Q.Which one of the following is not related to vermiculture?
a. Maintains soil fertility
b. Breakdown of inorganic matter
c. Gives porosity, aeration and moister holding capacity
d. Degradation of non biodegradable solid waste
a. a and b is correct
b. c and d is correct
c. b and d is not correct
d. a and c is not correct

Vermiculture is the deliberate use of earthworms to convert organic food waste into vermicompost, a nutrient-rich material that sustains plant growth, with the goal of continually growing the worm population for a sustainable harvest. Earthworms used for this fall into two functional groups — surface-dwelling, darker-coloured humus formers (the group actually used for vermicomposting) and deeper-burrowing humus feeders that keep soil porous — and India's vermiculture units draw on both native species (Periyonyx excavatus, Lampito mauritii, Octochaetona serrata) and introduced exotic species (Eisenia fetida, Eudrilus eugeniae). A practical unit is built as a shaded, layered pit (gravel, then coarse sand, then a loading layer of soil or biomass) where the worms are introduced and left to process the waste, releasing visible castings on the surface that signal harvest time; a separate liquid by-product, vermiwash, is collected from the bed's drilospheres and used as a nutrient-rich foliar spray. Because earthworms sustain the bacteria, fungi and protozoans that keep soil healthy, they are called both 'farmer's friends' and biological indicators of soil fertility, and the resulting vermicompost — rich in nutrients, better at holding moisture and aeration, and an eco-friendly amendment for both farms and terrace gardens — has grown into its own profitable retail industry, though the units themselves remain vulnerable to pests, predators and internal parasites whenever bed management slips.