Microwave power level and exposure time alteration of compost tea efficacy, and growth of Plectranthus amboinicus

Abstract

The unique properties of selective heating at the molecular level, and the resultant enhancement effect of microwave in agri-food sciences have been amply demonstrated. This study examined variations in microwave irradiation power level (0, 100, 200, 300 and 400 W) and exposure times (5 and 10 min) effects on the potency of municipal solid waste (MSW) compost tea and Plectranthus amboinicus plant growth and nutrient composition. A linear regression equation showed slopes of 0.160 o C/W for the 10 min exposure and 0.114 o C/W for the 5 min exposure. The turbidity of the microwaved compost tea reduced as the microwave power level and exposure increased. Electric conductivity, total dissolved solids and salinity of the MSW compost tea increased by a factor of 0.08 at the 400 W power level. Plant sap o Brix, nitrate and calcium concentrations were increased by power levels of ≥300 W. Stem diameter was increased by an average factor of 0.08 for the 5 min and 10 min exposure times following application of the 300 W microwaved MSW compost tea. Chlorophyll content rose by a factor of 0.09 at 10 mins between the 200 W and the 300 W after which it remained unchanged. On the other hand, anthocyanin content was consistently higher in plants treated with the 5 mins microwaved MSW compost tea compared to the 10 mins treatment irrespective of the microwave power level. To understand the mechanism of action of microwaved vermicast, current study is focused on microbial communities in MSW compost tea.

Potential effect of microwaved vermicast on dahlia plant growth and flower production

“…Also, there was a general trend of increasing tuberous roots fresh weight as microwave power output level increased from 100 W to 800 W. It is worth noting that dahlia plants that received the 400 W treated vermicast consistently had the highest incremental impact. These findings confirmed earlier observations made recently by Abbey et al 7 and Yu et al 8 The former reported that 400 W microwaved vermicast increased plant growth as compared to power output levels (i.e.<400 W or>400 W) studied. The increase in vegetative growth following treatment 400 W in the present study can be attributed to increased nutrients bioavailability in addition to the high anthocyanin and the chlorophyll contents as shown in Figure 1.…”

“…chinensis) plants. As a follow up, Yu et al 8 was able to increase the nutrient density of municipal solid waste compost tea, which ultimately enhanced plant growth and chemical composition of Plectranthus amboinicus. All these studies demonstrated that microwave irradiation can densify chemicals in natural growing medium amendments with positive response from different plant species.…”

Concentration, Temperature and Storage duration Influence Chemical Stability of Compost Tea

“…This has led to commercial production of different formulations of compost teas and exploitation of its use in agriculture. For instance, Yu et al (2019) increased the efficacy of compost tea using microwave irradiation at 400 W for 10 mins. The efficacies of different formulations of compost teas are well acknowledged and documented.…”