Evaluation of Different Ratios of Nitrogen, Phosphorus and Potassium on Some Vegetative and Reproductive Traits of Blackberry Cultivars in Greenhouse

Blackberry is a temperate plant that can also be grown in the greenhouse for off-season fruit production as well as greater profit. This study is conducted as a factorial experiment in a completely randomized design with three replications as a pot inside the soil. The first factor has been the cultivar (early, intermediate, and late) and the second one is the nutrition program at six levels of NPK(N0P0K0(control), N0P0K0, N50P0K25, N50P0K50, N50P25K50, and N50P12.5K25 kg/ha), applied as fertigation. Results show that the use of nutrients release the highest amount of nitrogen and potassium in the late cultivar. The highest shoot length and chlorophyll index belong to N50P0K25 treatment. Furthermore, blackberry’s response to different ratios of nutrients for shoot fresh weight in different cultivars show a different trend; however, the highest shoot fresh weight occurs in late cultivar in both N50P0K0 and N50P0K50 treatments. Results also show that maximum yield in early and intermediate cultivars in N50P0K25 treatment and in treatment with phosphorus (N50P25K50) could be observed in the late cultivar. The highest amount of soluble solids in early cultivar and N50P0K25 treatment belong to 12.9 Brixo. In general, though the use of NPK nutrients is effective in most studied traits, the role of N and K in improving the vegetative and reproductive traits in blackberry has been especially tangible for the two early and intermediate cultivars.