Easy on the N

摘要

If you think nitrogen is the end-all-be-all of vineyard production, you may want to take a closer look. It may sound like heresy to grape growers who drive their vineyards as hard as possible, but some vines might not need what is considered to be astaple of every plant's diet: Nitrogen. Not only can you often skip a postharvest application; you might not have to apply any nitrogen ever again. "Vineyard problems stemming from too much N are more common than those stemming from too little," says Bill Peacock of the University of California Cooperative Extension, Tulare County. "A vineyard can often coast for years without fertilization before vines can become deficient." It's important to emphasize that Vines do need nitrogen, as it's necessary tosupport early spring growth. But some already have enough for a very long time. Many factors come into play in determining the need for nitrogen, says Peacock. One big one is root-stock. "Vines grafted onto vigorous nematode-resistant rootstocks such asRamsey (Salt Creek), Freedom, and Harmony often do not require N fertilization due to their more vigorous and explorative root systems and excess vigor," he says.