Glossary (trial version)
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you wish to look up.
- Particle density
- dry mass per unit volume of soil particles.
- Participatory management
- (environmental) management undertaken by local people,
making use of local resources, indigenous environmental
knowledge and management practices. Usually established
and organised using participatory appraisal techniques.
- Peak runoff
- The maximum rate of runoff at a given point or from a
given area during a specified period, in reaction to rainfall.
- An organic soil, which contains at least 65% organic matter
(less than 35% mineral material), and is at least 0.5 m
in depth and 1.0 ha in areal extent.
- Permanent wilting point
- volumetric soil moisture content at the time when plants
will suffer from water strees, caused by deficiency in soil
- (1) Qualitatively, the quality or state of a porous medium
relating to the readiness with which such a medium conducts
or transmits fluids. (2) Quantitatively, the specific property
governing the rate or readiness with which a porous medium
transmits fluids under standard conditions. See also Hydraulic
- The numerical measure of energy with which water is held
in the soil, expressed as the common logarithm of the absolute
value of the matric head in centimetres of water.
- 1 Petagram = 1015 grams = 109 metric tons = 1 gigatonne (Gt)
- A measure of the hydrogen ion concentration in a solution,
expressed as the common logarithm of the reciprocal of the
hydrogen ion concentration in gram mol per litre.
- an instrument used to measure the elevation of the water
- Plant-available water
- The difference of water retained at field capacity (pF 2.2 or a suction of 0.33 bar) and water retained at wilting
point (pF 4.2 or a suction of 15 bar).
- geological epoch dated 1.8-1.6 million to 10,000 BP. During
the Pleistocene, the climate fluctuated between cold (glacial)
and warm (interglacial) periods, causing a rise and drop
of the sea level, due to melting of the glaciers and ice
- roots rising above the level of water or soil and acting
as respiratory organ in some peat swamp forest trees
- the leaching of soluble complexes (formed by chelation)
of aluminium and iron from the A-horizon of a soil, and
the subsequent deposition of these metals, together with
organic matter, in the B-horizon. This process leads to
the formation of a soil called a podzol.
- See voids.
- The volume of voids as a fraction of the volume of soil.
- Poverty trap
- Expression to indicate a situation where decreasing farm
income due to continuous lower nominal prices for agricultural
products causes that farmers are trapped in (developing)
regions where no other employment is available
- ppm, ppmv
- for liquids and solids ppm = parts per million = µg/g
or mg/kg, for mixtures of gases ppmv = µl/l; the volume
mixing ratio ppmv is the ratio of the number of moles of
water vapour to the number of moles of dry air contained
in the volume V occupied by the mixture.
- The total amount of water received from the sky (rain,
drizzle, snow, hail, fog, condensation, hoar frost, and
- Pressure head
- the water pressure in relation to the atmospheric pressure.
In the unsaturated zone, the pressure head is negative
This glossary is based up on the published
glossary taken from the following publication:
Rieley, J. O. and S. E. Page, (2005), Wise
Use of Tropical Peatlands: Focus on Southeast Asia, ALTERRA
- Wageningen University and Research Centre and the EU INCO
- STRAPEAT and RESTORPEAT Partnerships, Wageningen, The Netherlands.
here to download a PDF copy of the publication - http://www.restorpeat.alterra.wur.nl/download/WUG.pdf
(Filesize: 23.3 Mbytes)