Assessment of biological soil fatigue in horticultural monocultures

Abstract

Biological soil fatigue in horticultural monocultures awakes the highest interest and presents the highest discrepancy. Different studies associate it with soil pathogens as causing agents, while others determine it in the lack of these. This work deals with the assessment of fatigue existence, a phenomenon which can be appreciated in the field, but a numerical model that provides data about yield losses and lack of plant vigour has not been found. Trial planning consisted of adding fresh organic matter through biodisinfection techniques and providing knowledge about the phenomenon and its relation with the content of organic matter and soil microbiota. For this reason, soils of two greenhouses were compared, the differences between them were the type of crop (cucumber and tomato respectively) as well as the supplying or non supplying of organic amendments. The content of organic matter and the soil or telluric microbiota (fungi, bacteria and oomycetes) in the soils were studied, as well as its effect on cucumber and tomato seedlings under controlled conditions. The results showed that fatigue appeared in soil with low content of organic matter, which showed at the same time lower density and diversity of fungal population. The addition of fresh organic matter seems to reconstitute the productive capacity of the soils, and this mitigates the fatigue and monoculture effects.