A laboratory study of phosphorus mobilisation from commercial fertilisers

Soil Research ◽  
2003 ◽  
Vol 41 (6) ◽  
pp. 1201 ◽  
Author(s):  
D. Nash ◽  
M. Hannah ◽  
L. Clemow ◽  
D. Halliwell ◽  
B. Webb ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Total Variation ◽  
Laboratory Study ◽  
High Moisture ◽  
Single Superphosphate ◽  
South Eastern ◽  
Extractable P ◽  
Eastern Australia ◽  
Water Extractable ◽  
South Eastern Australia

Phosphorus (P) exported from pastures following fertiliser application contributes to the nutrients and associated problems in the streams and rivers of south-eastern Australia. This laboratory study examined whether attributes of P fertilisers may affect P exports soon after their application to field soils; 3 commercial fertilisers [diammonium phosphate (DAP), single superphosphate (SSP), and sulfur-coated single superphosphate (CSSP)] were applied to 2 repacked soils (Arawata and Ellinbank) at 5 moisture contents.Soil type was the most important factor affecting water-extractable P (expressed as a percentage of the P added as fertiliser), accounting for 30% of the total variation. The majority of this variation is explained by the water-extractable P concentrations in the Arawata low moisture treatments. These treatments [7, 6, and 6% soil moisture when equilibrated at 99, 95, and 86.5% relative humidity (RH), respectively] contained water-extractable P concentrations c. 3 times higher than the high moisture (c. 20 and 25% soil moisture) or the Ellinbank treatments. This result probably reflects differences in soil properties including the extent of water repellency and P adsorption.Fertiliser type explained only 6.9% (P < 0.001) of the total variation in water-extractable P, partially as a result of the 86.5% RH (a low moisture) Arawata treatment. In this Arawata low moisture treatment, the mean extractable P was similar for both DAP and SSP, 13.1% [least significant interval (l.s.i.) 16.7–10.3] and 11.3% (l.s.i. 14.3–8.9), respectively, but for SSP, water-extractable P increased over time unlike any other treatment. Water-extractable P from DAP was approximately double that from SSP for the Ellinbank and high moisture treatments. The higher water-extractable P following DAP application is explained in terms of its chemical properties and reaction products. Sulfur coating the SSP granules (CSSP) increased water-extractable P, as did higher soil moisture.This study suggests that under conditions present in most pastures in south-eastern Australia and depending on soil hydrology, water-extractable P and P export from fertilisers may increase in the order DAP > CSSP > SSP if overland flow occurs soon after their application.

Climatic conditions for seedling recruitment within perennial grass swards in south-eastern Australia

2012 ◽  
Vol 63 (4) ◽  
pp. 389 ◽  
Author(s):  
R. Thapa ◽  
D. R. Kemp ◽  
M. L. Mitchell
Keyword(s):  
Soil Moisture ◽  
New South ◽  
Perennial Grass ◽  
New South Wales ◽  
Climatic Conditions ◽  
South Eastern ◽  
South Wales ◽  
Eastern Australia ◽  
Moisture Conditions ◽  
South Eastern Australia

Recruitment of new perennial grass plants within existing grassland ecosystems is determined by seed availability, suitable microsites, nutrients and climatic conditions, water and temperatures. This paper reports on the development of criteria to predict recruitment events using modelled soil moisture conditions associated with recruitment of species in five field experiments at Orange (Phalaris aquatica), Trunkey Creek (Austrodanthonia spp.), and Wellington (Bothriochloa macra) in central New South Wales, Australia, and the frequency of those conditions during the past 30 years. Recruitment events were recorded when a rainfall event (median 68 mm across the three sites) kept the surface volumetric soil moisture (0–50 mm) above the permanent wilting point for at least 15 continuous days, allowing for, at most, two ‘dry days’ in between. A key finding from our study is that rainfall events creating favourable soil moisture conditions for seedling emergence typically occurred in the second half of February, sometimes extending to early March. Previously it was thought that recruitment would more likely occur through autumn, winter, and spring when rainfall in southern Australia is more reliable. The 30 years’ data (1975–2004) showed that the P. aquatica site had a median of 20 continuous moist days each year in February–March, whereas, there were 16 and 10 days for the Austrodanthonia and B. macra sites, respectively. The probabilities of exceeding seven or 15 continuous days of moist surface soil were 98% and 78% at the P. aquatica site, 91% and 49% at the Austrodanthonia site, and 73% and 30% at the B. macra site, and indicated that some recruitment is possible in most years. These analyses were extended to several sites across New South Wales, Victoria, and Tasmania to estimate the frequency with which recruitment could occur within natural swards. Across these sites, the probabilities of exceeding seven continuous days of soil moisture were >55% and of exceeding 15 continuous days were lower, which showed that suitable climatic conditions exist during late summer–early autumn across south-eastern Australia for a recruitment event to occur. Future research may show that the criteria developed in this paper could have wider regional application.

Experimental Embryonation and Survival of Eggs of Capillaria-Hepatica (Nematoda) Under Mouse Burrow Conditions in Cereal-Growing Soils

1987 ◽  
Vol 35 (4) ◽  
pp. 337 ◽  
Author(s):  
DM Spratt ◽  
GR Singleton
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
High Rate ◽  
Capillaria Hepatica ◽  
South Eastern ◽  
Eastern Australia ◽  
Soil Temperatures ◽  
Main Period ◽  
South Eastern Australia

The apparent absence of the nematode Capillaria hepatica in mice from regions of south-eastern Australia where plagues occur may be due to constraints on embryonation and survival of eggs in the mouse burrow, where C. hepatica is thought to be transmitted. Excavation of mouse burrows in the mallee wheatlands indicated that nest chambers generally were at depths of 200-400 mm. At these depths minimum and maximum weekly soil temperatures during the main period of mouse breeding ranged from 15 to 36.5�C and soil moisture contents were 14.5-32.8%. Embryonation and survival of C. hepatica eggs were assessed in the laboratory in three types of soil over these ranges of soil temperature and soil moisture content, emulating conditions of the mouse burrow. Two of the soil types, Walpeup sandy loan and Deniliquin riverine clay, are representative of the light and heavy soils, respectively, where mouse plagues occur in south-eastern Australia. The third type of soil was a potting mixture previously used experimentally and known to support a high rate of transmission of C. hepatica. Eggs were able to embryonate, and embryonated eggs to survive for 30 days, in each type of soil across the ranges of temperature and moisture content. The results further support the potential of C. hepatica to be used tactically in suppressing mouse numbers in the cereal-growing regions of south-eastern Australia.

scholarly journals Sensitivity of isoprene emissions to drought over south-eastern Australia: Integrating models and satellite observations of soil moisture

2019 ◽  
Vol 209 ◽  
pp. 112-124 ◽  
Author(s):  
Kathryn M. Emmerson ◽  
Paul I. Palmer ◽  
Marcus Thatcher ◽  
Vanessa Haverd ◽  
Alex B. Guenther
Keyword(s):  
Soil Moisture ◽  
Satellite Observations ◽  
South Eastern ◽  
Eastern Australia ◽  
South Eastern Australia
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