Copper(Cu)was designated as a specific substance in the Agricultural Land Soil Pollution Prevention Act in Japan.It has been known that high Cu concentrations in soil layers reduce rice crop production and thus agricu...Copper(Cu)was designated as a specific substance in the Agricultural Land Soil Pollution Prevention Act in Japan.It has been known that high Cu concentrations in soil layers reduce rice crop production and thus agricultural practices such as soil dressing have been applied to minimize the damages to crops by copper pollution.In this study,authors investigated the effects of percolation patterns of the under-plowsole and subsoil on growth and yield,and copper uptake of paddy rice.Six stratified paddy field models were constructed to conduct the growth tests under the condition in which the percolation patterns of the under-plowsole and subsoil were in an open and closed system.These models have a plow layer(10 cm thickness)and upper-plowsole(2.5 cm thickness)made with 12.5 cm-thickness of non-polluted soil dressing(3.7 mgCu?kg-1)and an underlying 15 cm-thickness of polluted under-plowsole(7.5 cm thickness)and subsoil whose Cu concentration was higher or lower than Japanese safety standard(approximately 100 mgCu?kg-1,150 mgCu?kg-1 and 500 mgCu?kg-1,respectively).During the tests,a constant water-ponding system was adopted,and mid-summer drainage was not done.As a result,Cu concentrations of the rice grains were 5%significantly higher in the open system percolation models regardless of the original amount of Cu in the under-plowsole and subsoil.On the other hand,authors did not recognize any significant differences in growth and yield of rice plants among the models.Authors concluded that the Cu concentrations in rice plants are affected by percolation patterns of polluted plowsole and subsoil even though they are covered with non-polluted soil dressing layers.展开更多
文摘Copper(Cu)was designated as a specific substance in the Agricultural Land Soil Pollution Prevention Act in Japan.It has been known that high Cu concentrations in soil layers reduce rice crop production and thus agricultural practices such as soil dressing have been applied to minimize the damages to crops by copper pollution.In this study,authors investigated the effects of percolation patterns of the under-plowsole and subsoil on growth and yield,and copper uptake of paddy rice.Six stratified paddy field models were constructed to conduct the growth tests under the condition in which the percolation patterns of the under-plowsole and subsoil were in an open and closed system.These models have a plow layer(10 cm thickness)and upper-plowsole(2.5 cm thickness)made with 12.5 cm-thickness of non-polluted soil dressing(3.7 mgCu?kg-1)and an underlying 15 cm-thickness of polluted under-plowsole(7.5 cm thickness)and subsoil whose Cu concentration was higher or lower than Japanese safety standard(approximately 100 mgCu?kg-1,150 mgCu?kg-1 and 500 mgCu?kg-1,respectively).During the tests,a constant water-ponding system was adopted,and mid-summer drainage was not done.As a result,Cu concentrations of the rice grains were 5%significantly higher in the open system percolation models regardless of the original amount of Cu in the under-plowsole and subsoil.On the other hand,authors did not recognize any significant differences in growth and yield of rice plants among the models.Authors concluded that the Cu concentrations in rice plants are affected by percolation patterns of polluted plowsole and subsoil even though they are covered with non-polluted soil dressing layers.
