Nutritional status, vegetative and generative behaviour of apple trees after the application of two biopreparations

A two year-experiment was carried out to study the effect of root inoculation with two biopreparations, Vambac® (VA-mycorrhiza genus Glomus, Gigaspora and the rhizospheric bacteria Agrobacterium radiobacter) and Amalgerol® (composed of vegetative and sea-algae oils and extracts) on leaf mineral concentration, vegetative and generative behaviour in two year old apple trees cv. ‘Jonagold’/M.9. Trees were grown in 10 l plastic pots in unsterilized sandy clay soil (Fluvisols) under climatic conditions of South Moravia (49°,25´ N; 16°,55´ E), Czech Republic. Leaves were sampled eight times during the experiment (four times per year) for analysis of: N, P, K, Ca, Mg, Zn, Fe, Cu, and Mn. Mycorrhizal infection was determined with the gridline-intersection method. Inoculated plants showed higher VA root infection during both years (best results were 46% on the first year and 41.7% on the second year) and higher leaf P concentrations, in particular when biopreparations were applied together (P = 0.23% DW), than non inoculated (4% of root infection during year one and 15% during year two; P = 0.183% DW). N, K, Ca and Mg were not significantly affected by treatments. In many cases application of biopreparations decreased Fe, Mn and Zn leaf levels. Shoot length was strongly enhanced in inoculated plants only during the first year (46% more than non inoculated). No significant differences were detected between inoculated and non inoculated plants for: trunk diameter, spur number, root volume, leaf dry weight, number of blossoms and yield. It is concluded that the studied biopreparations have the capacity to colonize and persist in the roots of apple trees (VA-mycorrhizal fungus), enhance the uptake of phosphorus and vegetative growth but they could decreased the uptake of Fe, Mn and Zn.