The following is straight from http://www.mayoclinic.com/health/organic-food/NU00255/NSECTIONGROUP=2
Apply chemical fertilizers to promote plant growth. Spray insecticides to reduce pests and disease. Use chemical herbicides to manage weeds. Give animals antibiotics, growth hormones and medications to prevent disease and spur growth.
Apply natural fertilizers, such as manure or compost, to feed soil and plants.
Use beneficial insects and birds, mating disruption or traps to reduce pests and disease.
Rotate crops, till, hand weed or mulch to manage weeds.
Give animals organic feed and allow them access to the outdoors. Use preventive measures — such as rotational grazing, a balanced diet and clean housing — to help minimize disease.
Now, the article is based in the US and standards and influences are very different there to other countries and so there is perhaps a truer slant to the further part of the article that sites lack of scientific evidence to back claims of nutritional differences. A point now heavily disputed as slowly scientists have gathered data to the contrary over time
(see following links from the international forum for organic agricultural movements:
But there are some pretty passionate organic farming families in the US who probably find this the most frustrating of all, as it is unlikely that their farms were part of the testing grounds.
I mean really, when you think about it, if there are all these differences and they were really being done as well as they can be done, it seems illogical that there would not be nutritional differences and benefits in organic food, just based on the fact that microbes provide minerals to plants as part of their waste process. That the diversity of microbes is in direct relation to what is in the decomposing matter they are feeding on (usually in the form of fertiliser) and that, therefore, there will be more presence of at least mineral diversity from the microbes in the plant's uptake from the soil.
There are, however a few points to consider.
I would think the main, obvious one, is the differences in what is being used as fertiliser.
Fertiliser is the big money spinning item in the farming world. You see a plant must have phosphate in order to photosynthesize (breath) and it can get it from microbes in the soil but we like to put it in the soil in the form of a mined substance we call various things like rock phosphate which is turned industrially into a thing called superphosphate so the plants really get pumping out of that soil!
Now the issue with this is that this can mean there is little else the plant is getting to eat. A little like taking a steroid to build big muscles and not having a balanced diet. You get the appearance of big muscles but the person could be very sick or get sick later as the lack of a certain nutrient, that may take longer to become apparent, exacts its effect.
So too, the plant can look big and green and healthy but actually be an empty hull. For more on this download my eBook elegant solutions for addressing climate change via the website www.sickclimate.com and read what the insects think of all this in the chapter on the electricity of life.
To finish off, these issues vary so much just in the different soil quality, water, environmental issues, plus the weather conditions of the area the food is being grown in, it is truly difficult to make a sweeping statement like this about nutritional content. The fact that, further in the article it studies people perception of organic as healthy and interchanges this with calorie count and weight loss is in itself worrying. Health and weight are related but not inclusive. I found it disturbing that a person thought an organic cookie would be less fattening than its conventional counterpart. It is these sort of furfies (Australian slang for a distracting stories) or 'look over here' factors that take away form the issue at hand of nutrition and health. Perhaps we should look at saying mental health and well being as opposed to health which appears to have been taken over by the weight loss industry?
For to eat organic is to begin to find connection with the food, where it came from, the people that grew it and how it was grown as more and more farming families try to put information out there about themselves and how their produce is made. They are often totally passionate about it and you the end user and your health! They are community people who care. Perhaps this is a better slant 'mental well being' through connecting with the health of the food you eat?
After all, we are what we eat!