Mechanisms controlling temporal variation in throughfall chemistry

Book · Mon Jan 01 04:00:00 EST 1979

OSTI ID:5300967

Bush, D S

The amount and concentration of K, Na, Ca, Mg, and NO/sub 3//sup -n/ in rainwater collected in the open was compared to the amount and concentration of these elements in rain collected under a Eucalyptus globulus canopy (i.e. throughfall). Throughfall contained higher concentrations and greater amounts of all elements than did precipitation. In the two years that throughfall samples were obtained, Na was the element present in greatest amount, followed by K > Ca > Mg > NO/sub 3//sup -n/. Variables which were found by statistical analysis, to influence the concentration of elements in enrichment for individual storms, were the volume of precipitation, precipitation intensity, the length of the dry period, and the concentration of atmospheric particulates. Laboratory investigation of the time course of nutrient release from eucalyptus leaves immersed in water, showed that elements are lost rapidly in the initial stage of wetting. The existance of surface particles on leaves was demonstrated by scanning electron microscopy. It was concluded therefore, that the source of the elements present in throughfall which were added to precipitation by the canopy (i.e. enrichment), was surface material deposited on leaves during the dry period between rains. A compartment model of the canopy is proposed to explain the observed temporal variation in throughfall between years, between storms, and within storms. This model depicts the canopy as a storage compartment of atmospheric and plant substances which accumulate during the dry period and are removed by rain.

• OSTI ID: 5300967
• Country of Publication: United States
• Language: English

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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALI METALS
ALKALINE EARTH METALS
ATMOSPHERIC PRECIPITATIONS
CALCIUM
CONTAMINATION
DISASTERS
ECOLOGICAL CONCENTRATION
ELEMENTS
EUCALYPTUSES
FOLIAR UPTAKE
HYDROGEN COMPOUNDS
MAGNESIUM
METALS
NITRATES
NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PLANTS
POTASSIUM
PRECIPITATION SCAVENGING
RAIN WATER
SAMPLING
SEPARATION PROCESSES
SODIUM
STORMS
SURFACE CONTAMINATION
TREES
UPTAKE
WATER