Effect of foliar potassium fertilization on yield and fruit quality of strawberry, raspberry and blueberry
On-farm trials were conducted to evaluate the effect of potassium foliar fertilization on yield and fruit quality of strawberry, raspberry and blueberry at Gharb region (Morocco) in 2017. The foliar fertilization treatments were: (T0) Control without foliar application, (T1) A foliar application of 1.6% K2SO4 at flowering stage, (T2) A foliar application of 1.6% K2SO4 at fruit growing stage and (T3) Two foliar applications of 1.6% K2SO4 at flowering and fruit growing stages. The experimental design for each crop was a completely randomized block with 3 replications. Data collected on the trials included growth parameters, fruit production and fruit quality parameters. For strawberry, a single foliar potassium spray at flowering increased yield by 10%. Two sprays increase yield by 7%. A single foliar application during fruit growth did not affect yield but increased fruit size by 4%. Foliar potassium fertilization improved sugar content and acidity of strawberry fruits but did not affect dry matter content. Chlorophyll content, leaf area and stomatal resistance of strawberry leaves were increased by foliar potassium fertilization. For raspberry, foliar potassium fertilization increased leaf chlorophyll, stomatal resistance and yield. Two foliar sprays of potassium sulfate increased yield by 40%. A single foliar application during fruit growth stage increased yield by 29% but had no effect on yield when applied at flowering. Two foliar sprays of potassium increased raspberry fruit size by 6%. Raspberry fruit titratable acidity was reduced by 13% with a single foliar potassium application and by 6% with two applications. Foliar potassium fertilization had no effect on sugar or dry matter content. For blueberry, a foliar potassium application during fruit growth improved fruit yield by 13% and fruit size by 19%. Application at early flowering increased fruit size by 13%. Foliar potassium fertilization increased sugar and dry matter content without affecting acidity. Foliar potassium fertilization increased leaf chlorophyll content and reduced stomatal resistance. Overall, results showed that potassium foliar fertilization significantly improved berries yield and fruit quality as well as crop growth parameters. The observed effects of foliar potassium fertilization on chlorophyll content, leaf area, stomatal regulation, cell turgor and translocation of assimilates contributed to improved fruit yield and quality.
Bamouh, A., Bouras, H. and Nakro, A. (2019). Effect of foliar potassium fertilization on yield and fruit quality of strawberry, raspberry and blueberry. Acta Hortic. 1265, 255-262
strawberry, raspberry, blueberry, foliar fertilization, potassium, yield, sugar content, quality