“The Effect of Eco Enzyme from Pineapple (Ananas comosus) Peel Waste on Soil pH, P Availability, Growth and Yield of Shallots (Allium cepa) in Ultisols ” (2023) TERRA : Journal of Land Restoration, 6(2), pp. 51–56. doi: 10.31186/terra.6.2.51-56.