Carbon inputs by wheat and vetch roots to an irrigated Vertosol

Soil Research ◽  
2012 ◽  
Vol 50 (3) ◽  
pp. 177 ◽  
Author(s):  
N. R. Hulugalle ◽  
T. B. Weaver ◽  
L. A. Finlay
Keyword(s):  
Unit Area ◽  
New South ◽  
Farming Systems ◽  
Triticum Aestivum L ◽  
Root Mortality ◽  
Root Carbon ◽  
South Wales ◽  
Wheat Stubble ◽  
Experimental Treatments

Research on the amounts of carbon that can be added to Vertosols of New South Wales and Queensland by crop roots in irrigated cotton farming systems is sparse. The objective of this study was to determine the amounts of carbon added to soil by roots of wheat (Triticum aestivum L.) and purple vetch (Vicia benghalensis L.) sown in rotation with irrigated cotton (Gossypium hirsutum L.). Measurements were made from 2008 to 2010 in an ongoing experiment near Narrabri, northern NSW, using a combination of soil cores and minirhizotron observations. The experimental treatments were: cotton monoculture; cotton–vetch (CV); cotton–wheat, in which wheat stubble was incorporated into the beds with a disc-hiller (CW); and cotton–wheat–vetch, in which wheat stubble was retained as in-situ mulch (CWV). Vetch was killed by a combination of mowing and contact herbicides, and the residues were retained as in situ mulch. Root length per unit area of vetch in CWV and wheat in both CW and CWV was comparable, although wheat had a higher concentration of roots in surface 0.10 m. Root growth of the CV treatment was sparse. Root carbon available for addition to soil was greater with vetch than with wheat and was in the order: vetch in CWV (5.1 t C/ha.year) > vetch in CV (1.9 t C/ha.year) > wheat in CW (1.6 t C/ha.year) = wheat in CWV (1.7 t C/ha.year). Intra-seasonal root mortality accounted for 12% of total root carbon in vetch and 36% in wheat. The remaining fraction consisted of carbon in the root mass at the end of the growing season. Carbon sequestered by root inputs of the rotation crops was estimated to be ~0.34 t C/ha.year for the vetch and wheat crops in the CWV rotation, 0.10 t C/ha.year for vetch in CV, and 0.08 t C/ha.year for wheat in CW. Rotation CWV was, therefore, the most effective in sequestering carbon from roots.

Evidence of High Sea Level during Isotope Stage 5c in Queensland, Australia

1985 ◽  
Vol 24 (1) ◽  
pp. 103-114 ◽  
Author(s):  
J. W. Pickett ◽  
C. H. Thompson ◽  
R. A. Kelley ◽  
D. Roman
Keyword(s):  
Sea Level ◽  
New South ◽  
Good Condition ◽  
Coastal Dunes ◽  
Intertidal Sediments ◽  
South Wales ◽  
Eastern Australia ◽  
Maximum Period ◽  
High Dune

Thirty-nine species of scleractinian corals have been recovered from under a high dune on the western (mainland) side of North Stradbroke Island, eastern Australia. The corals are associated with thin intertidal sediments and their good condition implies burial in situ and preservation in a saturated zone. Most likely this occurred as the coast prograded and a large dune advanced into the littoral zone, burying intertidal sediments and coral. The species assemblage indicates a sheltered environment but one open to the ocean without wide fluctuations in salinity. Three species yielded a mean 230Th/234U age of 105,000 yr B.P. which is significantly younger than the nearest Pleistocene corals at Evans Head, New South Wales. The corals provide evidence of a sea stand near present sea level during isotope Stage 5c, which is considerably higher than previously suggested for this period. Their good condition implies that the overlying parabolic dune is of comparable age and formed during that high stand of sea level. Also, the isotope age provides a maximum period for the development of giant podzols in the podzol chronosequences on coastal dunes in southern Queensland.

Field measurements of nitrogenase activity in soils amended with wheat straw

1983 ◽  
Vol 34 (6) ◽  
pp. 725 ◽  
Author(s):  
MM Roper
Keyword(s):  
Nitrogenase Activity ◽  
New South ◽  
Field Measurements ◽  
Field Capacity ◽  
Nitrogen Fertilizers ◽  
Free Living ◽  
Straw Decomposition ◽  
Indirect Measure ◽  
South Wales

Nitrogenase activity and decomposition of straw were examined in situ in two areas (Gunnedah and Cowra) representative of large areas of the New South Wales wheat belt. Measurements of nitrogenase activity were made by adapting the acetylene reduction assay for use in the field. Evolution of CO2 was monitored as an indirect measure of decomposition of straw. The addition of straw to soil stimulated nitrogenase activity which was related to the amount of straw added and the rate of straw decomposition. There were significant levels of activity provided the soil was moist and warm. Nitrogenase activity increased with mean daily soil temperature (up to at least 30�C) and decreased as the soil dried from field capacity. It is concluded that nitrogen fixation by free-living nitrogen-fixing microorganisms in soils amended with straw may contribute to the nitrogen status of the soil and thus reduce the need for nitrogen fertilizers.

scholarly journals The Pattern of In Situ Stress in Onshore Basins of New South Wales

2015 ◽  
Author(s):  
Mojtaba Rajabi* ◽  
Mark Tingay ◽  
Oliver Heidbach ◽  
Rosalind C. King
Keyword(s):  
New South ◽  
New South Wales ◽  
In Situ Stress ◽  
South Wales

If long fallow cropping is leaky then shallow groundwaters on the Liverpool Plains should be of recent origin

2004 ◽  
Vol 44 (10) ◽  
pp. 1051 ◽  
Author(s):  
R. R. Young ◽  
A. Broughton ◽  
J. M. Bradd ◽  
J. F. Holland
Keyword(s):  
Cropping Systems ◽  
New South ◽  
Shallow Groundwater ◽  
Agricultural Practices ◽  
Farming Systems ◽  
Deep Drainage ◽  
Site Specific ◽  
South Wales ◽  
Recent Origin ◽  
Unexpected Outcome

Previous groundwater studies have indicated that up to 195 000 ha of the Liverpool Plains catchment, south of Gunnedah, New South Wales, Australia, are at risk from shallow saline watertables. Replacement of hydraulically stable, native perennial grasslands with more ‘leaky’ annual cropping systems since the 1950s, particularly long fallow wheat–sorghum rotations, has been held responsible for an apparent increased frequency of shallow watertables and saline discharge. If so, then it follows that shallow groundwater in the alluvium will be recent (less than about 30 years old) and the solution to the problem is a straightforward reduction in deep drainage under farming systems via increased evapotranspiration. However, in this study, we have found levels of bomb pulse tritium in shallow groundwaters that indicate that about half of the shallow groundwaters in the Mooki subcatchment pre-date current agricultural practices. A hypothesis for this unexpected outcome suggests that the problem is complex and that solutions need to be site-specific.

Some characteristics of the trees used by sheep for diurnal camping and differences between the shade and nocturnal camps in a paddock on the northern tablelands of New South Wales.

1984 ◽  
Vol 6 (1) ◽  
pp. 3 ◽  
Author(s):  
JA Taylor ◽  
DA Hedges
Keyword(s):  
Tree Species ◽  
Unit Area ◽  
New South ◽  
New South Wales ◽  
South Wales

This paper examines some of the characteristics of trees under which sheep camped during the day and the differences between the shade and the nocturnal camps in a large paddock. Of the five tree species present, Merinos preferred to camp under Augophora floribunda and Brachychiton populneum during the day. The selected trees had a high canopy/bole ratio and either an elevated convex or a convex shaped canopy. Nocturnal camps occurred in an upperslope position and were much larger, better developed and had more sheep faeces per unit area than the shade camps in the paddock. Shade camps occurred downslope of the nocturnal camps and were within the area of the paddock used primarily for grazing.

Ecology of Nassella neesiana, Chilean needle grass, in pastures on the Northern Tablelands of New South Wales. I. Seed production and dispersal

2003 ◽  
Vol 54 (6) ◽  
pp. 613 ◽  
Author(s):  
M. R. Gardener ◽  
R. D. B. Whalley ◽  
B. M. Sindel
Keyword(s):  
South America ◽  
Seed Production ◽  
Seed Set ◽  
Unit Area ◽  
New South ◽  
New South Wales ◽  
Total Potential ◽  
South Wales ◽  
Eastern Australia ◽  
Flower Stem

Nassella neesiana (Trin. & Rupr.) Barkworth (Chilean needle grass) originated in South America and is now a widespread weed in pastures in south-eastern Australia. To date, little research on the biology of N.�neesiana has been undertaken in Australia. This study investigated several aspects of the biology of N. neesiana in pastures on the Northern Tablelands of New South Wales. The main flowering period for N. neesiana in Australia was shown to extend from November to February and is similar to that in South America. Potential for production of panicle seeds was large and varied from 1584 seeds/m2 in 1995 to 22 203 seeds/m2 in 1996 as a result of changes in the density of flowering tillers per unit area. Nassella neesiana produced a further 7.2 cleistogenes (hidden seeds in the flower stem) on average per tiller. Hence, total potential seed production (panicle seeds and cleistogenes) was 28 282 and 8036 seeds/m2 in 1996 and 1997, with the cleistogenes accounting for 21.5 and 26.1% of the total respectively. Furthermore, the production of cleistogenes was not affected by clipping flowering tillers at 3 different heights. Three possible dispersal mechanisms of N. neesiana seeds were investigated. Adherence of seeds to the wool appeared to be the most effective. Twenty-five per cent of seeds that were picked up naturally in the wool of sheep after grazing in a paddock of N. neesiana, remained after 5 months. Shearing just before seed set reduced the number of seeds adhering to the wool. An average of 1.7% of panicle seeds and 5.3% of cleistogenes fed to Angus steers passed through the animal intact within 4 days, but <50% of these seeds were viable. The majority of seeds recovered from a wind dispersal experiment were within 1 m of the parent plant and the furthermost seed was 2.8 m away. The implications of these results for management are discussed.

Effect of genotype × environment × management interactions on chickpea phenotypic stability

2019 ◽  
Vol 70 (5) ◽  
pp. 453 ◽  
Author(s):  
Peter Kaloki ◽  
Richard Trethowan ◽  
Daniel K. Y. Tan
Keyword(s):  
New South ◽  
Crop Improvement ◽  
Farming Systems ◽  
Environment Interaction ◽  
Environment Management ◽  
Crop Varieties ◽  
Genotype Environment Interaction ◽  
South Wales ◽  
Rainfed Farming ◽  
Main Effects

Crop varieties interact with the environment, which affects their performance. It is imperative to know how the environment affects these crop varieties in order to choose carefully the optimal environment for growth. Chickpea (Cicer arietinum L.) is grown in varying environmental conditions including conventional and no-tillage under both irrigated and rainfed farming systems. Hence, genotype × environment × management interactions can affect yield stability. An experiment was conducted in north-western New South Wales, Australia, to investigate these interactions and to determine possible environment types to help focus crop improvement. Eight environments were considered and genotype plus genotype × environment interaction (GGE) biplots were generated to assess genotype stability and interactions with environment. Genotype and environment main effects and genotype × environment interactions (GEI) accounted for 12.6%, 66% and 12% of the total variation in yield, respectively. The most productive and stable environments were not tilled, irrespective of moisture status. The most stable and productive genotype was Sonali, closely followed by PBA Slasher and ICCV 96853. The eight test environments grouped into two environment types that differentiated on the basis of tillage regime. Moisture was not a determinant of site grouping.

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