الفهرس 
Effect of mineral fertilizationOnly 14 pages are availabe for public view
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Abstract
Four field experiments were conducted in the Experimental Farm , Faculty of Agriculture , Minufiya University , Shebin El-kom to study the growth characters , physiological attributes, photosynthetic pigments , yield and yield components and economic evaluation of maize as affected by mineral and bio-fertilization of nitrogen (N) , phosphorus (P) and potassium (K) and their mixture compared to uninoculated and unfertilized plants (control) during 2011 and 2012 seasons . The four tested experiments are as follows : First experiment : Effect of mineral and bio fertilization of N : This experiment was carried out to study different levels of mineral nitrogen (N) fertilization , i.e 0 , 25 , 50 , 75 and 100 % of the recommended N level (RNL) , i.e 90 Kg N / fed as well as grain inoculation with mixture of non – symbiotic nitrogen fixing bacteria (NFB) , i.e Azotobacter chroococcum + Azosprillium brasilense + Bacillus polymxa . It included seven treatments which are as follows : 1- Zero RNL + uninoculation (control) 2- Zero RNL + NFB inoculation 3- 25 % RNL + NFB inoculation 4- 50 % RNL + NFB inoculation 5- 75 % RNL + NFB inoculation 6- 100 % RNL + NFB inoculation 7- 100 % RNL + uninoculation Second experiment: Effect of mineral and bio fertilization of P: This experiment was carried out to study different levels of mineral phosphorus (P) fertilization , i.e 0 , 25 , 50 , 75 and 100 % of the recommended P level (RPL), i.e 30 Kg P2O5 / fed as well as grain inoculation with Phosphate solubilizing bacteria (PSB), i.e Bacillus megaterium var. phosphaticum . It included seven treatments which are as follows : 1- Zero RPL + uninoculation (control) 2- Zero RPL + PSB inoculation 3- 25 % RPL + PSB inoculation 4- 50 % RPL + PSB inoculation 5- 75 % RPL + PSB inoculation 6- 100 % RPL + PSB inoculation 7- 100 % RPL + uninoculation Third experiment : Effect of mineral and bio fertilization of K : This experiment was carried out to study different levels of mineral potassium fertilization , i.e 0 , 25 , 50 , 75 and 100 % of the recommended K level (RKL) , i.e 24 Kg K2O / fed as well as grain inoculation with Potassium mobilizing bacteria (KMB) , i.e Bacillus circulans . It included seven treatments which are as follows : 1- Zero RKL + uninoculation (control) 2- Zero RKL + KMB inoculation 3- 25 % RKL + KMB inoculation 4- 50 % RKL + KMB inoculation 5- 75 % RKL + KMB inoculation 6- 100 % RKL + KMB inoculation 7- 100 % RKL + uninoculation Fourth Experiment : Effect of mineral and bio fertilization of NPK mixture: This experiment was carried out to study different levels of mineral fertilization of NPK mixture, i.e 0 , 25 , 50 , 75 and 100% of their recommended levels (RNPKL), i.e, 90 Kg N / fed, 30 Kg P2O5/fed and 24 Kg K2O/fed as well as grain inoculation with the mixture of NFB, PSB and KMB. It included seven treatments which are as follows : 1- Zero RNPKL + uninoculation (control) 2- Zero RNPKL + NFB , PSB and KMB inoculation 3- 25 % RNPKL + NFB , PSB and KMB inoculation 4- 50 % RNPKL + NFB , PSB and KMB inoculation 5- 75 % RNPKL + NFB , PSB and KMB inoculation 6- 100 % RNPKL + NFB , PSB and KMB inoculation 7- 100 % RNPKL + uninoculation The results could be summarized as follows : First experiment : Effect of mineral and bio fertilization of N : 1- Inoculation of maize grains with NFB caused a significant increase in the growth characters studied (plant height , no .of leaves/plant , total dry weight/plant and its organs , i.e leaves , stem and ears as well as leaf area and LAI) in the most growth stages (45 , 60 , 75 and 90 DAS) as compared with control treatment in the two growing seasons . However , SLW and SLA were not significantly affected mostly in both seasons . Increasing mineral N levels from Zero to 100 % from RNL combined with NFB inoculation significantly increased the growth characters studied at most growth stages in the two seasons . However , the differences between the application of 75 % from RNL combined with NFB inoculation and that of 100 % from RNL without biofertilization were not significant mostly at all growth stages in both seasons . 2- The values of physiological attributes studied (LAD , CGR , RGR and NAR) were mostly increased with increasing the mineral N fertilization levels and / or grain inoculation with NFB compared to the control treatment in favour of the plants fertilized with 100 % of RNL and inoculated with NFB at most growth stages (45-60 , 60-75 and 75-90 DAS) in the first and/or second seasons . 3- The values of photosynthetic pigments (Chl.a , Chl.b , Chl.a + Chl.b and Caroteniods) were positively responded to mineral N fertilization and / or inoculation with NFB compared to the control treatment in both seasons . Moreover , it can be noticed that maize plants fertilized with 100 % of RNL ( 90 Kg N / fed ) plus NFB inoculation had the highest significant values of the photosynthetic pigments studied in the two growing seasons . However , there are no significant differences between the treatment of N fertilization with 100 % of RNL without NFB inoculation and each of N fertilization with 75 % of RNL plus NFB inoculation ( in the first season ) as well as N fertilization with 50 % and 75 % of RNL plus NFB inoculation ( in the second season ) . 4- Grain inoculation with NFB significantly increased ear characters (ear length and diameter , ear weight , number of grains/ear , 100-grain weight) , grain yield and relative grain yielding ability / plant as well as yields/fed (grain , cob , ear , straw and biological) as well as fruiting indices (crop index , harvest index and migration coefficient) compared to the control treatment mostly in the first and / or second season . The highest significant values of most abovementioned characters were obtained when the plants were fertilized with 100 % from RNL and inoculated with NFB in both seasons compared to the other tested treatments . 5- The recommended level of mineral N fertilizer (90 Kg N / fed) can be reduced by about 25 % by adopting the technique of inoculation with mixture of non-symbiotic nitrogen fixing bacteria . This reflects directly on reducing fertilizer costs with producing approximately the same values of return effectiveness (benefit/cost ratio) in the first season . Second experiment: Effect of mineral and bio fertilization of P: 1- The growth characters studied , i.e plant height , no .of leaves/plant , total dry weight/plant and its organs ( leaves , stem and ears ) as well as leaf area and leaf area index were significantly increased when the plants were inoculated with PSB and / or fertilized with mineral P fertilizer at any tested level compared to untreated plants at most growth stages in both seasons . This increase was more pronounced with increasing P levels up to 100 % followed by 75 % of RPL in the presence of PSB inoculation for each mostly in both seasons . Moreover , the application of 50 % and 75 % ( in the first season ) and 75 % ( in the second season ) in the presence of PSB inoculation were superior to the application of 100 % of RPL in the absence of PSB inoculation for most growth characters at all growth stages in both seasons . 2- The application of mineral P fertilizer singly and/or combined with PSB inoculation significantly increased the values of physiological attributes (LAD , CGR , RGR and NAR) compared to the control treatment especially at 60-75 DAS in both seasons . The highest significant values of physiological attributes studied were recorded by mineral P fertilization at 100 % of RPL combined with PSB inoculation as compared with the other treatments in both seasons . 3- There are a significant increase in the photosynthetic pigments (Chl.a , Chl.b , Chl.a + Chl.b and Caroteniods) with increasing mineral P levels up to 100 % of RPL especially when the grains were inoculated with PSB . Plants fertilized with 75 % of RPL with PSB inoculation were superior to those fertilized with 100 % of RPL without PSB inoculation for different photosynthetic pigments studied . 4- The values of yield and yield components , i.e ear length and diameter , ear weight , number of grains/ear , 100-grain weight , grain yield , relative grain yielding ability / plant , yields/fed (grain , cob , ear , straw and biological) and fruiting indices (crop index , harvest index and migration coefficient) were mostly increased when the plants were inoculated with PSB compared to the control treatment in the two seasons . Raising mineral P fertilizer levels associated with PSB inoculation significantly increased the values of abovementioned yield components up to 100 % of RPL which produced the highest values followed by 75 % of RPL in both seasons . However , there are no significant differences among the treatments of P fertilizer at 100 % of RPL without PSB inoculation and those of P fertilizer at 25 % or 50 % of RPL with PSB inoculation for the most yield and yield components studied . 5- The application of 100 , 75 and 50 % of RPL with PSB inoculation in a descending order , contributed the higher values of economic evaluation studied ( total and net return/fed , change in total return % and return/cost ratio ) than that obtained by the application of 100% of RPL without PSB inoculation . it could be concluded that PSB inoculation was found to be reduced the mineral P fertilization by about 25-50 % and this in turn reduced fertilizers costs and consequently increased net return and benefit/cost ratio in the first and / or second seasons . Third experiment : Effect of mineral and bio fertilization of K : 1- Maize plants inoculated with potassium mobilizing bacteria (KMB) alone were superior to those uninoculated with KMB and unfertilized with mineral K fertilizer (control treatment) for all growth characters studied with exception of SLW and SLA at most growth stages in both seasons . The highest values of most growth characters studied were attained when the plants were inoculated with KMB and fertilized with mineral K fertilizer at 100 % of RKL . However , there are no significant differences between the application of mineral K fertilizer at 100 % of RKL without KMB inoculation and each of 75 % of RKL ( in the first season ) as well as 50 % and 75 % of RKL ( in the second season ) in the presence of KMB inoculation . 2- The application of mineral K fertilizer and / or inoculation with KMB caused a significant increase in each of CGR , RGR and NAR at 60-75 DAS and LAD at 45-60 , 60-75 and 75-90 DAS compared to the control treatment in the two seasons . The highest values of the four physiological attributes studied (LAD , CGR , RGR and NAR) were recorded mostly by the application of 75 % and 100 % from RKL with the inoculation of KMB in the first and second season , respectively , without significant differences between them at most growth stages in both seasons 3- The application of mineral K fertilizer at any level in the presence of KMB inoculation significantly increased the most of photosynthetic pigments studied (Chl.a , Chl.b , Chl.a + Chl.b and Caroteniods) compared to the control treatment . The application of 75 % and 100 % of RKL with KMB inoculation were most effective for increasing the photosynthetic pigments studied compared to the other treatments . 4- Plants fertilized with 100 % of RKL and inoculated with KMB produced the highest significant values of the yield and yield components studied compared to the other mineral and biofertilization treatments as well as the control treatment in the first and / or second season . However , the plants fertilized with 75 % of RKL and inoculated with KMB surpassed those fertilized with 100 % of RKL in the absence of KMB inoculation for most yield and its components studied without significant differences between them . 5- The application of 75 % of RKL with KMB inoculation produced economically the higher total return of yield , net return , change in total return and benefit/cost ratio and lower total cost production than the application of 100 % of RKL without biofertilizer inoculation . Fourth experiment: Mineral and bio fetilization of NPK mixture: 1- The values of growth characters studied , i.e plant height , no .of leaves/plant , total dry weight/plant and its organs leaves , stem and ears) as well as leaf area and leaf area index were significantly and positively responded to the inoculation with the triple biofertilizers (NFB+PSB+KMB) in both seasons compared to the uninoculated and unfertilized plants (control treatment) . Moreover , the values of the abovementioned characters were gradually and significantly increased with raising the levels of the mixed mineral fertilizers ( N + P + K ) up to 75 % (in the first season) and 100 % of RNPKL (in the second season) in the presence of the triple biofertilizers for each . However , the values of SLW and SLA were not significantly affected by either mineral NPK fertilization or triple biofertilization in both seasons 2- Application of mixed mineral NPK fertilizer at any level and / or inoculation with triple biofertilizers increased the tested physiological attributes (LAD , CGR , RGR and NAR) as compared with the control treatment . The values of physiological attributes obtained by the application of 75 % of RNPKL (in the first season) as well as 50 % or 75 % of RNPKL (in the second season) with triple biofertilizers inoculation were superior to that obtained by the application of 100 % of RNPKL without triple biofertilizer inoculation . 3- The maize plants fertilized with any level of mixed mineral fertilizers NPK and inoculated with the triple biofertilizer had values for all plant photosynthetic pigments studied (Chl.a , Chl.b , Chl.a + Chl.b and Caroteniods) higher than that obtained by the control plants in both seasons . There are no significant differences among the application of mixed mineral fertilizer at the levels of 50, 75 and 100 % of RNPKL (with triple biofertilizer inoculation) as well as that of 100 % from RNPKL (without inoculation) for all photosynthetic pigments studied in the first and / or second season . 4- Plants fertilized with mixed mineral fertilizer at any level and inoculated with triple biofertilizers significantly surpassed those control treatment in yield and yield components , i.e ear length and diameter , ear weight , number of grains/ear , 100-grain weight , grain yield , relative grain yielding ability / plant , yields/fed (grain , cob , ear , straw and biological) and fruiting indices (crop index , harvest index and migration coefficient) in the first and / or second season. Fertilization of plants with 75 % or 100 % of mixed mineral NPK in the presence of triple biofertilizers produced the highest values of yield and yield components studied without significant differences between them in both seasons compared to the other tested treatments. 5- The data of economic evaluation showed that maize plants fertilized with 50 and 75 % of RNPKL with triple biofertilizers inoculation produced net return (2735 and 3570 EGP/fed) and benefit/cost ratio (1.808 and 2.002 EGP return/EGP cost) , respectively higher than that obtained by plants fertilized with 100 % of RNPKL without triple biofertilizers inoculation which gave 2410 EGP/fed for net return and 1.650 EGP return/EGP cost for benefit/cost ratio, as an average for both seasons . Final conclusion It can be recommended to the inoculation of maize grains with the tested bacteria of nitrogen fixing, phosphate solubilizing and potassium mobilizing before sowing either separately or mixed, where it was found to be not only saving about 25 % in the rates of nitrogen, phosphate and potassium mineral fertilization but also increasing in the net return per feddan of maize (S.C. 128 hybrid) under the conditions of this experiment in Minufiya Governorate.