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vertosol soil

Catalogue: GRDC Updates
Many soils may already have lost much of this extra, slow release P reserve... Soil testing for available P status commonly involves a Colwell test on the 0-10 cm layer... The paper summarises some recent work that attempts to quantify the differences in availability of sparingly soluble P sources as affected by soil acidification...
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Catalogue: GRDC Media
Subsoil reserves of mineral nutrients such as P have been run down over recent decades, with practices such as direct drill cropping accelerating the loss... The GRDC fact sheet recommends testing subsoil (10 to 30 centimetres) P levels, using both the Colwell-P and BSES-P tests across the farm, as the key to making an informed decision about fertiliser strategy... Soil testing provides an understanding of your fertility profile and is a vital step in making informed fertiliser decisions...
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Catalogue: GRDC Updates
Root proliferation in response to S fertiliser is questionable and requires more research... We are using young seedlings to screen because a) they fit in the scanner (!) and b) early responses to banded nutrients by seedlings are easily measured at this stage... Interestingly we did observe an increase in root proliferation in the band of S; this was accompanied by increased P uptake and the result suggests that the form in which we applied S (i.e. gypsum) increased the availability of P. Further work is currently being undertaken to confirm this, and to set up experimental conditions that will allow us to apply banded S so that the S remains available, whilst not increasing P availability in the soil...
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Catalogue: GRDC Final Reports
ROOTMAP can be used to improve the strength of an experimental design by simulating the effect of different seasons on an experiment; identifying treatments most likely to provide the range of results needed; identifying the number of replications required to produce stable results; investigating the relationship between root growth in a glasshouse study and in the field; and extending the design to test other treatments that might be relevant to the hypothesis... ROOTMAP can also be used to extend research findings beyond pot boundaries and beyond the 2D measurement method used... To date, the use of ROOTMAP has been largely restricted to the creators and developers of the model and close collaborators because of the level of programming and modelling skills required to run it...
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Catalogue: GRDC Updates
Figure 1: Effects of (a) application of an additional 40-60 kg P/ha to soils prior to planting, relative to normal starter P applications alone; and (b) placing that additional P deeper in the soil profile (15-20cm), compared to surface (5-7cm) bands... half of the soil P removed by cropping comes from below the top 10cm and about 90% of that removed P comes from forms/pools of P not measured in the Colwell (bicarbonate P) soil test; and (ii) when luxury rates of P are applied annually , >95% of the residual P stays in the top 10cm of the profile and the depletion of the subsoils continued unchanged... , we used a bioassay to assess how much of the P in the various pools was actually available for plant uptake, and how well this correlated with what the Colwell test predicted...
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Catalogue: Ground Cover
Vertosol soils reveal dual-purpose potential.. The cracking clay soils of northern NSW may be grazed without detracting from yields.. Tracking collars were used to create a map of 'livestock residence' during the grazed period and clods were collected from 10 to 20-centimetre depth and scanned using CT (soil X-rays) to assess changes in porosity (Figure 1)...
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