Optimizing Sago Waste Ameliorants for Shallot Cultivation on Peatland in Meranti Islands Riau Province, Indonesia

Abstract The shallot plant is a strategic vegetable horticultural commodity with high economic value. The development of shallot cultivation on peat is constrained by low soil fertility. Productivity can be optimized with the right type of ameliorant and variety. This study aims to determine the effect of ameliorant types on three shallot varieties in peat. This research was conducted in Alah Air Village, Tebing Tinggi District, Meranti Islands Regency, Riau Province, Indonesia, from October to December 2023. The study used a Randomised Group Design (RAK) with three replications. The treatments were five types of ameliorants (dolomite, dolomite + bokashi sago bark, dolomite + bokashi sago leaf fronds, dolomite + bokashi sago pulp, dolomite + bokashi sago bark + sago leaf fronds + sago pulp) and the groups were three Cultivar of shallots (Bima Brebes, Trisula, SS Sakato). Observations were made on peat soil, sago waste bokashi, plant growth, and production parameters such as plant height (cm), number of leaves (blade), root length (cm), number of tubers, wet weight per clump (g), dry weight per clump (g), weight per tuber (g), and percentage of tuber shrinkage (%)The results of peat testing at the beginning and end of the study showed that there was an increase in pH (3.95 to 5.30 and 5.13), C-organic, total N, K, Mg, Ca, Na, and Fe, and a decrease in Al, H, and CEC. The testing results on three sago waste bokashi showed that sago pulp bokashi had the highest nutrient content compared to sago bark bokashi and sago leaf fronds bokashi. The type of ameliorant significantly affected the number of bulbs of three varieties of shallots. Still, it did not significantly affect plant height, number of leaves, root length, wet bulb weight per clump, dry bulb weight per clump, and percentage of bulb shrinkage.