Comparison of bicarbonate-extractable soil phosphorus measured by ICP-AES and colourimetry in soils of south-eastern New South Wales

Soil Research ◽  
2009 ◽  
Vol 47 (7) ◽  
pp. 742 ◽  
Author(s):  
M. R. Hart ◽  
P. S. Cornish

Soil testing for plant-available phosphorus (P) in Australia is most commonly conducted using alkaline sodium bicarbonate extraction (Olsen or Colwell tests), followed by a colourimetric assay to measure the concentration of P in solution. Analysis by inductively coupled plasma (ICP) spectroscopy has become increasingly popular internationally for other soil P tests, especially Mehlich 3, due to its efficiency and ability to measure multiple elements in the one extract. The use of ICP in place of colourimetry has been used in some Australian laboratories for bicarbonate-extractable P. However, the method is known to measure forms of P (organic) that are not measured by the colourimetric assay. This study presents data comparing soil Colwell P measured by the 2 methods for 714 soil samples from pastoral sites in south-east New South Wales. Measurement by ICP consistently yielded significantly higher P concentrations than the colourimetric method (ICP-P = 1.122Col-P + 57.0, r2 = 0.95, P < 0.001). Differences between the 2 techniques were more marked in 0–20 mm than 0–100 mm depth soil samples, and in soils with greater clay contents, suggesting that the difference was related to soil organic matter, and thereby organic P contents. Relative differences were greatest in soils with lower P concentrations, i.e. within the agronomic optimum range of most interest to farmers. ICP analysis cannot be directly correlated with colourimetrically measured P in bicarbonate extracts, and would need to be developed and calibrated as a separate, new soil P test.

2001 ◽  
Vol 41 (2) ◽  
pp. 187 ◽  
Author(s):  
R. Aldaoud ◽  
W. Guppy ◽  
L. Callinan ◽  
S. F. Flett ◽  
K. A. Wratten ◽  
...  

In 1995–96, a survey of soil samples from subterranean clover (Trifolium subterraneum L.) paddocks was conducted across Victoria, South Australia, New South Wales and Western Australia, to determine the distribution and the prevalence of races of Phytophthora clandestina (as determined by the development of root rot on differential cultivars), and the association of its occurrence with paddock variables. In all states, there was a weak but significant association between P. clandestina detected in soil samples and subsequent root rot susceptibility of differential cultivars grown in these soil samples. Phytophthora clandestina was found in 38% of the sampled sites, with a significantly lower prevalence in South Australia (27%). There were significant positive associations between P. clandestina detection and increased soil salinity (Western Australia), early growth stages of subterranean clover (Victoria), mature subterranean clover (South Australia), recently sown subterranean clover (South Australia), paddocks with higher subterranean clover content (Victoria), where herbicides were not applied (South Australia), irrigation (New South Wales and Victoria), cattle grazing (South Australia and Victoria), early sampling dates (Victoria and New South Wales), sampling shortly after the autumn break or first irrigation (Victoria), shorter soil storage time (Victoria) and farmer’s perception of root rot being present (Victoria and New South Wales). Only 29% of P. clandestina isolates could be classified under the 5 known races. Some of the unknown races were virulent on cv. Seaton Park LF (most resistant) and others were avirulent on cv. Woogenellup (most susceptible). Race 1 was significantly less prevalent in South Australia than Victoria and race 0 was significantly less prevalent in New South Wales than in South Australia and Western Australia. This study revealed extremely wide variation in the virulence of P. clandestina. The potential importance of the results on programs to breed for resistance to root rot are discussed. in South Australia.


1995 ◽  
Vol 2 (4) ◽  
pp. 398 ◽  
Author(s):  
J. C. Noble ◽  
D. J. Tongway ◽  
M. M. Roper ◽  
W. G. Whitford

The effects of prescribed fires on nutrient pools, soil micro-organisms, and vegetation patch dynamics were studied in three semi-arid mallee shrublands in western New South Wales. Repeated sampling of surface soil strata (0–2 and 2–4 cm) was undertaken at strategic times (immediately before and after the fire, after opening autumn rain, mid-season in the winter, and at the end of the spring) in five microsites (inner, middle and outer mallee litter zones, bare soil, and Triodia hummock). These samples were later analysed for pH, electrical conductivity, organic carbon and available nitrogen. The effect of fire on soil micro-organisms in these microsites was also examined by measuring nitrogenase activity and enumerating soil Acari. Carbon and nitrogen levels were consistently higher in the inner mallee microsites whereas bare soil sites provided the lowest values. Significant microsite x soil depth interactions were recorded in two shrubland sites while highly significant (P < 0.001) depth x sampling time interactions were recorded in three sites. The most sensitive soil parameter with respect to microsite was electrical conductivity, particularly in the surface 0–2 cm stratum. Highest values were again recorded from the inner mallee microsites and the lowest from bare soil sites. Nitrogenase activity was highest in soil samples associated with mallee litter and, where litter was removed by fire, activity decreased markedly except in the bare soil samples where activity was higher in the burnt samples. Soil microarthropod populations also declined notably following fire. Mites from the Prostigmata greatly outnumbered those from other suborders, a total of 12 families (15 genera) being enumerated in control sites compared with three families (three genera) only of Cryptostigmata. Nonetheless the most abundant mites were cryptostigmatids (Aphelacarus spp.) found in unburnt hummocks beneath Triodia plants. The ecological and management implications of these spatial and temporal fluxes in soil chemistry and soil biology are discussed in relation to their effects on landscape processes, particularly water and nutrient redistribution.


1992 ◽  
Vol 14 (2) ◽  
pp. 214 ◽  
Author(s):  
RL Pressey

Information on the features to be protected in a system of conservation reserves is an obvious requirement. The quality of the data base will primarily determine the effectiveness of conservation planning in protecting the full range of natural features in a region. However, the way in which data are used to make decisions on the locations of protected areas is also critical. Rigorous procedures for reserve selection can make the difference between achieving reservation goals or not. Research on reserve selection in New South Wales over recent years has concerned both data bases and procedures for guiding decisions. Reserve planning in many regions is based largely on some form of land classification like vegetation types or land systems. There are good reasons for using such land classes to guide the selection of reserves and to judge their representativeness. Nevertheless, they can have considerable limitations as a basis for protecting all the species in a region. These limitations are reviewed with references to more detailed discussions of particular issues. The paper also reviews a variety of procedures for selecting reserves which have been tested and applied in New South Wales. Some of the recent procedures are conceptually simple but very useful in identifying the requirements of reservation goals and demonstrating the options available to planners for representing particular features. Three principles are proposed which should underpin any attempt at systematic conservation planning.


1981 ◽  
Vol 8 (2) ◽  
pp. 255 ◽  
Author(s):  
NC Shepherd

Over 7 weeks a group of five dingoes killed 83 red kangaroos within 150 m of a watering point in north-western New South Wales. All except three of these kangaroos were juveniles. Detailed autopsies were performed on 17 of the dead kangaroos: primary predation was the only significant gross pathological finding; the dingoes had eaten portions from about half the kangaroos killed. The daily rate of killing was estimated to be about 0.38 kg prey per kg predator. The rate of killing and the selection for juvenile kangaroos suggested that dingoes could have a direct effect on kangaroo densities by limiting rate of increase. The significance of this finding is discussed with reference to the difference in abundance of kangaroos between the New South Wales and Queensland sides of the border fence.


1963 ◽  
Vol 3 (10) ◽  
pp. 190 ◽  
Author(s):  
JD Colwell

The usefulness of five contrasting methods of soil analysis for estimating the phosphorus fertilizer requirements of wheat in southern New South Wales has been investigated, using yield data provided by 27 field experiments. Because the level of yield of wheat is strongly affected by seasonal environmental conditions poor correlations are obtained between soil analysis and absolute or relative yield of wheat, Much better and often significant correlations are obtained between soil analysis and the absolute increase in yield from fertilizer application. The best correlations were obtained with an 0.5M NaHCO3 extraction of soil phosphorus. A regression response surface calculated from these relationships provides a method for making direct estimates of fertilizer requirements for maximum economic return to farmers under average climatic conditions. The precision of these estimates is limited more by the flatness of the response surface and uncontrolled variation in the field data, than by inadequacies in the representation of available phosphorus by the NaHCO3 analysis.


1998 ◽  
Vol 20 (2) ◽  
pp. 251
Author(s):  
R.W. Turnbull

Distribution of the platypus (Ornithorhynchus anatinus) in the Bombala River catchment in south-eastern New South Wales was surveyed using questionnaires. Platypuses were reported from all streams in the catchment. The majority of positive sightings were from downstream areas whereas very few positive sightings were reported from headwater areas. The difference between frequencies of headwater and downstream reports of sightings was significant. The platypus was considered common throughout the catchment.


1966 ◽  
Vol 6 (20) ◽  
pp. 17 ◽  
Author(s):  
F McMullen

A factorial glasshouse pot trial was used to examine the supply of phosphorus, boron, zinc, copper, cobalt, magnesium, molybdenum, potassium, and manganese, to the Dwalganup strain of Trifolium subterraneum L. growing in virgin granite soils from Bendemeer, New South Wales. Calcium sulphate was applied as a basal nutrient. Significant dry matter responses were obtained on all four virgin soils to the application of phosphorus, molybdenum, and potassium; to copper on two soils; and to boron and cobalt on one soil. Phosphorus was so deficient that responses to other plant nutrients did not occur in its absence. On all soils, significant first order interactions were recorded between phosphorus and other deficient elements. In addition, significant interactions were recorded between molybdenum and magnesium, copper and molybdenum, boron and molybdenum, copper and cobalt, and potassium and molybdenum.


1975 ◽  
Vol 15 (75) ◽  
pp. 475 ◽  
Author(s):  
H Brownlee ◽  
BJ Scott ◽  
RD Kearins ◽  
J Bradley

Merino ewes at 3.7, 4.9 and 6.2 ha-1 grazed dryland lucerne (Medicago sativa cv. Hunter River) topdressed annually with superphosphate at 0, 125 and 251 kg ha-1, from September 1969 until December 1972, in an experiment at Condobolin, New South Wales. Superphosphate increased ewe liveweights, total forage available and phosphorus content of the forage by a small amount but did not increase wool production per head. The Bray soil phosphorus test in the top 8 cm of the soil profile rose from 8 p.p.m. to 48 p.p.m., but most of the phosphorus was concentrated in the 0-4 cm layer, where we consider that dry conditions reduced its availability to the lucerne. As stocking rate increased, ewe liveweights and wool production per head decreased and the sheep required more handfeeding for survival. The treatment with the greatest gross margin was the lowest stocking rate with nil fertilizer.


Soil Research ◽  
1997 ◽  
Vol 35 (5) ◽  
pp. 1165 ◽  
Author(s):  
Bernd G. Lottermoser

Total heavy metal concentrations [cobalt (Co), chromium (Cr), copper(Cu), iron (Fe), mangnese (Mn), nickel (Ni), lead (Pb), and zinc (Zn)]were determined in surface soil samples from Port Macquarie, New South Wales,Australia. Composite topsoil samples (0–10 cm depth) had mean values(per kg) of 13 mg Co, 1020 mg Cr, 59 mg Cu, 136·7 g Fe, 719 mg Mn, 149mg Ni, 20 mg Pb, and 47 mg Zn. The topsoils were generally characterised by alow pH (3·8–5·2) and a mineralogy dominated by haematite,magnetite, quartz, and kaolinite. Chromium was predominantly present in thetopsoils as Cr3+ in microcrystalline chromite(FeCr2O4) and, to a lesser degree,in kaolinite and haematite. Differences in Cr soil concentrations with depthwere due to variations in the relative abundance of the various soilcomponents, rather than Cr3+ mobility within the soilprofile. The elevated heavy metal concentrations are the result of soildevelopment over metal-rich bedrock (serpentinite matrix melange) andassociated enrichment of relatively immobile elements (Cr, Fe, Ni) in theresidual soil profile. The ANZECC and NH&MRC (Australian and New ZealandEnvironment and Conservation Council and National Health & MedicalResearch Council) environmental investigation limits were exceeded for100% of the sample sites for Cr, 47% for Cu, 61% for Mn,and 58% for Ni.


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