Vermicompost and Rice Husk Biochar Interaction Ameliorates Nutrient Uptake and Yield of Green Lettuce Under Soilless Culture

Various kinds of substrates have been widely used for vegetables grown in soilless culture systems. The use of biochar is getting a lot of attention. However, the ideal proportion of biochar in the substrates combined with the use of vermicompost for high yields has not been thoroughly studied. This study aimed to examine in the pot experiment the effect of a combination of rice husk biochar (15% and 30%) and vermicompost (50, 100, 150, 200, and 250 g per pot) in growing substrate on nutrient uptake and yield of green lettuce. The other components of the substrates were cocopeat and sand. The results showed that the 30% of rice husk biochar in the growing substrate resulted in a significantly higher uptake of N, P, and K in leaves compared to lower biochar content with an average increase of 52%, 67%, and 117%, respectively. Maximum total fresh weight of marketable yield was obtained with 30% of biochar and 250 g per pot vermicompost in the substrate.