ISHS Acta Horticulturae 382: IV International Symposium on Soil and Substrate Infestation and Disinfestation
IMPROVED SOIL DISINFESTATION BY BIOTOXIC VOLATILE COMPOUNDS GENERATED FROM SOLARIZED, ORGANIC-AMENDED SOIL |
| Authors: | A. Gamliel, J.J. Stapleton |
| Keywords: | Cruciferae, volatile compounds, poultry manure, integrated control |
| Abstract:
Combining organic amendments with soil solarization is a nonchemical approach to improve control of soilborne plant diseases. Pathogen control in the solarized-amended soil is attributed to combination of thermal killing and generation of biotoxic volatile compounds. Apparently, pathogen sensitivity to volatile compounds is increased as soil temperature increased, and in addition the pathogens are exposed to antagonistic microbial activity. Toxic compounds were detected in soil amended with cabbage residues during heating including alcohols, aldehydes, sulfides, isothiocyanates and other. A significant relationship between amount of volatile compounds generated and level of pathogen control was established. Overall microbial activity was reduced in cabbage-amended soil after heating. However, microbial activity was not inhibited by volatile compounds alone. It is possible, that volatile compounds emanating from heated soil are selectively toxic, or that microbial antagonism plays a role in pathogen control. Field solarization of soil amended with composted chicken manure gave better control of Meloidogyne incoqnita and Pythium ultimum and higher yield of lettuce and tomato than either treatment alone. Numbers of propagules of pathogenic fungi, as well as of total fungi, were significantly reduced in the rhizosphere of plants grown in compost-amended, solarized soil. Colonization of plant roots by bacteria such as fluorescent pseudomonads and Bacillus spp. was not inhibited by the combined treatment of solarization of manure-amended soil. | |
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