ISHS Acta Horticulturae 51: Symposium on Protected Cultivation of Flowers and Vegetables
THE EFFECT OF STEAM STERILISATION OF SOIL ON THE MANGANESE UPTAKE BY GLASSHOUSE CROPS |
| Authors: | C. Sonneveld, S.J. Voogt |
| Abstract:
During steam sterilisation of soil easily reduceable manganese compounds are converted to exchangeable manganese. The amount of exchangeable manganese released during the process depends on the amount of reduceable manganese present in the soil, the duration of the steaming treatment and the temperatures reached. Manganese uptake by the crops is influenced by a great many factors. On Dutch steam sterilised glasshouse soils it was found that the uptake is controlled mainly by the cation exchange capacity, the exchangeable manganese content and the pH of the soil. The incidence of manganese toxicity does not depend only on the amount of manganese absorbed by the crop, but also on the sensitivity of the crop to manganese toxicity. Sensitive crops may display manganese toxicity symptoms at contents as low as 200 to 300 ppm Mn of the dry leaf matter. Less sensitive crops may stand contents of 1 500 ppm or more. There are sometimes great differences between varieties of the same crop in their sensitivity to manganese toxicity, despite the fact that the amount of manganese taken up may be the same. This has been demonstrated for instance in lettuce. Variations in sensitivity have also been found in different rose varieties. Differences in manganese uptake have been demonstrated in some chrysanthemum varieties. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
