Organically versus conventionally grown produce: Common production inputs, nutritional quality, and nitrogen delivery between the two systems

Authors: Lester, Gene; Saftner, Robert

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2011
Publication Date: 9/12/2011
Citation: Lester, G.E., Saftner, R.A. 2011. Organically versus conventionally grown produce: Common production inputs, nutritional quality, and nitrogen delivery between the two systems. Journal of Agricultural and Food Chemistry. 59:10401-10406.

Interpretive Summary: Consumption of organic products is growing at a rate of 20 to 30% per year in the United States and 30 to 50% per year in Europe. Quality claims of organic foods being superior to conventionally grown foods have oftentimes relied on inaccurate comparisons. We addressed matching or ‘pairing’ common production (e.g. physical and chemical properties of soils, water sources, fertilizer sources and amounts, crop type and maturities) and post-harvest methodologies (e.g. processing, handling and storage conditions) of organic and conventionally grown produce. Our findings utilizing the pairing of common production variables indicated that soil nitrogen delivery rates specifically affected nutritional quality differently in organic and conventional produce. Our findings are initially intended to benefit other researchers, mainly soil biologists, in profiling nitrogen as a promising new approach to help growers improve the nutritional quality of both organic and conventional produce.

Technical Abstract: One distinguishing and over-ridding conclusion found in reviews comparing organically vs. conventionally grown produce is that variables shared alike by organic and conventional produce during production, harvest and post-harvest handling and storage were not applied. As a result, accurate and meaningful conclusions comparing the nutritional quality of organic and conventional produce are difficult to ascertain. Paring common production variables such as the physical, biological and chemical/nutritional attributes of soils, the irrigation sources and amounts, crop varieties, crop maturities and harvest dates, pre- and post-harvest processing, handling and/or storage methods would, individually and collectively, provide greater clarity as to how inputs unique to organic and conventional systems affect produce nutritional quality. Variables to be paired during production, harvest and post-harvest handling and storage studies comparing organic vs. conventional produce are discussed along with findings indicating that organic crops often have higher dry matter, ascorbic acid, phenolics and sugars and lower moisture, nitrates, and proteins contents and yields than conventionally grown crops. Recent studies of nutritional quality in organic vs. conventional produce also indicate that soil nitrogen delivery rates strongly affect nutritional quality. Nitrogen profiling is a promising new approach to improving the nutritional quality of both organic and conventional produce.