Study and assessment of compost of different organic mixtures and effect of organic compost tea on plant diseases

Summary

Four compost treatments representing different organic mixtures were studied:
- Treatment T1: 100% cattle manure
- Treatment T2: 80% cattle manure and 20% sheep manure
- Treatment T3: 70% cattle manure, 20% sheep manure and 10% poultry
manure.
- Treatment T4: 50% cattle manure, 20% sheep manure, 20% poultry manure
and 10% crushed wheat straw.
The results showed that the temperature was higher for the 4th treatment which
was richer in carbon than the other treatments.
The initial alkaline pH decreases for all treatments and approaches neutrality
at the end of composting process, essentially for the first treatment. There is also a
decrease in the carbon / nitrogen ratio.
At the maturity stage, a compost tea was prepared from different composts
after five days extraction period. The four compost teas were tested on different plant
pathogens: Fusarium roseum var sambucinum, Fusarium oxysporum, Fusarium
oxysporum, Fusarium solani var coeruleum, Phytophtora erythroseptica and
Rhizoctonia solani. All the treatments were efficient against these pathogens and
especially the 4th treatment which considerably reduces also the dry rot of Fusarium
solani in potato tubers during storage. This is considered an important result since
Fusarium solani seems to be the most important pathogen in Tunisian soils.
Our studies should be carried out in order to determine the better combination
of organic mixtures, the better method of compost tea extraction (aerobic or
anaerobic), the optimal period of extraction and doses to be used.