Effect of pre-crops, cover crops and manure application on organic potato production in a field experiment in eastern Austria

Abstract

The effect of different preceding crops, cover crops  and  manure application on the agronomic performance of potato was studied in two consequantial years in an organic farming system. The effect of lucerne, field pea and spring barley as pre-crops, non legume and mixture used as cover crops were tested as well as the influence of farmyard manure application on potato yield and quality. The cover crop treatments were studied in comparison to control bare fallow. The overall yields of main crop potato remained significantly (P < 0.01) less in 2010 than in 2011. The subsequent crop response to preceding crops was negligible since there was no indication of a greater tuber yields (fresh tuber, marketable and dry matter) after legume pre-crops compared to barley. Cover crops and manure both slightly increased tuber dry matter (DM) yield from 4.9 t ha^-1 to 5.2 t ha^-1 in 2010 only, on the contrary DM yield was not affected by cover crop and manure in 2011. The percentage of small sized tubers (< 35 mm in diameter) was distinctly increased in 2011 (25.6 %) compared with 2010 (4.7 %). Moreover, cover crops regarded as green manures significantly (P < 0.01) increased the percentage of large sized tubers (> 65 mm in diameter) on average of two years. However, the tuber quality was generaly higher in 2010 than in 2011. Regarding tubers with potato virus Y, common scab, malformation, growth cracks and greening, the percentage was lower in 2010.

Keywords: organic farming, nitrogen availability, potato yield, preceding crop, cover crop, manure application