Berry yields of two Finnish sea buckthorn cultivars under organic farming methods

The effects of different organic farming methods on berry production by two Finnish sea buckthorn (Hippophae rhamnoides L. ssp. rhamnoides) cultivars, 'Terhi' and 'Tytti', were studied in field experiments over 4 years at Merikarvia, western Finland. Four organic fertilisers, five mulches, and two land contours were used. Two experiments were conducted. In the first, fertilisation experiment, the fully-crossed effects of four different fertilisers and two land contours were tested for both cultivars. In the second, mulch experiment, the fully-crossed effects of five different mulches and two land contours were tested for the cultivar 'Tytti'. Some sea buckthorn bushes produced a small number of berries in the second growing season. According to the three-way interactions, the effect of fertiliser on yield depended on the land contour in 'Terhi', but not in 'Tytti'. Apatite increased yields in bushes grown on flat land. Yields increased in the third and fourth growing seasons, when 'Terhi' produced larger berries and yields than 'Tytti'. 'Terhi' had a higher yield on ridged beds than on flat land. Berry size was larger on ridged beds compared to flat land in both cultivars. The effect of mulch depended on the land contour in the second and fourth growing seasons. In the second growing season, straw mulch increased berry production on the flat land compared to the other mulches. In the fourth growing season, a plastic mulch increased yields compared to organic mulches. The results of this experiment provide information on ways to improve sea buckthorn berry yields when organic farming methods are used.