Soil phosphorus status and environmental risk of phosphorus run-off from pastures in south-eastern New South Wales

Soil Research ◽  
2016 ◽  
Vol 54 (6) ◽  
pp. 685 ◽  
Author(s):  
M. R. Hart ◽  
P. S. Cornish

Soils were sampled from 136 sites representing the major soil types in the Sydney drinking water catchments to provide an overview of agronomic phosphorus requirement and phosphorus environmental risk for the various pastoral land uses, which together comprise 40% of the 15700-km2 catchment area. Critical values for Colwell P (estimated from the phosphorus buffering index) were subtracted from the measured Colwell P to derive a ‘normalised’ Colwell P for each site, with negative values broadly signifying potential agronomic response and positive values warranting an assessment of environmental risk. Normalised Colwell P was above zero at approximately half the sites, and >50mgkg–1 at 20% of sites that were considered to present a significant environmental risk, highlighting the need for more effective use of soil testing. Colwell P was highly variable within soil type and land use. No category could be singled out for special attention for management except for dairy and former dairy sites. Where dairy effluent must be applied to soils already high in P, a plan is needed to manage stormwater run-off. Pastures at approximately 20% of sites were ‘degraded’, where the priority should be to improve pasture management and reduce the risk of phosphorus loss in surface erosion.

Soil Research ◽  
1966 ◽  
Vol 4 (2) ◽  
pp. 115 ◽  
Author(s):  
K Spencer

Twenty-three basaltic soils from elevated areas in northern New South Wales were examined for sulphur and phosphorus status by growing Phalaris tuberosa L. in pots in a glasshouse. Sulphur deficiency was more common and more severe than was phosphorus deficiency. To determine whether there may be some topographic control of sulphur or phosphorus status, soil colour was examined, as in general the reddest soils were found in the highest positions in the landscape. The soils were first considered as one group and then as subgroups of sedentary, colluvial, and alluvial soils. Using redness to rank the soils, there was no overall relationship to sulphur or phosphorus status. However, colour of the sedentary soils was significantly correlated with sulphur status (r = 0.92***), the reddest soils being the most deficient. The sulphur status of the brown colluvial and greyish brown alluvial soils showed no relationship to colour; they were uniformly severely deficient. Phosphorus deficiency was not associated with soil colour. Neither soil pH nor redox potential was related to the sulphur and phosphorus status of the soils. There was only a weak correlation (r = 0.60**) between the water-soluble sulphur content of all soils, but a stronger correlation (r = 0.81**) when only the sedentary soils were considered. Several soil phosphorus fractions could be satisfactorily used to distinguish between phosphorus-deficient and phosphorus-sufficient soils.


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.


1979 ◽  
Vol 1 (4) ◽  
pp. 351 ◽  
Author(s):  
AD Wilson

This paper reviews those aspects of the scientific literature that bear on the management of the native saltbush, grassland, belah and bluebush communities of south-west New South Wales. In includes information on the structure, vegetation change, erosion, animal production and management, and includes tables of the characteristics of the major plant species. Grazing can induce major vegetation changes in saltbush areas, but only relatively minor changes in the more stable communities, such as belah. Erosion hazards are severe in the bluebush communities, although they are generally stable at present. Animal production is closely related to the winter incidence of rainfall, when both sheep and cattle concentrate their grazing on annual plants. In summer saltbushes, bluebushes and copper burrs become the main constituents and diet quality is adequate for maintenance. Research suggests that controlled continuous grazing is the best option for both production and pasture management in these communities. The future use of controlled burning to reduce unpalatable shrubs in belah communities is indicated.


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.


1973 ◽  
Vol 13 (65) ◽  
pp. 705 ◽  
Author(s):  
BJ Scott

The dry matter production of a pasture of barrel medic (Medicago truncatula cv. Jemalong) under different rates and methods of application of superphosphate was examined, during 1971 and 1972, on a phosphorus deficient soil at Condobolin, New South Wales. The treatments were factorial combinations of four rates of superphosphate (0, 126, 376, and 753 kg ha-1) and four methods of application of superphosphate (surface spread i.e. topdressed, surface applied in bands, placed at 5 cm depth, and placed at 1 0 cm depth). The dry matter production and phosphorus uptake results demonstrated the effectiveness of subsurface placement of superphosphate, but relative ineffectiveness of surface application during the dry winters experienced. The results also showed that root development in the dry 0-2 cm zone was restricted compared with that in the deeper moist soil layers. Soil phosphorus tests showed that one year after topdressing phosphorus had not moved below the 2-4 cm depth layer, even at 753 kg ha-1 of superphosphate.


1982 ◽  
Vol 4 (2) ◽  
pp. 78
Author(s):  
PA Wright

The extensive and radical change in pastoral land treatment and management which has taken place on the Northern Tablelands of New South Wales since 1950 has greatly increased the demand on available water, and has at the same time affected the amount and rate of water run-off into streams and dams, and the nature and permanency of springs and streams. This has not only created problems of water scarcity on the Tablelands, but it has serious implications for the Darling River system, of which the Tablelands form a major source of supply, because of reduced run-off into headwater streams, and additional retention of water for livestock in larger, and an increased number of, farm dams. The onset of drought in 1980 precipitated an immediate and serious shortage of water for livestock and urban use. A recognition that this was partly man induced led to the establishment of a Water Management Research project, jointly sponsored by land users and the University of New England. In 1981-2 a detailed study was undertaken of a typical Tablelands area, the Severn River basin, to ascertain and quantify the effects of changed land management. The results of the study, its implications, and conclusions drawn from it are discussed.


1991 ◽  
Vol 42 (3) ◽  
pp. 531 ◽  
Author(s):  
DC Godwin ◽  
GJ Blair

Seed collections of 'naturalized' white clover (Trifolium repens L.) accessions, believed to have been derived from a Dutch 'wild white' clover introduced into the Northern Tablelands area of New South Wales were made. The collections were made from areas with low, high, and intermediate concentrations of extractable soil phosphorus. In a controlled environment pot experiment, the shoot and root growth and P uptake of each of these accessions was compared over a range of six P rates to three commercially available accessions-Ladino, Grasslands Huia, and Haifa and an accession from Algeria. Various methods of determining the efficiency of ultilization of P were examined. By all methods studied, Ladino generally was more efficient at utilizing applied P. Ladino produced a larger shoot biomass and greater length of root than other accessions, had a higher P uptake, and was more efficient in utilizing this P for the synthesis of biomass. The rankings of the clover accessions in terms of P efficiency changed according to the definition used. The study suggests that some scope exists for selection for P efficiency in clover accessions.


Sign in / Sign up

Export Citation Format

Share Document