Influence of Climatic Conditions on Development and Yield of Potato Plants Growing Under Organic and Conventional Systems in Poland

A field study was conducted in 2012 and 2013, two seasons with very different temperature and rainfall patterns in Poland, with 2012 being a normal good year for potato production, and 2013 being poor. Four potato cultivars (Viviana, Gawin, Legenda, Gustaw) were grown under organic and conventional systems. Morphological and physiological characteristics of the plants were determined, as well as tuber yield and size distributions. As expected, the organic production system resulted in less than optimal plant growth, tuber yield and tuber size even in the normal season of 2012. But the reduction in these parameters was even more pronounced in 2013. For example, in the poor growing year, total yield was reduced by 45 % in conventional, but 55 % in organic. Tuber size was particularly impacted in organic production in an unfavorable year, as small tubers increasing by 39 % in conventional, but 149 % in organic. Thus, the impact of unfavorable weather conditions results in greater losses in crop value for organic growing systems than conventional.