bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of grazing intensity and number of grazings on herbage production and seed yields of Trifolium subterraneum, Medicago murex, and Ornithopus compressus
Authors: Conlan DJ , Dear BS , Coombes NE
Published: March 2005

The impact of grazing intensity and number of grazings was assessed on the growth and seed production of 5 annual pasture legumes [Trifoliunz subterraneum var. subterraneum cv. Karridale, var. brachycalycinum cv. Clare, var. yanninicum cv. Trikkala; Medicago murex (murex medic) cv. Zodiac; Ornithopus compressus L. (yellow serradella) cv. Avila]. There were 7 grazing treatments: an ungrazed control; and 2 grazing intensities (light and heavy), each for 3 periods of grazing (winter, winter-early spring, winter-late spring). Tethered sheep in small experimental plots were used to provide controlled herbage removal across all cultivars through winter and winter-spring grazing. This grazing system resulted in significantly different levels of herbage being present in the light and heavy grazing treatments following each grazing period. Grazing had variable effects on seed production: <35% increase for Trikkala, and no significant effect for Karridale. Both cultivars continued growth and seed production late in the season after grazing pressure was removed on 8 November. Seed yield of Clare was reduced by 46-49% by heavy grazing treatments. Seed yield of murex medic was not significantly affected by grazing, while that of serradella was reduced by 30-55% by grazing late in the season. The seed yield responses show that cultivar and species responses to grazing may be highly variable. Under favourable spring conditions, Trikkala, Karridale, and murex medic can be grazed heavily until late in the season without adversely affecting seed yield, whilst Clare and Avila cannot.
Influence of defoliation on some aspects of regrowth and senescence of Persian clover herbage grown in pots
Authors: Stockdale CR
Published: March 2005

This experiment investigated the effects of defoliation management of Persian clover (Trifolium resupinatum) on herbage production, and in particular, regrowth and losses of production due to senescence. Three heights of defoliation of Persian clover (0, 5, 10 cm above soil level) were superimposed on 3 frequencies of defoliation (4, 6, 12 weeks between harvests until early October; 3, 4.5, 9 weeks subsequently) in a completely randomised pot experiment with 3 replicates. Defoliation management had a large effect on yield of harvested herbage, in agreement with earlier studies with Persian clover in mixed swards or as a monoculture in the field. The amount of herbage that grew below defoliation height and subsequently died was 0-21% of the total herbage grown. The amount of dead and dying matter in herbage above and below defoliation height increased as both defoliation height and interval increased. This represented up to 61% of the total herbage grown. Aspects of regrowth (leaf area, petiole number, petiole extension rate, yield of herbage during growth, biomass of root relative to shoot) were measured. Except at very long defoliation intervals, vegetative growth of Persian clover herbage was positively associated with all of the above variables. The pattern of change with time in the rate of green herbage accumulation following defoliation reflected the balance between changes in the growth of new plant tissue and the loss of mature tissue to senescence and decomposition.
Increased calcium concentration in narrow-leafed lupin epidermal tissue reduces infection by Diaporthe toxica
Authors: Williamson PM , Sivasithamparam K , Cowling WA
Published: March 2005

This study examines the effect of calcium (Ca) supply on infection of narrow-leafed lupins (Lupinus angustifolius) by Diaporthe toxica the cause of lupinosis in animals. Susceptible cv. Yandee and resistant breeding lines CE2:435 and 75A:258 were grown in solution culture at varying levels of Ca supply. Epidermal Ca concentration increased with increased Ca supply in both resistant and susceptible narrow-leafed lupins. There was an inverse relationship between the concentration of epidermal Ca and the frequency of infection by the fungus.
Evaluation of legumes for introduction into native grass pastures on the North-west slopes of New South Wales
Authors: FitzGerald RD
Published: March 2005

A range of pasture legumes was either broadcast or drilled into native grass pastures on the North-west Slopes of New South Wales to identify legumes that would persist in that environment and improve the quality of winter pastures based on native grasses. There were 2 experiments conducted over 12 sites. In the first, sites were selected to permit identification of effects of altitude and 2 soil types on legume adaptation. In the second, the lower altitude range was extended and a wider range of soil types was sampled. Subterranean clover (Trifolium subterraneum L.) was the most persistent and productive species, with cultivar performance varying with altitude. At the lowest altitude (340 m) the early-maturing cv. Dalkeith was the most productive, and at 500-600 m there was little difference between the tested cultivars. Stand density, herbage yield, and seed yield all declined as altitude increased, but the decline was greater with earlier maturing cultivars than with the later maturing cv. Woogenellup White clover (T. repens cv. Haifa) established poorly in native grass swards, but plants that did establish persisted during favourable seasons at higher altitudes. Herbage yields of woolly pod vetch (Vicia dasycarpa cv. Namoi) and rose clover (T. hirtum cv. Hykon) occasionally exceeded yield of subterranean clover at some lower altitude sites, but those species failed to persist at other sites where grazing management may have been unsuitable. Barrel medic (Medicago truncatula) established satisfactorily but did not persist on the more acidic soils (pH <6.0). Both drilling and broadcasting establishment techniques produced satisfactory legume stands. Legume plant density was generally greater on heavier soils of basaltic origin than on lighter soils of rhyolitic origin.
The effect of cold disinfestation treatment on the quality of Washington navel oranges in Sunraysia
Authors: Edwards M , Predebon S , Dale M , Buchanan G
Published: March 2005

Trials over 2 years were undertaken to determine the effect of cold disinfestation at 1�C on the internal and external quality of Washington navel oranges. Chilling injury in the form of cold scald and rind pitting were significantly increased by cold disinfestation. The incidence and severity of chilling injury was low (maximum 7% of fruit rejected due to chilling injury), indicating that 16 days storage at 1�C will result in minimal fruit loss due to chilling injury. Extended storage at 10�C after cold disinfestation at 1�C for 16 days increased the severity of the chilling injury symptoms observed. The incidence of postharvest fungal breakdown was high in the second year of the trial and red Altemaria spot was high in the first year. Oleocellosis was present in almost all fruit tested and severe in 75% of the fruit. The overall external quality of the fruit was highly influenced by grower but no correlation between fruit quality and specific management practices could be made. These results indicate that 'in transit' cold disinfestation would be a feasible treatment for export Washington navel oranges but with provisos: that total transit time is kept to a minimum, and that care is taken to minimise postharvest fungal breakdown and incidence of oleocellosis.
Validation of 'Downcast' in the prediction of sporulation-infection periods of Peronospora destructor in the Lockyer Valley.
Authors: Fitz Gerald SM , O'Brien RG
Published: March 2005

The disease forecasting system 'Downcast' was developed in Canada to indicate sporulation-infection periods of Peronospora destructor (Berk.) Caspary in onions. During 1989, observations were made of downy mildew development in trap plants and of disease progress in an unsprayed plot of onions in the Lockyer Valley, Queensland, and related back to predicted sporulation-infection periods using the forecaster. Over 113 days, there were 20 days when sporulation and infection were predicted, and of these 14 occurred during 4 weeks in July and August. Of 16 groups of trap plants exposed in the field, each for 7 days, 7 were subjected to predicted sporulation-infection periods. Two predicted sporulation-infection periods early in the season did not result in infection of trap plants or of plants in the field plot, probably due to absence of inoculum. Subsequently, groups of trap plants exposed in the field during predicted sporulation-infection periods became infected while those exposed when weather was unsuitable remained healthy. 'Downcast' shows promise as a technique for more effective management of disease caused by Peronospora destructor.
Selenium concentrations in tissues of sheep given a subcutaneous injection of barium selenate or sodium selenate
Authors: Archer JA , Judson GJ
Published: March 2005

Young sheep were allocated to 6 treatment groups, each of 8 ewes and 8 wethers. Treatments given were nil, 0.1, or 0.5 mg selenium (Se)/kg body weight as a subcutaneous injection of sodium selenate (Na2SeO4), and 0.8, 1.4, or 2.9 mg Se/kg body weight as a subcutaneous injection of barium selenate (BaSeO4). At 14, 28, 56, and 112 days after treatment, 2 ewes and 2 wethers from each group were slaughtered and samples of blood, liver, kidney, cardiac and skeletal muscle, lymph nodes, and faeces were collected for Se assay. On days 0, 1, 3, 7, 13, 27, and 55 blood and spot faecal samples were taken for Se assay from the 24 sheep selected for slaughter on day 112. In sheep given Na2Se04 there was a rapid but transient increase in the mean Se concentration in tissues, particularly the liver of sheep given the highest dose of Na2SeO4. In these sheep on days 14,28,56, and 112 the respective mean liver concentrations were 169, 62,25, and 6.9 �mol/kg DM: the mean value on day 14 was 15 times the mean value in untreated sheep. In sheep given BaSeO4 there was a gradual increase in mean Se concentration of tissues during the experiment. Faecal Se concentrations increased in sheep given the Se injections. The marked but transient increase in liver Se concentrations in sheep given Na2SeO4 suggests that this organ provides an important protective mechanism against toxicity by readily accumulating and excreting Se into the gut. Our results indicate that the BaSeO4 doses were unlikely to cause Se toxicity in young sheep or result in Se residues in tissues above those recommended for human consumption. The BaSeO4 should be administered subcutaneously in the neck or other sites of the body not sold for human consumption, since deposits of BaSeO4 remain at the site of injection for at least 112 days and may be dangerous if inadvertently consumed.
Evaluation of some factors involved in reducing browsing damage to eucalypt trees by sheep
Authors: Haines PJ , Bell AB , Thatcher LP
Published: March 2005

These experiments evaluated in northeastern Victoria the factors affecting the severity of browsing damage to eucalypts by sheep. We aimed to develop management options for integrating sheep grazing in agroforestry systems. One-year-old tree seedlings were planted into annual pasture and grazed at high stocking rates (44 sheep/ha) for up to 1 week when the pasture was abundant. In experiments 1 and 2, crossbred weaners almost totally defoliated Eucalyptus camaldulensis (river red gum) seedlings after 96 h grazing; damage from older Merino wethers was minimal. Of the 4 eucalypt species tested for relative acceptability or palatability to crossbred weaners, E. camaldulensis was the most heavily browsed and E. globulus spp. bicostata (southern blue gum), least. The height of the pasture immediately surrounding the seedlings, and therefore visibility of the seedling to the sheep, did not affect browsing extent. In experiment 3, potential repellents were applied either on the ground around E. camaldulensis seedlings or sprinkled on the foliage. Six repellants provided short-term protection from crossbred weaner sheep; Replex 1 and 3, and egg and paint were the most effective. After 4 days grazing, seedlings treated with Replex 3 had sustained 24% mean browsing damage compared with 90% for the control.
The developing relationship between Stylosanthes and anthracnose after 14 years in a North Queensland pasture. 3. Diversity in the plant population
Authors: Davis RD , Boland RM , Lisle AT
Published: March 2005

Host-plant diversity in a mixed accession Stylosanthes spp. pasture 14 years after establishment was demonstrated in families derived from seed and in cuttings obtained from the pasture. Glasshouse examination of the progeny from 181 field plants inoculated with 4 different pathogenicity strains of Colletotrichunz gloeosporioides indicated the widest possible spread of diversity in disease reaction. The progeny exhibited wider variation in resistance to the disease than the originally sown accessions, and when transplanted to a field site, plant phenotypic variability became increasingly evident as the progenies matured. Of 1339 transplanted progeny, 369 were not able to be conclusively categorised according to the descriptions of the originally sown accessions, indicating that outcrossing had occurred. The demonstrated plant variability is, arguably, encouraging for the management of anthracnose using genotype mixtures in the vast areas of low-input beef pastures in northern Australia.
Methodology for estimating wild oat seed production and the seed bank. - Comment on - 'Effect of crop rotation, tillage practice, and herbicides on the population dynamics of wild oats in wheat', by R.J. Martin and W.L. Felton (Aust. J. Exp. Agric. 1993, 33, 159-65)
Authors: Medd RW
Published: March 2005

No abstract available.
Effect of field peas and wheat on the yield and protein content of subsequent wheat crops grown at several rates of applied nitrogen
Authors: Rowland IC , Mason MG , Pritchard IA , French RJ
Published: March 2005

The responses of wheat to various rates of N fertiliser were compared following field peas (PW) or wheat (WW) in the previous year. Seventeen trials were carried out at 5 sites between 1986 and 1991. The trials were on medium- and fine-textured soils (clay loams or shallow duplex soils). The overall grain yield of PW appeared greater than WW in 11 trials [was significantly greater in 9 (P<0.05)], and did not appear different in 6 trials. When no N was applied the yield advantage of PW was 41% (PW 1.91 t/ha cf. WW 1.37 t/ha). Quadratic response curves were fitted to all yield data. Rotation x N rate interaction was significant (P<0.05) in 10 comparisons. In 5 trials, while there was a yield increase to N fertiliser with WW, the yields decreased with PW. In 3 trials while there was an increase with WW there was no response with PW or a reduction at higher rates of N. In the remaining 2 trials there were responses with both PW and WW, but this was greater for WW. The response curves in these 10 trials either converged and met, indicating that the difference between rotations was due to N availability, or converged but did not meet, indicating that N was important but did not explain the whole difference. Where there was no interaction between rotation and N rate the response curves were parallel. The type of response could not be predicted. It was not profitable to apply N fertiliser to wheat in the PW rotation in 11 of the 17 trials. The average yield advantage of PW over WW, in the absence of N was 540 kg/ha, while there was an average increase of 1.7% grain protein.
The use of the PCR-RAPD technique in improving the plant variety rights description of a new Queensland apple (Malus domestica) cultivar
Authors: Tancred SJ , Zeppa AG , Graham GC
Published: March 2005

A new early maturing Queensland apple cultivar (GB 63-43), has been differentiated from 3 cultivars of similar appearance, Summerdel, Jonathan and Royal Gala with a molecular technique. The Polymerase Chain Reaction and Randomly Amplified Polymorphic DNA procedures have shown the presence of a DNA band of about 700 bp only in the 3 comparator cultivars when the primer M-4 (5' GGCGGTTGTC 3') is used. This distinguishing band can be used to support existing published Plant Variety Rights data with the advantage that trees can be sampled even when dormant or are too young to bear fruit. Additionally, false identification due to variations in tree and fruit characteristics caused by environmental influences is avoided as the techniques directly measure variations in the apple DNA.
Nutritional evaluation of whole plant maize ensiled at three chop lengths and fed to lactating dairy cows
Authors: Stockdale CR , Beavis GW
Published: March 2005

Whole crop maize (Zea mays) was chopped at 3 lengths before ensiling; the maize was harvested with a precision chop harvester with screen apertures of either 9 cm2 (fine chopped maize), 36 cm2 (medium chopped maize), or no screen at all (coarse chopped maize). The 3 silages were each fed as a supplement to pasture to lactating dairy cows in 2 experiments. Although some of the variables measured to assess silage quality suggested that the preservation process may have deteriorated as length of chop increased, length of chop of maize generally appeared to have little effect on silage quality or milk production. In experiment 1, cows ate about 7 kg DM of pasture and 8-9 kg DM of maize silage per day. Mean daily milk yields for the cows offered fine, medium and coarse chopped silage were 18.0, 17.7 and 18.2 kg/cow, respectively. In experiment 2, where daily intakes of each maize silage covered the range of 0-10.7 kg DM/cow, regression analysis could not detect any differences in milk responses between chop lengths. We concluded that aspects other than nutritional considerations should determine the length of chop that farmers aim for when making maize silage; these include ease of compaction in the bunker to ensure the production of good quality silage, and fuel consumption during harvesting.
Assessing Wiltshire Horn-Merino crosses. 3. The 50% Wiltshire Horn as a prime lamb producer
Authors: Rathie KA , Teasdale CK
Published: March 2005

Wiltshire Horn-Merino (WH-M) and Border Leicester-Merino (BL-M) ewes, both with 50% Merino ancestry, were mated in late spring to lamb in 1985 and 1986 to either Dorset Horn (DH) or WH-M rams. Lambs from WH-M sires grew more slowly than lambs from DH sires, by 2 to 13% depending on dam breed and age of lamb. Lambs from WH-M dams grew 3 4 % slower than lambs from BL-M dams in 1985, a year of good pasture and with only DH rams used. In the following year, they grew at a similar rate from birth to weaning if from DH sires, but 11% more slowly if by WH-M sires. From weaning to turnoff, the ranking was reversed, with lambs from WH-M dams growing 11% faster, and sire breed not significant. When mated to DH rams, both the WH-M and BL-M ewes produced lambs with similar dressing percentages and fat depths over the 12th rib. Lambs sired by WH-M rams were leaner than those sired by DH rams, particularly for single-born lambs. The WH-M ewes tended to have a higher percentage of lambs marked per ewe joined than the BL-M ewes, but the advantage was not statistically significant. The difference was mainly due to fewer barren ewes, but the WH-M ewes also showed slightly higher prolificacy. The WH-M ewe shows good fertility and prolificacy, and when mated to a DH ram gives lambs with growth and carcase characteristics very similar to a BL-M identically mated. Mated to a WH-M ram, it gives slower growth but leaner carcases capable of being efficiently grown to heavier liveweights than conventional Australian 3-breed crosses.
Effects of herbicides on wallaby grass (Danthonia spp.). 2. Established plants
Authors: Lodge GM , McMillan MG
Published: March 2005

Three experiments were conducted at Tamworth, New South Wales, in 1990-92 to assess the effects of a range of broadleaf and grass herbicides, 6 rates of glyphosate and paraquat + diquat, and 4 rates of 2,4-D amine and diuron on the phytotoxicity, dry matter yield, inflorescence number, and seed yield of established Danthonia (wallaby grass) plants. Phytotoxicity was scored visually on a 0-5 scale (0, no phytotoxicity; 5, 100%). Danthonia dry matter yields were not affected (P<0.05) by any herbicide tested, except glyphosate applied at 2360 g a.i./ha. Phytotoxicity was highest for the glyphosate treatment (1440 g a.i./ha) in that study. All rates of glyphosate, and paraquat + diquat rates >250 + 150 g a.i./ha reduced (P<0.05) inflorescence number compared with the unsprayed control. Paraquat + diquat had no significant effect on seed yield, but glyphosate rates >360 g a.i./ha reduced (P<0.05) seed yield compared with the control. In 1992, no damage was observed on 2,4-D amine treatments and phytotoxicity scores were low (<2) for all diuron treatments. Danthonia inflorescence numbers and seed yields were higher (P<0.05) on plots mown in early spring than on unmown treatments. The lack of effect of herbicides such as diclofopmethyl, simazine, fenoxaprop-ethyl, and diuron on Danthonia dry matter yield, and the low phytotoxicity, indicated that a range of chemicals may be used on established Danthonia swards to control perennial and annual grass weeds. Seed yield was more affected than dry matter yield by herbicide, and paraquat + diquat should be used in preference to glyphosate on seed crops.
Effect of nitrogen, phosphorus, and potassium on yield and petiolar nutrient concentration of potato (Solanum tuberosum L.) cvv. Kennebec and Atlantic
Authors: Maier NA , Dahlenburg AP , Williams CMJ
Published: March 2005

Data are presented from 3 field experiments that studied the effects of nitrogen (N) up to 360 kg N/ha, phosphorus (P) up to 100 kg P/ha, and potassium (K) up to 480 kg K/ha on tuber yield and the concentration of N, P, and K in petioles of youngest fully expanded leaves (P-YFEL) of potato cvv. Kennebec and Atlantic sampled when the length of the longest tubers was 10-15 mm. Data on the significance of relationships between total N and P, total N and nitrate-N, and chloride and nitrate-N in P-YFEL are also presented. At 1 site, Atlantic yielded 18% higher than Kennebec; at another, it yielded 21% less. Significant K x cv. and N x cv. interactions occurred at some sites. Increasing rates of applied N significantly increased total N concentrations in P-YFEL at all sites and nitrate-N concentrations at sites that were N-deficient. At 1 site, increasing the rate of applied P from nil to 100 kg P/ha significantly increased total N concentration from 2.8 to 3.4%. Total N concentrations in P-YFEL of Atlantic were significantly lower than Kennebec. For total N, there were significant N x K and P x cv. interactions. There was no significant interaction between N, P, and K in their effects on nitrate-N concentration in P-YFEL. At all sites, the application of N and P significantly increased P concentrations in P-YFEL, and mean concentrations were significantly greater in Kennebec than Atlantic. At sites deficient in K, the application of K significantly decreased P concentration. Significant N x cv. and P x cv. interactions occurred at 2 sites. At both K-deficient and non-responsive sites, increasing rates of applied K significantly increased K concentrations in P-YFEL. Differences between cultivars in K concentration were not significant at 2 sites, and although significant at the third, the difference (0.2%) was of little practical importance. At 2 sites, significant N x K and K x P interactions were found. Significant positive linear relationships were found between total N and P concentrations in P-YFEL for both the experimental sites (r = 0.46-0.84) and commercial crops (r = 0.43-0.61). Except at site 1 (r = 0.85), total N and nitrate-N concentrations were not highly correlated. For 1 experimental site and for all the growing regions, there were significant negative linear relationships between nitrate-N and chloride concentrations in P-YFEL (r = -0.38 to -0.83). We suggest that the synergism between total N and P and the negative correlation between nitrate N and chloride are important factors to be considered to ensure reliable interpretation of early-season, petiole plant test data for these nutrients in potato crops; that the critical P and total N concentrations are different for Kennebec and Atlantic; and that when K is not yield-limiting, the main effects and interactions between K and total N, P, or nitrate-N do not confound the use of these nutrients in P-YFEL to assess the P, N, or K status of potato crops.
Temperate rice technology for the 21st century: an Australian example
Authors: McDonald DJ
Published: March 2005

Performance of the New South Wales rice industry is examined in the context of global rice production and demand into the 21st century. The need to double global production of rice by 2030 without major expansion of area will ensure strong export demand from temperate rice growing areas including southern New South Wales. Factors leading to the very high yields now achieved are discussed and the potential for further increasing average yields that are already the highest in the world is explored in terms of maintaining gains already made, raising the yield ceiling closer to the environmental limit, and reducing the gap between potential yield and those achieved by producers. Details are provided of the release and utilisation of varieties from the breeding program, and significant barriers to further yield increase are identified. The importance of 'Ricecheck' (a simple decision support system for farmers) is discussed. Problems of tailoring crop and land use practices to obtain environmental stability while at the same time substantially increasing productivity are highlighted.
Effect of sowing time and nitrogen on rice cultivars of differing growth duration in New South Wales 2. Biomass production and partitioning
Authors: Reinke RF , Lewin LG , Williams RL
Published: March 2005

In New South Wales, rice cultivars with shorter growth duration are sought to reduce water use and to increase the efficiency of rice production. We examined the biomass accumulation of a short-duration cultivar in comparison with 3 long-duration cultivars across a range of sowing time and nitrogen treatments. The biomass accumulation of the short-duration cultivar was smaller than that of the long-duration cultivars, but the yield potential was similar. This was achieved by the production of similar number of florets per m2, despite smaller biomass at flowering, and greater harvest index. Only early-sown treatments resulted in smaller yield of the short-duration cultivar due to restricted biomass accumulation and floret production. A simple biological model of post-anthesis growth, which included the effect of low temperature, predicted growth with an accuracy similar to that of the measurements. The low temperature function assumed growth stopped following a daily minimum temperature below a specified threshold, and the number of days without growth was a function of the severity of the temperature. We concluded that the yield of short-duration cultivars may be less stable when stress occurs during grain filling because there is less biomass at anthesis and, therefore, less reserve available to fill the grain.
Modelling leaching and recharge in a bare transitional red-brown earth ponded with low salinity water in summer
Authors: Cai L , Prathapar SA , Beecher HG
Published: March 2005

A modelling study was conducted to evaluate water and salt movement within a transitional red-brown earth with saline B horizon soil when such waters are used for ponding in summer. The model was calibrated using previously published experimental data. The calibrated model was used to evaluate the effect of depth to watertable, saturated hydraulic conductivity, and ponding water salinity on infiltration, water and salt movement within the soil profile, and recharge. The study showed that when initial soil water content and the saturated hydraulic conductivity (Ks) are low, infiltrating water will be stored within the soil profile even in the absence of a shallow watertable. Once the soil water content is high, however, recharge will be significant in winter, even if there is no net infiltration at the soil surface. Infiltration rates depend more on Ks than the depth to watertable if it is at, or below, 1.5 m from the soil surface. When Ks is high, recharge under ponding will be higher than that under winter fallow. Subsequent ponding in summer and fallow in winter tend to leach salts from the soil profile, the leaching rate dependent on Ks. During winter fallow, due to net evaporation, salts tend to move upwards and concentrate near the soil surface. In the presence of shallow watertables, leached salts tend to concentrate at, or near, the watertable.
Effects of sowing time on growth and grain yield of lupin and field pea in south-eastern New South Wales
Authors: Heenan DP
Published: March 2005

Cultivars of lupin and field pea were grown at different times over 4 years on a red earth at Wagga Wagga, New South Wales, to assess the influence of sowing time on growth and production from each crop. The cultivars of field pea (Pisum sativum) included Dinkum, Derrimut, Dunn, and Maitland; lupins used were Lupinus angustifolius cvv. Danja, Gungurru, and Geebung, and either the L. angustifolius line 75A/330 (1989-90) or L. albus cv. Ultra (1991-92). When autumn rain was sufficient to allow sowing, highest yield and dry matter production of lupin were gained by sowing from late April to 19 May. Yields declined with later sowing, though high spring-summer rainfall in 1992 reversed the decline. There was little difference between Danja, Gungurru, and Geebung, but these were usually higher yielding than the semi-dwarf 75Al330 when sown early. However, Ultra produced higher yields than the L. angustifolius cultivars in 1991 and 1992, particularly under high rainfall conditions. Early-sown crops (late April-mid May) of field peas were often severely infected with black spot blight and, in 1 year, with sclerotinia. In 1992 these diseases devastated all cultivars when sown on 1 May. Sowing later markedly reduced disease infection but also reduced grain yields and dry matter when sown after late June. The semi-leafless, semi-dwarf cultivar Dinkum was usually the lowest yielding and displayed the highest incidence of black spot blight.
Acidification rates in the central wheatbelt of Western Australia. 1. On a deep yellow sand
Authors: Dolling PJ , Porter WM
Published: March 2005

The rate and mechanisms of acidification were determined on a deep yellow sand under a cereal-annual pasture rotation in Western Australia. The rate of acidification was determined from a linear regression analysis between soil pH and years since clearing, using 39 sites that had been cleared for 12-74 years. Uncleared sites were sampled. Soil was sampled to a depth of 80 cm in 10-cm increments. The rate of acidification (kmol H+/ha . year) was calculated from the rate of pH decline, the pH buffer capacity, and bulk density. The rate of acidification 12-74 years since clearing was estimated as 0.19-0.23 kmol H+/ha. year, requiring 10-11 kg CaCO3/ha.year to neutralise. The greatest acidification occurred in the 10-20 and 20-30 cm layers, with acidification occurring to a depth of 80 cm. The rate of pH decline for each depth below 10 cm was 0.007 units/year. The surface soil (0-10 cm) did not acidify. The contribution of potential acidifying processes was estimated using soil measurements and paddock histories. The main cause of acidification appears to be the carbon cycle (grain removal and removal of animal products and waste products to sheep camps), with negligible acidification from the nitrogen cycle. Possible errors in the methodology are discussed.
Nitrogen-containing fertilisers restrict grain intake by cattle
Authors: Hough GM , Sawyer GJ , Coupar FJ , Baker JE , Morris RJ
Published: March 2005

Supplements of barley, a barley-lupin mix (BL), or lupin grain containing urea plus ammonium sulfate (4% + 0.5%, low N; 6% + 1.0%, high N) were offered ad libitum to Holstein-Friesian steers. Supplement intake was restricted by increasing the amount of urea and ammonium sulfate (average intake of 1.7 and 1.4 kg DM/day.100 kg LW for cattle offered low and high N supplements). Supplement intakes were 14-56% greater than predicted from previous studies. Despite the high N content of the diet consumed by steers offered supplements containing lupin (up to 4.8% N with the high N supplement), feed conversion efficiency (FCE) of these cattle was better (P<0.01) than for cattle offered barley supplements (5.3, 5.8, 6.1 kg DM/kg LW gain for lupin, BL, barley). In another experiment, Holstein-Friesian steers offered grain immediately before an ad libitum supplement of barley containing 8% urea consumed 30-50% more grain than those without immediate prior exposure to grain. When the intakes of Holstein-Friesian steers offered ad libitum supplements of either barley or lupin containing either 8% urea or 5.7% diammonium phosphate (DAP) were compared, supplement intakes across grains averaged 1.3 and 0.6 kg DM/day. 100 kg LW. These levels of urea and DAP were predicted to result in similar intakes. However, to achieve a desired level of supplement intake, less DAP was required than urea. Both liveweight gain and FCE were 22-24% greater for cattle offered lupin than those offered barley supplements. Adding urea at 0, 0.5, or 1.0% to a barley supplement containing 4% DAP did not affect supplement or hay intakes by Holstein-Friesian steers, which averaged 0.8 and 1.7 kg DM/day.100 kg LW, respectively. Liveweight gain and FCE were increased by 25% by adding urea to a barley supplement containing DAP. Finally, 3 different methods of introducing a grain supplement containing DAP to Holstein-Friesian steers were compared: a 4-phase, 16-day introductory period; a 2-phase, 7-day introductory period; no introductory period. In steers with and without immediate prior exposure to grain, neither method of introduction nor previous exposure to grain affected supplement intake, liveweight gain, or FCE.
Pasture management influences runoff and soil movement in the semi-arid tropics
Authors: McIvor JG , Williams J , Gardener CJ
Published: March 2005

The influence of pasture management (sowing introduced species, timber treatment, clearing and cultivation, stocking rate) on runoff and soil movement was measured on a neutral red duplex soil at Cardigan, near Charters Towers. Runoff and soil movement were greatest in native woodlands and least in developed pastures, although the differences were often not significant. Runoff and soil movement were related to cover levels on the plots. In small rainfall events (total 4 0 mm and intensity e l 5 mm/h), runoff and soil movement decreased rapidly as cover increased, and only small cover levels (40%) were needed to reduce them to a low level. As the size of the storm increased, greater cover levels were required, and for very large events (total >100 mm and intensity >45 mm/h) cover had no effect on runoff although it still reduced soil movement. On neutral red duplex soils, managers should maintain at least 40% groundcover but this would still allow large losses of suspended sediment in large storms.
Nodulation failure is important in the poor growth of two lupin species on an alkaline soil
Authors: Tang C , Robson AD
Published: March 2005

This study examined the effects of inoculation of Bradyrhizobium sp. (Lupinus) on the nodulation and growth of 2 lupin species on an alkaline soil in the field. Plants of L. angustifolius cv. Gungurru (alkaline-sensitive) and L. pilosus Murr. P23030 (alkaline-tolerant) were either not inoculated or inoculated with Bradyrhizobium (strain WU425 or WSM1253) and grown on an alkaline clay, an acid loam, and a limed acid loam. On the alkaline soil, plants of both lupin species without inoculation nodulated poorly and had low nitrogen (N) concentrations in shoots. Inoculation with bradyrhizobia on the alkaline soil greatly increased nodulation and N concentrations in shoots, but nodule number of L. angustifolius was still lower than that on the acid soil. Lupin species differed in growth and nodulation on the alkaline soil, L. pilosus being more tolerant than L. angustifolius. Effects of liming on growth and nodulation were not significant. A survey of a farmer's crop of L. albus cv. Kiev mutant, adjacent to the field trial, showed that poor growth was associated with high soil pH and poor nodulation.
Effect of phosphorus as fertiliser or supplement on the forage intake of heifers grazing stylo-based pastures
Authors: Coates DB
Published: March 2005

The effect of phosphorus (P) fertiliser and P supplement on the forage intake and liveweight gain of yearling Droughtmaster heifers grazing tropical legume based pasture was determined. Forage intake was calculated from estimates of faecal output using slow release, chromic oxide capsules and the predicted in vivo dry matter digestibility of forage selectively grazed by steers fistulated at the oesophagus. Faecal output, forage intake, and liveweight gain increased with increasing rates of fertiliser or with P supplement. Average gross forage intake (kg/day) of supplemented heifers grazing unfertilised pasture during the growing season was nearly 50% more than that of unsupplemented heifers grazing similar pastures, and liveweight gain over the growing season was increased by 65%. Similar, but greater, increases in forage intake and liveweight gain occurred with heifers grazing pasture fertilised annually with 10 kg P/ha as superphosphate. Dietary P concentrations on pasture that had received just 1 application of fertiliser (10 kg P/ha) 5 years before the study were only marginally higher than on unfertilised pasture, but forage intakes were higher and not significantly increased by supplementation. However, the liveweight gain of unsupplemented heifers grazing pasture that was fertilised on 1 occasion was depressed compared with heifers receiving supplement or grazing pasture fertilised more frequently.
Conservation tillage increases in soil water storage, soil animal populations, grain yield, and response to fertiliser in the semi-arid subtropics
Authors: Radford BJ , Key AJ , Robertson LN , Thomas GA
Published: March 2005

We compared 4 tillage practices (traditional, stubble mulch, reduced, no tillage) during 10 years under rainfed conditions on an alluvial soil in the semi-arid subtropics of central Queensland. In the final 4 years, responses to applied fertiliser nitrogen (N), sulfur (S), and zinc (Zn) were determined. We measured soil water storage, soil nitrate accumulation, grain yield (sorghum, wheat), grain protein content, and populations of soil macrofauna, with the aim of identifying soil-conserving practices that also produce high yields of high quality grain. Stubble mulch, reduced tillage, and no tillage all outyielded traditional tillage when soil fertility was adequate. With applied N, S, and Zn, the mean wheat yields from traditional, stubble mulch, reduced, and no tillage were 2.44, 3.32, 3.46, and 3.64 t/ha, respectively. The yield responses to tillage practices were due to increases in storage of soil water or efficiency of crop water use or both. Populations of soil macrofauna averaged (per m2) 19 (traditional tillage), 21 (stubble mulch), 33 (reduced tillage), and 44 (no tillage). The effect of the tillage practices on soil animal populations may be a factor contributing to the measured differences in soil water storage and water use efficiency. We conclude that conservation tillage practices can greatly increase grain yields, provided crop and fallow management practices are appropriate. Potential yield advantages are realised if crop establishment, crop nutrition; and control of weeds, bests, and diseases ark adequate.
Management of lesion nematode (Pratylenchus jordanensis) on replanted apple trees
Authors: Stirling GR , Dullahide SR , Nikulin A
Published: March 2005

Chemical and non-chemical strategies for managing lesion nematode (Pratylenchus jordanensis) on apple replants were investigated in field experiments at Applethorpe, Queensland. In the first experiment, old trees from a nematode-infested orchard were removed in June 1987 or April 1988. Plots then received one of the following treatments: solarisation; fallow; animal manures (� 900 kg urea/ha); green manure crops of forage sorghum or lablab bean ploughed in (� 1800 kg urea/ha); ethylene dibromide or methyl bromide. Lesion nematode populations before replanting apple trees in July 1988 were generally lower if trees had been removed 12 months rather than 3 months previously. Nematodes increased on forage sorghum, but populations were reduced substantially when the crop was ploughed in with urea. Methyl bromide was the only treatment to reduce nematode populations at planting to very low levels. Two years after planting, nematode populations on apples were reduced by some of the chemical and non-chemical treatments. Most non-chemical treatments increased the growth of replanted apple trees, but methyl bromide produced the largest trees. In a second experiment, methyl bromide again enhanced early growth, but after 5 years, trees mulched with sawdust or sawdust and manure had the lowest nematode populations and produced yields as good as, or better than, methyl bromide. The results of both experiments suggested that lesion nematodes on apple replants could be managed without fumigant nematicides through a combination of early removal of the previous orchard, incorporation of animal manure or a green manure crop with urea, choice of an appropriate rootstock, and maintenance of a layer of organic mulch around trees.
Mortality, wastage, and lifetime productivity of Bos indicus cows under extensive grazing in northern Australia. 3. Comparison of culling strategies
Authors: O'Rourke PK , Fordyce G , Holroyd RG , Sullivan RM
Published: March 2005

were evaluated for 2 herds at Swan's Lagoon in the northern speargrass region and 1 herd at Kidman Springs in the semi-arid tropics by editing the records from actual culling to simulate more stringent culling policies. The greatest impact was for young cows, with 13.6 and 27.5% of 2-year-old cows in the 2 herds at Swan's Lagoon failing to rear a calf, and 39.8% at Kidman Springs failing to rear a calf. The corresponding failure rates as 3-year-old cows were 48.1, 54.9, and 80.2%, respectively. Culling for 2 consecutive reproductive failures at Kidman Springs resulted in cumulative wastage of cows >60% by 4 years of age. Other strategies based on 1 or 2 failures had cumulative wastage 80% by 5 years of age and were too severe to be sustained in the harsh environment at Kidman Springs, with low productivity. At Swan's Lagoon, heifer replacement rates were 17.5-22.2% for strategies based on 2 failures and averaged 37.3% for a single reproductive failure but were 28.7% when failure as a 3-year-old was not penalised. At Kidman Springs, heifer replacement rates were 29.3% for 2 consecutive reproductive failures and reduced to 21.3% when 2-year-olds were retained but were very high (33.7-56.7%) for stricter culling strategies. With current branding rates, only culling on 2 reproductive failures in the speargrass region and extremely limited culling on 3 failures in the semi-arid tropics can be recommended as practical options. The lifetime number of calves reared from cows up to 10 years of age at Swan's Lagoon averaged 3.1 when culling was based on 2 failures and 2.2 for culling on a single failure; this increased to 2.8 calves reared when the strategy was relaxed for 3-year-olds. At Kidman Springs the number of calves reared was 2.3 with culling on 2 consecutive reproductive failures but was closer to the actual level at 2.9 when 2-year-old cows were not culled for reproductive failure.
Mineral supplementation and wool production of young Merino sheep on the south coast of Western Australia
Authors: Doyle PT , Love RA , Plaisted TW
Published: March 2005

Wool-free liveweight change (LWC), wool growth rate, annual wool production, and wool characteristics of young Merino wethers fed supplements of lupins with gypsum or a multi-element mineral lick were examined in 12 experiments at 5 farms between 1989 and 1992. The source of sheep varied between experiments; age was 4.5-6.5 months and liveweight 28-37 kg at the beginning of supplementation. Sheep were fed lupins, lupins coated with gypsum (15-20 g/kg lupins), or lupins along with access to the mineral lick (offered at 140 g/sheep.week). The amount of lupins offered in all treatments within any experiment was the same. Supplementary feeding varied between experiments from 150 to 240 days. The sheep grazed annual pastures at stocking rates of 8-1 6.7ha. Average lick intake was 12-18 g/sheep. day. During supplementary feeding, there was considerable variation in LWC (-80 to +110 g/day) and clean wool growth rates (3.8-15.1 g/day) within and between experiments. However, there was no significant positive effect of gypsum or mineral lick supplementation on LWC or clean wool growth rates during or after supplementary feeding in any experiment. There were positive (P<0.01) relationships between LWC and clean wool growth rates during supplementation. Also, for some spring-shorn sheep types, staple strength of wool was linearly related (P<0.01) to LWC in the period before the position of break in the wool staple. Annual wool production, average fibre diameter, and staple strength of midside wool were not significantly increased by supplements of gypsum or mineral lick in any experiment.
Lupin and cowpea supplements for growth, wool production, and reproduction in rams
Authors: Pomares CC , Galloway DB , Holmes JHG , Clarke IJ , Tilbrook AJ
Published: March 2005

Lupins and cowpeas were fed at 0.0, 0.5, 1.0, and 2.0% liveweight (LW) to groups of 6 or 7 South Australian Merino rams for 11 weeks as supplements to a maintenance diet of grass hay. Productive and reproductive parameters were examined. Supplementation at all levels of either grain increased (P<0.001) LW, condition score, backfat thickness, and wool growth, with rams showing similar responses when given cowpeas and lupins. The weights of the pancreas of rams decreased (P<0.01) as the levels of supplementation increased. Semen characteristics (volume, concentration, motility, etc.) and response to freezing did not differ between the diets. Feeding either legume increased (P<0.001) testicular size, lupins giving a slightly greater response than cowpeas. Sperm production per g testicular tissue was not significantly altered. Increasing levels of either supplement increased (P<0.001) the weights of the seminal vesicles, more (P<0.01) so with lupins. The same effects occurred with the weight of epididymides except for rams fed cowpeas at the highest level. Histologically, the testes revealed an increase (P<0.001) in the number of round spermatogenic cell nuclei and the cross-sectional diameter of stage 8 tubules in rams after legume grain supplementation at 2.0% LW compared with controls. The response was higher in lupin-fed rams (P<0.05). Plasma luteinising hormone (LH) and follicle stimulating hormone (FSH) were measured in rams fed at maintenance or with lupins or cowpeas at 2.0% LW. Rams responded equally to all legumes. Concentrations of LH in peripheral blood increased (P<0.001) by 140% and FSH concentrations were elevated (P<0.01) 4-fold. Cowpeas, a tropical grain legume similar in nutrient composition to lupins, have similar potential when used as a supplement to improve productive and reproductive capabilities of Merino rams.