The environmental and biodiversity benefits of organic farming are widely recognized, but there is still controversy about the effects of organic production methods on the nutritional composition of food and human health. In the first part of this article therefore, we critically review the evidence that organic farming methods improve the nutritional quality of food crops. Moreover, we summarize our current understanding of how quality gains are linked to the implementation of the “innovations” introduced into conventional crop production during the intensification or “green revolution” of agriculture over the last 100 years. In the second part of the article, we critically review the evidence for the range of health benefits related to organic food consumption. Specifically, we describe and discuss the results from: (i) dietary intervention studies which have found that organic food consumption substantially reduces pesticide exposure in humans and affects feed intake, growth, hormone balances and immune system responsiveness in animal models; (ii) human cohort/epidemiological studies which have reported significant positive associations between organic food consumption and the lower incidence of a range of diseases including obesity, metabolic syndrome, cancer, hypospadias, pre-eclampsia, eczema and middle ear infections in infants; (iii) interactions and trade-offs between diet (e.g., whole-grain, fruit and vegetables and reduced red-meat consumption) and food types (organic versus conventional) concerning public health and future food security. The article also identifies knowledge gaps and highlights the need for (i) long-term, factorial field experiments to understand the relative effects of agronomic and pedoclimatic drivers on crop quality and safety, and (ii) clinical trials and additional human cohort studies to confirm the positive health outcomes linked to organic food consumption. The main conclusions from our review are that there is growing evidence that (i) agricultural intensification has resulted in a reduction in the nutritional quality of food and the sustainability of food production, and (ii) organic farming practices not only improve food quality and human health, but also food security. This is particularly true where current nutritional guidelines (increasing whole-grain, fruit and vegetable products, while reducing red-meat consumption) are implemented.

Background: Consumer demand for organic spelt wheat has increased rapidly and production has expanded into semi-arid regions, where it was not traditionally grown. Methods: Here, we report the results of a factorial field experiment designed to compare the performance of four spelt varieties grown in rain-fed and irrigated, conventional and organic production systems in a semi-arid environment. Results: Irrigation resulted in 2.5-fold higher grain yields, a reduction in grain protein, taller plants and an increase in stem lodging. While yields of all varieties were similar and low in rain-fed production, the variety Züricher Oberländer Rotkorn (ZOR) produced the highest, Filderstolz and Oberkulmer intermediate and the variety Rubiota the lowest grain yields in irrigated systems. Organic production with chicken or sheep manure as fertilizer resulted in 15% higher yields that mineral NPK fertilizer-based conventional production protocols. Conclusions: Rain-fed spelt production results in very low yields and is therefore unlikely to be commercially viable. Results suggest that organic fertilization regimes and the variety ZOR will result in the highest yields in irrigated systems, while the two traditional spelt varieties Filderstolz and Oberkulmer will more reliably produce grain protein levels that comply with bread-making quality standards.

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