Abstract

Enhancement of natural growing medium amendments with microwave irradiation has been demonstrated but has received less research attention. A greenhouse experiment was carried out to determine the effect of microwaved vermicast on dahlia (Dahlia pinnata ‘Cobequid Celestial Star’) plant growth and flower production. Fresh, moist vermicast was treated with microwave irradiation power levels 100 W, 200 W, 400 W and 800 W with non-microwaved vermicast as the control (0 W). The temperature of the microwaved vermicast increased from 35^oC at 100 W to 80^oC at 400 W, but dropped to 70^oC at 800 W. The density of bacteria colonies was high in treatments 0 W, 100 W and 200 W, and the least in treatment 400 W while treatment 800 W did not support bacteria growth. Total nitrogen content did not change much but leaf tissue phosphate content increased from 0.70% (100 W) to 0.83% (800 W). Leaf tissue chlorophyll content was increased by treatment 400 W followed by the FV while anthocyanin content consistently increased with an increase in power output level. Microwave irradiation increased total plant and tuberous roots fresh weights. Those treatments ≥200 W had the greatest positive impact on total number of floral organs and longevity of flowers as compared to the 0 W and the 100 W treatments. Overall, it was demonstrated that microwave irradiation at 400 W improve vermicast chemical properties and enhance dahlia plant growth and flower production. Further study on microbial structure will be necessary.

Keywords

dahlia, microwave irradiation, vermicompost, organic amendment, edaphic factors, flower production, micro-nutrients analyses, microwaved vermicast, tuberous roots, bio-physicochemical properties, preliminary findings, favorable nutrient, bioavailable leading, dahlia flowers