Assessment of the Short-Term Fertilizer Potential of Mealworm Frass Using a Pot Experiment

• Published in: Frontiers in sustainable food systems Vol. 5
• Main Authors: Houben, David, Daoulas, Guillaume, Dulaurent, Anne-Maïmiti
• Format: Journal Article
• Language: English
• Published: Frontiers Media 28.07.2021; Frontiers Media S.A
• Subjects: Agricultural sciences; Agronomy; fertilizer; frass; insect excreta; Life Sciences; mealworm; nitrogen mineralization; organic amendment; mealworm; nitrogen mineralization; insect excreta; frass; NPK; organic amendment; Tenebrio molitor; fertilizer
• ISSN: 2571-581X; 2571-581X
• DOI: 10.3389/fsufs.2021.714596

The forecasted growth of insect production in the next few years will generate high quantities of frass (insect excreta). Although frass is increasingly considered a potential fertilizer, the dynamics of nutrient supply by frass is still poorly understood. Here, we aimed at gaining insight into the short-term fertilizer value of frass from mealworm ( Tenebrio molitor L.) in order to optimize its sustainable use in agroecosystems. Using a short-term pot experiment, we showed that, even though frass has a great potential to be used as a substitute of mineral NPK fertilizer, its N fertilizer potential is mediated by its rate of application. At 10 t ha −1 , due to its fast mineralization coupled with improvement in microbial activity (assessed using Biolog EcoPlate), frass was as effective as mineral fertilizer to supply N to plant. By contrast, at 5 t ha −1 , the lower frass mineralization induced a reduced N uptake compared to its mineral control. Unlike N, frass was as effective as mineral fertilizer to supply P and K to plants irrespective of its application rate. This was attributed to the presence of P and K in a readily available form in frass. Taken together, our results indicate that mealworm frass supplies very rapidly N, P and K to plants but its effects on N dynamics should be better investigated to warrant its sustainable use as an alternative fertilizer for managing NPK nutrition in cropping systems.