from Billie R. DeWalt – Appropriate Technology in Rural Mexico: Antecedents and Consequences of an Indigenous Peasant Innovation, in widespread use by the early 1950s, the tube was originally crafted from maguey leaves.

 

 

 

 

 

 

 

 

 

 

 

 

 

and the improved sembradora, designed in consultation between farmers and blacksmiths, with a modified plowshare for increased depth so the seeds could reach the subsoil moisture level (~ 20 cm), reinforced frame, and welded tube: