It's Sunday. I know it is Sunday because my neighbor is spraying his organic nectarines. Organic farming requires weekly spraying. I'm not sure what he is spraying. It might be sulfur, oil, or copper sulfate. Copper sulfate is extremely toxic to fish and animals, but since it can be mined from the earth, it is an organic pesticide. Buy it at Whole Paycheck market.
City people think of organic as braless hippie chicks in long dresses and their bastard children picking bugs off the vines. Who hasn't picked tomato worms from their backyard tomato vines? Well, modern organic agriculture is big business and the 640 acre organic block sits next to the 640 acre convention block. My neighbor had a good thing going. He is a good farmer and puts out a quality product, but last year the largest grower in the state came on the market with 1100 acres of organic nectarines. The market went caput. Organic farming is no longer for hippies living off the land - or small farmers trying to find a niche market. Organic farming is big agribusiness. I suggest you read The Omnivores Dilemma, by Michael Pollan.
I think conventional farming is safer. Remember the parents who bought their child organic apple juice because it was safer? The child died from e. coli that came from the manure spread on the organic orchard. Synthetic fertilizers don't pose that hazard. My fear is that when I buy conventional lettuce I might be getting organic, because when the organic market is saturated, organic produce is simply diverted into the lower priced conventional market. Maybe we need a 'certified safe conventional' label.
We don't use copper sulfate on our vineyard because it will eventually poison the soil, but if our vineyard were classified organic, we would be spraying Bordeaux mixture which contains copper sulfate. Sulfur also changes the pH of the soil. Our soil is alkaline which limits the vegetal growth of the vines. Using sulfur over long periods of time in large amounts will acidify the soil and act as a fertilizer to the grapes, lowering the wine quality in return.
Pesticides got a bad name back in the 1950's when DDT (synthetic) and lead arsenate (organic) were used without regard to the environment. Today, in the Yakima Valley we suffer from poisoned soils from apple orchards that would have been classified as organic because they used lead arsenate as a primary pesticide. These heavy metals are poorly water soluble and are persistent in the soil for years. Just because it comes from the earth, doesn't mean it is safe. Mother nature, by nature, is very toxic. A list of all organic chemicals can be found here. I find it interesting that synthetic chemicals are organic and organic chemicals are inorganic. Go figure.
I calculate that it would take three times the diesel to farm our grapes organically. First there is mechanical weeding under the vines. One tractor can do about 1-2 acres a day. We have 35 acres, so one tractor would be dedicated to weed control, 8 hours a day, 5 days a week. Synthetic chemicals have a spray interval of 14 to 21 days and are sprayed at rates of ounces per acre. Organic chemicals have a spray interval of 7 days and are sprayed a rates of pounds per acre. Using this much diesel is not earth-friendly. Sustainable farming involves making the most earth-friendly choices by balancing all factors.
Hence, we farm sustainable, but not organically.