FERTILISER EFFECT ON CLOUDBERRY GROWTH AND VITALITY IN PEAT – A PILOT STUDY

Cloudberry is a perspective berry crop for extracted peat bog recultivation in Latvia. The study aimed to assess the effect of different fertiliser doses on cloudberry variety Nyby vitality. In 2023, cloudberries were propagated and in September planted outside into outdoor flower beds (24 pots in each bed) with milled raw peat. The beds were separated into four treatments with different doses of complex fertiliser 12-8-16 with micronutrients: control C, N12, N24, and N36 (respectively, 0, 12, 24, and 36 kg ha^-1 of N was added throughout the season). Plant leaf chlorophyll in SPAD units was measured weekly from May to August 2024. Leaf size and density were measured at the end of August. Leaf tissue nutrient analysis was done at the end of July to assess the nutritional status of treatments. Results revealed significantly higher chlorophyll content for fertilised cloudberries than the control, but no differences between the fertilised treatments. Leaf size and density did not increase significantly for fertilised treatments. Additionally, leaf tissue nutrient content in Nyby: 1) exceeded wild cloudberry nutrient concentrations; 2) were similar to suggested levels for Rubus berries. Considering that cloudberry vitality did not differ between the fertilised treatments, the lowest dose of fertiliser could be determined as effective, following the principles of sustainable fertilisation practices. The study will continue to assess fertiliser dose effects on cloudberry development.