An extensive study of over 250 soil samples from three south Indian States -Kerala, Karnataka and Tamil Nadu - has shown that most of the banana fields contain amounts of copper, magnesium, chromium and cobalt that are higher than the threshold levels.
Researchers from the Laboratory of Plant Science and Ecology at Mahatma Gandhi University, Kottayam, collected the different soil samples, categorised them according to soil taxonomy and used atomic absorption spectroscopy studies to analyse the level of different heavy metals.
“We found an unusually high level of magnesium in the fields studied. While the magnesium content of soil in South Indian soil is known to be between 30 and 220 mg/kg, the average of the samples tested was above 900 mg/kg,” says dr. K.S. Nidheesh, from St Joseph’s University, Dimapur in Nagaland.
“This is a result of farmers using chemical fertilizers without proper soil testing and applying above the recommended level. As banana is highly prone to insect and nematode attack, they also more pesticides, which get accumulated in the soil.”
Calcium levels almost reached the thresholds in many fields. Another heavy metal recorded was manganese, a major component of pesticides used against fungal diseases like Fusarium wilt.
Though the concentration of iron was high, this might be due to the laterite-based soil of the Deccan Plateau. Chromium, which rarely occurs naturally in soil, was detected in all the samples studied, and The Hindu reported that many samples were at levels near the threshold.
“This is a result of farmers using chemical fertilizers without proper soil testing and applying above the recommended level. As banana is highly prone to insect and nematode attack, they also more pesticides, which get accumulated in the soil.”
Calcium levels almost reached the thresholds in many fields. Another heavy metal recorded was manganese, a major component of pesticides used against fungal diseases like Fusarium wilt.
Though the concentration of iron was high, this might be due to the laterite-based soil of the Deccan Plateau. Chromium, which rarely occurs naturally in soil, was detected in all the samples studied, and The Hindu reported that many samples were at levels near the threshold.
