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Abstract CONCLUSIONS Four experiments were carried out on rice as an indicator plant. Two experiments out of the four were conducted in greenhouse at Giza, the other two were conducted in the field at Kafr EI-Sheikh Governorate. The first pot experiment was initiated to study the effect of phosphorus, iron and zinc fertilizations on dry matter yield, mineral content and uptake of rice plant. The treatments consisted of all possible combinations of three levels of phosphorus 0, 60 and 120 ppm ; as superphosphate 15% P20s’ three levels of iron; 0,5 and 10 ppm,;!as FeS0 4 .7H 2 0 and three levels of zinc; 0,5 and 10 ppm; as ZnS0 4 .7 H 2 0. Each treatment was replicated three times in factorial design and arranged randomizely in the greenhouse. The soil used in the experiment was clay loam. The first field experiment was carried-out to study the effect of the fertilization with P, Fe and Zn on the yield and chemical composition of rice plant. In a factorial design, P, Fe and Zn were applied at levels equivalent to ° (PO), 30 (Pl) and 60 (P2) Kg P20s/fed. as superphosphate; ° (Fe 0), 3 (Fel) and 6 (Fe2) kg Fe Ifed as FeS0 4 and O(ZnO) 3(Zn 1”>and 6 (Zn 2) Kg Zn/fed. as zns04• The soil where the experiment was conducted was clay. -~ -~~- -123 The second pot experiment was devoted to study the effect of nitrogen and manganese fertilization on dry matter yield, mineral content and uptake of rice plant. Three levels of nitrogen and manganese., 0, 90 and 180 ppm N, as ammonium sulphate and 0, 5 and 10 ppm Mn as MnS0 4 were used. The agronomic practices were the same as in the first pot experiment. The second field experiment was conducted to examine the effect of soil fertilization with nitrogen and manganese on the yield components and chemical composition of rice plant. The treatments consisted of all possible combinations of three levels of nitrogen; 0, 40 and 80 kgN/fed.; and three levels of manganese; 0,3 and 6 kg Mn/fed. as MnS0 4 . The Results obtained had shown the following 1- Pot experiment (I) 1.1. Dry weight of rice shoots and roots increased highly significant and progressively as a result of phosphorus application. Application of iron has a slight or no effect on increasing the dry weight of rice shoots and roots. Zinc application high significantly increased the dry weight of rice shoots and roots. 1.2. Addition of phosphorus increased the beneficial effect of iron and zinc. Maximum dry matter yield of rice shoots and roots was obtained with application of the second levels of P, Fe and Zn. -- --~---- - 124 - 1.3. Application of phosphorus gradually increased P-content of both shoots and roots. However, phosphorus efficiency tended to decrease upon increasing the rate of P application especially for shoot fraction. Phosphorus content of rice shoots and roots did not show a distinct response to the different treatments of iron and zinc, except for Zn2 level compined with PI level where a noticeable increase was observed only with shoots fraction. 1.4. Phosphorus uptake of rice shoots and roots highly significant increased with increasing the rate of phosphorus application. Addition of iron has slight or no effect on the amount of phosphorus uptake by rice shoots, although the amount of phosphorus uptaken by rice roots increased as affected by the different iron treatments. 1.5 Application of Zinc has a significant increase on phosphorus uptaken by rice shoots and roots. The highest phosphorus uptake was recorded with the vJif;\ treatment of PI combined Fe2 and Zn2. 1.6 Application of phosphorus led to increase the mean ’/ values of iron content of rice plants. However, the concentration of iron of both shoots and roots tended to decrease wity increasing the rate of phosphorus application. Iron content of rice plants progressively inceased with application of iron levels. On the other --- ~------- --~ ~--- - 125- hand, application of first level of Zinc increased iron content of shoots and roots, but with increasing the rate of applied Zinc, iron content diminished to almost its content of control plants. 1.7. Applioation of phosphorus highly significant increased the amount of Fe-uptake of rice shoots and roots. Application of iron first level significantly increased iron uptake of shoots and roots, however the effect of second level showed a slight increase. Addition of Zinc at the first level highly significant increased iron uptake of rice shoots and roots; while the addition of the second level has a slight or no effect on iron uptake of rice shoots and roots. The mutual effect of P, Fe and Zn showed statistical insignificancy on iron uptake of rice shoots and roots. 1.8. Application of phosphorus gradually and highly significant increased Zn-content and uptake of rice shoots and roots. Iron application has slight or no effect on Zinc-content and uptake of rice shoots. However._ the effect of iron application was of a higher mangitude in decreasing Zn-content of roots fraction than in shoots. Application of Zinc levels gradually and materially increased Zinc content and uptake of rice shoots and roots. 1.9. Statistical analysis showed that the interaction between phosphorus and Zinc was significant in rice shoots, whereas was not significant with rice roots. The highest Zn-uptake was recorded for ”P11eo,zn2” treatment. 2. Field experiment (I) 2.1. Application of phosphorus up to the second levels, highly significant increased both straw and grain yield. Iron application has slight effect on rice straw yield, but showed no effect on grain yield. Zinc application highly significant increased both straw and grain yield with increasing the rate of applied zinc. 2.2. The interaction effect between phosphorus, iron and zinc on rice straw and grain was insignificant , although the highest yield was recorded at~p~Fel~n2~ treatment for straw and P2FelZn2 treatment for grains. 2.3. Phosphorus application progressively increased phosphorus content and uptake of both straw and grainwith increasing phosphorus levels. Iron application has slight or no effect on phosphorus content and uptake of rice straw and grain. Zinc application has slight effect on phosphorus content of straw and grain. However, phosphorus uptake in both straw and grain highly significant increased with znSo4applications. 2.4. The interaction between phosphorus and zinc was significant in increasing phosphorus uptake of straw whereas showed non significant effects on phosphorus uptake of grains. 2.5. Application of phosphorus highly significant increased Fe-uptake ·of rice straw and grain at all rates of P application. Addition of FeS04 significantly increased Fe-uptake of straw, but has no effect on grain. Zn application has slight effect on Fe-uptake of rice straw, while Fe-uptake of rice grain significantly increased with increasing zinc fertilization. 2.6. Phosphorus application at both levels used highly significant increased Zn-uptake of rice straw and grain. The application of FeS04 at all levels of Zn application significantly decreased Zn-uptake of straw, but not in grain. Zn application highly significant increased Zn-uptake of both straw and grain. A highly significant positive interaction between phosphorus and Zinc was recorded only in rice straw. The mutual effects of phosphorus, iron and zinc showed insignificant effect on the amount of zn-uptake of both rice straw and grain. 3~ Pot experiment (II): 3.1. Dry matter of rice shoots and roots highly significant increased with nitrogen applications ~p to 180 ppm. Dry weight of rice shoots and roots remains stable or slightly increased with application of manganese. 3.2. Nitrogen content and uptake of rice shoots and roots significantly and progressively increased with application of nitrogen. Application of manganese showed no effect on nitrogen content of rice plants, while nitrogen uptake slightly increased with application of manganese sulphate. The mutual effect of nitrogen and manganese on nitrogen uptake of rice shoots and roots was slight at all levels used, except with ”N2,Hn2”treatment where the highest nit/rogen uptake was recorded. 3.3. Application of nitrogen highly significant increased manganese content and uptake of rice plants. Manganese content and uptake increased progressively with manganese application for shoots. Nitrogen and manganese interaction on manganese uptaken was significant for shoots, but non significant for roots. 4. Field experiment (II) 4.1. Yields of both grain and straw high significantly increased with increasing nitrogen application. Application of MnS04 at the low dose resulted in a slight increase in rice dry weight, while the high dose tended to show an adverse effect. Application of nitrogen in presence of manganese caused a slight decrease in the yields of rice grain and straw, especially at the higher dose of applied manganese. 4.2. Application of nitrogen highly significant increased the nitrogen uptake of rice grain and straw with increasing nitrogen application. The mutual effect of nitrogen and manganese application on nitrogen uptake of rice grains and straw was not significant at all levels used, however the highest nigrogen uptake was obtained with combination of N2,Mnl for either rice grains or straw. 4.3. Application of nitrogen significantly increased manganese content and uptake of rice plants. The mutual effect of nitrogen and manganese on manganese uptaken by rice straw and grains was not significant. |