Influences of Different Organic Fertilizers and Amendments on Nematode Trophic Groups and Soil Microbial Communities during Strawberry Growth

摘要

Beneficial soil nematodes are usually more abundant in crop management systems subjected to sophisticated crop sequences and organic amendments. However, the effect of the non-plant-parasitic and bacteria-feeding nematodes on plant-growth-promoting bacteria and on horticultural plants is not still well understood, particularly concerning the application of organic inputs and microbial inocula as soil amendments. A rhizobox experiment and a field study were conducted on 'Elsanta' strawberry to monitor the structure of nematode communities and microbial populations, as well as plant growth, in response to addition of five different organic fertilizers and amendments: dry manure, a seaweed extract, a compost extract, a stillage from yeast production, and a microbial consortium composed of mycorrhizal fungi, Plant Growth Promoting Rhizobacteria (PGPRs) and Trichoderma. Plants not receiving any treatment were used as control. Soil samples were taken before applying the products and in the fall. Plant growth was enhanced by the products. They generally induced an increase in the total population of nematodes, by increasing the bacterial and fungal feeding species, as well as the microbial rhizospheric populations. All products induced a decrease in the plant parasite nematode species. This resulted in lowering the ratio between plant parasite and the other trophic groups. Some products influenced the nematode community even if they were applied as foliar, suggesting an effect through the exudates the plant releases into the rhizosphere. The increase in bacterial and fungal-feeding nematodes induced by the microbial inoculum may affect the efficacy of this kind of products. Since the various organic amendments and fertilizers applied affected the nematode community in a relatively short time, long term effects of these products may benefit soil quality and plant growth and health.