|
A survey of pesticide and copper residues of the citrus orchard soil was conducted during October 1979-June 1980 in Jeju, Seogwipo county. The citrus orchards were classified into five groups according to different cultivated period; 5 year orchard, 10 year orchard, 15 year orchard, 20 year orchard, and 30 year orchard. Each of the above samples was divided again to three layers of soil depth; the surface layer(0∼10㎝), the middle layer (10∼20㎝), and the bottom layer (20∼40㎝). In this experiments, Kelthane and Akar, as well as copper residues were detected in all soil samples. Residue levels of above chemicals were increased in soils of orchard with longer cultivation periods, and at the same time, decreased with soil depth. The residues of those ranged as follows; a) from trace to 1.359ppm in Kelthane, b) from trace to 0.925ppm in Akar, and c) from trace to 40.734ppm in copper. It is noted that the average residues of Kelthane was 0.251ppm, Akar, 0.120ppm, and that of copper was 2.168ppm, respectively.
|