This study was conducted during 2007, 2008 and 2009 seasons on 7-year old Superior grapevines in a private vineyard in Nubaria region at the 90th kilometer of Alexandria Cairo desert Road.
The vines were grown in a sandy soil under the drip irrigation system, planting distance was 2 x 3 meter between the vines and the rows and supported by the Spanish Parron system. Winter pruning was carried out in the third week of December in all seasons of study, 100 buds per vine were left (10 canes each with 10 buds) according to vine vigor. The aim of this investigation was to study the effect of N source: Granular ammonium nitrate, liquid ammonium nitrate, granular calcium nitrate, ammonium sulphate, calcium Cyanamid and vine prunings on growth and fruiting of Superior grapevines, 70 units per Feddan were used annually from each source. The quantity of different sources was divided into three doses:
1- 15 units of N were added during the period from budburst to the beginning of bloom
2- 35 units of N were added during the period from berry set to veraison
3- 20 units of N were added after harvest.
Vine prunings were added once during winter.
The results showed that bud burst started in March ranging between the second and eighth day, end of shoot growth date ranged September 8th to 25th for granular and liquid ammonium nitrate, granular calcium nitrate and calcium Cyanamid. Liquid forms of N had a longer period of days. Ammonium sulphate fertilizer and vine prunings were found to have short periods of growing period in days.
Also, the soluble forms of N gave highest values of average shoot length. As for wood ripening coefficient forms of N which contain calcium element resulted in the highest values of this parameter in comparison with the other forms of N meanwhile vine prunings were found to have the least values. T.S.S % and acidity % were affected by N forms. All chemical N fertilizers increased these values but vine prunings reduced them. As for nitrate and nitrite juice berry content, it was found that vine prunings had the lowest values in this respect as compared with other treatments. The highest values came from liquid N form.
Berry set %, adherence strength and berry firmness were affected with different N forms. The highest values resulted from fertilizers which contain calcium element. Liquid N was found to reduce number of leaves per shoot, shoot thickness and increased weight of prunings/vine. Also, number of clusters per vine, cluster weight, yield per vine and leaf content of N, P, K were affected by N forms. Calcium cyanamid had higher values in this respect in the first season than vine prunings. Organic manure which had the highest values in the second and third seasons. Similar results were noticed on leaf area (cm2), total leaf area / per vine (m2) and leaf area (cm2) per cluster which were increased by the application of granular and liquid ammonium nitrate. Vine prunings as organic manure were found to have the least price for N unit.