Biochar Effects on Vitis Vinifera L. Fine Roots Seasonal Pattern: Field Trial Results

Effects of biochar on productivity of crop plants, such as grapevine, has been widely reported (Baronti et al., 2010; 2014; Genesio et al. 2015). However, despite their importance, very few knowledge have been produced on the effects of biochar on plant fine roots. Ephemeral fine roots, the major water and nutrient absorbing structures in plants, require up to 33% of global annual net primary productivity in terrestrial ecosystems and up to 50% of daily photosynthate for growth and maintenance in crop plants (Jackson et al. 1997). Therefore, fine root lifespan has important implications for plant growth, crop productivity, below-ground carbon (C) and nutrient cycling. This study, conducted in a vineyard, is aimed at investigating the impact of biochar application (at the rate of 10 t/ha) on soil chemical and physical properties, fine roots dynamics and ectomycorrhizal mycelium production during one year sampling. Results show that biochar improves soil organic carbon content while pH value, cation exchange capacity, total nitrogen, total phosphorous and available phosphorous remained unaffected. Biochar did not show any significant effect in ectomycorrhizal mycelium annual production, but immediately after the soil amendment it determines an increase of fine root mean annual biomass, production and lifespan (i.e. turnover rate). Data indicate that the fine root biomass increase is mainly due to the radial growth since mean fine root diameter was higher in treated plants while fine root length did not show any variation. The present study highlights the significant hort-term influence of biochar, on fine root dynamics.