Vol. 16—1962 - NorthEastern Weed Science Society

The results were similar to those obtained previously. There was more
arsenic in the bluegrass grown in the 1 and 100 ppm P nutrient solutions
than in that grown in the 10 ppm P nutrient solution.. Likewise, crabgraas
grown in the 1 ppn P nutrient solution had a much higher concentr~tion of
arsonic than crabgrass grown in the higher phosphorus nutrient solutions
or thall bluegrass grown in the 1 ppm P nutrient solution.
ljlir~~ Research Officer in ••Weed Control, Field Crops Section,
Canada Department of llgriculture Research Station, Fredericton, New Brunswick.
formerly Research Ass; st.",11t.-: DAn",..t.mAYlt, "f' ","'10m 0.,.""" l~,,+"~.. o
EFFIDJTOF PHOSPHORUSON THEUPTAKEOF TRICALCIUMARSENATE
BY BWmRASS LNDCRABGRASS
C. Fred Everett
l
and Richard D. Ilnicki 2
ABSTRACT
The phosphorus level in a soil is considered to be one of several
factors which influence the phytotoxicity of arsenic.
303
An established Kentucky bluegrass sward was fertilized in the fall
with three rates of phosphorus: 0,75 and 150 lb. F20S/a. The soil was a
Nixon sandy loam which was low in available phosphori\ls. Two pH levels,
S.O and 6.0, were established by additions of sulfuric acid. "Low lime"
tricalcium arsenate at 0, 3, 6 and 9 lb. of As per thousand square feet
was applied the following March. Grass was harvested in June and August
of the same year.
The arsenic and phosphorus coneerrtr-atdona in the grass were not
affected by the additions of phosphorus to the sward. The higher pH slightly
decreased the arsenic content of the grass. The application of higher
rates of arsenate slightly increased the ars~nic concentration. There was
no visible sign of injury to the bluegrass.
In the greenhouse Merion blue'grass and crabgrass plants grown in a
nutrient solution with 10 ppn of phosphorus were preconditioned for one
week in nutrient solutions having 1, 10 and 100 ppm of phosphorus. "low"
lime" tricalcium arsenate and sodium arsenite treatments were applied and
the plant tops harvested 24, 48 and 72 hours later.
High levels of phosphorus in the zmtrient solution reduced the phytotoxicity
of the arsenate treatments to practically nil, but they did not
influence the phytotoxicity of the arsenite treatment. The phosphorus
concentration in the bluegrass tops grown in the 100 ppn P nutrient
solution was five fold greater than that in the bluegrass grown in the 1
ppm P nutrient solution. Bluegrass from the 1 and 100 ppn P nutrient solutions
contained two to three times as much arsenic as bhiegraae grown
in the 10 ppm P nutrient solution. On the other hand, crabgraae had the
most arsenic when grown in the 1 ppm P nutrient solution and by far the
least when grown in the 100 ppn P nutrient solution.
"low lime"6tricalcium arsenate was synthesized in the laboratory and
tagged with As7. This was applied to nutrient solutions as above. The
bluegrass and crabgrass toPll. 6were
harvested 9, 18 and 36 hours later,
digested and counted for As7•