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Abstract SIMMARY Response of Some Sugar Beet Varieties to Potassium and Magnesium Fertilization Two field experiments were carried out in Sakha Agricultural Researcn Station, at Kafr EI Sheikh Governorate during 1996/97 and 1997/98 seasons, to study the response of three sugar beet varieties to potassium and magnesium fertilization. The experiments were laid out in a split split-plot design with four replications in the two seasons. Each experiment included 27 treatments which were the combination between: • Three sugar beet varieties namely; Kawemira, Plena and Top. • Thr~e potassium levels; zero, 24 and 48 kg K20/fad. r • Three magnesium levels; zero, 9 and 18 kg MgO/fad. The area of the sub-sub plot was 10.5 m2 with six ridges. Sugar beet seeds were planted in hills 20 em apart. Sowing date was on 15 and 21 October in 1996/97 and 1997/98 seasons respectively. Harvesting was done after 190 days from planting. Nitrogen at a rate of 90kg N/fad was applied in the form of ammonium nitrate (33.5% N). P at rate of 15.5 kg P20s/fad was applied in the form of calcium super phosphate (15.5°/0 PzOs). K in the form of potassium sulphate (48%K20). Mg in the form of maqnesium SUlphate (49% MgO). P fertilizer was added in one application during seedbed preparation. Meanwhile levels of K and Mg as well as N fertilizers were added at two equal doses, one after thinning and before the first irrigation and the other before the second irrigation. 120 Cultural practices were followed as recommended for the region at appropriate dates. Data on growth characters! physiological characters, root characters, yield characters, technological characters and impurities were recorded. The results of the combined analysis of both seasons could be summarized as follows: I. Growth Measurements: 1. Number of leaves per plant was significantly affected by varieties. Top! Kawemira and Plena gave 20.69! 21.59 and 22.15 leaves/plant respectively. Pleno was significantly more leafy as compared with Kawemira which significantly surpassed Top. 2. Top ~ariety surpassed significantly Kawemira and Plena in I leaf area/plant without significant difference between the two later varieties. Results showed that there was no relevance between leaf area index and sugar beet varieties. 3. Top, Kawemira and Plena were significantly different in their root lengths. Top was of the shortest root (25.50 cm compared with Kawemira (26.17 em) and Plena (26.05 em), without significant difference between Kawemira and Plena. Whereas! results showed that Plena was of the highest root diameter (6.90 cm) followed by Kawemira (6.82 cm) then Top (6.70 cm). 4. Top had the heaviest fresh and dry weight of leaves per plant and that both Kawemira and Pleno had nearly similar fresh and dry weight of leaves /plant. 5. Top, Kawemira and Plena did not significantly differ in their root fresh and dry weight /plant as well as total fresh and dry weight Iplant. 121 6. Number of leaves Iplant of sugar beet significantly increased with the increase in potassium application from 0 to 24 and 48 kg K20/fad. 7. Leaf area per plant increased significantly due to increasing potassium application levels from 0 to 24 and 48 kg K20/fad. These increase were 3.56 and 5.56 cm2 for the two mentioned a.pplication levels of potassium, respectively, as compared with tile control treatment. 8. Root length increased significantly as potassium fertilizer level incre •• ed from 0 to 24 and 48 kg K20/fad. Such increase was 0.98 and 1.35 cm as a result of the application of 24 and 48 kg K20/fad, respectively. 9. Incre~sing potassium fertilizer from 0 to 24 and 48 kg K20/fad I significantly increased root diameter of sugar beet plant by 0.19 and 0.36 cm as compared with the control 10. Fresh and dry weight of leaves per plant significantly increased as potassium level increased. 11. The fresh and dry weight of sugar beet root were increased significantly with increasing potassium application and the highest root fresh and dry weight was obtained when potassium was applied at the rate of 48 kg K20/fad. 12. Potassium fertilizer application significantly increased total fresh and dry weight of sugar beet plant and the highest level i.e, 48 kg K20/fad produced the highest amount of dry matter in plant. 13. Number of leaves Iplant of sugar beet significantly increased with the increase of magnesium application from 0 to 9 and 18 kg MgO/fad. 122 14. Increasing magnesium application to sugar beet plant significantly increased leaf area per plant and the highest leaf area/plant was obtained when magnesium was applied at 18 kg MgO/fad. Whereas, leaf area index was not significantly affected by the application of magnesium. 15. Root length of sugar beet plant was significantly increased when magnesium application was increased from 0 to 9 and 18 I<g MgO/fad. 16. Increasing magnesium application to sugar beet plant up to 9 I<g MgO/fad caused a significant increase in root diameter but further increase up to 18 kg MgO/fad caused a significant reductfn. 17. Fresh and dry weight of leaves, fresh and dry weight of root and total fresh and dry weight of pl,~nt were significantly increased with the increase in magnesium application up to 18 kg MgO/fad. 18. There was a significant effect for the interaction between varieties and potassium fertilizer levels on the total fresh weight of sugar beet plant. The greatest total fresh weight of sugar beet plant was obtained by growing Pleno variety under the application of 48 kg K20/fad. 1s. There was a significant effect for the interaction between varieties and magnesium fertilizer levels on the total fresh weight of sugar beet plant. The greatest total fresh weight of plant was obtained by grOWing Kawemira under the application of 18 kg MgO/fad. 20. The interaction between potassium fertilizer levels and magnesium fertilizer levels was statistically significant on: 123 Number of leaves of sugar beet plant, leaves area of sugar beet plant, dry weight of leaves of sugar beet plant The highest values of the previous characters were recorded by the combination of 48 kg K20/fad + 18 kg MgO/fad. II. Some physiological characters: 1. The three tested varieties significantly differed in their specific leaf area where Kawemira gave the highest value (0.97) and Pleno fhad the Lowest specific leaf area (0.95) and Top was in between (0.96). , , 2. The three tested varieties did not significantly differ in their net assimilation rate, relative growth rate as well as the crop growth rate. 3. Results revealed that there were significant differences among varieties in their total chlorophyll content. 4. There was a significant increase in the specific leaf area by increasing the application of potassium fertilizer up to 48. 5. Potassium application up to 48 kg K20/fad did not significantly increase most of the tested physiological characters of sugar beet plant namely; net assimilation rate, relative growth rate, crop growth rate and total chlorophyll. 6. There was a significant increase in the mean value of specific leaf area by increasing the application of magnesium up to 18 kg MgO/fad. 7. The average values of net assimilation rate, relative growth rate. crop growth rate and Total chlorophyll were not significantly affected by the application of 9 and 18 kg MgO/fad. 8. The effect of the interaction between varieties and potassium fertilizer on the specific leaf area, net assimilation rate, relative 124 growth rate, crop growth rate and total chlorophyll of sugar beet plant was not statistically significant. 9. The effect of interaction between varieties and magnesium tertilizer levels on specific leaf area, net assimilation rate, relative growth rate, crop growth rate and total chlorophyll was not statistically significant. 10. The effect of potassium fertilizer levels with magnesium fertilizer levels on specific leaf area, net assimilation rate, relative growth rate, crop growth rate and total chlorophyll of sugar beet plant was not statistically significant. III. Root characters: 1. Varieties were significantly differ in their root length at harvest. 2. Diffe~ences among varieties in root weight and root diameter were not significant, whereas, significant differences among varieties in root length were obtained. Plena produced the •I longest length followed by Top and Kawemira in a descending order. ). Root diameter significantly increased when potassium application level was increased from 0 to 24 and 48 kg K20/fad. ~. Increasing potassium application level from 0 to 24 and 48 kg K20/fad caused a significant increase in root weight of sugar beet plant. 7’ Increasing magnesium application level from 0 to 9 and 18 kg MgO/fad increased root length and root diameter of sugar beet plant. 125 6. Root weight of sugar beet at harvest increased significantly and continuously when magnesium fertilizer was increased from a to 9 and 18 kg MgO/fad. 7. The effect of the interaction of between varieties and K levels on root weight, root length, and root diameter at harvesting time was not statistically significant. 8. The effect of the interaction between varieties and magnesium fertilizer levels on root weight, root diameter and root length was not statistically significant. 9. The effect of the interaction between potassium fertilizer levels with magnesium fertilizer levels on root weight, root length and root diameter was not statistically significant. IV. Yield and yield components: 1. Varieties did not significantly differ in top yield and sugar yield (ton/fad). 2. Varieties exhibited significant differences in root yield and bioloqical yield. Kawemira variety significantly yielded out the other two varieties with an average root yield of 18.63 ton/fad. ’Nhile the lowest root yield resulted from Plena variety with an average yield of 17.94 ton/fad. 3. Plena surpassed both Top and Kawemira in leaves /root ratio and Kawemira variety had the lowest leaves /root ratio. 4. There was a significant decrease in top yield and leaf Iroot / ratio by increasing potassium fertilizer level from zero up to 48 kg K20/fad. /5. Increasing potassium fertilizer application levels from 0to 24 and 48 kg K20/fad caused significant increase in root yield Ifad. f~ ( I , , 126 Such increases were 1.28 and 3.26 ton/fad as compared with the control treatment. 6. The biological yield of sugar beet significantly increased with increasing potassium application up to 48 kg K20/fad. ). Increasing potassium fertilizer levels from a to 24 and 48 kg K20/fad significantly increased sugar yield by 9.3 and 21.4% respe9tively, over the check treatment. 8. The ’maximum root yield (18.68 ton/fad) was obtained under the application of 18 kg MgO/fad. Wh~reas! there was no significant difference in top yield of sugar beet as a result of increasing magnesium application. 9. Magnesium fertilizer significantly increased biological yield of sugar beet plant and the highest biological yield was obtained by the application of 18 kg MgO/fad. 10. Increasing magnesium fertilization to sugar beet plants from 0 to 9 and 18 kg MgO/fad significantly decreased leaves Iroot ratio. )J. Magnesium fertilizer application at the rate of 9 kg MgO/fad significantly increased sugar yield by 4.7% as compared with the control treatme nt. 12. The effect of the interaction between varieties with potassium fertilizer levels was significant on root, biological and sugar yields. The highest values of the previous characters were recorded by growing Kawemira variety under the application of 48 kg K20/fad. 1:~. The effect of the interaction between varieties and magnesium fertilizer levels on top yield, root yield, biological yield and sugar yield was not significant. 127 14. There was a significant effect for the interaction between potassium fertilizer and magnesium fertilizer on root yield. The highest values of root yield was recorded by the combination of 48 kg K20/fad + 9 kg MgO/fad. V. Technological characters: 1. Varieties did not significantly differ in T.S.S%, sucrose%, purity<%and extractlonss. ~. Increasing potassium fertilizer application from 0 to 24 and 48 k.gK20/fad caused a significant increase in T.S.S. 3. Sucrose %, purity % and extraction % were not significantly affected by potassium application. 4. T.S.S%, sucrose % and extraction % were not significantly affected by the application of different levels of magnesium fl9rtiliz,r. /. Purity % of sugar beet plant significantly increased when magnesium fertilizer level raised from 0 to 9 kg MgO/fad. , I 6. Total soluble solids percentage, sucrose percentage, purity percentage and extraction percentage were not significantly attected by varieties. 7. T.S.soJO, sucrose %, purity% and extraction% were not significantly affected by K x Mg levels. 8. The effect of the interaction between potassium and magnesium fertilizers on T.S.S%, sucrosess, puritYO/oand extractlonx was not statistlcally significant. 128 VI. Impurities (sodium, potassium and a-amino·nitrogen contenU;, 1. Differences among varieties in impurity components in terms of Na and K content were not significant. With regard to a-amino-nitrogen results indicated that varieties differed significantly in a-amino-nitrogen. Pleno variety had the highest mean values. 2. Differences among potassium fertilizer levels in impurity components in terms of Na, K and a-amino-nitrogen were not significant. 3. Increasing magnesium fertilizer levels up to 9 kg MgO/fad increased significantly Na content and a-amino-nitrogen but had no effect on K content. 4. The effect of the interaction of varieties with potassium fertilizer levels on Na, K and a-amino-nitrogen was not significant. 5. Varieties acted independently under the different levels of rnagn9sium fertilizer in affecting onl Na, K and a-ami nonitrogen. 6. The effect of potassium and magnesium fertilizers on Na, K , .~ , and a-amino-nitrogen was not significant. |