RESUMO
Several factors are involved in the incidence of blossom-end rot (BER) in tomato fruit, but the main one is insufficient Ca uptake and transport through the plant, resulting in Ca deficiency in the fruit. Sprays of Ca-containing products are considered to be a possible measure to overcome the local Ca deficiency in tomato fruit. Therefore, the main objective was to evaluate the effectiveness of additional Ca supply to tomato fruits for increasing Ca content and reducing fruit damage. Sprays of five different commercial preparations containing (Brexil Duo, Calmax Zero N, Ca(NO3)2, CaCl2) or promoting (Greenstim) Ca uptake were tested using BER-sensitive large-fruit variety 'Beorange'. The experiment was conducted in the commercial greenhouse 'Getlini EKO', Latvia, during the autumn-spring season of 2020/2021 under controlled conditions, eliminating the adverse impact of external factors. The results revealed that none of the preparations were effective in increasing Ca content, preventing BER, and did not promote the tomato yield. As good agricultural practices were followed in the greenhouse to manage BER, we concluded that a non-marketable yield of around 15% should be expected for 'Beorange' when grown under artificial light, possibly due to the impact of abiotic stresses and genetically determined susceptibility.
RESUMO
The present study was carried out to evaluate the leaf nutrient status of commercially grown strawberries in Latvia during 2014-2022. The results of N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, Mo and B in 200 strawberry leaf samples from different strawberry-producing farms were analysed over three periods: 2014-2016, 2017-2019, and 2020-2022. According to leaf analyses, plant fertilization was only partly well managed by the growers. During the research period, strawberries in Latvia were generally sufficiently supplied with N, P, K, Mg, Fe, Mn, Mo, and B, while the level of Ca, S, Zn, and Cu was considered low. The deficiency of these nutrients was characteristic for more than 50% of the samples. Since Ca, S, Zn, and Cu are essential for berry formation and quality and contribute to stress resistance; their deficiency could be one of the limiting factors for strawberry yield. The significant positive correlations found between nutrients, including deficient ones, confirmed their close relationship in the uptake process and the importance of sufficient supply. The results clearly indicated that fertilization could currently be an issue that limits the strawberry harvest in Latvia, and adequate provisions of Ca, S, Zn, and B should be the main focus.
RESUMO
In Latvia, cloudberries are considered a valuable delicacy and have aroused interest in the possibility of commercial cultivation, as currently, they are collected only in the wild. A complex study was carried out to provide insight into the growth conditions of wild cloudberry in Latvia. The knowledge gained would provide a basis for the development of cloudberry cultivation technologies in the hemiboreal zone. Habitat characteristics, composition of surrounding vegetation, and plant mineral nutrition status were investigated in 18 study sites. Overall, the species composition of cloudberry study sites corresponded to two plant community classes: Cl. Vaccinio-Piceetea and Cl. Oxycocco-Sphagnetea. The most common species were Sphagnum magellanicum, Vaccinium myrtillus, and Oxycoccus palustris. The results clearly indicated acidic peat soils with high organic matter content and low degree of decomposition as being most suitable for cloudberry cultivation. High nutrient uptake capacity was found for wild cloudberry growing in nutrient-poor environments, as most of the leaf nutrients corresponded to the optimal levels determined for different cultivated berries. However, balanced fertilization to ensure successful plant vegetative and root growth would be recommended. The first results on wild cloudberry in Latvia indicated that optimization of P, S, B, and Mo should be the main focus.
