ࡱ> 7 ?bjbjUU 27|7|;l,8,8,8,8,X8>Y99999999XXXXXXXTZ t\X99999XRB99XRBRBRB999XRB9XRBN RBLNO99 p~Y65,8<NO Y0>YN,L]RBL]ORBIMPROVEMENT OF MAIZE GROWING ON K-DEFICIENT SOIL BY FERTILIZATION AND CHOICE OF HYBRID Kovacevic V. Faculty of Agriculture,University J. J. Strossmayer in Osijek, Croatia Abstract Potassium (K) nutritional problems (edge necrosis of leaves, stalk lodging inclination at maturity, low yields) connected with high levels of magnesium (Mg) and strong K- fixation have been found on some hydromorphic soils. Ameliorative KCl fertilization resulted by normalization of yields and improvement of K and Mg status in maize. Also, by choice of tolerant genotypes could be acceptable solution. For example, we found that maize hybrids contained Os1-48 inbred line as parent had higher yields and low percent of stalk lodging in comparison with the hybrids of Os87-24 (means 5.64 and 4.16 t ha-1, 4.9 and 59.1%, respectively). Key words: ear-leaf at siking, magnesium oversupply, maize hybrids, potassium deficiency, grain yield INTRODUCTION Potassium (K) is an essential element for plants. Low K supplies for field crops have been found in some hydromorphic soils of the Eastern Croatia. Overcoming this problem is possible by adequate K fertilization and by choice of more tolerant genotypes. Importance of genetic aspects of plant mineral nutrition was elaborated in numerous studies including Saric (1981, 1983), Saric and Kovacevic (1980). In this study was reviewed response of maize to fertilization with potassium chloride and testing maize hybrids under conditions of low K supplies in Eastern Croatia. MATERIAL AND METHODS Response of maize was tested under field conditions. The field trials were conducted in four replicates. In general, maize was sown at end of April and it was harvested manually at end of September or at beginning of October. Ameliorative fertilization was made on usual fertilization only in the first year of testing, while for the next years usual fertilization was used. Ear-leaf was taken for chemical analysis at the beginning of the silking stage. Grain yields were calculated on 14% grain moisture basis. The field trials including response of maize hybrids to KCl fertilization Residual effects of ameliorative fertilization with KCl (spring 1990) on maize yields and nutrtional status of six maize hybrids (1993) on Mikanovci strong K-fixing soil was tested. The experimental plot measured 294 and 39 m2, for fertilization and hybrid, respectively (Kovacevic et al. 1996). Five maize hybrids were grown on Gundinci K-deficient soil for three growing seasons (2001, 2002 and 2003) and their response to two levels of KCl (500 and 1250 kg K2O ha-1 applied before sowing (April 2, 2001) was tested. Experimental plots measured 165 m2 and 28 m2, for fertilization and hybrid, respectively. Maize was sown on planned plant density (PPD) 58310 ha-1. Grain yields were calculated on 90% PPD (2001 and 2002) and 70% PDD (2003). These investigations (the 2001 and 2002 growing seasons) were in detail elaboreted by Kovacevic et. al. (2003). Response of three maize hybrids to P and K fertilization (spring 2001) were tested Luzani hydromorphic soils. The experimental plot measured 63 and 21 m2, for fertilization and hybrid, respectively (Kovacevic et al. 2003). Monoammonium phosphate (MAP: 12% N + 52% P2O5) and KCl were sources of P and K, respectively. Calcium ammonium nitrate (CAN) was used for corrections of different N levels. Grain yields were calculated on 90% PPD. Testing ogf maize genotypes on soil stress induced by K-fixation Two groups of maize hybrids (total 14) of same inbred line as a male parent (Os1-48 and Os 84-27, for the A and B group, respectively) were grown on Mikanovci strong K-fixing soil (the 1990 growing season). Experinmental plot of the hybrids measured 7 m2. Yields, stalk lodging and stalk base composition elaborated by Kovacevic and Vujevic (1993). Ten maize hybrids were grown on K-deficient Zupanja fluvisol for 1998 growing season. Experimental plot of the hybrid measured 14 m2. Yields and ear-leaf nutrtional status were shown in detail by Kovacevic et al. (2001). RESULTS AND DISCUSSION Low K and oversupplies of Mg in maize leaves in our investigations (Tables 1, 4 and 5) were found. Acute K deficiency in maize is in close connection with K concentrations in dry matter of ear-leaf (silking stage) less than 1.0 % K, while normal Mg concentrations are in range from 0.20 to 0.50% Mg (Bergmann, 1992; Mengel and Kirkby, 2001). In general, considerable role of KCl fertilization and genotype on maize properties on Mikanovci K-fixing soil was found. Fertilization with KCl resulted by eliminating unbalance between K and Mg in maize. At the same time, considerably increased plant density realization and decreased grain moisture and stalk lodging at maturity stage. Also, considerable role of heredity on tested properties was found. For example, stalk lodging difference at maturity among the six hybrids were from 5.7 to 27.2% (Table 1). Maize yield increases in the Gundinci experiment as affected by 1250 kg K2O ha-1 application was 17% (Table 2). Response of maize hybrids to KCl fertilization was specific. In 2001 yields of two hybrids (OsSK444 and OsSK458) were higher (average 11.18 t ha-1) in comparison with remaining three tested hybrids (average 10.70 t ha-1). Yield increases of individual maize hybrids under influences of applied fertilization were in range from 5.4% (Florencia) to 28.3% (OsSK458). Similar findings were found in the next year. Drought stress in the 2003 growing season was main reason for low maize yield. It was only 5.03 t ha-1 or for more than 50% lower in comparison to two previous years. However, residual effect of KCl fertilization (yield increase for 10% in comparison with the control) was found, but only two hybrids (Bc 5982 and Florencia) significantly increased yield as affected by KCl application three years ago. Mean grain yields of maize in the Luzani experiment were moderate in comparison with the genetic potential of these high-yielding maize hybrids and the weather characteristics during the growing seasons (8.01 and 7.14 t ha-1, for the 2001 and 2002, respectively). Also, the yields are. In 2001, only the higher rate of fertilizers resulted in significant yield differences as follows: yield increases for 18% (influences of P) and 22% (influences P and K) and yield decreases for 10% (influences of K). We presume that the main reason for this type of corn response to fertilization is affected by the ameliorative fertilization before sowing and incorporation of the fertilizers in the surface layer until 10-15 cm by presowing soil tillage treatments. In our investigation we found considerable influences of the hybrids on maize yields. In both year of testing the hybrids OsSK444 and Bc5982 had similar yields. However, the yields of the OsSK552 were for 9% lower and for 10% higher in comparison to the remaining two hybrids for the 2001 and the 2002, respectively (Table 3). Table 1. Residual influences of KCl fertilization (spring 1990) on maize (Kovacevic et al. 1996) FactorMaize properties (the 1993 growing season)*FertilizationMaizeYieldThe ear-leaf (% in DM)%kg K2O ha-1hybridt ha-1**KMgPDRGMSL150 1000 1900 32501.83 4.08 6.32 7.040.31 0.54 0.82 1.181.08 0.90 0.71 0.4767.9 82.4 89.8 93.634.1 27.4 25.2 25.027.3 17.8 10.0 3.8LSD A (fertilization) 5% LSD A (fertilization) 1%0.44 0.640.06 0.090.06 0.08OsSK 377 OsSK382 OsSK 407 OsSK 552 OsSK 644 Bc 66-614.60 4.99 5.31 4.95 4.70 4.350.65 0.68 0.68 0.71 0.85 0.710.93 0.73 0.82 0.75 0.71 0.7976.7 80.5 93.1 87.3 77.5 85.423.5 21.8 25.3 27.7 35.5 33.924.6 27.2 12.2 12.7 5.8 5.7LSD B (hybrid) 5% LSD B (hybrid) 1%0.23 0.300.04 0.050.03 0.04* DM = dry matter; PDR = plant density realization: 100% = 68027 (OsSK377); 63492 (OsSK382, OsSK407 and OsSK552) and 54945 (OsSK644 and Bc66-61) plants ha-1: GM = grain moisture at harvest; SL = stalk lodging. Typical example of heredity role on maize tolerance to soil stress is testing fourteen hybrids of two parents (Os 1-48 and Os87-24, respectively) tested on usual fertilization on Mikanovci strong K-fixing soil (Table 4). These results indicated that Os1-48 inbred line could be used as source of property characterizing resistance to stalk lodging at maturity stage under conditions of K deficiency (Kovacevic and Vujevic, 1993). Table. 2. Response of maize to KCl fertilization for three growing seasons Influences of fertilization (spring 2001) and hybrid on maize yields (t ha-1)* K2OThe growing season MeanMaizeThe growing seasonMean(kg ha-1)200120022003hybrid200120022003 Control 500 1250 10.09 11.04 11.54 9.13 10.63 11.28 4.72 5.28 5.12 7.98 8.98 9.31OsSK 444 OsSK 458 OsSK 552 Bc5982 Florencia11.02 11.34 10.55 10.66 10.889.74 10.18 10.84 10.44 10.525.06 5.51 4.53 4.12 6.008.61 9.01 8.64 8.41 9.13LSD 5% LSD 1%0.84 1.270.45 0.690.29 n.s.LSD 5% LSD 1%0.47 0.620.69 0.910.36 0.47* on 90% (for 2001 and 2002 ) and 70% (for 2003) of theoretical plant density (100% = 58310 plants ha-1) Table 3. Grain yields of maize as affected by P and K fertilization (Kovacevic et al. 2003) Grain yield of maize (t ha-1) on 90%TPD* and 14% grain moisture basisMaize hybridAmeliorative amounts (kg ha-1) on ordinary fertilization (the factor A)(the factor B)abcdefP2O5K2OMean0 75015007501500c + e (B)The 2001 growing season OsSK 444 Bc5982 OsSK5527.14 7.45 8.297.40 8.02 8.409.39 8.55 8.977.35 6.72 7.776.45 6.82 7.459.18 8.87 9.977.82 7.74 8.48Mean (A)7.637.948.977.286.919.348.01LSD 5% LSD 1%A 0.51 0.70B 0.28 0.37AB 0.76 1.02The 2002 growing season **OsSK 444 Bc5982 OsSK5526.25 6.51 5.887.66 7.56 6.938.24 7.92 7.197.35 7.30 6.467.24 7.19 6.567.61 7.82 7.037.39 7.37 6.67Mean (A)6.207.397.787.026.987.48LSD 5% LSD 1%A 0.52 0.73B n.s.AB n.s. * TPD = theoretical plant density: 58310 plants ha-1; 90% TS = 52479 plants ha-1 ** residual influences of ameliorative fertilization (ordinary fertilization of the experiment) Table 4. Response of maize hybrids on Mikanovci K-fixing soil (Kovacevic and Vujevic, 1993) YieldStalk* (%)YieldStalk* (%)Pedigree(t ha-1)SLKMgPPedigree(t ha-1)SLKMgPMaize hybrids of Os1-48 inbred line (A) as male parent (the A group)Maize hybrids of Os87-24 inbred line (B) as male parent (the B group)Os87-44 x A Os84-15 x A Os84-25 x A Os84-24 x A Os86-39 x A Os89-24 x A B x A5.23 6.30 5.56 5.89 4.45 7.20 4.838.8 4.8 4.1 4.6 7.5 4.1 0.70.30 0.30 0.18 0.17 0.18 0.30 0.210.48 0.55 0.52 0.48 0.71 0.45 0.520.11 0.07 0.14 0.08 0.16 0.07 0.27Os87-61 x B Os88-15 x B Os86-92 x B Os87-56 x B Os84-24 x B Os87-57 x B A x B2.83 4.71 2.90 3.52 5.45 4.28 5.4079.0 83.3 23.7 52.1 95.6 74.1 5.30.18 0.21 0.17 0.21 0.18 0.19 0.180.64 0.88 0.74 0.74 0.68 0.68 0.690.18 0.29 0.22 0.21 0.24 0.22 0.19Mean A5.644.90.240.530.13Mean B4.1659.10.190.720.22LSD 5% LSD 1%0.53 0.720.04 0.050.09 0.120.03 0.04LSD 5% LSD 1%0.53 0.720.04 0.050.09 0.120.03 0.04* K. Mg and P in three developed the lowest nodes of stalk at maturity (% in dry matter); SL=stalk lodging Table 5. Influence of soil and genotype on maize yield and K and Mg status (Kovacevic et al. 2001) Grain yield (t ha-1), and ear-leaf K and Mg status (% in dry matter at silking stage) of ten maize hybrids on Zupanja K-deficient fluvisol (the 1998 growing season) LSDOsSK 382OsSK 444OsSK 458eOsSK 497eOsSK 552OsSK 554OsSK 558OsSK 568eOsSK 602OsSK 617e5%1%t ha-16.917.317.145.273.614.245.089.598.015.981.291.80K0.700.790.530.520.560.540.670.750.730.590.130.19Mg1.191.131.241.271.461.481.501.001.261.220.150.25 Acute K deficiency (mean 0.64 % K) and oversupply of Mg (mean 1.23% Mg) were found in the maize on Zupanja fluvisol. Grain yield differences among the hybrids were from 3.61 (OsSK552) to 9.59 (OsSK568exp.) t ha-1. Their nutritional status were 0.56% K and 0.75% K, 1.46% Mg and 0.99% Mg, for OsSK552 and OsSK568exp. respectively (Table 5). We presume that maize hybrids characterizing higher K and lower Mg uptake could be better choice for K-deficient soils. CONCLUSIONS Ameliorative potassium application especially affected maize yields under K deficient conditions. For practical purpose could be recommend combination of adequate fertilization and growing of more tolerant genotypes. ACKNOWLEDGEMENTS: This study is dedicated to Academician Miloje R. Saric university professor and full member of the Serbian Academy of Sciences and Arts (September 12, 1925 December 6, 2002) as expression of authors gratitude for long-term successful scientific cooperation including leadership his PhD Thesis (June 2, 1980, Faculty of Agriculture of University Novi Sad). Academician Saric was one of leading phytophysiologists with high reputation among the members of world scientific community. REFERENCES BERGMANN W. (1992): Nutritional disorders of plants - development. visual and analytical diagnosis. Gustav Fischer Verlag Jena. Stuttgart. New York. KOVACEVIC V., BANAJ D., ANTUNOVIC M., BUKVIC G. (2001): Influences of genotype and soil properties on corn potassium and magnesium status. In: Plant nutrition - food security and sustainability of agro-ecosystems (Developments in Plant and Soil Sciences, Volume 92; W. J. Horst et al. eds). Kluwer Academic Publishers Dordrecht/Boston/London. p. 90-91. KOVACEVIC V., BANAJ D., ANTUNOVIC M., BUKVIC G. (2003): Role of fertilization and hybrids for improvement of maize growing on K-deficient soil. In: Fertilizers in context with resource management in agriculture. Vol. I (Schnug E., Nagy J., Nemeth T., Kovacs Z., Dovenyi-Nagy T. Editors). International Scientific Centre of Fertilizers (CIEC) Braunschweig Budapest -Vienna , p. 99-103. KOVACEVIC V., BANAJ D., BRKIC I., BUKVIC G. (2003): Influences of fertilization by phosphorus and potassium on yield and nutritional status of corn. In: Proceedings of the Union of Scientists Rousse, Bulgaria 2003 (in press). KOVACEVIC V., KADAR I., BRKIC I., JOSIPOVIC M. (1996): Response of corn (Zea mays L.) hybrids to potassium fertilization on strong K-fixing soil. IXth International Colloquium for the Optimisation of Plant Nutrition, 8-15. September 1996, Prague, Czech Republic, p. 458-461. KOVACEVIC V., VUJEVIC S. (1993): Magnesium uptake and lodging tolerance in maize (Zea mays L.) hybrids. In : "Magnesium 1993", John Libbey Ltd London p. 89-97. MENGEL K., KIRKBY E. A. (2001): Principles of plant nutrition. Kluwer Academic Publishers, Dordrecht/Boston/London. SARIC M. (1981): Genetic specifity in relation to plant mineral nutrition. Journal of Plant Nutrition 3 (5) 743-766. SARIC M. (1983): Theoretical and practical approaches of the genetic specifity of mineral nutrition of plants. Plant and Soil 72, 137-150. SARIC M., KOVACEVIC V. (1980): The genotype specifity related to mineral nutrition in maize In. Maize Physiology (Saric M. 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