Interaction of white mulch and nitrogen fertilization timing in the late season on flowering and yield components of strawberry (Fragaria × ananassa Duch.) in the following spring

Effects of nitrogen fertilization timing close to the beginning of short-day period and white mulch on flowering and yield components have been studied in ‘Paros’ and ‘Queen elisa’ strawberry cultivars. Split plot experiment in a randomized complete block design with eight treatments (two mulch treatments × N fertilization during four different times from last week of August to third week of September) and three replications were used. Total soluble carbohydrates and total soluble proteins of leaves were measured in October. Yield components of both cultivars were evaluated during next spring. Soluble carbohydrates and soluble proteins were increased in plants subjected to nitrogen in the second and the third week of September as well as mulch in both cultivars. This was accompanied by an increase in inflorescence, flower and fruit number per plant in next spring. The greatest flowering enhancement, increased number of flowering and number of inflorescences per plant occurred when N fertilization started second and third week of September compared with the last week of August. General results showed that flower and fruit number per plant were higher in ‘Paros’ compared to ‘Queen elisa’, but average of fruit weight and yield were higher in ‘Queen elisa’ compared to ‘Paros’. These results suggest that application of nitrogen in the second and third week of September, along with the use of mulch can increase strawberry fruit production.