Effect of various nitrogen sources on yield and some properties of potato plant

In this investigation, the effects of some slow release and conventionally used fast release nitrogen sources in the soils of Niǧde-Misli plain on tuber yield, and protein, starch and NO- 3 contents of tubers of the potato plants grown under greenhouse conditions were determined. Effect of nitrogen levels on tuber yield, as mean of nitrogen sources were found as follows: N2>N1>N4>N3>N 0. On the other hand, increasing levels of nitrogen applied to the soil increased the protein and starch contents of the potato tubers. The highest and lowest tuber yield as mean of N levels was obtained with AS+AZN and AS+PG respectively. According to efficiency of nitrogen sources on tuber yield, nitrogen sources were grouped as: first group AS+AZN, AS+SCU, AZN, FLD; second group FLD, SCU; third group SCU, AS+FLD, AS+N-serve and last group AS, AS+PG. Differences between the groups were is statistically significant (p<0.05). AS+PG (AS+Phosphogypsum). AS (Ammonium sulfate) and AS+N-serve applications caused the highest increase in the starch content but the lowest increases in the tuber yield and protein contents of the tubers. Effects of various nitrogen sources and levels varied on the NO- 3 content of the tuber; the highest NO- 3 content was determined with the AS, where as the lowest NO- 3 contents with the AS+N-serve. SCU (Sulphur coated urea), FLD (Floranid) and the AS+PG and AZN (Azolon) sources.