Cracking is a difficult phenomenon to study, even in controlled environments, as it is the result of a combination of genetic and environmental factors. To act against this problem, numerous compounds have been used in the field to try to improve the quality and productivity of cherries and to mitigate cracking through crop nutrition.
Indeed, calcium has proven to be a key nutrient that can improve both product quality and reduce susceptibility to cracking. However, there are also new compounds that may have the potential to offer new methods to reduce cracking. For example, biostimulants are natural compounds that can be derived from fungi, bacteria or seaweed extracts.
The quality and yield of agricultural products are improved as these substances are associated with increased tolerance to abiotic stresses and enhanced plant growth, thus providing a sustainable alternative to the use of conventional chemicals.
The aim of the collaborative study between the University of Trás-os-Montes and Alto Douro (Portugal) and the Polytechnic University of Cartagena (Spain) was to improve the quality and profitability of sweet cherry trees cv. Sweetheart by administering foliar biostimulants based on calcium and seaweed (Ascophyllum nodosum).
This research was conducted in 2021 in an orchard located in Santa Eulália, São Martinho de Mouros, Portugal. The Sweetheart cultivar was chosen to conduct this trial, in a cherry orchard with a planting density of 4 m × 4 m, corresponding to 625 trees per hectare.
Twelve trees were chosen to receive each treatment, which included two concentrations of calcium (Kit Plant Ca), 300 g hL-1 (Ca_300) and 150 g hL-1 (Ca_150), two concentrations of algae biostimulant (Foralg), 150 mL hL-1 (Seaweed_150) and 75 mL hL-1 (Seaweed_75), a combination of 300 g hL-1 calcium and 150 mL hL-1 algae (Ca_300; Seaweed_150) and a control group that received water instead of seaweed or calcium.
The application of 300 g hL-1 calcium led to a significant 52% reduction in cracking index and a substantial 136% increase in orchard yield. Similarly, but less pronounced, the application of 150 mL-1 seaweed resulted in a 2% increase in fruit weight and a 3% decrease in cracking index.
The results obtained show that the quality and yield of the cherries were improved by the pre-harvest application of both algae- and calcium-derived biostimulants. The cracking index was significantly reduced by both nutrients, particularly in the calcium-treated cherries.
On the one hand, the use of Ascophyllum nodosum produced larger fruits, but the orchard yield decreased. On the contrary, the application of calcium produced smaller fruit, but also substantially reduced the cracking index and significantly increased the orchard yield.
Despite the need for further research and strategies, these results indicate that the nutrients examined in this study may serve as sustainable and innovative alternatives that producers could implement in their orchards to improve the profitability and marketability of cherries.
Source: Santos, M.; Maia, C.; Meireles, I.; Pereira, S.; Egea-Cortines, M.; Sousa, J.R.; Raimundo, F.; Matos, M.; Gonçalves, B. Effects of Calcium- and Seaweed-Based Biostimulants on Sweet Cherry Profitability and Quality. Biol. Life Sci. Forum 2023, 27, 45. https://doi.org/10.3390/IECAG2023-15876.
Image: SL Fruit Service
Melissa Venturi
University of Bologna (IT)
10 Jun 2025
The 2025 Picota cherry season in Spain’s Jerte Valley starts two weeks late, but expectations are high for a medium-to-large harvest with excellent fruit quality. Rain and hail had minimal impact. The UK remains the top export market for the product, followed by Spain.
19 Jan 2026
Cherry stems, pits and pomace account for up to 30% of total output. This article explores how to turn agro-industrial waste into high-value products via green extraction and biorefineries. A concrete opportunity to support the circular bioeconomy.
26 Jun 2026
A three-year study in Poland compares organic and conventional sour cherries, showing that cultivar, climate and season affect fruit quality more than orchard management alone. Oblačinska stands out as the most promising cultivar for high-quality organic production.
26 Jun 2026
A Tasmanian study examines how clear and opaque rain covers change orchard microclimate, light, leaf physiology and cherry quality, combining replicated field trials and grower case studies to help producers improve fruit performance, harvest timing and storage potential.
