The effect of nitrogen fertilizing on nitrate content in irrigated stands of early potatoes
1991
Hamouz, K. (Vysoka Skola Zemedelska, Prague-Suchdol (CSFR))
Field trials under irrigation in the early-potato growing region were performed to study the effect of gradated nitrogen application rates 0, 60, 120, 180 and 240 kg per ha at a uniform rate of 40 t of manure per ha on nitrate content in tubers. Gradated nitrogen rates resulted in the increase of nitrate content in tubers. The tubers from the early harvesting date on 5th to 7th June exhibited the highest content of nitrates afterwards their content gradually decreased. Of the two investigated varieties, the Klara variety composed on an average 62 per cent of nitrates more than the Resy variety. A limit acceptable in the CSFR for 1990 being 300 mg of NaNO3 per kg was exceeded almost exclusively in the Resy variety on the earliest date on June 5-7th at rate of 240 kg, exceptionally 180 kg per ha, in the Klara variety this limit was very often exceeded at nitrogen rates of 240 and 180 kg per ha on June 5-7th but even in the later dates. The limit was exceeded exceptionally also at nitrogen rate of 120 kg per ha.
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