From Middle High German tüngen, from Old High German -tungen (in gitungen), derived from tung (“dung”). The modern consontanism is formally Central and Low German (compare Middle Low German düngen), but it must be due largely to dialectal re-voicing given that Dung (which see for more) was a predominantly southern word.
düngen (weak, third-person singular present düngt, past tense düngte, past participle gedüngt, auxiliary haben)
| infinitive | düngen | ||||
|---|---|---|---|---|---|
| present participle | düngend | ||||
| past participle | gedüngt | ||||
| auxiliary | haben | ||||
| indicative | subjunctive | ||||
| singular | plural | singular | plural | ||
| present | ich dünge | wir düngen | i | ich dünge | wir düngen |
| du düngst | ihr düngt | du düngest | ihr dünget | ||
| er düngt | sie düngen | er dünge | sie düngen | ||
| preterite | ich düngte | wir düngten | ii | ich düngte1 | wir düngten1 |
| du düngtest | ihr düngtet | du düngtest1 | ihr düngtet1 | ||
| er düngte | sie düngten | er düngte1 | sie düngten1 | ||
| imperative | düng (du) dünge (du) |
düngt (ihr) | |||
1Rare except in very formal contexts; alternative in würde normally preferred.