Dwalganup/Daliak, Yarloop/ Seaton Park and Seaton Park/Midland B. Beginning with 50/50 mixtures, our results indicate that Daliak dominates the first mixture fairly rapidly; that Seaton Park dominates the second mixture, but more slowly; and that the two strains in the Seaton Park/Midland B mixture may coexist for long periods (up to c. 100 years). Results for some other mixtures, viz. Dwalganup/Northam, Daliak/ Dinninup and Geraldton/Dinninup are presented. The effects of intervention of a cereal crop in the pasture system are considered briefly. The findings are discussed in relation to density dependence, constant v. variable environments, importance of seed characters, genetic changes, and also long-term coexistence.
Effect of sowing time on growth, yield and water-use of rain-fed wheat in the Wimmera, Vic
Authors: O'Leary GJ , Connor DJ , White DH
Published: November 2004

Crops of wheat (Triticum aestivum cv. Olympic) were sown after a 10-month fallow at three times in both 1979 and 1980 in the Wimmera district of Victoria. Total above-ground plant material (biomass) and soil water content were measured for each crop at monthly intervals from sowing to anthesis and thereafter every 2 weeks. The duration of the phenophase, sowing to anthesis, varied from 88 to 163 days, but the maximum difference between anthesis date for the early (May) and late (August) sown crops was only 21 days. The duration of this phenophase was best described by a photothermal unit of 6846 day-degree-hours (>2�C, >6 h). The pattern of biomass accumulation varied markedly between crops, with biomass ranging from 9 to 13 t ha-1 and yield between 3 and 4 t ha-1. Total wateruse efficiency in the production of biomass to anthesis ranged from 30.5 to 19.8 kg ha-1 mm-1 and in the seasonal production of grain from 8.6 to 6.6 kg ha-' mm-'. Whilst the data include only one early sown crop, it was possible to identify an optimum balance between pre- and post-anthesis growth in crops sown in June to produce 9 t ha-1 of biomass at anthesis in early November, a yield sink of 12500 grains m-2 and in the 2 years of the experiment a grain yield of 4 t ha-1.
Effect of environmental conditions on growth and rubber production of guayule (Parthenium argentatum)
Authors: Downes RW , Tonnet ML
Published: November 2004

Nine lines of guayule were grown in the field near Narrabri and Canberra. Rubber percentage and dry matter production were estimated after four years' growth. Although dry matter yield per plant was comparable in the two locations, the rubber content was higher at Narrabri. Rubber percentage was greater after winter than after summer, indicating that cool conditions were favourable for rubber accumulation. This was supported in phytotron studies where rubber percentage was much higher at 15/10 than 24/19�C day/night temperatures. In contrast, elongation of shoots was promoted by high temperature, high radiation conditions. In a phytotron study guayule transpired substantially less than wheat per unit leaf area. The agronomic consequences of these findings are discussed.
Phosphorus metabolism in ruminants. 1. Techniques for phosphorus depletion
Authors: Ternouth JH , Davies HMS , Milton JTB , Simpson-Morgan MW , Sands NE
Published: November 2004

A dietary technique and a parotid saliva replacement technique for depleting ruminants of phosphorus are described. The unilateral parotid depletion technique, involving permanent re-entrant parotid duct catheterization, with phosphorus-free artificial saliva returned to the duct, rapidly depressed blood and ruminal inorganic phosphorus concentrations of animals fed on a low-phosphorus diet. The parotid technique is capable of removing the total extracellular fluid inorganic phosphorus of cattle, goats and sheep in 5-14 h and is of value for creating acute phosphorus deficiencies in adult ruminants. Removal of phosphorus from the ruminant is slower with the dietary technique.
Fate of urea nitrogen applied at planting to grain sorghum grown under sprinkler and furrow irrigation on a cracking clay soil
Authors: Wright GC , Catchpoole VR
Published: November 2004

Uptake of nitrogen (N) fertilizer and yields of grain by sorghum on Cununurra clay in north-western Australia have been found previously to be higher under sprinkler than under furrow irrigation. The cause of this was investigated using a 15N balance technique on field microplots. Additional data on sequential changes in the distribution of mineral-N in the soil, and on volatilization of ammonia, were collected from outside the 15N microplots. The improved effectiveness of N fertilizer under sprinkler irrigation was associated with less upward movement of 15N into the top of the ridge and thus out of the rooting zone of the crop. Furrow irrigation caused 22% of the 15N applied to move into the top of the ridge, sprinkler irrigation caused only 2% of the 15N to do this. The urea appeared to move upwards during the first irrigation, and this N became unavailable to the sorghum because of soil dryness, high temperatures, and osmotic effects in the surface soil. Loss of 15N from the soil-plant system was approximately 27% under both systems of irrigation. This loss was attributed to denitrification, because there was no evidence for large losses of N by leaching or volatization of ammonia.
Responses to protein meal supplements by lactating beef cattle given a low-quality pasture hay
Authors: Lee GJ , Hennessy DW , Williamson PJ , Nolan JV , Kempton TJ , Leng RA
Published: November 2004

A feeding experiment (47 days) was undertaken to evaluate the role of protein meal supplements for Hereford cows given a low quality subtropical grass hay and suckling calves (mean age 37 � 2.2 days). The rates of supplementation were 0, 5.25, 10.5, 15.75, and 21.0 g pelleted protein meal /kg liveweight W0.75. The consumption of grass hay, and the estimated total metabolizable energy intake (MEI) by cows, were significantly (P < 0.01) increased by supplements of protein meal, and their rate of liveweight loss was reduced (P < 0.01). Unsupplemented cows lost 2.56 kg/day compared with a 0.15 kg gain/day for cows given the highest rate of supplementation. Daily milk production and yields of milk protein, lactose, solids-not-fat and fat increased linearly (P < 0.01) with increasing amounts of protein meal. Throughout lactation, daily milk yield declined most rapidly (P < 0.01) in cows given the lower rates of protein supplementation: on day 33 the milk yield in the cows given 21 g protein meal/kg W0.75 was 83% higher than that of the unsupplemented cows. In a second period the rate of supplementation of cows was altered on day 34 from 0 to 21.0 g/kg W0.75. Milk yield at day 47 increased to the same output as that of cows supplemented at 21.0 g/kg W0.75 from day 1. Growth rates of calves, over both periods, tended to be higher in those calves whose dams received the higher rates of supplementation, but the differences did not become significant (P < 0.05) until day 47. There were no significant differences (P < 0.05) in voluntary intakes of hay by the calves whose dams received the various rates of protein supplementation. The concentration of total volatile fatty acids (VFA) was higher (P = 0.06) in the rumen of supplemented cows, but the molar proportions of VFA did not differ between treatments, viz. acetate, 0.71; propionate, 0.16; butyrate, 0.09; other VFA, 0.04. Rumen ammonia concentration was higher (P < 0.01) in cows supplemented with protein meal at the higher rates. The kinetics of plasma glucose and its products in the cows were studied on day 28 by means of a single intravenous injection of [2-3H] and [U-14C] glucose, and on day 29 by means of an intravenous injection of [2-3H] glucose and [14C] sodium bicarbonate. The rates of irreversible loss of glucose C and of bicarbonate C were higher in all supplemented cows. The results are discussed in relation to the availability of substrates for glucose synthesis, glucose oxidation and utilization for synthesis of lactose in milk.
Effect of rumination on reduction of particle size of rumen digesta by cattle
Authors: Kennedy PM
Published: November 2004

Two Hereford steers, fitted with cannulas in the oesophagus and rumen, were given four forage diets in either the chopped or ground and pelleted form. Collections from the oesophageal fistula were made of boluses regurgitated during rumination of the chopped diets. Diets were given at 95% of voluntary feed consumption at intervals of 2 h. Rumination of the chopped diets required 28-36000 chews/day compared to values of 3-10 000 chews/day for the pelleted forms. The weight of material regurgitated during rumination averaged 786 g, of which 493 g was swallowed before chewing commenced. Fractionation of particulate DM by wet sieving showed that the material retained in the mouth for chewing contained 41% more large particulate matter than did regurgitated material. Approximately 70% of large particles in the mouth were comminuted to small particles during one cycle of rumination. Comminution per chew was positively related to the amount of large particulate matter retained in the mouth for chewing and negatively to the number of chews/cycle. Rumination accounted for approximately 85% of comminution of large particles which entered the rumen. Measurements of digestion of dietary materials from nylon bags and rates of outflow of small particles and water from the rumen were used in conjunction with intake and chewing measurements to predict the rumen content of large particles.
Mycotoxins and toxigenic fungi in insect-damaged maize harvested during 1983 in far North Queensland
Authors: Blaney BJ , Ramsey MD , Tyler AL
Published: November 2004

A survey for mycotoxins and toxigenic fungi in maize (Zea mays) grown during 1983 in Far North Queensland is reported. Zearalenone was detected in 148 of the 174 samples examined. Low concentrations of aflatoxins were detected in three of the samples. Ochratoxin A, sterigmatocystin, T-2 toxin and deoxynivalenol were not detected. The 1983 season was unusual in that plants were stressed from low rainfall in the early stage of growth. Insect damage, mainly by ear worms (Heliothis sp.), was severe. Despite this, there was no significant increase in zearalenone concentrations compared to a previous survey in 1982, when insect damage was minimal. Ten samples were used for fungal isolations. Fusarium moniliforme was the most frequently isolated fungus, and its isolation frequency increased in visibly damaged kernels. F. graminearum was most frequently isolated from kernels with a purple discoloration. The correlation between the isolation frequency of F. graminearum and zearalenone concentrations indicated that F. graminearum produced most of the zearalenone in the samples. Other fungi isolated included F. subglutinans, F. oxysporum, Aspergillus jlavus, A. niger, Penicillium sp., Trichoderma sp., Nigrospora sp., Curvularia sp., Drechslera sp., Acremonium zeae and Rhizoctonia sp.
Genetic variation in osmoregulation in bread and durum wheats and its relationship to grain yield in a range of field environments
Authors: Morgan JM , Hare RA , Fletcher RJ
Published: November 2004

The association between osmoregulation and grain yield was examined using measurements of osmoregulation made on wheat plants grown in pots in a glasshouse and measurements of grain yields made in a wide range of field environments. Osmoregulation was determined from measurements of relative water contents and osmotic potentials made on the flag leaves of plants droughted near anthesis. The genotypes were advanced lines from two distinct breeding programs - one for bread wheats and one for durum wheats. All the genotypes in each program (27 bread and 14 durum) were closely related in having a common parent. The grain yields of the bread wheats were evaluated in 56 field trials covering a period of 4 years, and those of the durum wheats were evaluated in seven field trials in one year. Both droughted and irrigated sites were represented. Four field environments were also included for F4 segregating lines reported previously. Considerable variation in osmoregulation occurred which was positively associated with grain yield over the full range of environments sampled for each genotype group. The yields of genotypes which were high in osmoregulation were 11-17% higher in bread wheats and 7% higher in durum wheats than those which were low in osmoregulation, when class differences were based on rnaximising the average yield differences between osmoregulation groups. These results add further evidence favouring the use of glasshouse measurements of osrnoregulation as a selection criterion in wheat breeding.
Canopy development modifies the water economy of chickpea (Cicer arietinum L.) in south-western Australia
Authors: Siddique K. H. M. , Sedgley R. H.
Published: November 2004

Soil water balance and plant data from a time of sowing trial, and estimates of transpiration efficiency, were used to assess the importance of soil cover, provided by developing canopies, on the water use and its partitioning between soil evaporation and transpiration. As reported in an earlier paper, time of sowing strongly affected the timing and rate of canopy development, and had little effect within years on total water use, which was 221 mm in 1982 and 185 mm in 1983. Time of sowing also modified the pattern of water use, and this was reflected in substantial effects on the partitioning of water use, between soil evaporation and transpiration, and in turn on yield and water use efficiency. Estimated water use by soil evaporation ranged from 100 to 125 mm in 1982 and from 75 to 115 mm in 1983. The majority of this, an average of 80 mm, in 1982 and 75 mm, in 1983, occurred during the winter months, June to August, and varied mildly with soil cover. Soil cover had its greatest effect on water use through transpiration during spring, when temperatures were rising rapidly. Transpiration varied between sowing dates by 20 mm in 1982, and by 40 mm in 1983. Measures to improve water use efficiency should aim to reduce soil evaporation during winter both directly, by increasing soil cover, for example, by mulches or earlier-developing canopies, and indirectly by increasing infiltration. In spring, measures to improve water use efficiency should aim at reducing transpiration by minimising canopy development to what is required by the crop to maximise harvest index.
Effect of temperature and solar radiation on the development of dry matter and attributes of elephant grass (Pennisetum purpureum Schum.)
Authors: Ferraris R , Mahony MJ , Wood JT
Published: November 2004

Nineteen accessions of elephant grass (Penniseturn purpureurn) were grown in a long-day photoperiod at 5/10, 18/13, 21/16, 27/22, 33/28 and 36/3l�C day/night temperatures during spring, summer and autumn in the Canberra phytotron. The temperature optimum for dry matter production was 33/28�C, and the magnitude of dry matter production was dependent on the solar radiation received; the low radiation levels in autumn reduced yields of advanced plants. Except at the lowest temperature, cumulative yield was associated with cumulative radiation. Rate of stem elongation was highest at 33/28�C under the spring and summer radiation regimes. Under autumn radiation conditions, rate of elongation was highest at 27/22�C. Rate of leaf appearance and leaf area per plant were linearly related to temperature and were little affected by radiation level. Rate of tiller production showed two maxima, at 18/13-21/16�C and at 33/28-36/31�C, and the maximum temperature was dependent on radiation level. The accessions Q5083, Bana grass and Taiwan consistently produced high yields throughout the range of temperatures tested. The results are discussed in relation to accession performance in the field.
Nutrition of the pregnant ewe and its effect on gestation length, lamb birth weight and lamb survival
Authors: Holst PJ , Killeen ID , Cullis BR
Published: November 2004

The nutrition of grazing, pregnant crossbred ewes was managed so that from 6-15 and from 15-20 weeks of pregnancy, ewes were offered either high (H) or low (L) quality and quantity of nutrition as provided by pasture. At one week prior to parturition, the ewes in each of the four treatment groups (HH, HL, LH, LL) were then placed onto good pasture for lambing. Differential nutrition during pregnancy significantly affected gestation length of the ewes, with HH ewes having the shortest gestation. By day 148, 1.6 times more HH ewes had lambed compared with the LL group ewes. Significant differences were observed in lamb birth weight5 with nutrition in the last trimester (15-20 weeks) having a greater influence on birth weight. This was particularly so for twins. There was no significant difference in the survival of the single lambs, but for twin lambs survival was lowest with the LL ewes. These results show the consequences of maintaining or altering nutrition of single- and twin-bearing ewes during pregnancy. Birth weight of twin-born lambs was most responsive. Apart from lambs of the LL group ewes, the weaning weights of surviving lambs were largely unaffected by prenatal nutrition to one week prepartum.
Effects of time of urea application on combine-sown Calrose rice in south-east Australia. II. Mineral nitrogen transformations in the soil-water system
Authors: Humphreys E , Muirhead WA , Melhuish FM , White RJG , Chalk PM , Douglas LA
Published: November 2004

A combine-sown crop of Calrose rice was grown on an alkaline self-mulching, grey clay soil. Prilled urea was broadcast onto the dry soil surface or into the floodwater at one of four different times: sowing, before permanent flood, after permanent flood or panicle initiation. Within 24 days of fertilisation at sowing, levels of extractable N in the control and fertilised treatments were not significantly different. The rapid disappearance of fertiliser N was associated with rapid loss of NO-3 from the top 20 cm, and this loss appeared to be due to denitrification rather than leaching. The notable difference between fertilisation before and after permanent flood was the distribution of the fertiliser N in the soil and water. Fertiliser applied to the dry soil before flooding was carried deeper into the soil, while fertiliser applied a few hours later into the floodwater was located in the water and top 2 cm of soil. Therefore the potential for loss by ammonia volatilisation and nitrification/denitrification was probably higher in the latter treatment. Fertiliser N topdressed at panicle initiation was also located in the floodwater and top 2 cm of soil. However, fertilisation at this later growth stage was not associated with a yield decline when compared with fertilisation before permanent flood (Part I). Presumably this reflected the greater ability of the plants to compete with the processes leading to fertiliser N loss at this later growth stage, together with a lower ammonia volatilisation potential due to the influence of greater canopy cover on various factors influencing ammonia volatilisation. The data suggested that the efficiency of fertilisation at sowing and before permanent flood might be improved further by deep placement of the fertiliser or by use of a nitrification inhibitor.
Indigofera species with agronomic potential in the tropics. Rat toxicity studies
Authors: Aylward JH , Court RD , Haydock KP , Strickland RW , Hegarty MP
Published: November 2004

Lack of information on the feeding value and on the presence of deleterious substances in many species belonging to the genus Indigofera has limited the potential use of these species as feed and fodder legumes. To obtain such information, leaves and seeds of 46 accessions representing 19 species of Indigofera that had shown some agronomic value were incorporated into a semi-synthetic diet at 5% w/w (seed) or 20% w/w (forage). The diets were fed to groups of young rats for 4 weeks, and dry matter intakes and growth rates relative to control diets were measured. Selected organs were examined for any histological changes. Seed and forage samples were analysed for indospicine, a hepatotoxin, and for the presence of another potentially deleterious substance, 3-nitropropanoic acid. Thirteen of the accessions representing 8 species were readily eaten and did not depress growth rates relative to control feeds, and another 13 representing 10 species gave acceptable growth rates. Liveweight gains were less affected by forage diets than by those containing seeds. With the exception of those in rats fed on diets containing I. spicata and I. nigritana, the organs of all other rats were histologically normal. It is unlikely that the concentration of 3-nitropropanoic acid (0.5-3.4 mg g-1 dry matter) in any feed was high enough to cause any of the observed toxic signs. Indospicine was present in only 4 of the 23 species tested, including all accessions of I. spicata, and the concentration of indospicine was a good indicator of the toxicity of these feeds. It is concluded that accessions that had produced growth rates comparable to those of controls may be recommended as non-toxic feeds suitable for further testing.
Uptake and distribution of chloride, sodium and potassium ions and growth of salt-treated pistachio plants
Authors: Walker RR , Torokfalvy E , Behboudian MH
Published: November 2004

Plant growth rates and rates of uptake and root to shoot transport of chloride and sodium were compared between seedlings of the rootstock Pistacia atlantica Desf. and a scion cultivar P. Vera L. cv. Kerman treated with 30 mM NaCl for 63 days. Uptake and distribution of chloride, sodium and potassium ions were then investigated in P. atlantica and in another rootstock P. terebinthus L. subjected to periods of increasing salinity, commencing with 30 mM chloride and 18 mM sodium, and then increasing sequentially by these amounts every 3 weeks to reach a maximum of 150 mM chloride and 90 mM sodium. Shoot growth rates of P. Vera and P. atlantica were not affected by treatment with 30 mM NaCl. Rates of uptake and root to shoot transport of chloride were similar between the two species. However, the rates of uptake and root to shoot transport of sodium by P. atlantica were approximately 2-fold and 4-fold higher, respectively, than in P. vera. The chloride and sodium accumulated in the shoots of both species was diluted by growth, with the result that there was no marked increase in leaf and stem chloride and sodium concentrations in either species with time. After 63 days of salt-treatment, mean leaf chloride concentrations were less in P. atlantica, which had a higher relative growth rate and a higher shoot to root ratio than P. vera. Mean leaf sodium concentrations were higher in P. atlantica, reflecting the greater rate of root to shoot transport of sodium by this species. Sequentially increasing salinities up to a maximum of 150 mM chloride and 90 mM sodium had no significant effect on the dry matter production of P. atlantica and P. terebinthus. Laminae chloride concentrations of both species increased as the level of salinity was increased. Sodium concentrations in laminae of P. terebinthus showed a small but significant increase during treatment with the two highest salinity levels. Chloride concentrations on a tissue water basis were highest in laminae and petioles of salt-treated plants, whereas sodium concentrations were highest in roots, especially the proximal root, indicating retention of sodium in the lower part of the plant.
Effect of photo-translation on fleece growth in cashmere goats
Authors: McDonald BJ , Hoey WA
Published: November 2004

Cyclical changes in fleece parameters were studied in mature feral doe goats exposed to either natural light (NL) followed by continuous light (CL) then NL, or CL followed by NL then CL.Results show that both initial translocations (NL-CL and CL-NL) were recognized immediately and reflected in changes in volume growth rate, length, diameter, brush end fibres of cashmere and cashmere : hair ratio. Cyclic activity continued after the change in photoperiod. Progressive alterations in cycle amplitude, period and frequency appeared in CL following the initial NL-CL change. Following the initial CL-NL change, cycles of some cashmere fleece parameters continued to be influenced by previous CL exposure and did not immediately adopt NL cyclicity. Mean cycle periods of 252-261 days were common to all CL photoperiods and to NL following CL. This suggests that CL exposes a unique cycle of fleece growth, which is independent of photoperiod and retained for some time after the cessation of CL, owing to transient modification of pineal function. Differences between the response to the first and second translocation may be a function of interactions between the cycle status and translocation, rather than solely the change from one photoperiod to another.The NL-CL change resulted in two cycles of cashmere growth in the 392 days following the initial translocation. This would allow two fleeces to be harvested during that time compared with the one expected in NL alone. Exploitation of this principle may represent an opportunity to increase cashmere production.
Decline of vesicular-arbuscular mycorrhizae in long fallow disorder of field crops and its expression in phosphorus deficiency of sunflower
Authors: Thompson JP
Published: November 2004

Poor growth of crops after long fallows (> 12 months) in cracking clay soils of the northern areas of the Australian grain belt is known as 'long fallow disorder'. Various crop species, including wheat (Triticum aestivum L.), chickpea (Cicer arietinum L.), grain sorghum [Sorghum bicolor (L.) Moench], sudan grass [Sorghum sudanense (Piper) Stapf], sunflower (Helianthus annuus L.), soybean [Glycine max (L.) Merr.] and maize (Zea mays L.), had less root colonization with vesicular-arbuscular mycorrhizal (VAM) fungi and plant weight after long fallows than after short fallows. An experiment was conducted with a phosphorus-deficient soil that had been either fallowed for 3 years or sequentially cropped to cotton, sorghum and sunflower. Cropped soil had more mycorrhizal propagules consisting of intact spores and colonized roots than long fallow soil. In the glasshouse, mycorrhizal colonization of sunflower (cv. Hysun 33) developed quickly in previously cropped soil to peak at 80% of root length at 72 days (flowering), but in long fallow soil it proceeded slowly, attaining 35% of root length at 72 days. Inoculation of long fallow soil with 20% w/w cropped soil resulted in extensive root colonization (89% at 72 days), eliminated P deficiency symptoms and more than doubled plant growth and final P uptake. Inoculation with similar soil treated with gamma radiation to kill propagules of mycorrhizal fungi had no effect on plant growth. Sunflower grew extremely poorly in irradiated soil with considerable leaf necrosis due to P deficiency. Reinoculation with cropped soil resulted In high levels of mycorrhizal colonization and good plant growth. It was concluded that long fallow disorder is caused by a decline in viable propagules of mycorrhizal fungi during fallowing, resulting in poor root colonization and symbiotic effectiveness of a subsequent crop. Fertilizing with phosphorus (50 mg P/kg soil) delayed the development of mycorrhizal colonization, but increased final lengths of colonized roots at 72 days. Zinc fertilizer (15 mg Zn/kg soil) slightly improved mycorrhizal colonization, and basal fertilizer (N, K, S, Ca) substantially improved colonization in long fallow soil inoculated with cropped soil.
Seed production in Brachiaria decumbens and Paspalum plicatulum as influenced by system of residue disposal
Authors: Stnr WW , Humphreys LR
Published: November 2004

Long-established swards of Brachiaria decumbens cv. Basilisk and of Paspalum plicatulum cv. Rodds Bay at Mt Cotton, south-east Queensland, were cut, field dried and burnt, or cut and the residues removed in late November or early January. Burning initially reduced tillering, especially when the interval between cutting and burning was 7 days, but this difference disappeared in P. plicatulum when there was a long interval to floral initiation. A juvenility requirement was evident in the short day P. plicatulum swards, where late burning or cutting delayed floral initiation 11 days relative to early defoliation. Strong compensatory and hierarchical effects on the components of seed yield occurred, and seed yield was similar in cut or burnt treatments, except for 23% decrease in late cut P. plicatulum. Late defoliated B. decumbens yielded 31% more seed than early defoliated swards, due mainly to reduced spikelet number per raceme (branch). Burning slightly increased synchrony of inflorescence exsertion in P. plicatulum and reduced crop lodging, although in a subordinate experiment with P. plicatulum lodging was positively related to level of nitrogen supply rather than to defoliation treatment.
Genetic shift in Setaria sphacelata in response to grazing
Authors: Hacker JB
Published: November 2004

Seven populations of Setaria sphacelata cv. Nandi were studied as spaced-plants. Six populations were derived from nitrogen-fertilized pastures grazed continuously at high, medium or low stocking rates and fertilized with high or low levels of N fertilizer. The seventh was derived from a commercial seed sample of the cultivar. Plants grown from the commercial seed sample were more erect, more variable in growth habit and taller than plants derived from the pastures. Genetic differences in the populations from the grazed pastures were largely associated with flowering date, with progressively earlier flowering in populations from more heavily grazed pastures. This was evident in both the heavily and lightly fertilized pastures. The earlier flowering was associated with a larger number of flower heads at a set date but was not associated with any detectable yield difference. Heavily grazed pastures were characterized by populations which were more variable in growth habit and sometimes more variable in flowering date than lightly grazed pastures. This could have been due to a random effect of faecal areas in heavily-grazed pastures promoting growth but reducing palatability, hence resulting in the retention of high variability. The populations did not differ significantly in chemical composition or in vitro digestibility.
Studies with the Australian Cashmere Goat. II. Effects of dietary protein concentration and feeding level on body composition of male and female goats
Authors: Ash AJ , Norton BW
Published: November 2004

The effects of plane of nutrition (ad libitum and 75% ad libitum) and dietary crude protein concentration (11.3, 16.0 and 20.9% crude protein) on body composition of male and female weaner goats were studied in a comparative slaughter experiment. The initial chemical composition of the body (water, ash, protein, fat) and dissectible tissue fractions of the carcass (muscle, fat, bone) of the experimental goats were estimated from regression equations, derived from a group of twelve comparable kids. The final chemical composition and carcass tissue distribution were determined directly by chemical and dissection analyses. There was no effect of dietary crude protein concentration on the chemical composition of the empty body weight (EBW) gain or on carcass tissue distribution. The lack of any response to dietary protein was attributed to similar levels of protein/energy available at the small intestine despite large differences in crude protein intake. Ad libitum feeding, however, resulted in significantly more fat (31.0 v. 22.6% of EBW gain) and less water (51.1 v. 56.4% of EBW gain) in the composition of the gain compared with restricted feeding. There was no effect of feeding level on protein or ash content of the body. Goats fed ad libitum had significantly less muscle (60.1 v. 62.5%) and more dissectible fat (19.5 v. 16.3%) in their carcasses than kids restricted in their intake. Females had significantly more fat (32.7 v. 22.4% of EBW gain) but less water (48.4 v. 57.9% of EBW gain) and nitrogen (2.2 v. 2.8% of EBW gain) in their body gain than did males. Similarly, the carcass of females contained more dissectible fat (22.6 v. 13.2%) but less bone (15.8 v. 19.3%) and muscle (58.5 v. 64.1%) than males. The efficiency of utilization of dietary energy for growth and fattening (kf) was similar (0.32) for all groups of kids.
Epidemiological studies on the anthracnose diseases of Stylosanthes spp. caused by Colletotrichum gloeosporioides in North Queensland and pathogenic specialization within the natural fungal populations
Authors: Davis RD , Irwin JAG , Cameron DF , Shepherd RK
Published: November 2004

Field experiments were conducted during three wet seasons (1982-84) on two sites in north Queensland to examine the natural occurrence of anthracnose caused by Collectotrichum gloeosporioides on six Stylosanthes spp. The disease incidence varied from moderate to high in a number of accessions, while others showed good field resistance for the duration of the experiment. Anthracnose severity was similar at both sites, although total rainfall each season was c. four times higher at one site than at the other. In some cases disease severity was higher at the drier site. It was difficult to determine a relationship between the environmental parameters measured (rainfall, temperature and relative humidity) and disease incidence and severity. Disease severity patterns varied between accessions at the same site, indicating a response to a factor or factors not associated with the measured weather parameters. There were seven pathogenicity groups, based on host specificities in glasshouse studies, identified within the Type A fungal population and a further seven groups within the Type B population. This indicates an increase in the number of fungal groups reported in Australia, and suggests that a stepwise increase in specificity may be occurring within the fungal population.