Begged forth by the sages; made the earth bountiful
'Rsibhir yacito bheje navamam parthivam vapuh' (SB 1.3.14).
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Prithu
पृथु
Also known as पार्थिवं वपुः · Parthiva-vapu (the earthly form)
Prithu is Hindu tradition's first consecrated emperor — the fountainhead of the chakravartin ideal: son of Vena, who made the earth cultivable, from whom the earth itself takes her name 'Prithvi' (traditional etiology). SB 1.3.14: begged forth by the rishis, the Lord accepted 'the ninth, an earthly form', with which the herbs of the earth were milked (Prithu = the ninth avatara, unanimous identification).
Śrīmad Bhāgavata Mahāpurāṇa 1.3.14 — Sanskrit Wikisource (pinned oldid=369178)
Milked all treasures from the earth (further evidence at SB 2.7.9)
'dugdha vasuni vasudha sakalani yena' (SB 2.7.9). The same act is stated at SB 1.3.13, where the relationship prithu->milked->earth is already recorded; only the new evidence is added here.
Prithu — avatara of — Krishna
Ninth: begged by the rishis, the Lord accepted an earthly form — Prithu per the unanimous reading: 'rsibhir yacito bheje navamam parthivam vapuh' (SB 1.3.14). Evidence: identity STRONG_CONTEXT; assumption EXPLICIT.
Prithu — milked — Earth (Mahi)
With Prithu the herbs of the earth were milked: 'dugdhemama osadhih' (SB 1.3.14). Evidence: EXPLICIT.