# Evaluation of the Effect of Biostimulation on the Yielding of Golden Delicious Apple Trees
## 2 Materials and Methods  
The study was carried out from 2008 to 2017 in south-eastern Poland in the Sandomierz Upland (50\({}^{\circ}\)39\({}^{\prime}\) N; 21\({}^{\circ}\)34\({}^{\prime}\) E). The experimental material consisted of trees of the cultivar Golden Delicious germinated on the rootstock M.9. The trees were planted in the spring of 2003 at a spacing of 3.0 \(\times\) 1.0 m on loess soil as one-year germinants. The crowns of the trees were guided in an axial form, and metal poles with wires and wooden stakes were used as supports in the rows. Within each combination, randomly analyzed characteristics from 100 vines were tested. The experiment evaluated the yield and quality of apple trees of the Golden Delicious variety fertilized with two programs:  
1 st Control (standard fertilization program used on a daily basis in practice, based on macro and microelements):  
- Yara Mila Complex (Hydrocomplex) 12-11-18-300 kg \(\times\) ha\({}^{-1}\) in sprinkled form at the green bud stage;  
- Tropicote saltpeter-200 kg \(\times\) ha\({}^{-1}\) in sprinkled form after flowering;  
- Agroleaf 52% P-5 kg \(\times\) ha\({}^{-1}\) in the form of a spray in the green bud phase;  
- Calcinit-calcium nitrate-5 kg \(\times\) ha\({}^{-1}\) in the form of a spray in the green bud phase-7-10 days later-4 treatments at 7-10 day intervals;  
- Calcium chloride-6 kg \(\times\) ha\({}^{-1}\) in the form of a spray in the green bud phase-6 treatments at 7-10 day intervals. 2 nd Biostimulation (fertilization program based on macro and microelements and enriched with N Pro technology and Seactiv Complex, which is based on sea algae extracts and shows a biostimulating effect):  
- Eurofertil 34 N Pro 8-8-17-300 kg in sprinkled form at the green bud stage;  
- Sulfammo 30 N Pro-100 kg/ha in sprinkled form after flowering;  
- Fertileder Leos-51 \(\times\) ha\({}^{-1}\) in the form of sprays at the green bud stage;  
- Fertileder Gold-31 \(\times\) ha\({}^{-1}\) in the form of sprays at the pink bud stage;  
- Fertileder Axis-31 \(\times\) ha\({}^{-1}\) in the form of sprays after flowering;  
- Fertileder Vital-31 \(\times\) ha\({}^{-1}\) in the form of sprays-2 treatments at 10-14 day intervals;  
- Fertileder Elite-31 \(\times\) ha\({}^{-1}\) in the form of sprays-3 treatments from the walnut stage at 14-day intervals. The combinations were trees fertilized with two technologies: standard (1) and enriched with N Pro technology and Seactiv Complex (2). The tested trees were fertilized every year throughout the test cycle in accordance with the above-mentioned recommendations developed throughout the experience. In both combinations, the value of macro and micronutrients was at a similar level. The experiment was set up in a random block design consisting of 2 combinations in 5 repetitions. Replications were plots with 10 apple trees. During the experiment, chemical thinning after flowering and manual correction after the fall of apple buds in June were performed every year, leaving a similar number of fruits on the tree. Measurements and observations carried out between 2008 and 2017 concerned fruit yield and quality. Fruit harvesting was carried out on 20-30 September, separately from each tree within each combination, by determining the number of fruits on the tree (pcs.). The date of harvest maturity was determined using starch samples and organoleptic evaluation. Fruit harvested separately from each tree was used to determine the yield (kg-tree\({}^{-1}\); kg-ha\({}^{-1}\)). The commercial yield was determined on the basis of the percentage share of apples, \(>\)7.5 cm in diameter. The average weight of one apple (g) was determined. Fruit sizing was carried out on a randomly selected batch of 100 apples from each repetition. The firmness of the flesh in the fruit was determined using a firmness meter one day after harvesting on the basis of 10 apples from each repetition.