Influence of biostimulant application in containerized Eucalyptus globulus Labill. seedlings after transplanting

The use of biostimulants (amino acid containing protein hydrolysate) in forestry field has re- ceived much less attention so far than in agriculture. Promising evidences were reported in literature with useful application for nursery activities, stimulating early growth and reducing transplanting stress. This study investigates the potential benefits induced by an amino acid-based animal-derived protein hydro- lysate biostimulant (Siapton® by Isagro) in containerized Eucalyptus globulus seedlings following transplant- ing. Foliar and soil drench applications were applied using two different concentrations each (2.5 ml.l−1 and 5.0 ml.l−1 for foliar, 10 ml.l−1 and 20 ml.l−1 for soil). Measures on seedling height, apical shot formation, total aboveground (dry weight of leaves and stem) and belowground biomass (dry weight of roots) 120 days after transplanting were made to quantify the effect on growth. The contrasts analysis on results revealed a positive effect of the biostimulant on many of the measured parameters, especially with foliar application using the lowest concentration (2.5 ml.l−1). The foliar application was overall suggested as more efficient than soil drench also allowing lower inputs (i.e. biostimulant quantity). The main consequence of the treatment was an increased biomass allocation in the stem (above ground biomass) due to a stimu- lated leaves production which might suggest an increased photosynthetic activity and growth. Conversely no influence was detectable on total height of seedlings neither on the collar diameter. The biostimulant treatment on containerized Eucalyptus globulus positively influenced some features of seedlings’ growth after transplanting and the use of biostimulant with foliar application during the hardening phase in the nursery, appears to be a promising technique to potentially improve seedling growth after transplanting. An inter- esting impact from application of biostimulant on biomass accumulation following transplanting was here demonstrated. Anyway, further research to verify the results on different tree species as well as under open field conditions is envisioned.