Page 26 - Volume 2, Issue 1, January 2009
Basic HTML Version
© Benaki Phytopathological Institute
Giannopolitis & Kati
26
Table 2.
Glyphosate adsorption and pH of four soils, at weekly intervals after the addition of
0.3 g of superphosphate per 100 g of soil (260 ppm P). Sorption was determined with batch
equilibration experiments using 1 g of soil and 10 ml of a 20 ng/ml solution of glyphosate.
Soil
KA1
H1
K2
H3
Control
+P Control
+P
Control
+P
Control
+P
Days
Glyphosate adsorbed ng/g
8
102.5 131.8 138.2
152.1
94.7
90.1
41.6
37.9
15
97.8 125.2 108.1
135.6
97.1
92.5
41.6
36.6
21
98.0 129.3 116.6
157.3
96.9
96.8
38.1
39.5
30
101.5
129.1 109.2
172.0
99.6
100.5
45.5
39.3
Mean
100.0 128.9**
118.0
154.3*
97.1
95.0 NS
41.7
38.3 NS
Days
pH (H
2
O)
8
5.7
5.2
7.1
6.7
7.6
7.4
8.2
7.5
15
5.7
5.1
7.2
6.6
7.6
7.5
8.3
7.3
21
5.8
4.9
7.3
6.4
7.6
7.5
8.2
7.3
30
5.8
5.0
7.2
6.4
7.6
7.5
8.2
7.4
Mean
5.8
5.1**
7.2
6.5**
7.6
7.5*
8.2
7.4**
Means for +P are statistically different at the 0.05 (*) and 0.01 (**) levels, or non-statistically different (NS), according
to a t-test comparison with the respective control means.
Figure 1.
Glyphosate adsorption by the four soils, 3 weeks after the addition of superphosphate at 0.3 g/100 g (260 ppm
P). Adsorption was determined with batch equilibration experiments using 1 g of soil and 10 ml of one of three glyphosate
solutions (4.0, 8.3 and 25.7 μg/ml).
