United Kingdom
April 15, 2009
Crop growth, drinking water and
recreational water sports could all be adversely affected if
predicted changes in rainfall patterns over the coming years
prove true, according to research published this month in
Biology and Fertility of Soils.
Scientists from Biotechnology
and Biological Sciences Research Council (BBSRC)-funded
North Wyke Research have found for the first time that the rate
at which a dried soil is rewetted impacts on the amount of
phosphorus lost from the soil into surface water and
subsequently into the surrounding environment.
Dr Martin Blackwell who is one of the project leaders said: "Our
preliminary results show that despite best efforts, the changing
climate may limit our ability to mitigate phosphorus losses at
certain times of the year, especially summer.
"This is really worrying because high phosphorus concentrations
in surface waters can lead to harmful algal blooms which can be
toxic, cause lack of oxygen during their decay and disrupt food
webs. This can also affect the quality of water for drinking and
result in the closure of recreational water sport facilities."
Under laboratory conditions Dr Blackwell and his team re-wet
dried samples of UK grassland soil over different time periods,
ranging from two hours to 24 hours using the same quantity of
water. The leachate – water that has washed through the soil –
was then analysed for phosphorus. The study showed that the rate
at which a dried soil is rewetted affects the concentration and
forms of phosphorus lost in leachate which could potentially
contaminate surface water bodies (e.g. rivers and lakes).
The current research looked at only one soil type so it is not
yet known whether other soil types would react in the same way.
This is what Dr Blackwell and his team will look at next.
Commenting on the findings, Prof Douglas Kell BBSRC Chief
Executive said: "If we are to ensure safe and sufficient food
and water supplies in the future then we must be absolutely
clear on the challenges that a changing climate presents us.
Having this information now means that we can be prepared to
deal with the consequences of altered rainfall patterns at a
local, national and international level to secure harvests, and
protect water supplies."
This work is published in the journal Biology and Fertility of
Soils
To view the paper online visit
www.springerlink.com/content/m518138780326733/?p=5fb100b6878d4285b76bede4a9534b32&pi=1
The Biotechnology and Biological Sciences Research Council
(BBSRC) is the UK funding agency for research in the life
sciences. Sponsored by Government, BBSRC annually invests around
£420 million in a wide range of research that makes a
significant contribution to the quality of life for UK citizens
and supports a number of important industrial stakeholders
including the agriculture, food, chemical, healthcare and
pharmaceutical sectors. BBSRC carries out its mission by funding
internationally competitive research, providing training in the
biosciences, fostering opportunities for knowledge transfer and
innovation and promoting interaction with the public and other
stakeholders on issues of scientific interest in universities,
centres and institutes.
The Babraham Institute, Institute for Animal Health, Institute
of Food Research, John Innes Centre and Rothamsted Research are
Institutes of BBSRC. The Institutes conduct long-term,
mission-oriented research using specialist facilities. They have
strong interactions with industry, Government departments and
other end-users of their research.
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Effects of soil drying and rate of re-wetting on
concentrations and forms of phosphorus in leachate
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M. S. A. Blackwell1,
P. C. Brookes2,
N. de la Fuente-Martinez1,
P. J. Murray1,
K. E. Snars2,
J. K. Williams1
and P. M. Haygarth1,
3
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(1) |
North Wyke
Research,
Okehampton,
Devon, EX20 2SB,
UK |
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(2) |
Rothamsted
Research,
Harpenden,
Hertfordshire,
AL5 2JQ, UK |
|
(3) |
Centre for
Sustainable
Water
Management,
Lancaster
Environment
Centre,
Lancaster
University,
Lancaster, LA1
4YQ, UK |
Received:
19 January 2009 Revised:
12 March 2009 Accepted:
20 March 2009 Published
online:
4 April 2009
Abstract The
drying and
re-wetting of soils
can result in the
modification of the
amounts and forms of
nutrients which can
transfer, via
leachate, from the
soil to surface
waters. We tested,
under laboratory
conditions, the
hypothesis that the
rate of re-wetting
of a dried soil
affects the
solubilisation and
concentrations of
different forms of
phosphorus (P) in
leachate. A portion
of grassland
pelostagnogley soil
(sieved moist <2 mm)
was dried at 35°C
and another portion
maintained at
approximately 40%
water-holding
capacity. Water
(25 ml) was added at
ten regularly spaced
time intervals in
2.5-ml aliquots to
the surfaces of both
soils over periods
of 0, 2, 4, 24 and
48 h, resulting in
different rates of
application. The
leachate was
collected and
analysed for
dissolved (<0.45 μm)
and particulate
total P and
molybdate reactive
and unreactive P.
The rate of
re-wetting
significantly
changed the
concentrations of P,
especially dissolved
forms, in the
leachate. Dissolved
P concentrations
were highest in
leachate from the
2-h treatment, while
particulate P
concentrations were
highest in the 0-h
treatment leachate.
In all cases, most P
was unreactive and,
therefore, likely to
be in an organic
form. Soil drying
decreased microbial
biomass, but this
could not be
directly linked to
an increase of P in
leachate. These
results suggest that
changes in patterns
of rainfall
frequency and
intensity predicted
by climate change
scenarios could
significantly affect
the quantities of P
leached from soils.
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