In order to achieve sustainable food production, non-chemical weed management practices need to be developed for fruit growing. Tailor-made floor management systems enable efficient weed regulation, but they also affect the soil quality in an orchard. In this article, the effects of various floor management systems in a ‘Red Jonaprince’ apple (Malus × domestica Borkh.) orchard on the soil properties and the trees’ nutritional status and initial development during the first two years after the orchard’s establishment were assessed. The experiment was set up in the spring of 2017 in the Experimental Orchard of WULS. ‘Red Jonaprince’ cv. trees grafted on M.9 rootstock were planted with 3.5 × 1 m spacing between them. Different floor management systems were applied to the rows, including the selected organic mulches: Miscanthus × giganteus straw (MG1 and MG2), spent mushroom substrates (SMS1 and SMS2), herbicide strip (HS), clear mechanical soil cultivation (MC), and synthetic black mulch (BC). The organic mulches affected the soil properties significantly. Spent mushroom substrates (SMS1, SMS2) increased the P and K contents in the soil, increased the salinity 10-fold, and retarded the growth in terms of the trunk cross-section area (TCSA) and its increment compared with other systems. Miscanthus × giganteus straw mulch (MG1, MG2) was associated with a more vigorous shoot growth compared with other combinations in the first year of the study as it provided a better tree nitrogen nutritional status. The floor management system affected the generative development of the trees. Mulching with a spent mushroom substrate boosted the flower bud formation intensity, but it did not affect the yielding quantity. Moreover, due to the poor fruit set, the trees mulched with a spent mushroom substrate (SMS2) gave a low initial bearing. High crop loads were noted for the trees treated with black synthetic mulch (BC) and the trees mulched with Miscanthus × giganteus straw (MG1). This was an effect of the tree size rather than the blooming intensity, while there were no differences in the cropping efficiency index (CEI) parameter.

Effective thinning methods that balance yield, fruit quality, and ripening dynamics are essential to ensure efficient and sustainable apple production. This study examined the effects of various thinning treatments on ‘Gala Vill’ apples (Malus × domestica Borkh.) to assess their impacts on fruit set, yield, and quality parameters. The experiment was conducted in 2020 at the experimental orchard of WULS located in Wilanów, Warsaw, Poland. The treatments included chemical thinning using different doses of metamitron (Brevis 150 SG) alone and in combination with kaolin clay at two concentrations (50 and 100 kg∙ha⁻¹), and, as alternatives to the chemical method, using kaolin clay alone (50, 100, and 200 kg∙ha⁻¹) and artificial shading. The results highlight the effectiveness of thinning treatments in modulating key agronomic traits. Artificial shading significantly reduced the number of fruitlets, demonstrating its utility as a non-chemical thinning option. Metamitron application effectively reduced the number of fruitlets in a dose-dependent manner. Combining metamitron with kaolin clay did not enhance the thinning effect compared with metamitron alone. However, kaolin clay applied independently, particularly at higher concentrations, was associated with improved fruit setting and yield. For instance, kaolin clay at 200 kg∙ha⁻¹ (KC200) resulted in the highest fruit set (85.2) and yield (10.1 kg·tree⁻¹), suggesting its adverse effect on thinning to promote fruit retention under certain conditions.

The aim of this study was to investigate the effect of gibberellins on the setting and quality of parthenocarpic apples (Malus × domestica Borkh.). The experiment was conducted in 2021 on the ‘Golden Delicious’ cultivar in the Warsaw University of Life Sciences experimental orchard. During the trial, we compared the effect of various gibberellins, such as GA₃, GA₄₊₇, and a mixture of GA₃ + GA₄₊₇. These gibberellins were administered to both intact and mechanically injured flowers (damaged by emasculation and style removal) at the pink bud stage. The results clearly demonstrate that gibberellins applied during blooming supported the induction of parthenocarpic fruit setting in Golden Delicious apples; however, fruitlet retention remained significantly lower than in natural pollinated flowers. The most efficient treatment among emasculated flowers was the mixture of GAs, resulting in a final fruit retention of 23.6%. Fruit size and morphology differed across treatments: GA₃ applied on intact flowers resulted in the largest parthenocarpic fruits, while the GA₄₊₇ and GAs mixture promoted a more elongated fruit shape. Moreover, gibberellin treatment affected other fruit quality traits. Almost all GA treatments led to a higher soluble solids content in fruits. In addition, apples derived from intact flowers treated with GA₃ showed reduced firmness. Overall, our findings indicate that gibberellins can support fruit set, even when flowers are injured, and to lower extent modify fruit quality, but the results depend on flower condi-tions and the type of GA used.