"as much as a shovel can hold or lift at one time," 1530s, from shovel (n.) + -ful.
Entries linking to shovelful
shovel n.
"instrument consisting of a broad scoop or curved blade with a handle," Middle English shovel, from Old English scofl, sceofol "shovel," from Proto-Germanic *skublo (source also of Old Saxon skufla, Swedish skovel, Middle Low German schufle, Middle Dutch shuffel, Dutch schoffel, Old High German scuvala, German Schaufel). The Old English noun is related to scufan "push away, thrust, push with violence" (see shove (v.)). Shovel-ready, with reference to construction projects, is attested by 2006.
-ful
word-forming element attached to nouns (and in modern English to verb stems) and meaning "full of, having, characterized by," also "amount or volume contained" (handful, bellyful); from Old English -full, -ful, which is full (adj.) become a suffix by being coalesced with a preceding noun, but originally a separate word. Cognate with German -voll, Old Norse -fullr, Danish -fuld. Most English -ful adjectives at one time or another had both passive ("full of x") and active ("causing x; full of occasion for x") senses.
It is rare in Old English and Middle English, where full was much more commonly attached at the head of a word (for example Old English fulbrecan "to violate," fulslean "to kill outright," fulripod "mature;" Middle English had ful-comen "attain (a state), realize (a truth)," ful-lasting "durability," ful-thriven "complete, perfect," etc.).