The Wine Institute and the California Association of Winegrape Growers have announced a code of "sustainable" environmental practices for the state's vintners, who produce more than 90 percent of the nation's wine.

The voluntary code, which includes a 360-page workbook, was two years in the making and addresses water, land and pesticide use. It urges self-regulation by California grape growers and wine makers.

Environmental groups have charged that the wine industry contributes to soil erosion, watershed loss and pollution. They argue the voluntary code may not go far enough.