Nitrogen fertilization ensures the proper growth of trees. The aim of the study was to evaluate the impact of differentiated nitrogen fertilization on selected parameters. It was assumed that such analysis is an indirect picture of the needs of cherries grown in herbicide fallow. The content of minerals in two layers of the soil, in leaves, and its influence on tree growth, and the content of chlorophyll in leaves were assessed. The experiments were carried out in three different cherry orchards. Three levels of fertilization were applied in each orchard: 0 kg, 60 kg, and 120 kg N ha⁻¹. As expected the fertilization resulted in an increase in the content of nitrate and ammonium forms of nitrogen in the soil, however, their content was also dependent on precipitation and temperature. Additionally, high nitrogen fertilization increased the content of phosphorus and potassium and decreased the magnesium in the topsoil layer. High nitrogen fertilization caused the decreased content of phosphorus and potassium in the leaves. The level of calcium and magnesium in leaves increased with fertilization of 60 kg N ha⁻¹ but decreased with the dose to 120 kg N ha⁻¹. The use of nitrogen fertilization increased the vegetative growth of trees measured by leaf area and trunk cross-sectional area. However, the chlorophyll content was not dependent on the amount of nitrogen fertilization. Based on the results, it can be concluded that 60 kg N ha⁻¹ is the optimal dose, ensuring proper nutrition of cherry trees.

Nitrogen fertilization is a basic agrotechnical orchard treatment, and affects quality and size of the crops. The aim of this study was to assess the impact of nitrogen fertilization on the yield and quality of sour cherry fruit of the ‘Łutówka’ cultivar. The course of climatic conditions in relation to the timing of flowering and fruiting was analyzed. The trials were carried out in three different experimental sour cherry orchards (quarters) with different planting dates (1999, 2001 and 2002) located at the experimental orchard of the Poznań University of Life Sciences in Poland. In each orchard, three levels of fertilization were used: control without fertilization, fertilization at a dose of 60 kg N ha⁻¹ and fertilization at 120 kg N ha⁻¹. Increasing the dose of N did not have a significant effect on sour cherry yield. However, it resulted in a reduction of fruit weight, extract content, acidity and TSS/TA ratio, whereas the brightness (L*) and redness (a*) of the fruit surface color increased. Temperature and precipitation had the greatest influence on the course of flowering, fruiting and fruit ripening. Particularly important was the course of climatic conditions at the beginning of the growing season, especially during flowering, when there is a high risk of spring frosts. The timing of flowering and fruiting was correlated with the sum of active temperatures. The greatest relationship for the flowering date was found for SAT (sum of active temperatures) when the base temperature equals 11 °C and the temperature for the harvest date equals 9 °C.

Late pear cultivars, such as ‘Conference’, can be stored for a long period if kept in good storage conditions. A three-year study (2011–2013) compared the impact of six-month storage using four technologies—normal atmosphere, normal atmosphere + 1-methylcyclopropene (1-MCP), controlled atmosphere, and controlled atmosphere + 1-MCP—on the quality parameters of ‘Conference’ pears, such as mass loss, firmness, total soluble solids, acidity, antioxidant capacity, and the incidence of diseases and disorders. Additionally, the study analysed different storage conditions in terms of profitability, based on the market prices for pears in the seasons during which the pears were stored. The storage conditions had a very strong influence on the fruit quality parameters, and were found to affect most visibly the mass loss and the incidence of postharvest diseases and disorders. The storage of ‘Conference’ pears for 180 days in normal atmosphere is not economically viable, even if the fruit is subjected to 1-MCP treatment; at the same time, it is profitable to store ‘Conference’ pears in controlled atmosphere for the same period, no matter whether 1-MCP was applied or not.

In perennial fruit crops, bearing can be influenced by various factors, including environmental conditions, germplasm, rootstocks, and cultivation methods. Cherries, one of the most important and popular fruit species from the temperate climate zone, achieve high prices on the market. New agricultural technologies and environmental factors force a change in the approach to cherry cultivation. Old-type cherry orchards, with their high demand for water, nutrients, and manual work, are replaced by orchards of self-pollinating cherry cultivars grown on dwarf rootstocks. These changes make it necessary to search for ways to regulate fruiting, in particular to thin buds, flower, and fruit. In light of environmental regulations and consumer pressure, thinning methods are being sought that either do not involve the use of chemicals or that use eco-friendly chemical agents. This review examines recent progress in understanding the effect of thinning methods on the physiology, tree growth, and fruit quality of cherries; discusses horticultural practices aimed to ensure regular cropping and their influence on fruit quality; and provides suggestions for future research.

The study’s objective was to evaluate the influence of thinning on the quality and regularity of yield of ‘Regina’ cherries grown on a dwarf Gisela 5 rootstock. The experiments were conducted in the years 2009–2012 in Western Poland. Trees were thinned using a chemical agent, ammonium thiosulphate (ATS), at doses of 20 g ATS L⁻¹, 30 g ATS L⁻¹ and 40 g ATS L⁻¹, and by hand, and the results of chemical and hand thinning were compared with those obtained for unthinned trees. The course of weather conditions in winter and during flowering had a significant impact on yield. Chemical thinning is known to be an effective method to regulate fruiting of pome trees, but it can also be successful if applied to cherry trees, as reflected by the alternate bearing index, which was the lowest after applying ATS at a dose of 40 g. ATS treatment improved fruit quality in full crop years. Thinning resulted in, among other things, larger and darker fruit and higher content of total soluble solids and titratable acidity. Treatment with 40 g ATS L⁻¹ significantly stimulated the vegetative growth of trees.

Sour cherry (Prunus cerasus L.) is one of the most important fruit crops in Poland and ‘Łutówka’ is the dominant cultivar in commercial orchards. The experiment was carried out in 2007–2013 in three orchards; in each of them, three levels of fertilization were applied: 0 N kg ha⁻¹, 60 kg N ha⁻¹, and 120 kg N ha⁻¹. The activity of dehydrogenase and protease in the soil was studied depending on nitrogen fertilization. The abundance of soil microorganisms was assessed: bacteria, fungi, actinomycetes, and nitrogenous bacteria (Azospirillum and Azotobacter) in the years during the experiments carried out with fertilization of 60 kg N ha⁻¹ in all orchards. The enzyme activity of dehydrogenases increased after the use of 60 kg N ha⁻¹ from 3.8 to 6.7 (cm³ H₂ 24 h⁻¹ kg⁻¹ DW soil), but a further increase in the dose to 120 kg N ha⁻¹ caused a decrease in activity to 5.1 (cm³ H₂ 24 h⁻¹ kg⁻¹ DW soil). The activity of proteases was dependent on nitrogen fertilization, but to a large extent it was related to the course of climatic conditions. There is no relationship between the growth and the activity of proteases. The yield and selected quality parameters of the cherry fruits were associated with both dehydrogenases and proteases. The use of lower doses of nitrogen fertilizers allows for maintaining biological balance in the soil and a more efficient use of nutrients, contributing to less environmental pollution.