1 1 Effects on Enhanced Potassium Doses on Yield, Quality and Nutrient Uptake of Tomato B. YAGMUR, B. OKUR, A. R. ONGUN Ege University, Faculty of Agriculture, Dept. of Soil Sciences Bornova-İzmir/Turkey ABSTRACT Turkey produces 7 million tons of tomatoes in 160 thousand ha of land per year and occupies 7 % of the world production. Of the production, 73% is consumed fresh, 25 % is processed and 2 % is exported. According to the 1998 statistics, t of total t tomato produced in Turkey is production under greenhouse conditions. Tomato production with share of 51 % is the first order in the vegetable production. The objective of the study was to examine the effect of K fertilization on greenhouse tomato yield and quality parameters. Enhanced levels of K ( kg K 2 O ha -1 ) and required amounts of N (240 kg N ha -1 ) and P (120 kg P 2 O 5 ha -1 ) were applied ⅓ as a base and the remaining as side dressing. Results showed that the highest dose of K yielded the highest. Similarly the highest K dose was also positively effective on some fruit parameters as average fruit weight, fruit width, ten fruit weight and acidity. On the other hand, 240 K 2 O ha -1 dose had positive impacts on total soluble solids, Vitamin C and color of fruits. 1. Introduction In ha of the total ha vegetable area in Turkey production is under greenhouse conditions (Abak et al., 2000). 95 % of greenhouse crops comprise vegetables, 4 % ornamental plants and 1 % fruits (Anonymous, 1999). 51 % of vegetable production in greenhouse conditions is tomato production (Tuzel and Eltez, 1997; Sevgican et al., 2000). The important tomato producers are China with 18 million tons, USA with 10 million tons, Italy and Turkey with 7 million tons and Spain 3.5 million tons. At present the production level of the country, the contribution of tomato to world production is 7 %. 73 % of tomato produced in Turkey is consumed as fresh, 25 % is used for paste processing and 2 % is exported. Per 100 g tomato contains 0.55 mg vitamin B6, 1700 IU Vitamin A, 0.10 mg Vitamin B1 and 21 mg Vitamin C (Sevgican, 1981). The major problems appeared in greenhouse growing are fertilization and irrigation. Correct fertilization and irrigation in almost all of the greenhouses is not made. The effect of inorganic fertilization on the yield and quality is important with respect to balanced nutrition of plants (Mengel and Kirkby, 1982). In this research, tomato was grown under greenhouse conditions to determine the effects of K fertilization on yield and some quality properties and estimate the optimum fertilizer application.
2 2 2. Materials and methods The experiment was carried in a grower s greenhouse in İncirliova, Aydin. As the material, Fantastic 144 (F 144) tomato variety was used. Soil samples were taken 0-30 cm depth before the experiment. Irrigation water and leaf samples were taken during experiment and fruit samples at harvest time. The plots were arranged in random plots design with four replicates as four K treatments 0,120, 240, 360 kg ha -1 K 2 O. All plots received 240 kg ha -1 N and 120 kg ha -1 P 2 O 5. One third of N, P and K were incorporated as a basal dressing and the second third of fertilizers was applied after sowing as fertigation. (NH 4 ) 2 SO 4 (21 % N), TSP (43 % P 2 O 5 ) and K 2 SO 4 (50 % K 2 O) in was used in the base dressing and KNO 3 (13 % N, 46 % K 2 O), MAP (12 % N, 61 % P 2 O 5 ) and NH 4 NO 3 (33 % N) in the fertigation. The experimental treatments are as follows: N 0 P 0 K 0 -Control N 1 P 1 K kg N ha -1, 120 kg P 2 O 5 ha -1, 120 kg K 2 O ha -1 N 1 P 1 K kg N ha -1, 120 kg P 2 O 5 ha -1, 240 kg K 2 O ha -1 N 1 P 1 K kg N ha -1, 120 kg P 2 O 5 ha -1, 360 kg K 2 O ha -1 The soil was analyzed for its physical and chemical properties using the standard methods (Jackson 1967; Bouyoucus, 1962; Soil Survey Staff, 1951; Black, 1965; Bingham, 1949; Pratt, 1965; Bremner, 1965; Lindsay and Norvell, 1978). Some of the analytical data are given in Table 1. Table 1. Some physical and chemical properties of the experimental soil. ph 7.72 P (mg kg -1 ) 4.12 Water soluble salt (%) K (mg kg -1 ) CaCO 3 (%) 6.90 Ca (mg kg -1 ) Sand (%) Mg (mg kg -1 ) Loam (%) Na (mg kg -1 ) Clay (%) Fe (mg kg -1 ) Texture Sandy-loam Cu (mg kg -1 ) 1.05 Org. Matter (%) 2.14 Zn (mg kg -1 ) 1.12 Total-N (%) Mn (mg kg -1 ) Available Table 2. Some physical and chemical properties of irrigation water. ph 7.50 Cl me l EC µmhos cm SO 4 me l Na me l HCO 3 me l K me l B trace Ca+Mg me l SAR 1.75 Class of irrigation water C 3 S 1 In leaves, primary and secondary elements, in fruit ph, color, total soluble solids (Brix, TSS), dry matter, acidity and Vitamin C contents together with fruit weight were measured according to Hortwirth (1960), Joslyn (1970), Pearson (1970), Hunter (1973) and Kacar (1972). The results were statistically analyzed by TARIST pocket program (Acikgoz et al., 1993)
3 3 3. Results and Discussion The effect of the different rates of K on the yield and nutrient content of tomato are given in Table 3. Table 3. The effect of potassium on the yield and nutrient content of tomato. Dose Yield Increase Total (%) Total (mg kg -1 ) kg K 2 O ha -1 t ha -1 (%) N P K Ca Mg Na Fe Cu Zn Mn LSD LSD The highest yield was obtained at the rate of 360 kg K 2 O ha -1 (N 1 P 1 K 3 ) is 8.52 t ha -1 and the lowest yield at the control parcel (N 0 P 0 K 0 ) as 5.90 t ha -1. The effect of different rates of K on the yield is significant at 1 % level. Yield with enhanced K doses increased 22 %, 33 % and 44 % respectively. Total nitrogen content of the varied from 3.14 to 3.60 %, P 0.39 to 0.42 %, K 2.87 to 4.20 %, Ca 3.70 to 3.76 %, Mg 0.40 to 0.42 %, Na 800 to 850 mg kg -1, Fe 114 to 140 mg kg -1, Cu 17 to 18 mg kg -1, Zn 32 to 38 mg kg -1 and Mn 81 to 89 mg kg -1. Total Table 4. Comparison of leaf nutrients with the cited reference values. Reuter-Robinson (1986) Bergmann (1993) IFA (1992) Ongun (2001) N (%) P (%) K (%) Ca (%) Mg (%) Fe (mg kg -1 ) Cu (mg kg -1 ) Zn (mg kg -1 ) Mn (mg kg -1 ) When the figures in the Table 4 are compared with our findings; results showed that the nutrient status of tomato was optimum except Mg and Zn. Significant relationships were found between the fertilizer rates and N, K, Fe and Mn contents in leaves. Increasing K rates increased % TSS, terrible acidity, Vitamin C content, average fruit weight, average fruit diameter and ten fruit weight but decreased ph and color parameter (Table 5). TSS and Vitamin C contents increased up to 240 kg K 2 O ha -1 but decreased at 320 kg K 2 O ha - 1. Significant relationships were determined between the enhanced fertilizer rates and TSS, average of fruit weight and ten fruit weight, acidity, Vitamin C and average fruit diameter. Similar results were also obtained by the other researchers (Karakas, 1994; Aydin, 1996 and Yagmur, 1997).
4 4 Table 5. The effect of K doses on some quality parameters of tomato. Dose TSS Acidity Color Vit. C Fruit Fruit diameter Ten fruit kg K 2 O ha -1 ph (%) (%) (a/b) (mg 100 g -1 ) weight (g) (cm) weight (g) LSD LSD Conclusion In conclusion, results revealed that K fertilization did not affect the ph and color parameters of tomato, but significantly affected the average fruit weight, fruit diameter, average ten fruit weight and titrable acidity. The optimum dose for these parameters was 360 kg K 2 O ha -1 and for TSS, Vitamin C and color 240 kg K 2 O ha -1. References Abak, K., Erkan, O., Eser, B., Halloran, N., Yanmaz, R., Sari, N., Ekiz, H., Sebze Tariminda 2000 lerde Uretim Hedefleri V. Turkiye Ziraat Mühendisligi Teknik Kongresi, Ocak, Ankara-Turkey. Acikgoz, N., Akkas, M, E., Moghaddam, A., Ozcan, K., Tarist PC ler icin Istatistik ve Kantitatif Genetik Paket.Uluslararasi Bilgisayar Uygulamalari Semp. Konya-Turkey. Anonymous, Tarım Istatistikleri Ozeti T.C. Basbakanlik Devlet Istatitik Enstitusu, Yayin No: 2275 Aydin, S., Sanayi Domatesinde Potasyumlu Gubrelemenin Kimi Kalite Ogelerine Etkisi. Ege Tarimsal Arastirma Ens. Dergisi. (ANADOLU) 6(1): Bergmann, W.,1993. Ernährungsstörüngen bei Kulturpflanzen. Gustav Fischer Verlag. Jena Stuttgart. Bingham, F.T., Soil Test for Phosphate. California Agriculture 3 (7): Black, C.A., Methods of Soil Analysis Part-II. American Soc. of Agronomy Inc., Publisher Madison Wisconsin, USA., Bouyoucos, G. J., A., Recalibration of The Hydrometer Method for Making Mechanical Analysis of The Soils, Agronomy Journal, 4(9) :434. Bremner, J. M., Total Nitrogen, Editor C.A. Black. Methods of Soil Analysis part 2. American Society of Agronomy. Inc. Publisher, Madison, Wisconsin, U.S.A Hortwirth, W., Official Methods of Analysis A.O.A.C. Chapter 29. Sugars and Sugar Products. A.O.A.C. Benjamin Franklin Station. Washington, 4D.C. Hunter, R.S., The Measurement of Appearance, Hunter Lab. Inc., Fair Bx Virginia. IFA, International Fertilizer Industry Assocation World Fertilizer Use Manuel. ISBN Jackson, M.L.,1967. Soil Chemical Analysis Prentice, Hall of India Private Limited, New Delhi.
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