Related Rule
Argentina
Practice Relating to Rule 53. Starvation as a Method of Warfare
Section A. General
III. Military Manuals
Under Argentina’s Law of War Manual (1989), it is “prohibited to starve the civilian population of the adversary”. 
Argentina, Leyes de Guerra, PC-08-01, Público, Edición 1989, Estado Mayor Conjunto de las Fuerzas Armadas, aprobado por Resolución No. 489/89 del Ministerio de Defensa, 23 April 1990, § 4.03.
In addition, starvation of civilians as a method of combat is specifically prohibited in non-international armed conflicts. 
Argentina, Leyes de Guerra, PC-08-01, Público, Edición 1989, Estado Mayor Conjunto de las Fuerzas Armadas, aprobado por Resolución No. 489/89 del Ministerio de Defensa, 23 April 1990, § 7.08.
Section B. Sieges that cause starvation
III. Military Manuals
Argentina’s Law of War Manual (1969), in a chapter dealing, inter alia, with siege warfare, provides: “Belligerent forces must try and conclude agreements which facilitate … the free passage of … essential foodstuffs and clothing.” 
Argentina, Leyes de Guerra, RC-46-1, Público, II Edición 1969, Ejército Argentino, Edición original aprobado por el Comandante en Jefe del Ejército, 9 May 1967, § 1.014.