EN
Over 1998-2000 field experiments were carried out to define the effect of various organic fertilisers and the tillage methods on the content of nitrogen in soil and yielding and the quality of Ibis potato tubers. The research showed that fertilising the potato with manure or white mustard stubble intercrop enhanced the tuber yield and decreased their accumulation of nitrate nitrogen. Manure as compared with other fertilisers tested ensures also the best health status of tubers after harvest and after storage. However barley straw facilitates nitrate nitrogen liberation and its increase in tubers and deteriorates their storage life, causing an increase in rots. On the other hand, ploughless tillage (with cultivator) decreases the yield and causes tuber infection with common scab, increasing the nitrates in topsoil and in potato tubers and total losses after storage.