ISHS Acta Horticulturae 698: VI International Symposium on Chemical and non-Chemical Soil and Substrate Disinfestation - SD2004
PRELIMINARY RESULTS OF PHYSICAL SOIL DISINFESTATION BY HOT AIR |
| Authors: | W.T. Runia , A. Greenberger |
| Keywords: | soil disinfestation, hot air, metam sodium, steam, substrate cultures, flowers, open field vegetables, arable crops, Meloidogyne fallax |
| Abstract:
In the Netherlands, where methyl bromide as soil fumigant has been banned completely since 1992, several alternatives are applied to control soilborne pathogens and pests. In protected cultivation fruit vegetables are completely grown in substrates and cut flowers partially. Soil with cut flowers is frequently steam sterilized. In field vegetables and arable crops the soil can be fumigated once in five years with metam sodium. A new development in physical soil disinfestation is the application of hot air. The method has been developed in Israel and is applied in this country commercially for some years now. The method is based on blowing extremely hot air into rotavating humid soil. An optimal speed of blowing air and rotavator enables each individual soil particle to reach a temperature high enough to weaken or kill any pathogen or pest attached. The efficacy of hot air treatment in Israel was mainly established in commercial fields, infested with pathogenic nematodes or fungi. There were no results available based on scientific trials. Nevertheless an improved growth in several crops like potato, cauliflower, kohlrabi and the flower crop Esclepia was noticed. Pathogens may still be present in the soil after the hot air treatment but are regarded to be weakened by the hot air and not viable anymore to infect new crops. Research in the Netherlands against Meloidogyne fallax showed no direct decrease in nematode counts after hot air treatment, whereas metam sodium and steam sterilization reduced the nematode counts for at least 99%. Currently the viability of the nematodes is determined in a field trial with potato as an intolerant test crop. Effects on yield, quality and nematode infestation levels are measured. In a bio assay with tomatoes planted in hot air treated soil and steam sterilized soil a higher fruit weight of tomato was produced, metam sodium showed the same fruit weight in comparison with untreated soil. All treatments resulted in a lower root knot index. Hot air treatment is a very promising method for soil disinfestation; further research has to be performed to establish the possibilities and limitations of this method under several climatic conditions. Thanks to the limited fuel consumption and a sufficient disinfestation capacity this method might be an economically interesting alternative to methyl bromide for open field as well as protected cultivation. | |
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