bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between the Southern Oscillation Index and Australian sugarcane yields
Authors: Kuhnel I
Published: November 2005

This study examines the relationship between the Southern Oscillation Index and the sugarcane yield anomalies at 27 mills in north-eastern Australia (Queensland) for the period 1950-1989. The major results of this work indicate that the SO1 alone seems to have only a limited value as predictor of total sugarcane yields over large areas (i.e. the whole of Queensland). However, on a smaller scale, the SO1 appears to be a useful indicator of yields for the northern sugarcane districts. In these northern areas, the highest correlations with the SO1 are reached during the southern hemisphere spring and summer months 6 to 11 months prior to the harvest. They are negative and explain about 40% of the total variance. They also suggest that a positive SO1 during the spring and summer months tends to be followed by lower-than-normal yields at the following harvest and vice versa. This signal is rather robust and withstands rigorous significance testing. Moreover, it appears that the relationship between the SO1 and the sugarcane yields has been relatively strong and stable for the past 40 years, but weakened substantially during the 1930-1940 period.
Short-term effects of tillage and stubble management on earthworm populations in cropping systems in southern New South Wales
Authors: Doube BM , Buckerfield JC , Kirkegaard JA
Published: November 2005

The effects of tillage and stubble management on the population distribution of earthworms were examined under wheat on a red-earth soil at Harden and under canola on a red-brown earth at Temora in the wheatbelt of southern New South Wales. At Harden, a five-year pasture had been followed by a conventionally cultivated oat crop in the year before the experiment. At Temora, a six-year pasture immediately preceded the experiment. Tillage treatments at Temora, and tillage and stubble treatments at Harden, were established during February-May 1990 and earthworm populations were measured in September. A number of earthworm species (Aporrectodea trapezoides, Microscolex dubius and M. phosphoreus) were present at both localities, but the introduced species A. trapezoides made up 97-99% of the earthworms collected. Earthworms were substantially more abundant at Temora (425 m-2) than at Harden (122 m-2). At Temora there was no effect of the intensity of tillage (4, 1 or 0 passes prior to sowing) on earthworm numbers. Earthworm densities were reduced in waterlogged soil. At Harden the direct-drill (DD) plots had a greater population density and biomass of earthworms and cocoons than the tilled plots. The size (mean weight) of adult earthworms, and the number of cocoons per adult, were also greater in the DD plots. However, no differences in earthworm populations were detected between minimum tillage (one cultivation prior to sowing) and stubble incorporation (three cultivations prior to sowing). On DD plots, burning stubble resulted in significantly smaller adult earthworms, a lower density of cocoons and a lower mean number of cocoons per adult than in the unburnt plots, but the differences in numerical abundance and in biomass were not statistically significant. Similarly, plots which had standing stubble contained fewer and smaller adults than those in which stubble was bashed and in close contact with the soil. There was a strong positive correlation between earthworm biomass and the amount of stubble present on the surface of the plots at the beginning of the winter (r2 = 0.64, P < 0 01). The contrasting effects of tillage at the two sites and the impact of stubble management on earthworms are discussed in terms of the effects of recent paddock history and management practices on the amount, quality and distribution of suitable organic food for earthworms. The influence of these factors is reflected in the number, biomass and reproductive performance of the earthworms.
Irrigation of bananas with secondary treated sewage effluent. I. Field evaluation of effect on plant nutrients and additional elements in leaf, pulp and soil
Authors: Johns GG , McConchie DM
Published: November 2005

The effects of irrigating banana plants in the field with secondary treated sewage effluent were examined, using plots watered with sprinklers and drippers at a site on the north coast of N.S.W. A total of 1030 mm of effluent was applied over 19 months during which rainfall totalled 3231 mm. Water budget calculations indicated that c. 57% of the irrigation applied would have been lost as profile overflow, and only c. 43% transpired. An 84 year water budget indicated that profile overflow could average 751 mm/year without irrigation, and 929 mm/year if irrigated according to a slightly drier schedule than used in this study. Compared to typical characteristics of secondary treated effluent, the material used in this study was towards the dilute extreme of the normal range, and failed to supply the plants' requirements for most nutrients. Soil sodium increased by up to 5 x on the effluent plots during the trial, and remained at double the control level at the end. Exchangeable sodium percentage (ESP) values reached 4% during the trial, and remained at 2.5% at the end. No other soil parameters were affected substantially. Size of mature banana plants and number of bunches produced were not measurably affected by irrigation with effluent. The only plant chemistry parameter affected was leaf lamina boron concentration, which increased by almost 100% at times during the trial, and remained significantly elevated at the end. A possible hazard from irrigating with the effluent used may be the displacement from the profile of other cations by sodium. A separate lysimeter trial is underway to check for such an effect. Heavy metal and trace element concentrations in the effluent were such that it could take between 270 and 5000 years to exceed recommended cumulative loading limits if effluent use was appropriate to crop water requirements.
Irrigation of bananas with secondary treated sewage effluent. II. Effect on plant nutrients, additional elements and pesticide residues in plants, soil and leachate using drainage lysimeters
Authors: Johns GG , McConchie DM
Published: November 2005

The effects of irrigating banana plants with secondary treated sewage effluent were examined using lysimeters at Woolgoolga, N.S.W. Lysimeters were sheltered from rain so that they received only effluent or tap water without substantial leaching occurring. Total application was c. 4700 mm over c. 30 months, equivalent to about 8 years field requirements for supplementary irrigation. At the end of the growth period, plants and soils were analysed for a wide range of chemical parameters. Soil profiles were then leached and the collected leachate was also analysed. Irrigation with effluent had no effect on plant size. Plants watered with effluent contained 225% more sodium, 81% more boron, 43% more copper, 26% more chloride, and about 16% more nitrogen, phosphorus, potassium and magnesium than plants watered with tap water. Soils watered with effluent accumulated more phosphorus, sulfate, chloride, calcium and sodium than soils watered with tap water. Phosphorus sorption results indicated that it would take over 200 years of supplementary watering with effluent to saturate the profile with P. Leachate collected after the growth period from lysimeters watered with effluent contained negligible phosphorus, but considerable sodium, chloride, sulfate, and magnesium. There was no evidence of sodium in effluent displacing calcium from the profile. The high concentration of magnesium in leachate from both treatments indicated that magnesium was displaced by the high levels of potassium fertilizer applied to ensure adequacy for growth of banana plants. Boron concentrations in the leachate indicated that boron would not accumulate in the profile under natural rainfall conditions. Other trace elements were also most unlikely to accumulate to problem levels. Pesticide residue testing of banana pulp, soils and leachate indicated minimal likelihood of problems associated with such residues in local effluent. It was concluded that supplementary irrigation of bananas with the effluent tested was unlikely to cause any problems with either soil or plant chemistry, given the considerable surplus of rainfall which occurs locally in most autumns.
Evaluation of advanced industry breeding schemes for Australian beef cattle. I. Method of evaluation and analysis for an example population structure
Authors: Nitter G , Graser HU , Barwick SA
Published: November 2005

A method is presented for evaluating industry breeding schemes for Australian beef cattle. Multitrait selection is considered. The criteria of evaluation are the annual genetic gains in the breeding objective and its component traits, and the net present value of the return from investment in the scheme. The main methods employed by the PC computer program ZPLAN, developed to facilitate such evaluations, are described and are applied to an example population. A deterministic approach is taken to the prediction of annual genetic gain. Various selection groups are defined in the population, each with particular information sources for index selection, and allowing also for two-stage selection. Gene flow methods are applied to assess the discounted return from investment in one round of selection over a defined investment period. The associated fixed and variable costs are calculated, and used to derive the net present value, or profit, from the selection. An example population with a breeding unit of 10000 cows, supplying bulls to a total population of 200000 cows, is envisaged. Seventy percent of the cows in commercial herds are assumed to be mated by bulls derived from the breeding unit. Genetic and biological/technical parameters required by the program are presented. Criteria considered to be available for use in selection are weights at birth and at 200, 400 and 600 days of age. Results are given for individual selection groups and for the whole population. The annual genetic response in the breeding objective ($1.43) comprised $2.21 gain in growth traits (sale weight direct and maternal), $0.37 gain in reproduction traits (cow survival and weaning rates and bull fertility), $0.06 loss in carcass traits (dressing and saleable meat percentages and fat depth), a $1.00 increase in the cost of maintaining cows and a $0.09 loss for increased calving difficulty. The return, cost and profit per cow in the population from one round of genetic selection using the available growth measures was $8.14, $1.34 and $6.81, respectively.
Evaluation of advanced industry breeding schemes for Australian beef cattle. II. Selection on combinations of growth, reproduction and carcase criteria
Authors: Graser HU , Nitter G , Barwick SA
Published: November 2005

Eight beef breeding schemes, requiring different levels of performance recording of young cattle, were evaluated for their genetic gains and economic parameters: costs, return and profit. A population 20 times the size of the breeding unit was assumed. Schemes which utilized performance recording beyond traditional weight measurements were more profitable. The fertility measures, days to calving and scrotal circumference, were the most cost effective additional selection criteria. For the fertility measures, costs increased by $0.90 per cow in the breeding unit, while profit per cow in the total population increased by $2.17. More intensive performance recording lead to a more balanced genetic gain, especially in carcase and fertility traits. Mature weight is expected to increase in all schemes evaluated, with a consequent negative effect on the $ gain.
Wool prices and sheep breeding objectives - a historical perspective
Authors: Cottle DJ
Published: November 2005

An analysis of weekly wool prices for different fibre diameter market indicators from 1950 to 1993 was conducted to determine appropriate economic values for the calculation of sheep selection indices. An important determinant of breeding objectives and selection indices is the percentage increase in the value of wool for each 1 8m reduction in fibre diameter, termed index percentage (IP). From 1950 to 1981 the appropriate IP value for fine (20 8m), medium (21 8m) and strong (23 8m) wool Merinos was 5%. From 1981 to 1993 the mean weekly IP values for fine, medium and strong wool Merinos were about 20, 15 and 8% respectively. The 5 year moving average IP values in 1993 for fine, medium and strong wool Merinos were 25, 20 and 8% respectively. The distributions of weekly wool prices and IP values are not normal and are positively skewed. Therefore, a safer, more conservative approach is to calculate the median weekly IP values for any period or to use median weekly wool prices to calculate IP values. The median weekly IP values for 1981-1993 were 20, 11 and 8% for fine, medium and strong Merino wools respectively. Thus recently there has been a larger relative premium for fibre fineness which could be a permanent trend. Selection efficiencies for clean fleece weight and fibre diameter in fine and strong wool Merinos are predicted to be at least 90% when 10% and 5% indices are used respectively. Selection efficiency in medium wool Merinos when a 5% index is used is only 79% if the 'true' IP is 15%, or 90% if the 'true' IP is 10%. The 10% and 5% indices are currently calculated and made available to the ram owners who participate respectively in the N.S.W. Merino fine and medium wool sire evaluation schemes. It is suggested that there is a case for using indices with higher fibre diameter premiums (i.e. 20% and 10% respectively), than those currently provided in the fine and medium wool schemes.
Selenium concentration in the blood of ruminants grazing in northern New South Wales. 4. Relationship with tissue concentrations and wool production of Merino sheep
Authors: Langlands JP , Donald GE , Bowles JE , Smith AJ
Published: November 2005

Relationships between selenium (Se) concentrations in blood and tissues, and between Se in blood or plasma and wool production were examined in fine-wool Merino ewes. Flock 1 contained 136 ewes, none of which were mated, and flock 2 contained 93 ewes which reared a lamb to weaning and 27 ewes which failed to lamb. Both flocks grazed Se deficient pastures, and were supplemented with varying quantities of sodium selenate given by mouth as aqueous solutions at 14-day intervals. Ewes in flock 1 were allocated to 17 and in flock 2 to 7 supplementation treatments, the range being from 0 to 8 mg Se/l4 days in both flocks. Wool production was measured before treatments were imposed, and for 2 years for flock 1 and 1 year for flock 2 after treatments were imposed. Samples of blood and plasma were taken at 3-monthly intervals from all sheep during the period of supplementation, and samples of liver, kidney and diaphragm were taken at the end of the experiment from sheep in flock 1; all samples were analysed for Se. Relationships between Se concentrations in blood, plasma or tissues and the quantity of supplementary Se given approached an asymptote at higher levels of supplementation, indicating that absorption or ultilization of Se were impaired at these levels; there was no evidence of clinical or subclinical toxicity. The asymptote was reduced in ewes which reared a lamb. Wool production generally increased when small quantities of supplementary Se were given, but there was no further response at higher levels, the greatest response of approximately 10% was observed in ewes which reared a lamb to weaning. Relationships between wool production, and blood, plasma and tissue Se concentrations were derived using a bent stick model which predicted that ewes would respond to supplementary Se when blood Se concentration was <O.022 to <0.076 8g Se/mL in the different groups; the higher values were observed in ewes rearing a lamb to weaning. The corresponding range in plasma was <0.014 to <0.044 8g Se/mL. It is suggested that Se concentrations <0.070 and <0.040 8g Se/mL in blood and plasma respectively indicate breeding ewes may respond to supplementation and could be used as guidelines for extension purposes; corresponding values for non-breeding sheep were <0.040 and <0.020 8g Se/mL respectively.
Influence of dietary intake and genetic capacity for wool growth on the composition of mid-trunk skin of Merino sheep
Authors: Williams AJ , Williams AJ , Morley FC , Morley FC
Published: November 2005

Some nitrogenous constituents in the skin were examined in sheep from two flocks with different genetic capacities for wool growth and in sheep consuming different diets. In the first comparison, in which the sheep consumed a maintenance (1 x M) ration, the average water, lipid and nitrogen contents of skin were similar for the two flocks. The collagen content of skin from sheep with low wool growth (Fl-) was greater than that in skin of high producers (I?]+)-0.40 v. 0.36 g g-1 dry defatted skin (P < 0.05). The F1+ sheep also maintained lower concentrations of non-peptide cystine in plasma (51 v. 68 8mol L-l: P < 0.05) and in skin (1.1 v. 1.9 8mol g-l dry defatted skin: P < 0.05). In a second experiment, sheep bred from the two flocks (Fl+ and F1-), consumed rations providing either 0.8 x M or 2 x M (the latter diet containing 12.5% formaldehyde treated casein). Trephine-sampled skin from the high producing sheep and from the sheep with greater intake had lower concentrations of collagen per unit mass of skin (P < 0.05), but similar collagen per unit area of skin. Both diet and flock influenced the weight of skin sampled by trephine. The distribution ratios of non-peptide a-amino nitrogen and of cystine between skin and plasma were significantly greater in the F1+ derived sheep: 4.35 v. 3.1 L plasma kg-1 skin for cystine. In a third comparison, skin was sampled from sheep of an unselected flock (n = 50) after each received one of four dietary treatments ranging from 0.7 x M to 2.6 x M (ad lib.) for 60 days. As the dietary allowance increased, the weight of skin per unit area of skin increased, the quantities of total protein and of saponifiable lipid per unit mass of dry skin remained constant, but the content of hydroxyproline significantly decreased from 0.20 to 0.13 mmol g-l dry skin (P < 0.05). The quantities of non-collagenous protein solubilized by first sodium chloride (0.5 mol L-l) and then tartaric acid (0.1 mol L-l) per unit mass of collagen increased significantly with increased intake of feed.
Persian clover and maize silage. I. Silage as a supplement for lactating dairy cows offered herbage of different quality
Authors: Stockdale CR
Published: November 2005

A penfeeding experiment, involving 29 lactating dairy cows, was undertaken to assess the use of Persian clover (Trifolium resupinaturn) herbage instead of perennial ryegrass (Lolium perenne)-dominant herbage as the basal ration in diets in which maize silage (0 to 10.6 kg DM/cow day-1) was used as a supplement. This was supported by a second experiment in which 16 cows grazed limited amounts of Persian clover pasture (herbage allowance of 16.5 kg DM/cow day-1) and were supplemented with various amounts of maize silage (0 to 8.3 kg DM/cow daym-1). In the pen experiment, feeding maize silage to cows grossly underfed with perennial ryegrass pasture resulted in a marginal response to additional feeding of 0.9 kg milk for each of the first 5 kg DM of supplement eaten. This level of supplementary feeding constituted about 40% of the diet. Thereafter, maize silage resulted in virtually no additional milk and the best fed cows only produced about 20 kg of milk. A much greater response in milk yield (1.4 kg milk/kg DM of additional maize silage eaten) was obtained when Persian clover was substituted as the basal ration. There were no differences in milk composition or changes in body condition between cows offered the different basal herbages. Milk fat content averaged 3.9% across all cows, while milk protein content and change in body condition increased by 0.03% and 0.13 units for each additional kg DM of maize silage eaten each day. In the grazing experiment, when a small amount of maize silage was fed to the cows, the marginal return was 1.2 kg milk for each additional kg DM of maize silage eaten. This is only slightly lower than that reported for the indoor feeding study. A major reason for the good response was the negligible substitution of maize silage for Persian clover that occurred with the first increment of supplement in the diet. With higher levels of maize silage feeding, no extra milk was produced. It was the increase in the level of substitution at the higher levels of maize silage that eliminated the possibility of additional responses in milk production.
Persian clover and maize silage. II. Effects of variations in clover and silage consumption on the productivity of dairy cows at various stages of lactation
Authors: Stockdale CR
Published: November 2005

Four experiments, involving 62 animals, were undertaken to establish the effects of variations in Persian clover (Trifolium resupinaturn) and maize (Zea mays) silage consumption on the productivity of dairy cows at various stages of lactation. The research was specifically designed to exclude the effects of the substitution of one feed for another on the responses obtained. Feeding maize silage to cows fed 7-8 kg DM day-1 of Persian clover in early lactation resulted in marginal responses of 1.3-1.4 kg of milk per kg DM of supplement. As level of feeding increased, whether due to additional Persian clover or maize silage, returns to maize silage diminished. In late lactation, 0.9 kg of extra milk was produced from each additional kg DM of maize silage eaten. All of these responses were greater than expected and approached those reported for the use of high energy concentrates. However, there were two exceptions to this general conclusion. Firstly, at very low levels of Persian clover (4.0 kg DM/cow day-1), a protein deficiency prevented responses in milk as more maize silage was offered. Secondly, it was demonstrated that maize silage starch was also important to achieving good responses in milk yield. With only 5% grain in the maize silage in one experiment in mid lactation, the return to extra feeding was only 0.7 kg of milk/kg DM, which was below that obtained in both early and late lactation. The relationships of rumen parameters to differential feeding were variable. Ammonia concentration and acetate proportion both decreased as maize silage intake increased. Of the faecal variables measured, nitrogen concentrations were variable while lignin concentrations were negatively related to maize silage intake, and starch contents showed strong positive correlations.
Persian clover and maize silage. III. Rumen fermentation and balance of nutrients when clover and silage are fed to lactating dairy cows
Authors: Stockdale CR
Published: November 2005

Six rumen fistulated dairy cows, at various stages of lactation, were housed in metabolism stalls on a total of nine occasions in three experiments in which various combinations of Persian clover (Trifolium resupinatum) and maize (Zea mays) silage were offered. These experiments considered some aspects of digestion of Persian clover and Persian clover/maize silage diets in order to understand the good milk yield responses attributed to maize silage measured in previous research. Rumen ammonia concentrations and nylon bag degradation rates suggested that the cows made better use of one or both feeds when Persian clover and maize silage were offered together than they did when Persian clover was offered alone. While Persian clover and maize silage appeared to be a substantially inferior diet in terms of apparent in vivo digestibility coefficients and availability of nutrients when compared with Persian clover offered alone, milk yields were unaffected. In addition, no matter how much maize silage was offered, milk fat content remained constant. These results were attributed to an improved balance of absorbed nutrients.
Dung burial by native and introduced dung beetles (Scarabaeidae)
Authors: Tyndale-Biscoe M
Published: November 2005

The quantity of dung buried and shredded by dung beetles at four sites in south-eastern Australia was found to be positively correlated with the dry weight (biomass) of beetles in the pads. Each of the four sites has two abundant native species of dung beetles, and one to five well-established introduced species present. At Uriarra, where only one introduced species is common, a mean of 7 . 2 l � 1.94% (1990-91) and 6.01�1.31% (1991-92) of the dung was buried per week. At Fyshwick, with two common introduced species of dung beetles, 22.27� 4.03% (1990-91) and 12 04�2 72% (1991-92) of the dung was buried per week. Braidwood, with four introduced species, had a mean of 15.81� 2.82% (1991-92) weekly dung buried, and Araluen, with five introduced species, had 30.18�8- 73% (1992-93) dung buried per week. Dung beetle numbers were low at all sites during the first half of 1991-92 season due to a drought throughout the region. Dung shredding averaged less than 12% over the seasons at all sites, but fluctuated from 0 to 70%, depending mainly on beetle numbers in the dung pads on individual occasions. Increasing numbers of exotic dung beetles throughout the pastoral areas of Australia should result in increased amounts of dung buried and shredded, with correspondingly increased benefits to Australian agriculture.
Effect of redefoliation on the regrowth and water soluble carbohydrate content of Lolium perenne
Authors: Fulkerson WJ
Published: November 2005

Plants of Lolium perenne, set up in a minisward in a glasshouse, were redefoliated at 3, 6 or 3 plus 6 days after defoliation at 2 or 5 cm stubble height. Regrowth, water soluble carbohydrate (WSC) content, and tillers per plant and tiller weight were measured. At the extreme, 70% of plants died when they were defoliated at 2 cm stubble height and redefoliated at 3 plus 6 days later. The mean total regrowth at the 3 leaves per tiller stage (and including the DM yield at each redefoliation) of the surviving plants was 4% of plants not defoliated and cut to the same stubble height. Redefoliation had a less marked effect on plants cut at 5 cm stubble height, reducing total regrowth by 55, 78 and 95%, for plants redefoliated at 3, 6 or 3 plus 6 days, respectively. There was a very significant relationship between tillers per plant and stubble WSC (mglplant) (Adj r2 = 0.90; P = 0.001) or stubble DM (g/plant) (Adj r2 = 0.89; P = 0.001) at the 1+ a leaf stage of regrowth on DM yields at the 3 stage of the regrowth cycle. These results confirm the dramatic effect of redefoliation on regrowth of ryegrass plants, and support the recommendation that grazing duration in the field be restricted to less than 3 days to prevent stock regrazing new leaf.
Seasonal nutrient intake and phosphorus kinetics of grazing steers in northern Australia
Authors: Hendricksen RE , Ternouth JH , Punter LD
Published: November 2005

The growth of Bos indicus cross-steers grazing native grass and native grass-legume (Stylosanthes scabra cv. Seca) pastures was monitored for 392 days in five unreplicated experimental paddocks, each grazed by three steers. Two phosphorus (P) fertilizer rates: F1, 4-5 kgP/ha every 2 years and F2, 9.0 kgP/ha annually, together with an unfertilized control, FO, were studied. P supplement was supplied to cattle in two additional paddocks (FOS and F1S) at the rate of 5 gP/ha/day-l. In the dry, wet and late wet seasons, pasture yield and pasture component yield were measured. At the same time, the nutrient intake and P kinetics of resident steers were measured using chromic oxide capsules and intravenous injections of 32P . Additional non-resident steers, fistulated at the oesophagus, grazed the pastures intermittently to provide estimates of dry matter digestibility, fibre, nitrogen (N) and P content of the selected diet. Phosphorus fertilizer increased legume and native grass growth which resulted in more dry matter containing higher concentrations of P and N than unfertilized pastures. Both P fertilizer and supplement increased dry matter intake and liveweight gain of cattle. During the experimental period of 13 months, steers which grazed pastures that received the (F2) fertilizer treatment gained on average 0.43 kg/day compared with 0.19 kg/day for those which grazed unfertilized FO pastures. Supplementation increased wet season liveweight gain from 0.45 to 0.59 kg/day and 0.46 to 0.73 kg/day for FO and F1 treatments respectively. Only cattle which grazed pastures that received the F1S and F2 treatments gained weight in the dry season. Nitrogen was the primary nutrient limiting cattle growth from unfertilized pastures in the dry season, but when pastures were fertilized (4.5 kgP/ha every 2 years) and legumes established, P was the primary limiting nutrient. Intakes of P ranged from 7 to 35 mg/kg LW and were lower than those recommended by recognized authorities for the steer growth rates we recorded. Both the absorption and faecal excretion of dietary P were closely related to P intake. Endogenous faecal P values varied with P intake in the range 9-22 mg/kg liveweight. Endogenous faecal P was also related to dry matter intake and plasma inorganic P. The coefficient of P absorption was lowest (0.65) for steers grazing unfertilized native pasture (FO), but increased with P intake to 0.85 for steers grazing the F1S treatment. We conclude that the P requirements of growing cattle grazing native grass and native grass-legume pastures in northern Australia are about half those recommended by most authorities.
The growth of phosphorus kinetics of steers grazing a subtropical pasture
Authors: McLean RW , Ternouth JH
Published: November 2005

The growth and nutrient balances of steers grazing predominantly buffel (Cenchrus ciliaris) grass pastures fertilized with phosphorus (P) at annual rates of 0, 2.5, 5 and 15 kg P ha-1 were studied in three different seasons. There were two additional treatments in which steers grazing the 0 and 2.5 kg P ha-1 treatments were supplied daily with phosphorus supplement at 5 g head-1 throughout the study. Liveweight gain was increased by P fertilization but not P supplementation. Over a period of 15 months, the steers grazing the 15 kg P ha-1 pastures gained 80 kg more than those on the unfertilized pastures. This was associated with a small increase in dry matter intake and larger increases in P and nitrogen (N) intakes. Generally, the apparent absorptions of N, P and calcium by the steers were positive. In each season, the P intake, dietary faecal P and endogenous faecal P were all higher in cattle grazing fertilized pastures. After making allowance for an underestimation of pasture intake, our estimates of P intake were considerably less than published requirements to sustain the liveweight gains recorded. Endogenous faecal P values (13-19 mg kg-1 liveweight) were lower and the efficiency of absorption (mean 76%) was significantly higher so that the P requirements of cattle grazing tropical pastures appear to be much lower than recently published values.
Editorial
Authors: Fegent Jenny
Published: November 2005

The peppermint cultivar Todd's Mitcham forms the basis of a newly
established peppermint oil industry in north-eastern Victoria. In this study
the effects of Puccinia menthae on growth and yield
components of Todd's Mitcham peppermint grown in pots were investigated.
Rust infection significantly (P<0.05) reduced oil content, stolon number,
leaf area, and root, stem, and leaf weights per plant, and increased
defoliation by 67%. There was a negative linear relationship between
oil yield and level of defoliation. Relationships between the amount of
disease, measured as incidence and severity, and levels of defoliation were
linear and logarithmic, respectively. The impact of disease on various
components of growth and yield is discussed.
Editorial
Authors: Fegent Jenny , Banerjee Saumitra
Published: November 2005

IsaBrown pullets were obtained from a commercial breeder at 15 (Expt 1) and 16
(Expt 2) weeks of age and housed in either single-bird or multiple 5-bird
cages in a high rise, windowless layer house in which temperatures were
maintained below 30˚C by computerised control of fans and evaporative
cooling pads. In Expt 1, they were fed either a grower diet or a pre-layer
diet consisting of the grower diet containing additional calcium to 18 weeks
of age and then maintained during lay to 56 weeks of age on diets containing
either 160 or 180 g crude protein (CP)/kg. In Expt 2, they were fed the
grower diet to 19 weeks of age and then 1 of 5 diets similar in all
ingredients except that the lysine concentration varied between 7.35 and 8.95
g/kg in increments of 0.4 g/kg. The L-lysine HCl supplements were
added in lieu of solka floc, an inert cellulose supplement.
In Expt 1, mortality was low (2.25%), peak egg production was high
(95–98%), and the mean rate of lay at 56 weeks of age was above
88%. The diet fed prior to lay had no significant effect on production
during lay. Feed intake and egg production were similar for hens fed both
dietary protein levels during lay, and egg weight and egg mass output were
greater for hens fed the diet containing 180 g CP/kg. Hens in
multiple-bird cages ate significantlyless feed for a significantly smaller
daily egg mass output. In Expt 2, increasing the dietary lysine concentration
significantly reduced feed intake and significantly increased lysine intake,
egg shell breaking strength, and albumen height. Multiple-caged hens had a
significantly lower hen-housed egg production as a result of a 7-fold increase
in mortality compared with hens in single cages, due mainly to cannibalism.
The daily lysine requirement formaximum egg production approximated 940 mg for
hens in single cages and 975 mg for hens in multiple-bird cages.
Free space experimental scattering database continuation: experimental set-up and measurement precision
Authors: Geffrin Jean-Michel , Sabouroux Pierre , Eyraud Christelle
Published: November 2005

In the present paper, the experimental set-up of Institut Fresnel used to measure the scattered fields of different elongated objects is precisely described. Since the special issue on ‘Testing inversion algorithms against experimental data’, the modifications of this system, outlined here, have mostly been done to improve the synchronization of the apparatuses and the precision of our measurements. Due to a large number of requests from the inverse problem community, it has been decided to add new measurements to the Institut Fresnel's database. All the new targets presented here are two-dimensional inhomogeneous ones. They are made of different dielectrics or are mixing metal and dielectric parts. Both TE and TM polarizations are measured for each target, from 2 to 10 GHz and even 18 GHz for the most complex target. In the first part of this paper the set-up is described precisely. The second part is devoted to the presentation of the targets. Finally, some TE and TM comparisons of measurements and direct problem simulations are shown to accredit our experimental method and to give an idea of the accuracy of these measurements.
Stereoselective disposition of fluoxetine and norfluoxetine during pregnancy and breast‐feeding
Authors: Kim John , Riggs K. Wayne , Misri Shaila , Kent Nancy , Oberlander Tim F. , Grunau Ruth E. , Fitzgerald Colleen , Rurak Dan W.
Published: November 2005

Aims

To compare the disposition of fluoxetine and norfluoxetine enanantiomers in the mother, foetus and infant.

Methods

Blood from pregnant women taking fluoxetine (n = 9), during pregnancy was sampled in the third trimester and at delivery (maternal and cord venous blood), and from the infants 48 h after delivery. The subset of these women who were breastfeeding, plus additional subjects recruited in the postpartum period, were studied further, and maternal and infant blood, and breast milk was sampled between 6 days and 11 months (n = 23). Drug and metabolite concentrations were measured using gas chromatography/mass spectrometry or liquid chromatography, tandem mass spectrometry.

Results

There was a high correlation between maternal and foetal (cord blood) fluoxetine and norfluoxetine enantiomers (r2−0.9), the mean foetal/maternal ratios (95% confidence intervals) being 0.91 (0.61, 1.02) and 1.04 (0.93, 1.05), for fluoxetine and norfluoxetine, respectively. In 2 day old infants exposed to the drugin utero, the fluoxetine and norfluoxetine plasma concentrations were the same as in cord blood at delivery. Over the next 2 months, the plasma concentrations in the infants fell progressively. Stereoselective disposition of both the drug and metabolite in the mother, foetus, infant and breast milk was observed. The S : R ratios in the foetus and newborn (∼3) were significantly higher than in the serum (∼2) or breast milk (∼1.9) of the mothers, resulting in greater exposure of the foetus and infants to the biologically active enantiomers, particularly S‐norfluoxetine.

Conclusions

Foetal and infant exposure to fluoxetine and norfluoxetine is enhanced by their stereoselective disposition in the mother, foetus, breast milk and infant. Increased exposure may also result from decreased metabolism of the drug in the foetus and neonate.
Lanthanide and trace element mobilization in a lateritic toposequence: inferences from the Kaya laterite in Burkina Faso
Authors: Dequincey O. , Chabaux F. , Leprun J.‐C. , Paquet H. , Clauer N. , Larque P.
Published: November 2005

The geochemical development of laterites, a very common superficial formation in the tropics, is still a matter of debate. To determine the main steps of their formation, and to interpret lateral geochemical variations often observed within laterites, we studied the Kaya ferricrete in northern Burkina Faso by analysing two profiles in contrasting topographic positions. We determined the mineralogy and the composition in major and trace elements of whole rocks and of < 0.2 µm granulometric fractions. The nature and proportion of relictual primary minerals and of secondary clays and Fe‐oxyhydroxides control the distribution of major and soluble trace elements. The distribution patterns of Fe, transition metals, lanthanides, U and Th in the two profiles require (i) an initial accumulation in the top ferruginous horizon during its formation and (ii) a secondary redistribution downwards in the underlying horizons. Lanthanides, Ni and Co were remobilized to a much greater extent than Cu and Sc, whereas Fe, V, Cr and Th accumulated in the ferruginous horizon. The uphill better drained profile showed more intense redistribution than the downhill profile. Uranium in particular is poorly redistributed in the downhill profile, whereas it was redistributed like the lanthanides in the uphill profile. Remobilizations are also more intensely recorded in the fine fractions than in the whole rocks. These results allow us to propose a scenario for the formation of the Kaya laterite that accounts for both vertical and lateral chemical distributions. They also highlight the potential of multimethod geochemical studies to uncover the sequence of evolution of weathering profiles.
Assessment of catch, effort and species changes in the pair‐trawl fishery of southern Lake Malawi, Malawi, Africa
Authors: WEYL O. L. F. , NYASULU T. E. , RUSUWA B.
Published: November 2005

Abstract  Catch per unit effort (CPUE) and species composition in the pair‐trawl fishery in commercial Area A of southern Lake Malawi were assessed from 1991 to 2001. CPUE declined from 1.7 t day−1 in 1995 to 0.5 t day−1 in 2001 and the fishery is considered depleted. In 2000/2002, catch composition differed significantly from a 1991 survey, and was dominated by haplochromine cichlids (92% by weight). Of 98 haplochromine cichlid taxa identified in the catch, 18 contributed ≥1% by weight. The artisanal fishery targeted similar species of a similar size. It was recommended that: (1) renewed investment and increased effort in the pair‐trawl fishery is not advisable; (2) there was a need for effort limitation in Area A and (3) the pair‐trawl fishery should not be managed in isolation of the artisanal fishery.
GIS visualisation and analysis of mobile hydroacoustic fisheries data: a practical example
Authors: COLEY A. R. , CLABBURN P.
Published: November 2005

Abstract  Hydroacoustic remote sensing of fish populations residing in large freshwater bodies has become a widely used and effective monitoring tool. However, easy visualisation of the data and effective analysis is more problematic. The use of GIS‐based interpolations enables easy visualisation of survey data and an analysis tool for investigating fish populations. Three years of hydroacoustic surveys of Cardiff Bay in South Wales presented an opportunity to develop analysis and visualisation techniques. Inverse distance weighted (IDW) interpolation was used to show the potential of such techniques in analysing survey data both spatially (1‐year survey) and temporally (by looking at the spatial changes between years). IDW was fairly successful in visualising the hydroacoustic data for Cardiff Bay. However, other techniques may improve on this initial work and provide improved analysis, total density estimates and statistically derived estimations of prediction error.
A review of management for fish and bitterns, Botaurus stellaris, in wetland reserves
Authors: SELF M.
Published: November 2005

Abstract  The bittern, Botaurus stellaris L., is a cryptic, fish‐eating, reedbed bird that was once widespread and common across the UK. It became extinct in 1886, only to return two decades later. After increasing to a peak of 80 booming males in 1954, the population declined to only 11 in 1997, and a second extinction in the UK seemed likely. In conjunction with partner organisations, the Royal Society for the Protection of Birds has undertaken research to determine the food and habitat needs of bitterns to support a major programme of work to reverse the fortunes of bitterns in the UK. Existing sites have been managed to increase populations of key prey species, notably European eel, Anguilla anguilla (L.) and rudd, Scardinius erythrophthalmus (L.), by increasing access into reedbeds along expanded gently‐shelving littoral zones, and by addressing issues relating to connectivity, water quality, zooplankton and macrophytes. Degraded sites have been also rehabilitated and new sites created. The project was successful, with an increase to 55 booming males in 2004, exceeding the target 6 years ahead of schedule. The reedbed works also benefited a wide range of other wetland species.
The eel fishery in Lough Neagh, Northern Ireland – an example of sustainable management?
Authors: ROSELL R. , EVANS D. , ALLEN M.
Published: November 2005

Abstract  Lough Neagh produces over 500 t of grown eel annually and employs 300 people fishing yellow and silver eel. Glass eel are transported upstream and stocked into the Lough. Since glass eel returns crashed in the 1980s, additional glass eel seed has been purchased from other fisheries. The fishery now faces ecological, social and economic pressures. Prices for the product have fallen; recruitment to the fishery has declined, and seed has decreased in availability and increased in price. Fishers are less inclined to take up the hard work required to make a living fishing eel and the fisher population is ageing. The European Commission has recognised the decline of eel and proposed emergency measures, which may further affect the viability of the fishery. The sustainability of the fishery is examined, based on the relationship between glass eel input and grown eel outputs over a period of 45 years, set against increasing environmental, socio‐economic, and natural resource pressures. Spawning escapement of silver eel is estimated by mark–recapture experiments.
Assessing the value of recreational sea angling in South West England
Authors: LAWRENCE K. S.
Published: November 2005

Abstract  A choice experiment was developed to assess how the value of the recreational sea angling experience in South West England would change as characteristics of the angling experience changed. Catch levels of anglers’ favourite species are extremely important, until they reach around six fish per day, at which point anglers become satiated. Anglers are discerning about the species they catch – they would pay only a third as much for increased catches of non‐favourite species than for the favourite species. Overall, increasing the size of individual fish would have a larger impact than increasing the catch per day, although this varies by species. In contrast, the presence or absence of rod or bag limits and the environmental quality of a site are only minor factors in anglers’ decisions on where to fish. These results will help fisheries managers to identify their goals with respect to sea angling.
Fish utilisation of managed realignments
Authors: COLCLOUGH S. , FONSECA L. , ASTLEY T. , THOMAS K. , WATTS W.
Published: November 2005

Abstract  One area of ecological benefit not yet fully evaluated in European waters is the utilisation of restored saltmarsh habitats by fish species. This study examines the utilisation of managed realignments and relic saltmarsh by fish species. Factors affecting habitat heterogeneity and fish populations are discussed, and recommendations are made with respect to scheme design and management that will maximise the biological and socio‐economic values. Fish populations in the high intertidal areas were assessed using a suite of techniques, including observations on feeding behaviour. Each microhabitat was discussed as a function of the extent of fish colonisation. A positive relationship between the degree of fish utilisation and habitat heterogeneity was ascertained using species richness, abundance and behavioural observations. This study will aid habitat valuation for economic justification of managed realignments, over and above existing drivers, such as compensatory habitat for encroachment, flood defence and the European Union Habitats Directive. The work now forms part of a wider European Interreg IIIb project, COMCOAST.
Hot springs, thermal springs and warm springs. What's the difference?
Authors: Pentecost Allan
Published: November 2005

Springs rising with water temperatures well above ambient have a fascination borne out of curiosity, spectacle and sometimes a need to understand the origins of the groundwater and its composition. While hot springs bring to mind boiling waters, explosive emissions of steam and volcanism, many exit temperatures are far lower than the boiling point of water, yet remain elevated above the mean air temperature or those of other springs in the surrounding country. This has led to some confusion in naming these springs. When does a hot spring cease to be hot?
The flooding of New Orleans
Authors: Waltham Tony
Published: November 2005

With its man‐made defences, New Orleans is at best only a marginally stable city, and it was destined to suffer as more powerful natural processes evolved. The aftermath of the August 2005 hurricane was the disaster that had been waiting to happen.