Answer:
"Preferred landfill of the city" comes from line 10 and 11 of the poem "Speaking with hands"
The poem was inspired by experiences given that the author grew up in Watts.
If we backtrack a little to line 1, the author states that there are no markets in Watts then goes on to state that people bought what there was to buy in the little markets.
Since by definition, landfill refers to a dump, a place where waste items and materials are buried or deposited, then the author is trying to use imagery to define how bad and terrible Watts was as a neighbourhood in relation to other parts of the city.
In order words, it was a slum where things rejected and refused by the people in the city were dumped. [See line 24-27]
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