Matthew Poole and continuators on Psalms 65:13

13 The pastures are clothed with flocks, the valleys also are covered over with corn , they shout for joy, they also sing .

This is added as the Effect of these Comfortable Rains, that they fill the Pastures with Grass for Cattel, and the Valleys (which he mentions as the most Fruitful places, though he doth not exclude the rest) with Corn for the use of Man.

(i. e.) They are abundantly satisfied with thy Goodness, and in their manner sing forth the Praises, and declare the Goodness of their Creator and Benefactor. Compare Psal 147. 8 such Passions or Actions, as these are oft figuratively ascribed to Life-less Creatures, both in Sacred and prosane Poetical Writings; which are said to Rejoyce or Mourn &c. when their Condition is such as calls for Rejoycing or Mourning, and would cause them to do so, if they were Capable of such Actions.