Amelioration of Aluminum Toxicity in Red Soil Through Use of Barnyard and Green Manure

Abstract

Aluminum toxicity can affect the growth of crops in the red soil of southern China. The present study investigates the effect of both the long‐term and the short‐term application of organic manure on the aluminum toxicity of the soil. A significant effect of barnyard and green manure on the detoxification of aluminum resulted from the long‐term application of manure in a pot culture. This was due mainly to the considerable accumulation of organic matter in the soil. Organic matter chelates and absorbs active aluminum; as a consequence, the aluminum toxicity was reduced. At the same time, the manure provided the crop with nutrients. In another pot culture, fresh green manure had remarkable effects on aluminum detoxification shortly after application, whereas fresh barnyard manure did not. This indicates the important role of low molecular organic acids, which are released during the decomposition of green manure, in the detoxification of aluminum in the soil. Furthermore, the ash elements, which were released by the decaying manure, may also detoxify soil aluminum.