الفهرس 
Effect of nitrogenOnly 14 pages are availabe for public view
 |  | from | 93 |  |  |
| | | from | 93 | | |
Abstract
Field experiments were carried out in the Faculty of Agriculture Farm, at Kafr El-Sheikh, Tanta University, Egypt, during the two successive seasons (1 99311 994) and 199411 995 to study the effect of nitrogen, phosphorus and potassium fertilization on growth, seed yield, yield components and oil yield of safflower. Twelve treatments, which were the combination among three nitrogen levels (i.e. 45, 60 and 75 kg N/fed.), two phosphorus levels (35, 45 kg P205/fed.) and two potassium levels (30, 40 kg K201fed.) were applied in each seasons. Nitrogen used was in the form of urea (46% N) and applied in two equal portion before the first and second irrigation, respectively. Calcium super phosphate (1 5.5% P205) and potassiuni sulphate (48% K20) fertilizers were applied during the soil preparation, respectively. A split-split plot design with four replicates was used in the two seasons. Nitrogen levels was randomly allocated to the main plots, phosphorus levels to the sub-plots and potassium levels to the sub-sub plots. Each sub-sub plots contained 6 rows 3 in. wide and 3.5 in. long and its size was 10.5 square meters (11400 feddan). Growth analysis determination were studied at three growth successive stages (i.e. 65, 85 and 105 days) from planting day in the two seasons. The results obtained could be summarized as follows : 1- Increasing nitrogen levels up to 75 kg Nlfed. increased the dry matter accuinulation per plant at all growth stages in both seasons. Increasing nitrogen rates up to 75 kglfed. increased stem dry matter at the second and third sampling dates in both seasons, while leaves dry matter increased at the first sampling date only. But, leaves dry matter was decreased at 85, 105 days and the recovered roots at all sampling dates. 2- Dry matter accumulation increased with increasing phosphorus rates up to 45 kg P205/fed. Increasing phosphorus rates increased stem percentage and branches at all sampling dates in both seasons. But, decreased the percentage of leaves at 65, 105 days in the first season and at 85 day in the second season. Aiso no significant effect on the percentage of leaves at 85 day in the first season, at 85, 105 days in the second season. The percentage of recovered roots decreased with increasing P205 rates only at 85 day or at 65 day for the first and second seasons, respectively. 3- Increasing potassium rates from 30 to 40 kg I&O/fed. iiicreased . dry matter accumulation, stem percentage and branches dry matter at all sampling dates in both seasons, except the last one. Also adding potassium fertilization increased recovered roots percentage at 65 days in the second season only. But decreased stem and branches dry matter at 65 days and leaves percentage at 85 day in the second season. 4 Increasing nitrogen rates fi-om 45 to 75 kg Nlfed. iiicreased plant height at all growth stages in both seasons. 5- Plant height was not affected by any levels of phosphorus or potassium fertilization at all sampling dates in the two seasons. 6- Nitrogen festilizer had a significant effect on nuniber of leaves at all growth stages tested in both seasons, except at 65 day stage in the first season. Increasing nitrogen rates up to 75 kg Nlfed. increased number of leaves.