Yield and Inorganic Ion Contents in Drained Solution by Different Substrate for Hydroponically Grown Strawberry

초록

This study aimed to determine the mineral composition of substrate and solutions employed for hydroponic cultivation of strawberry. Four different substrates, including peatmoss:perlite (v/v = 50:50; PP), rockwool (RW), coir dust:chip (v/v = 50:50; D50), and coir dust:chip (v/v = 100:0; D100), were analyzed using the and rural development administration (RDA) extraction before transplanting and after final harvest. Substrates were supplied with either University of Seoul (UOS) nutrient solution or distilled water, and mineral concentrations were determined in the solution drained from the substrate before transplanting as well as in the drainage during the entire growing period. Fruit yield, soluble sugar content and plant mineral content were measured. The european committee for standardization (CEN) method revealed elevated concentrations of potassium (115 to 119 mg.L-1; K) and sodium (26 to 50 mg.L-1; Na) in the D50 and D100 substrates, compared to other minerals, indicating that K and Na ions exist in water- soluble forms in the coir. The RDA method reported 20- to 200-fold higher concentrations of calcium (Ca) and magnesium (Mg) in the D50 and D100 substrates when, compared to the CEN method, implying that larger amounts of Ca and Mg may exist in the coir that are not in a plant-available form. When the substrates were washed with the UOS nutrient solution prior to before transplanting, a lower Ca concentration (33 to 34 mg.L-1) was observed in the solution drained from the coir substrate compared to PP and RW substrates (78 to 111 mg.L-1). After final harvest of plant and fruits, the K and Na concentrations in D50 and D100 substrates were decreased compared to the never-used ones, while the Ca (130 to 159 mg.L-1) and Mg (62 to 79 mg.L-1) concentrations were increased suggesting the gradual leaching of K and Na through the drainage and the accumulation of Ca and Mg in coir during growing period. The result of a lower K accumulation in the leaf tissue of plants grown on the D50 and D100 substrates may be associated with the higher accumulation of Ca and Mg in the coir due to antagonistic interactions between K, Ca and Mg. Quality characteristics such as plant growth and sugar content did not change among the different substrates, however, marketable fruit weight varied in the order of D100 > D50 > RW > PP. Increased root growth resulted for plants grown on D50 and D100 substrates, while roots were smaller in plants grown on PP substrate, which resulted in drainage of lower pH than the optimal level.

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