No abstract

Both mycorrhizal and Trichoderma spp. fungi are known for antagonistic effects against certain biological pathogens causing apple replant disease (ARD). The aim of this study was to assess the effectiveness of the bioinoculants based on endomycorrhizal and Trichoderma spp. fungi on the biological properties of soil as well as the parameters of the apple tree growths in a fruit tree nursery under replantation conditions. A two-year experiment was conducted on Jonagold apple trees grafted on to M.9 rootstock in western Poland. The trees were planted in the replant soil—from areas used for the production of apple trees, and in the crop rotation soil, that had not been used for nursery purposes before. A mycorrhizal inoculum and preparations containing Trichoderma spp. fungi were applied to the replant soil. Biological properties of the soil and the growth of the aerial and underground parts of the apple trees were assessed. The enzymatic (dehydrogenases and protease) and respiratory activity of the replant soil was significantly lower than that of the crop rotation soil. The apple trees grew worse when exposed to the ARD conditions. The effectiveness of applied bioinoculants in mitigating the effects of replantation in the nursery were shown. Both the treatment mycorrhization and the application of bioinoculants containing Trichoderma spp. increased the respiratory and enzymatic activity of the replant soil. The growth of the root system and the aerial parts of the trees (including leaves) was much better after the combined use of both types of fungi than in the replant soil that had not received the fungal treatment.

How soil is used affects its production characteristics in the future. Under ARD (Apple Replant Disease) conditions, replanted soil’s physical, chemical and biological properties deteriorate. Their improvement is possible through, for example, increasing the content of organic matter in the soil. The study aimed to assess the effect of two organic additives for replanted soil on its physical, chemical and biological properties, as well as on the vegetative growth of apple trees of the ‘Gala Schniga SchniCo(s)’ cultivar grafted on M.9 rootstock. The experiment was performed in 2021, in western Poland, on a nursery farm. The trees were planted in pots filled with soil from two stations: soil previously used for the production of apple trees (replanted soil) and nursery material (agricultural soil) unused for production so far. To fertilise it, three different portions of biocarbon and Carbomat Eco soil conditioner were added to the replanted soil. The experiment showed that apple trees grown on replanted soil had fewer side shoots, a smaller leaf area and a lower mass of leaves than those grown on agricultural soil. Furthermore, supplementation of replanted soil with organic additives caused a significant increase in its enzymatic activity and respiration, increased the rate of photosynthesis and improved several parameters determining the strength of vegetative growth in apple trees.