In 1914, the general officer commanding a field army employed his Foot Artillery (Fußartillerie) units by allocating them to army corps. Likewise, the commanding general of an army corps employed his Fußartillerie units, whether organic to his formation or attached, by assigning them to one of their two infantry divisions. The commanding general of the receiving infantry division, in turn, passed authority over those heavy artillery officers to the officer in charge of his field artillery.
Because of this practice, the officer in charge of the field artillery of an infantry division stood an even change of having the Fußartillerie battalion of his parent army corps under his operational command. Similarly, he could anticipate situations in which he gave orders to both the Fußartillerie battalion of his army corps and one or more army-level Fußartillerie units.
To put things another way, the general officers commanding the German armies and army corps of 1914 did no so much as “employ” their Fußartillerie units as “deploy” them.