SOLVENT EXTRACTION OF CROP RESIDUES FOR PRODUCTION OF GROWING MEDIA

Preparation of alternative soilless organic media was investigated to utilize tons of crop residues in Japanese agricultural areas. Leaves and stalks of eggplant were used in this study, and the effect of solvent extraction process for clearing plant growth inhibitors was examined as a secondary processing for soilless media making. Presumably phenolics associated with easily oxidative degradation was confirmed in water, methanol, ethanol, and acetone extracts by HPLC-electrochemical detector analysis. Germination tests using grape tomato seeds presented its delay especially in the case of methanol extracts addition. Finally, grape tomato was cultivated using crop residue media and mineral wool, commonly used growth media, as a control (cultivation period 33 days). The early stage of its cultivation using the crop residues after acetone extraction provided similar plant height and stem diameter to that in the control. This study could indicate the availability of solvent extraction process to produce organic soilless media from crop residues.