토마토 폐배지를 딸기 수경재배 배지로 재이용 가능성 연구

Abstract

The current study was performed to investigate the effect of recycling coir substrates on the growth, fruit yield, andquality of strawberry plants. Analysis of physical properties revealed that the pH of a fresh coir substrate was 5.04 whilethose of substrates reused for one and two years were 5.20 and 5.33, respectively. The electrical conductivity (EC) of anew substrate was as high as 4.58 dS·m−1. This can cause salt stress after transplanting. The EC tended to decrease asthe substrate was recycled, and the EC of a two-year recycled substrate was 1.48 dS·m−1. The fresh substrate had lowernitrogen and calcium concentrations, but higher phosphate, potassium, and sodium concentrations than the recycled coirsubstrate. The coir substrates recycled for one or two years maintained better chemical properties for plant growth thanthe fresh substrate. Strawberry growth varied depending on the number of years that the coir substrate was recycled. Ingeneral, strawberries grown in substrates that had been reused for two years did better than those grown in substratesthat had been reused once or were fresh. Ninety days after transplanting, a plant grown in a substrate that had been reusedfor two years contained 25 leaves, which was 3.6 more than with a fresh substrate. In addition, the plants grown in asubstrate that had been reused for two years exhibited larger leaf areas than those grown in other substrates. Coir substratesthat had been reused for one year increased the number and area of leaves, but not as much as the substrate that hadbeen reused for two years. One- and two-year reused coir substrates increased the weight of strawberries produced relativeto the unused substrate, but the difference was not statistically significant. The plants grown in two-year reused substrateswere longer and wider, as well. Also, the number of fruits per plant was higher when substrates were reused. Specifically,the number of fruits per plant was 28.7 with a two-year reused substrate, but only 22.2 with a fresh substrate. The fruitcolor indices (as represented by their Hunter L, a, b values) were not considerably affected by recycling of the coirsubstrate. The Hunter L value, which indicates the brightness of the fruit, did not change significantly when the substratewas recycled. Neither Hunter a (red) nor b (yellow) values were changed by recycling. In addition, there were nosignificant changes in the hardnesses, acidities, or soluble solid-acid ratios of fruits grown in recycled substrates. Thus,it is thought that recycling the coir substrate does not affect measures of fruit quality such as color, hardness, and sugarcontent. Overall, reuse of coir substrates from hydroponic culture as high-bed strawberry growth substrates would solvethe problems of new substrate costs and the disposal of substrates that had been used once.