Abstract: The continuous exploitation of tropical tasar food-plant, Terminalia tomentosa (W and A) rose on wastelands under the rain-fed conditions by rearing its economic insect pest; Antheraea mylitta (D) needs soil management for sustainable yields. To asses the feasibility, legumes like Sun hemp (Crotalaria juncea), Daincha (Sesbania aculeata), Green gram (Vigna radiatus) and Black gram (Vigna mungo) were raised during monsoon (June) season in the inter space of T. tomentosa economic plantation for biomulching. The Sun hemp has yielded highest biomass of 39.0 q ha -1, followed by Daincha, Green gram and Black gram with 26.6, 25.3 and 17.7 q ha -1, respectively after 45 to 50 days of sowing, has been mulched for soil fortification. The water holding capacity, electrical conductivity and organic carbon have been improved with reduced pore space and bulk density of the soil and enhanced leaf yield of tasar food-plant after legume biomulching. The superior Effective Rate of Rearing (ERR), higher cocoon and shell weights, better silk ratio and longer silk filament length of tasar silkworm in biomulch treatments have contributed to increase silk yield. Among the biomulches, Sun hemp has shown improved water holding capacity (56.9%) and moisture (68.5 and 37.9%) at 30 and 45 cm depth with electrical conductivity (0.30 mhos cm -1), bulk density (1.12 g cm -3), pore space (50.4%), organic carbon (0.61%) of soil, leaf yield (24.8 MT ha -1) of food plant and ERR (80.1%), cocoon weight (12.25 g), shell weight (1.90 g), silk ratio (14.03%) and silk filament length (724 m) specify its suitability in making tropical tasarculture sustainable under rain-fed conditions.