Influence of fall nitrogen and spring nitrogen-potassium applications on yield and fruit quality of 'Chandler' strawberry

Annual-hill strawberry (Fragaria xananassa Duch.) production with black plastic mulch and drip irrigation is gaining popularity in North Carolina, Two experiments (E1 and E2) were conducted on a Wagram loamy sand (Arenic Kandiudult) in 1992 and on a Norfolk sandy loam (Typic Kandiudult) in 1993 to investigate the effects of fall-applied N and spring-applied N and K on 'Chandler' strawberry yield and fruit quality, El treatments included factorial combinations of banded fall-applied N (0, 34, and 67 kg . ha(-1)) and drip spring-applied N (0, 0.19, 0.37, 0.56, and 0.75 kg . ha(-1). d(-1) and 0, 0.37, 0.75, and 1.12 kg . ha(-1). d(-1) in 1992 and 1993, respectively), E2 treatments included combinations of drip spring-applied N (0.56, 1.12, 1.68, and 2.24 kg . ha(-1). d(-1)) and K (0.46, 1.39, and 2.32 kg . ha(-1). d(-1) and 0, 0.75, 1.49, and 2.24 kg . ha(-1). d(-1) in 1992 and 1993, respectively), There were no significant interactions among main effects for any of the measured variables. Market yield maximized with total N at approximate to 120 kg . ha(-1) with one-half banded in the fall and the remainder drip-applied in the spring, Fruit firmness decreased with increasing N rate, Fruit pH and concentrations of total acids and soluble solids were not affected by N treatments, but soluble solids increased as the harvest season progressed, Plant crown number was not affected by N treatment but crown yield increased with N rate similar to market yield, There was no response to drip-applied K for any variable in either year, Based on soil test, fall-applied K (broadcast-soil incorporated) met the K requirements both years.