Manganese toxicity in an acid soil

Abstract

The occurrence of manganese toxicity in French bean grown on an acid soil (referred to as the Dagun soil) is reported. The manganese content of the plants in the field varies with the pH of the soil, reaching to 3,000 ppm at pH 4.4. Healthy plants contained between 200 ppm and 1,000 ppm manganese, and values greater than 1,000 ppm nay be regarded as indicating manganese toxicity. The amount of exchangeable manganese in the soil is not a reliable criterion for predicting manganese toxicity, but if the pH is low and the easily reduced manganese high, the soil can be regarded as suspect. French bean is a good indicator plant for excessive manganese in the soil. A pot trial indicated that the excessive uptake of manganese by French bean grown on the Dagun soil can be controlled by applying lime to raise the pH to about 5.4. Some evidence is presented that pineapples grown in the Dagun soil and peanuts grown on certain other soils suffer from manganese toxicity.