Ground peach pits: alternative substrate component for seedling production

The exploitation of agro-industrial wastes is a strategy to add value to seedling production and reduce environmental problems. The production chain for processed peaches generates, approximately, 21,000 tons of fruit worldwide, and the pits are used mainly to generate energy. The objective of the study was to investigate the use of different proportions of ground peach pits(GPP) as a substrate component for seedling growth of Eucalyptus dunnii in the nursery and field. Different proportions of GPP mixed with either commercial substrate(CS) or with brown peat(BP) were tested. The physical and chemical properties of the substrates, the morphological and physiological attributes of the seedlings and their correlation with substrate properties were evaluated. The GPP increased the density, aeration space and p H and reduced total porosity, liquid retention and electric conductivity of the substrate. The use of this component resulted in hormesis, a biphasic dose–response model in which low levels of exposure to this component stimulated biological performance of plants and high levels of exposure inhibited performance. For improved seedling growth in the nursery and adequate post-planting development of E. dunnii, GPP with CS is recommended at 20% of the total substrate and with BP between 15 and 30%.