49 J. Hortl. Sci. Vol. 12(1) : 49-53, 2017 Effect of N and K Fertilizers on Growth, Yield and Quality of Pear (Pyrus pyrifolia) PPS Gill, Sharanjit Kaur and NavPrem Singh Punjab Agricultural University, Ludhiana - 141004, India, Department of Fruit Science PAU Ludhiana, Punjab, India - 141 004 E-mail: parmpalgill@pau.edu ABSTRACT The effect of different combined doses of N and K fertilizers on plant growth, fruit quality and foliar elemental composition of pear cv. Patharnakh was investigated. Experimental plants were supplied with different levels of N (460, 690 and 920 g N /plant) and K (600, 900, 1200 and 1500 g K2O/plant) in the form of Urea and Muriate of Potash (MOP) fertilizers. From the results, it was found that nitrogen application increased number of fruits/plant, trunk cross-sectional area (TCSA), shoot length and leaf N content, whereas, K application improved fruit firmness, total soluble solids (TSS), and leaf K content. Fruits harvested from T4 (460 g N:1500 g K2O /plant) treatment recorded maximum firmness. Plants under T9 (920 g N: 600 g K2O /plant) treatment showed the maximum increase in shoot length, and TCSA, whereas, T6 (690 g N : 900 g K2O /plant) resulted in maximum fruit yield. Leaf N and K concentrations improved with applications of the respective fertilizer. Keywords: Pear, fertilization, growth, fruit quality, leaf nutrient content INTRODUCTION Among temperate fruits grown in North Western sub-tropics of India, pear occupies maximum acreage with ‘Patharnakh’ as the leading cultivar due to its high yield potential. However, fully grown-up plants of this cultivar show variability in fruit yield with small sized fruits which fetch poor market price. Improving the marketable yield of good quality fruits has always been a challenge for growers. Balanced nutrition of plants along with good cultural practices can help in improving quality fruit with high yields. Nitrogen is one of the most important elements for high productivity and growth of fruit plants (Titus and Kang, 1982) and also promotes fruit and seed development (Marschner, 1995). Similarly, potassium is considered as a quality improving element in fruit crops. Imbalanced use of nutrients or widespread use of N fertilizers alone leads to poor quality of fruits (Ganeshamurthy et al, 2011). High rates of N can be utilized by plant only in the presence of required K levels. Similarly, potassium (K) is the most aboundant nutrient in the fruit, where it influences the size, firmness, skin color, TSS and acidity (Brunetto et al, 2015). However, little information is available on the effect of combined application of nitrogen and potassium fertilizers on yield and quality in sub-tropical pears (Gill et al, 2012). Keeping in view the above, the present experiment was designed to study the effect of different combined doses of N and K fertilizers on growth, fruit yield and fruit quality and leaf nutrient content of Patharnakh pear plants. MATERIAL AND METHODS The present research was carried out at Fruit Research Farm and Leaf Analysis Laboratory of t he D ep a r t ment of F r u it S c ien c e, P u nja b Agricultural University, Ludhiana during the year 2013-14. The study was conducted on commercially bearing Patharnakh pear plants grafted on Kainth (Pyrus pashia), spaced at a distance of 7x7 m. The experiment was laid out in Randomized Block D es ign ( R B D ) a nd a ll t he t r ea t ment s wer e replicated thrice. Plants were applied with different combined doses of N (Urea) as N1- 460, N2- 690 and N3-920 g/plant and K (MOP) , as K1-600, K2- 900, K3- 1200 and K4-1500 g K2O/plant. Twelve fertilizers combinations include: T1- N1K1, T2-N1K2, Original Research Paper 50 Table 1. Effect of different combined doses of N and K fertilization on fruit yield, number of fruits, increase in TCSA and increase in shoot length of pear cv. Patharnakh J. Hortl. Sci. Vol. 12(1) : 49-53, 2017 Gill et al T3-N1K3, T4-N1K4, T5-N2K1, T6-N2K2, T7-N2K3, T8- N2K4, T9-N3K1, T10-N3K2, T11-N3K3 and T12-N3K4. Potash fertilizer was applied in December while nitrogen was applied in two split doses; before and after fruit set. A uniform dose of 320 g of P2O5 using single super phosphate (SSP) was applied to all experimental trees. Fruit yield per plant was calculated as the average weight of fruits multiplied by the number of fruits and expressed in kg per plant. Number of fruits per plant at harvest time were manually counted. The annual increase in T C S A ( c m) wa s r ec or ded wit h t he help of measuring tape at the height of 15 cm above the graft union. For determination of an increase in shoot length, four shoots were tagged around the plant in the dormant season. The increase in shoot length wa s mea s ur ed using a mea sur ing ta p e in the following dormant season and expressed in cm. At harvest, ten randomly selected fruits from each treatment were weighed on the electronic balance and expressed as mean fruit weight in ‘g’. TSS ( 0Br ix) wa s estima t ed with ha nd held digit a l refractometer (ATAGO, PAL -1, Japan). Titratable Acidity (TA) (%) of juice wa s determined by titrating against 0.1 N NaOH using phenolphthalein as an indicator. Fruit firmness (lbf) was measured with stand mounted penetrometer (model FT-327, USA) as the maximum force required to plunge a spher ical tip into the peeled skin of fruit. For estimation of nutrient content, leaf samples were collected in the month of July, washed with tap water and 0.1 N HCl, rinsed with distilled water, and dried in an oven at 60oC for 72 hours. The dried samples were ground and stored in butter paper bags for further a na lysis of nutrients. For nitrogen estimation Kel Plus Nitrogen Estimation System (Pelican Equipments, India) was used. Phosphorus was estimated by Vanado-molybdo phosphoric yellow colour method as described by Chapman and Pratt (1961) and expressed as %. For determination of leaf K%, the flame photometer method (AOAC, 1990) was followed. Statistical analysis of the experimental data was done using statistical package SAS 9.3 (The SAS s ys tem for Windows, Ver sion 9 . 3 , S AS Institute, Cary, NC). Data was analyzed for analysis of Va ria nce (ANOVA) using the Fischer LSD (p<0.05) for significant difference test. RESULTS AND DISCUSSION Differ ent combined doses of N a nd K significantly affected the fruit yield of pear plants (Table 1). The highest fruit yield was recorded in the T6 (N2K2) treatment which registered a value of 94.5 and 101.2 kg/plant during the years 2013 and 2014, respectively. At higher levels of N, the high yield might be due to increased availability and uptake of nutrients 51 J. Hortl. Sci. Vol. 12(1) : 49-53, 2017 Effect of N and K on Pear (Dhillon et al, 2011). The minimum fruit yield of 75.3 kg/plant during the year 2013 was recorded from plants under T12 treatment, while, for the year 2014, it was 78.9 kg /plant in T1 (N1K1) treatment. The intermediate levels of N and K dose resulted in better fruit yield of pear plants as compared to lower and higher levels of N and K fertilizers. Number of fruits per plant varied with different combined doses of N and K. Treatment T10 (N3K2) recorded the maximum of 643 and 691 fruits per plant, whereas, a minimum of 547 and 560 fruits/plant was registered for treatment T8 (N2K4) during the year 2013 and 2014, respectively (Table 1). Higher dose of N contributes to the greater number of fruits per plant (Dhillon et al, 2011). The effect of N and K applications on TCSA is presented in Table 1. The maximum increase in TCSA (2.25 cm) of plants was registered in fertilizer combination of the highest dose of N and the lowest dose of K, whereas, minimum TCSA (1.29 cm) was observed for T4 treatment. The maximum increase in shoot length (14.58 cm) during Table 2. Effect of different combined doses of N and K fertilization on fruit weight, TSS, TA and fruit firmness of pear cv. Patharnakh Table 3. Effect of different combined doses of N and K fertilization on leaf nitrogen, phosphorus and potassium content of pear cv. Patharnakh 52 Gill et al J. Hortl. Sci. Vol. 12(1) : 49-53, 2017 the year 2013 was observed for T9 (N3K1) and was statistically at par with treatments T10, T11 and T12 (Table 1). Similarly, Bennewitz et al (2011) reported that potassium application did not have a significant effect on the trunk cross-sectional area of apple trees. However, Kumar and Chandel (2004) reported that the girth of pear tree cv. Red Bartlet was significantly increased by both nitrogen and potassium application. Higher doses of N resulted in an increase in shoot length, whereas, with the higher dose of K, a slow increment in shoot length was recorded. Similar observation of an increase in lateral and terminal shoots of pear was reported by Yadav and Bist, 2003. Fruit weight was significantly affected by dosage of applied N and K fertilizers (Table 2). Maximum fruit weight of 155.7g and 150.2g was recorded for treatment T7 (N2K3) during the year 2013 and 2014, respectively. Increased fruit size in guava fruits with potassium applications was also reported by Gill and Bal (2010). Plants applied with N3K2 fertilizer combination registered minimum fruit weight of 133.7 g during 2013, whereas, for the year 2014, the minimum fruit weight (131.7 g) was observed for T9. Different nutrient levels of N and K significantly affected TSS content with the maximum of 13.48% registered for treatment T4 (N1K4) during the year 2013, while during following year, fruits from treatment T 3 (N1K3) registered maximum (12.77%) TSS content (Table 2). Similar increase in TSS with potassium application was observed in Patharnakh pear fruit (Prasad et al, 2015). Minimum TSS content of 11.14% and 11.23% was recorded in T9 (N3K1) treatment during the year 2013 and 2014, respectively. Maximum TSS was recorded in the fruits of plants applied with the lowest dose of N and higher dose of K. Fruits from higher N dose rate had lower soluble solids content in apple cv. ‘Golden Delicious’ (Raese et al, 2007). During the year 2013, TA of fruit juice showed a declining trend with an increase in levels of N and K fertilizers (Table 2). Raese et al (2007) reported similar results of decreased acid content with increasing N dose in apple. Maximum fruit juice acidity recorded for the year 2013 and 2014 was 0.352% and 0.360%, respectively for T1 (N1K1) treatment wherein the applied dosage of N and K was minimum. During 2013, minimum fruit firmness of 14.83 lbf was recorded in plants with the highest dose of N and the lowest dose of K while, during the year 2014 it was recorded as 15 lbf for treatment T 5 (N2K1) treatment. Similar decrease in fruit firmness with higher doses of N was reported by Okamoto et al (2001). In contrast, maximum fruit firmness of 17.14 lbf and 16.8 lbf, during 2013 and 2014 respectively, was retained by fruits harvested from T4 (N1K4) treatment. A linear increase in fruit firmness with increase in dose of K in combination with different N doses was observed (Table 2). A similar increase was observed by Gill et al (2012). The effect of N and K fertilizer combinations on leaf nitrogen, phosphorus and potassium content of pear cv. Patharnakh is presented in Table 3. It was observed that the highest dose of N in combination with the lowest dose of K resulted in maximum leaf N content (2.14%). The minimum content of leaf N (1.83%) was recorded for treatment T4 (N1K4) which is a combination of lowest N and highest K dose. Higher rates of N fertilizer frequently increased concentrations of leaf N in ‘Fuji’ apples (Raese and Drake, 1997). Maximum leaf phosphorus content (0.130%) was observed in the leaf of plants treated with T4 (N1K4) treatment. The highest dose of K result in high potassium content (1.31%) of leaf in treatment T8 (N2K4) and the minimum (0.91%) was recorded in T1 (N1K1) treated plant leaves, where K dosage applied was lowest. The higher leaf N and K contents may be due to enhanced accumulation and translocation of nitrogen (Walsch et al, 1989) and potassium (Smith, 1962) under higher supply from roots to leaves. Thus, it can be concluded that application of 690g of nitrogen and 900g of K2O was effective in improving fruit yield and quality of pear cv. Patharnakh. 53 A.O.A.C. 1990. Official and tentative methods of analysis. In: Association of Official Agric Chemists. 15th Eds., Washington, DC, USA Bennewitz,C.V., Cooper,T., Benavides, C.,Losak, J. and Hlusek, J 2011. Response of ‘Junagold’ apple trees to Ca, K and Mg fertilization in an andisol in South Chile. J Soil Sci. and Plant Nutri., 11: 71-81 Brunetto, G., Melo, G.W.B.D., Toselli, M., Quartieri, M. and Tagliavini, M. 2015. The role of mineral nutrition on yields and fruit quality in grapevine, pear and apple. Rev. Bras. Frutic., 37:1089-1104 Chapman, H.D. and Pratt, P.F. 1961. Methods of Analysis for Soils, Plants and Water. University of California, Division of Agriculture Science, Berkeley, USA Dhillon, W.S., Gill, P.P.S. and Singh, N.P. 2011. Effect of nitrogen, phosphorus and potassium fertilization on growth, yield and quality of pomegranate ‘Kandhari’. Acta Hort., 890:327-332 Ganeshamurthy, A.N., Satisha, G.C. and Patil, P. 2011. Potassium nutrition on yield and quality of fruit crops with special emphasis on banana and grapes. Karnataka J. Agric. Sci., 24:29-38 Gill, P.P.S. and Bal, J.S. 2010. Effect of pre-harvest applications of nutrient and growth regulators on quality of Sardar guava. Haryana J. Hort. Sci. 39 : 193-194 Gill, P.P.S., Ganaie, M.Y., Dhillon, W.S. and Singh, N.P. 2012. Effect of foliar sprays of potassium on fruit size and quality of ‘Patharnakh’ pear. Ind. J. Hort., 69:512-516 Kumar, J. and Chandel, J. S. 2004. Effect of different levels of N, P and K on growth and yield of pear cv. Red Bartlett. Prog. Hort., 36: 202-206 REFERENCES Marschner, H. 1995. Mineral nutrition of higher plants. 2nd (eds.). Academic press, London, pp 889 Okamoto, G., Jia, H., Kitamura, A. and Hirano, K. 2001. Effect of different fertilizer application levels on texture of ‘Hakuho’ peach (Prunus persica Batsch). J. Jpn. Soc. Hortic. Sci., 70:533-538 Prasad B., Dimri, D.C. and Bora, L. 2015. Effect of pre-harvest foliar spray of calcium and potassium on fruit quality of Pear cv. Pathernakh. Scientific Research and Essays, 10:376-380 Raese, J.T. and Drake, S.R. 1997. Nitrogen fertilization and elemental composition effects fruit quality of ‘Fuji’ apples. J. Plant Nutr., 20:1797-1809 Raese, J.T., Drake, S.R. and Curry, E.A. 2007. Nitrogen fertilizers influences fruit quality, soil nutrients and cover crops, leaf colour and nitrogen content, biennial bearing and cold hardiness of Golden Delicious. J. Plant Nutr., 30:1585-1604 Smith, C. B. 1962. Mineral analysis of plant tissues. Plant Physiol., 13: 81-108. Titus, J.S. and Kang, S.M. 1982. Nitrogen metabolism, translocation, and recycling in apple plants. Hort. Rev., 4:204-246 Walsch, C.S., Allnutt, F.J., Miller, A.N. and Thompson, A.H. 1989. Nitrogen level and time of mechanized summer shearing influence long term performance of a high density Red skin peach orchard. J. Amer. Soc. Hort. Sci., 114: 373-377 Yadav, A. and Bist, L.D. 2003. Effect of nitrogen on shoot growth, flowering, fruiting and fruit quality in pear cv. Bagugosha. Ind. J. Hort., 60:40-44 (MS Received 04 January 2017, Revised 05 April 2017, Accepted 27 May 2017) Effect of N and K on Pear J. Hortl. Sci. Vol. 12(1) : 49-53, 2017 00 Content JH June 2017.pdf 00 SPH-Journal November new 12.pdf 01 SPH-Journal November new 01.pdf 02 SPH-Journal November new 04.pdf 03 SPH-Journal November new 05.pdf 04 SPH-Journal November new 07.pdf 05 SPH-Journal November new 09.pdf 06 SPH-Journal November new 10.pdf 07 SPH-Journal November new 11.pdf 08 SPH-Journal November new 13.pdf 09 SPH-Journal November new 03.pdf 10 SPH-Journal November new 06.pdf 11 SPH-Journal November new 08.pdf