Factors affecting nitrogen fixation by dryland lucerne in central-western New South Wales

2002 ◽  
Vol 42 (4) ◽  
pp. 439 ◽  
Author(s):  
A. M. Bowman ◽  
M. B. Peoples ◽  
W. Smith ◽  
J. Brockwell

Eight stands of dryland lucerne (Medicago sativa L.) cv. Trifecta were grown on a red-brown earth at Trangie, New South Wales. The stands were of varying age and plant density. Their biomass production and capacity to fix atmospheric nitrogen were measured on 15 occasions over a 5-year period (1995-99). Biomass production (shoot dry matter) ranged from 0.22 to 4.87 t/ha.year and nitrogen fixed from 1.8 to 78.6 kg/ha.year. Whereas biomass production was highest in summer periods, most nitrogen fixation took place in winter and autumn. Irrespective of stand age, greatest productivity occurred in the early years of the experiment and declined thereafter. Plant density varied from 6 to 21 plants/m2 at the commencement of the study and decreased over time. We conclude that the productive life of dryland lucerne stands in this environment is probably limited by frequent periods of moisture stress and high soil temperatures in summer. Stands with a lucerne density of 8 plants/m2 or better produced twice as much shoot biomass and fixed nearly double the amount of shoot N as did stands with densities of 7 plants/m2 or less. There was no relationship between the age of lucerne stands per se and biomass production or nitrogen fixation. The practical implication of this work for farmers in the dryland cropping zone of central-western New South Wales who wish to maximise nitrogen fixation from the lucerne phase of their cropping rotations is to establish and maintain dryland lucerne at 8 plants/m2 or better.

1998 ◽  
Vol 38 (6) ◽  
pp. 555 ◽  
Author(s):  
A. M. Bowman ◽  
D. M. Hebb ◽  
D. J. Munnich ◽  
J. Brockwell

Summary. Populations of Rhizobium meliloti in self-mulching clay soils (Vertisols) at 48 sites on 27 properties in north-western New South Wales were classified according to number and ability to fix nitrogen with several species of Medicago. Rhizobia were counted using serial dilution, nodulation frequency, plant infection tests. Abilities of the soil populations to fix nitrogen were determined in the laboratory with whole-soil inoculation of Medicago seedlings in test tubes with shoots exposed to the atmosphere and roots within the tubes under bacteriological control, and in the field using a technique based on the natural abundance of 15N in the soil. The majority of soils contained >1000 cells of R. meliloti per gram. The major component of those populations fixed nitrogen with lucerne (Medicago sativa) and some components of some soils also fixed nitrogen with M. polymorpha, M. scutellata, M. littoralis, M. tornata, M. laciniata and Trigonella suavissima. However, a number of soils were located which contained few if any rhizobia effective in nitrogen fixation with M. polymorpha. Overall, the effectiveness of nitrogen fixation of the naturally occurring populations of R. meliloti in association with M. polymorpha, M. scutellata, M. littoralis and M. tornata was only 46% of the effectiveness of standard strains. At one particular site, where 10 lines of annual Medicago spp. were growing experimentally, fixed nitrogen as a proportion of shoot nitrogen averaged only 28%. At that site, there were no effective rhizobia for M. scutellata and it was wholly dependent on the soil as the source of its nitrogen. The results are discussed in relation to the need for a substantial input of legume nitrogen for restoring the natural fertility of self-mulching clay soils in degraded wheat lands of north-western New South Wales. It is suggested that lucerne, or perhaps other perennial Medicago spp., might fill this role better than annual medics such as M. polymorpha and M. scutellata that are more dependent than lucerne on specific strains of R. meliloti to meet their requirements for symbiotic nitrogen fixation.


2017 ◽  
Vol 5 (1) ◽  
pp. 20-38
Author(s):  
Gary L Sturgess

The transportation of convicts to New South Wales in the early years of settlement was a great deal more challenging than has generally been recognised. Arthur Phillip's success in bringing a convoy of eleven ships, including six transports carrying more than 750 convicts, on a voyage of eight months duration across the globe means we need to rethink his contribution to fitting out and managing Australia's First Fleet.


2005 ◽  
Vol 45 (3) ◽  
pp. 269 ◽  
Author(s):  
D. F. Herridge ◽  
M. J. Robertson ◽  
B. Cocks ◽  
M. B. Peoples ◽  
J. F. Holland ◽  
...  

Apparent nodulation failures and associated low grain yields have been reported for commercial mungbean (Vigna radiata) crops in southern Queensland and northern New South Wales. We therefore conducted on-farm surveys of 40 commercial mungbean crops in the region in which symbiotic traits, i.e. nodulation and nitrogen fixation, and biomass and grain yield were monitored. Effects of bradyrhizobial inoculation and inoculation methods on mungbean and soybean (Glycine max) symbiosis and yield were determined in experiments at 3 sites in northern New South Wales. Thirty-four of the 35 mungbean crops assessed for nodulation were nodulated. The relationship between soil nitrate to a depth of 90 cm at sowing and mungbean nodulation was not significant. However, at low-to-moderate soil nitrate levels (<100 kg N/ha), the mean nodule score was 1.6, compared with 0.5 at high (>100 kg N/ha) soil nitrate levels. Soil nitrate had a negative effect on the percentage of mungbean nitrogen derived from nitrogen fixation (%Ndfa). Mean %Ndfa values for soil nitrate levels <50, >50–100 and >100 kg N/ha were 35, 22 and 19% respectively. Grain yields of the surveyed mungbean crops varied from 0.3 to 2.1 t/ha, and were correlated with shoot dry matter. Grain yield was not significantly correlated either with sowing soil nitrate, nodule score or %Ndfa. In the inoculation experiments, mungbean did not nodulate as well as soybean, producing about one-third the number of nodules. Both species responded to inoculation with increased nodulation, although data from one of the sites suggested that responses during early growth of mungbean were not maintained during pod-fill. Effects of inoculation on mungbean %Ndfa were marginal. Average increases were 9%, based on natural 15N abundance, and 6%, based on the ureide method. Soybean %Ndfa, on the other hand, responded strongly to inoculation, with increases of 56 (15N) and 77% (ureide). Inoculation increased mungbean crop N by an average of 10% and grain yield by 6%, compared with responses to fertiliser nitrogen of 31% (crop N) and 10% (grain yield). For soybean, inoculation increased crop nitrogen by 43% and grain yield by 7%, similar to responses to fertiliser nitrogen of 45 (crop N) and 5% (grain yield). These results suggest that inoculated mungbean was N-limited and that inoculation of mungbean using current technology may be somewhat ineffectual. We concluded that low nodulation and nitrogen fixation of commercial mungbean most likely results from the suppressive effects of nitrate and/or insufficient numbers of bradyrhizobia in the soil. When low symbiosis and low soil nitrate are combined, N is likely to limit crop growth, and potentially grain yield. Suggested strategies for improving mungbean nodulation and nitrogen fixation in the northern grains belt include selection of more symbiotically competent plant and bradyrhizobial genotypes and more effective utilisation of established soil populations of mungbean bradyrhizobia.


1986 ◽  
Vol 26 (4) ◽  
pp. 493 ◽  
Author(s):  
H Marcellos ◽  
GA Constable

The effects of varying plant density and sowing date on grain yield of faba beans (Vicia faba L.) were determined in 6 experiments at Tamworth and Narrabri in northern New South Wales. The graph of grain yield rose to an asymptote as plant density was increased. Under conditions favouring high yields, a plant density of 20 m-2 gave near maximum grain yields, but for a wider range of circumstances a plant density of 30-35 m-2 was appropriate. If sowing was delayed after the end of April, grain yield was reduced as was dry matter yield and the duration of pod-filling. Late sowing also lowered the height of the first pod above ground, and increased the likelihood of yield loss through foliar disease.


2000 ◽  
Vol 40 (6) ◽  
pp. 831 ◽  
Author(s):  
G. A. Wicks ◽  
W. L. Felton ◽  
R. D. Murison ◽  
R. J. Martin

Four experiments in northern New South Wales comparing fallow management treatments of no-tillage, cultivated with the stubble retained, and cultivated with the stubble burned, from 1981 to 1990, were sampled for weeds between wheat harvest and seeding on a number of occasions during this period. Eighty weed species were identified, 23 of which were found at all 4 sites but only 13 were recorded in the samples taken. These were dwarf amaranth, wild turnip, spear thistle, Australian bindweed, fleabane, bladder ketmia, prickly lettuce, turnip weed, variegated thistle, common sowthistle, dandelion, wild oats and native millet. The density of weeds during the fallow period decreased by 97% from 1981 to 1990 with some species eliminated, probably because of the herbicides used, particularly glyphosate and chlorsulfuron. These included Boggabri and redroot amaranth, button grass, caustic weed, dense crassula, fat hen, legumes, common peppercress, hedge mustard, London rocket, shepherd’s purse, wild mustard, sorghum-almum, paradoxa grass, wild zinnia, and wireweed. Twenty-four weed species were classified as a problem or a potential problem in the future at 1 or more sites. Seventeen weed species, including perennial grasses, often were tolerant to glyphosate at the rates used. The densities of common sowthistle and wild oat were reduced after 10 years, but still remained at all 4 sites. Plant density of species with wind-blown seeds was greater in no-tillage plots than stubble-retained or stubble-burned plots. Weeds whose seeds are dispersed by wind and weeds tolerant to glyphosate were the most troublesome. The perennial grass native millet increased at all 4 sites.


1994 ◽  
Vol 34 (4) ◽  
pp. 449 ◽  
Author(s):  
RD FitzGerald

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.


1995 ◽  
Vol 27 (4-5) ◽  
pp. 553-561 ◽  
Author(s):  
M.B. Peoples ◽  
R.R. Gault ◽  
B. Lean ◽  
J.D. Sykes ◽  
J. Brockwell

1993 ◽  
Vol 1 (3) ◽  
pp. 117-118 ◽  
Author(s):  
Eric Cunningham Dax

Remarkably little is recorded to suggest that lunacy was regarded as a problem in the transports, by the reported suicides or the reactions to starvation, privation and cruelty in the early years of settlement [1]. Nevertheless, in 1787, Phillip, the first Governor of New South Wales, was specifically directed to exercise powers regarding the insane. Part of these orders were: “Wee have thought fit to entrust you with the care and commitment of the said ideots and lunaticks and their estates” [2]. From then onwards nothing is heard of “the lunaticks” until after Samuel Marsden was given official duties in this field.


1970 ◽  
Vol 10 (47) ◽  
pp. 745 ◽  
Author(s):  
TE Launders

Seasonal yields and persistence of Hunter River and three introduced lucerne (Medicago sativa) cultivars (African, Du Puits, and Hairy Peruvian) were compared with two C.S.I.R.O.-bred lines, a hay type (C.1212) and a creeping type (Cancreep), over a five-year period between 1963 and 1968 under dryland conditions at Narrabri, New South Wales. After two years, Hunter River had significantly higher plant density than all other cultivars. By maintaining this superiority throughout the experiment, it was never exceeded in dry matter production in any season after the third summer. Spring yields of Cancreep compared favourably with Hunter River for three seasons, and there was little difference between most cultivars for four summers. Cancreep and Hairy Peruvian matched Hunter River in autumn-winter production for two seasons. In all cases decline in production during the third and fourth years is attributed to a lack of persistence in cultivars other than Hunter River.


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