EFFECT OF CHICKEN MANURE FERTILIZATION ON VEGETATIVE AND REPRODUCTIVE PARAMETERS OF PLUM (PRUNUS DOMESTICA L.)

The investigation was conducted during the period 2018-2021 in an experimental plantation of the Institute of Agriculture – Kyustendil, Bulgaria with plum (Prunus domestica L.) cv. ʻStanleyʼ. The planting was created in 2013. Planting distances were 5x5 m. The following fertilization variants were investigated: V1 – unfertilized – (control), V2 – chicken manure 2.5 kg/tree, V3 – chicken manure 5.0 kg/tree. The correlation between the fertilizer rate and the trunk growth rate of the plum cv. ʻStanleyʼ was positive from the second year of chicken manure Vita organic application. The application of chicken manure at a rate of 2.5 kg/tree increased the canopy volume, and in the third year it was statistically significant at P<0.05 by 56.56%. On average for the period of the experiment, the fertilizer rate of 2.5 kg/tree increased the yield by 79.16%, and the average fruit weight by 5.93%. A higher content of dry matter and acids was found in the fruits at both fertilizer rates.