Organic installs are not attributed through AppsFlyer to any media source. These could be installs from users who directly installed the app without the AppsFlyer tracking URL, or when the matching of the click and launch was unsuccessful and the click goes to organic.
Non-organic installs are traffic that was attributed through AppsFlyer.
This means that an app install or launch was performed through an AppsFlyer tracking link, AppsFlyer is then able to match the click and the capture launch through its SDK. When this occurs, AppsFlyer attributes the launch to non-organic.
Keep in mind that AppsFlyer uses last click attribution, meaning that the last ad interaction takes credit for the app install or action. AppsFlyer does not credit more than one media source per install. For details of AppsFlyer's attribution, click here.