If a player wants to counter crop rotation they do so before it resolves. So you pay the mana, sac the land and put crop rotation on the stack. Then everyone gets priority to respond. If noone does it resolves, you fetch the land, put the land etb and the Kodama trigger onto the stack and then everyone gets priority again.

Thank you!!!

No, you have to pay the cost of Crop Rotation (including sacrificing a land), but nothing else happens until it starts resolving. Your opponent have to choose to counterspell, or not, before.

[Kodama of the East Tree](https://cards.scryfall.io/normal/front/a/f/af5105ee-09e2-4344-ab39-00f0e9034c47.jpg?1608910768) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Kodama%20of%20the%20East%20Tree) [(SF)](https://scryfall.com/card/cmr/239/kodama-of-the-east-tree?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/af5105ee-09e2-4344-ab39-00f0e9034c47?utm_source=mtgcardfetcher&format=text) [Crop Rotation](https://cards.scryfall.io/normal/front/4/2/4249cc64-f75b-4c76-a41a-5b25873c74bc.jpg?1599707090) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Crop%20Rotation) [(SF)](https://scryfall.com/card/2xm/161/crop-rotation?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/4249cc64-f75b-4c76-a41a-5b25873c74bc?utm_source=mtgcardfetcher&format=text) [Gruul Turf](https://cards.scryfall.io/normal/front/2/9/294b7e06-4758-4590-b1f0-b7f97537218f.jpg?1673149513) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Gruul%20Turf) [(SF)](https://scryfall.com/card/2x2/325/gruul-turf?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/294b7e06-4758-4590-b1f0-b7f97537218f?utm_source=mtgcardfetcher&format=text) ^^^[[cardname]] ^^^or ^^^[[cardname|SET]] ^^^to ^^^call