IMPROVED FERTILIZATION STRATEGY FOR STRAWBERRY FERTIGATION CULTURE

Recently, soil culture with a fertigation system has been recommended to strawberry growers. Using the nutrient recipe for soilless cultures, they apply water and fertilizers on a gradual basis in small quantities over several times each day. However, due to environmental pressures related to fertilizer waste, a more optimal fertilization strategy is needed. In this study, the nutrient absorption characteristics of strawberry plants were determined. The total amounts of N, P, K, Ca and Mg accumulated by plants increased gradually as growth stages progressed , but the ratio of nutrient accumulation in the body showed a similar tendency. The ratio of P/N was 24%, K/N 128%, Ca/N 38%, and Mg/N 33%. Based on this finding, a nutrient formulation was developed. The newly developed nutrient formulation reflected the absorption ratio of K/N and Ca/N as they were, and 60% of the P/N ratio. Mg reflected as much as half the amount of Ca supply. The NH4 ratio to total N was set at 20%. The newly developed nutrient formulation was examined in soil culture. With the use of the new nutrient formulation in soil culture, there was a lower consumption of all minerals in comparison with the use of the soilless nutrient recipe. In particular, the consumption of Ca and Mg were decreased by 48% and 31%, respectively. After culture, the concentration of minerals in soil became higher than before culture, particularly, Ca and Mg. Thus, there needs to be more reduction in supply of Ca and Mg. Thus, the nutrient formulation was modified to N(NO₃:NH₄)-P-K-Ca-Mg-S=16.3(13:3.3)-2-7-3.5-1.8-1.8 me•L^-1.