Effects of different fertigation-growing medium systems on plant morphometric response during soilless strawberry growth

The use of organic peat-substitute growing media is arising in the strawberry soilless orchard in Trentino (Northern Italy). The field performances of these substrates often give contrasting results, probably because of the management standardized on peat. Thus, finding the right fertigation management is essential for the low technological local growing practice in order to determine and compare performance of these substrates. Therefore, the trial tested 3 substrates (85% peat and 15% coir (PC), 50% coir and 50% conifer wood (CW) and 100% coir (CC)); 3 electrical conductivity (EC) levels (0.9, 1.2 and 1.5 dS m-1) and 4 irrigation schedules (1.5 min every 15 min, 3 every 30, 4.5 every 45 and 6 every 60, 2,4 L h-1, with a time-window function of the drainage percentage and the leachates EC). During the season, chemical traits of the growing media and leachates were monitored. Strawberry (Fragaria × ananassa Duch.) plant vigour traits were measured: petiole and rachis length, runner and crown number, leaf chlorophyll content. Plants grown on PC reached the highest vigour whereas on CW showed the lowest. The lower EC level determined a minor vigour only at the end of growth. Irrigation schedule slightly effected the parameters. Growing medium played a major role in plant growth, not only for its physical properties, there was a diverse drainage percentage, but also for the chemical ones, as the nitrate concentration in the substrates and the leachate was different. Results showed that the effects of the different treatments tested did not overcome the characteristic effects of the diverse growing media.