Matsya Purana — Pṛthu
प्लक्षो ऽभवत्ततो वत्सः सर्ववृक्षो धनाधिपः एवमन्यैश्च वसुधा तदा दुग्धा यथेप्सितम् //
plakṣo 'bhavattato vatsaḥ sarvavṛkṣo dhanādhipaḥ evamanyaiśca vasudhā tadā dugdhā yathepsitam //
Then the plakṣa-tree became the calf, and Kubera, lord of wealth, became the milker; thus, by various others as well, the Earth was milked at that time to yield whatever was desired.
It reflects a creation-oriented motif: the Earth is portrayed as a sustaining source that can be ‘milked’ to manifest resources—here, especially vegetation and wealth—rather than describing dissolution (pralaya).
By framing Earth as a provider of ‘desired yields’ when properly approached, it supports the dharmic ideal that rulers and householders must steward land and resources responsibly—seeking prosperity through right means rather than exploitation.
No direct Vastu or temple rule is stated; however, the verse underlines land (vasudhā) as the primary source of materials (notably trees/wood), which later Vastu and ritual sections treat as essential for construction and sacrificial implements.