Oliveira de Almeida Machado


Die Bodenkultur - Journal for Land Management, Food and Environment

P. L. OLIVEIRA DE ALMEIDA MACHADO and M. H. Gerzabek:

The Influence of Organic Matter on Aluminium Toxicity to Maize (Zea mays L.)

Summary

The importance of soil organic matter in alleviating the toxic effects of aluminium (Al) to plants has long been assumed. In order to investigate this influence on the growth of maize an experiment with sand culture was conducted. Four Al-treatments were applied: 0, 25, 50 and 75 mg AI/L. These were combined with four levels of peat, which was mixed to the sand: 0.0, 0.5, 1.5 and 3.0 % peat. The pH of the nutrient solutions was maintained at 3.8 ± 0.1.

Increasing Al-concentrations in the nutrient solution in most cases resulted in a significant growth reduction of shoots and roots. Peat treatments clearly diminished these Al-toxicity effects. Al-concentrations in shoots were hardly influenced by the various treatments. Al-contents in maize roots were augmented more then tenfolds with increasing Al-concentration of the nutrient solution in peat free treatments. Peat in the growth medium decreased Al-contents of the roots significantly.

Shoot and root analyses reflected reductions in calcium, magnesium and phosphorus with increasing Al in the 0 % peat treatment. In the presence of organic matter these reductions were partly alleviated. Leaves of plants in peat-free pots showed symptoms of magnesium deficiency 12 days after addition of Al-treatments. Peat in the growth medium led to a higher Mg-level in shoots and roots and therefore to a reduction of Mg-deficiency.