Effect of growing medium and fertigation management on soilless strawberry quantitative and qualitative traits

Crop performances of peat-substitute growing media often give contrasting results in the low technological strawberry soilless orchards in Trentino (Northern Italy). Therefore, determining and comparing the performances of these substrates represents an essential issue. Plants of everbearing strawberry (Fragaria × ananassa Duch.) 'Capri' were transplanted in three different growing media: 85% peat and 15% coir (PC), 50% coir and 50% conifer wood (CW) and 100% coir (CC). Fertigation management consisted of 3 electrical conductivity (EC) levels (0.9, 1.2 and 1.5 dSm-1) and 4 irrigation schedules (1.5' every 15', 3' every 30', 4.5' every 45' and 6' every 60'; 2.4 L h-1 with a time-window function of the leaching percentage). Twice a week ripen fruits were harvested, sorted in marketable and discard, and analysed. The marketable yield was significantly lower in plants grown on CW, while recording no difference in the total yield. PC had the best performance in the first marketable flush, followed by CC and CW, because of the difference in the mean fruit weight. PC second flush was delayed in respect of CC and CW, letting them partially recover the gap. The 0.9 dS m-1 EC level determined a lower marketable production, especially during the first part of the second flush. This effect is explained not only by the fruit weight, but also by a lower number of differentiated flowers. Irrigation scheduling did not affect the results. Every factor influenced the fruit qualitative traits except the firmness. PC confirmed the best performance for a ready use, while CC and CW needed a more or less long period to reach the same results.