Effects of Foliar Application of Calcium Chloride and Potassium Sulfate on Physical and Biochemical Properties of Jujube Fruit (Ziziphus jujuba Mill.)

Document Type : Research Article

Authors

• Mohammad Ali Ahmadi ¹
• Saeid Daghighi ¹
• Farhad Azarmi-Atajan ²
• Hassan Bayat ¹

¹ Department of Horticultural Science, Agricultural Collage, University of Birjand, Birjand, Iran

² Assistant Professor, Soil Science Engineering Department, Agricultural College, University of Birjand, Birjand, Iran

https://doi.org/10.22067/jhs.2023.79367.1204

Abstract

Introduction
Jujube (Ziziphus jujuba Mill.) as one of the invaluable medicinal plants, is widely used in the pharmaceutical industry due to its vitamins, mucilage, antioxidants, alkaloids and phenolic compounds. South Khorasan province is the most important area of jujube fruit production in Iran. Optimum supply of nutrients in fruit trees can increase fruit quality. Calcium is one of the most important elements that can affect quantity, quality, storability and marketability of many horticultural crops. Due to the relatively high amount of lime in the agricultural soils of South Khorasan province, the amount of calcium in these soils is almost high. However, due to low mobility of calcium from soil to plant, calcium deficiency is common in horticultural plants. Also, potassium is required for cellular osmotic and ionic balances, electrochemical processes, neutralization of organic acids, regulation of stomatal function, cell division, enzyme activation, protein synthesis, as well as the synthesis and translocation of sugars. Foliar spraying is an effective way to supply nutrients needed by plants, especially in calcareous soils with high pH. In this method, nutrients are directly available to different parts of the plant in a short period of time. Studies have shown that leaf feeding with calcium and potassium can be useful for increasing the qualitative characteristics of fruit in most products, especially in arid and semi-arid regions. Nevertheless, little information is available regarding the foliar application of this element on jujube plant. Hence, the current research was aimed to investigate the effects of foliar application of calcium chloride and potassium sulfate on physicochemical properties and quality of fresh jujube fruit.
 
Materials and Methods
In order to investigate the effect of foliar application of calcium chloride and potassium sulfate on the physical and biochemical properties of the fruit of the jujube plant, two separate factorial experiment was conducted in the form of a randomized complete block design in three replications in two areas of Siojan and Mazhan, Khosef city in 2022. Experimental treatments included calcium chloride (0, 0.5 and 1%) and potassium sulfate (0, 0.1 and 0.3%). Fresh fruit was harvested at a crisp mature (white-red) stage mid in August. Data were analysed using SAS software (ver. 9.4) and comparison of means was made with LSD test at 1 and 5% probability.
 
Results and Discussion
The results of analysis of variance showed that calcium chloride foliar application in Siojan garden had significant effect on the physical and biochemical characteristics of jujube fruit. So that the highest fresh weight (4.07 gr), dry weight (1.89 gr), length (29.11 mm), diameter (21.52 mm) and texture firmness (18.81 N/cm²) of fruit were obtained from the level of 0.5% calcium chloride. Also, the foliar spraying treatment with 0.5% calcium chloride had the highest amount of carotenoid and total phenol in the fruit. The highest amount of calcium and potassium in the fruit was obtained from the level of 1% calcium chloride. The effect of foliar application of calcium chloride on physical and biochemical properties of jujube fruit in Mazhan garden was significant. In Mazhan garden, the highest fresh weight (3.9 gr), dry weight (1.37 gr), length (28.41 mm), diameter (20.91 mm) and texture firmness (18.61 N/cm²) of fruit were obtained from foliar application of 0.5% calcium chloride. The highest amount of carotenoids (0.443 mg/100 g of fresh weight) and phenol (9.53 mg of gallic acid per 100 g of fresh weight) in Mazhan garden was obtained from the level of 0.5% calcium chloride. The content of calcium and potassium of jujube fruit in Mazhan region was maximized with the application of 1% calcium chloride. The results showed that the application of potassium sulfate in Siojan garden had an significant effect on the physical and biochemical characteristics of the fruit. The highest fresh weight (3.63 gr) and dry fruit weight (1.89 gr), length and diameter and texture firmness  of fruit was obtained from the level of 0.3% potassium sulfate. Also, the highest amount of biochemical indices of jujube fruit in Siojan garden was obtained from the level of 0.3% potassium sulfate. The interaction effect of foliar application of calcium chloride and potassium sulfate on fresh and dry fruit weight, fruit length and carotenoids of fruit in Siojan garden was significant. In Mazhan garden, the fresh and dry weight of fruit, amount of carotenoids and total phenol of fruit were affected by the interaction effect of experimental treatments, and the highest level of these characteristics was obtained from the level of 0.5% calcium chloride and 0.3% potassium sulfate.
 
Conclusion
The results of foliar spraying of calcium chloride and potassium sulfate in both studied orchards showed that these treatments, both solely and in combination, had a positive and significant effect on various characteristics of jujube fruit. So the highest physical and biochemical characteristics of the fruit were obtained from the simultaneous application of 0.5% calcium chloride and 0.3% potassium sulfate. Therefore, Based on the results of this research, foliar spraying 0.5% calcium chloride and 0.3% potassium sulfate can have an effective role in increasing the quantity and quality of jujube fruit.

Keywords

• Foliar nutrition
• Nutrients
• Quality
• Yield

20.1001.1.20084730.1402.37.3.14.2

Main Subjects

• Pomology

References

1. Abdel-Hafeez, A.A., Mohamed, A.I., & Taha, N.M. (2010). Effect of some sources potassium and calcium as a foliar spray on fruit quality and storability of ˝Kelsey˝ plums. Egyptian Journal of Horticulture, 37(2), 151-168.
2. Al-Yousif, A.A., & Al-Masudey, M.Z. (2007). Effect of calcium on Ziziphus jujube fruit growth and their resistance to jujube fruit Fly (Carpomyia incompleta). Journal of Kerbela University, 5(4), 106-113.
3. Anttonen, M., Kalle, I., Hoppul, A., Rolf, N., Mighel, J., Verheul, L., & Reijoo, K. (2006). Influence of fertilization, mulch color, early forcing, fruit order, planting dates, shading, growing environment and genotype on the content of selected phenolics in strawberry (Fragaria ananassa) fruits. Journal of Agricultural and Food Chemistry, 54(7), 2614-2620. https://doi.org/10.1021/jf052947w
4. Ashoori, M., Lolaei, A., Zamani, S., Ahmadian, E., & Mobasheri, S. (2013). Optimizing quality and quantity parameters of apple cv. Red Delicious‘ by adjustment of calcium and nitrogen.International Journal of Agriculture and Crop Sciences, 5(8), 868-874.
5. Azadi Bougar, Sh., & Gharaghani, A. (2017). Effect of calcium and boron spray application on fruit’s quantitative and qualitative characteristics of ‘Golab-e Kohanz’ apple. Iranian Journal of Horticultural Science, 47(4), 811-822. (In Persian with English abstract). https://doi.org/10.22059/ijhs.2017.133069.844
6. Azam Ali, S., Bonkoungou, E., Bowe, C., DeKock, C., Godara, A., & Williams, J.T. (2006). Fruits for the Future 2: Ber and other jujubes. International Centre for Under utilised Crops, Southampton, UK: University of Southampton.
7. Barry, G.H., & Le Roux, S. (2010). Preharvest foliar sprays of prohexadione–calcium, a gibberellin-biosynthesis inhibitor, induce chlorophyll degradation and carotenoid synthesis in citrus rinds. Hort Science, 45(2), 242-247. https://doi.org/10.21273/HORTSCI.45.2.242
8. Barry, G.H., & Van Wyk, A.A. (2004). Novel approaches to rind colour enhancement of citrus. International Society of Citriculture, 3, 1076-1079.
9. Bravdo, B.A., Possingham, J.V., & Neilen, G.H. (2000). Effect of mineral and salinity on grape production and wine quality. Acta Horticulturae, 512, 23-30. https://doi.org/10.17660/ActaHortic.2000.512.2
10. Bravdo, B.A., Possingham, J.V., & Neilen, G.H. (2000). Effect of mineral and salinity on grape production and wine quality. Acta Horticulturae, 512, 23-30. https://doi.org/17660/ActaHortic.2000.512.2
11. Calvert, V.D., & Smith, C.R. (1972). Correction of potassium deficiency of citrus with KNO₃ Journal of Agricultural and Food Chemistry, 20(3), 659-661. https://doi.org/10.1021/jf60181a007
12. Chapagain, B.P., Wiesman, Z., Zaccai, M., Imas, P., & Magen, H. (2003). Potassium chloride enhances fruit appearance and improves quality of fertigated greenhouse tomato as compared to potassium nitrate. Journal of Plant Nutrition, 26, 643-658. https://doi.org/1081/PLN-120017671
13. Chuah, A.M., Lee, Y.C., Amaguchi, Y., Takamura, H., Yin, L.J., & Matoba, T. (2008). Effect of cooking on the antioxidant properties of coloured peppers. Food Chemistry, 111(1), 20-28. https://doi.org/1016/j.foodchem.2008.03.022.
14. Delgado, R., Gonzalez, M., & Martin, P. (2006). Interaction effects of nitrogen and potassium fertilization on anthocyanin composition and chromatic features of ‘Temprannillo’ grapes. International Journal of Vine and Wine Science, 40, 141-150. https://doi.org/20870/oeno-one.2006.40.3.870
15. Doleh, L., Hassanpour Asil, M., & Abdolahi, H. (2010). Effective parameters in determination of commercial fruit maturity of different pear (Pyrus communis) Cultivars. Iranian Journal of Horticultural Science, 41(2), 189-196. (In Persian with English abstract). https://doi.org/20.1001.1.2008482.1389.41.2.10.6
16. Ebrahimi, M., Pouyan, M., Ghous, K., Shahi, T., Hosseini, S., & Ragh Ara, H. (2022). Comparison of the efficiency of preferred grafting methods in jujube (Ziziphus jujuba Mill.) genotypes. The First National Conference on Production and Postharvest Technology of Horticultural Plants (PPTHP 2022), May 25-26, University of Birjand, Iran. (In Persian with English abstract)
17. Fallahi, E., Conway, W.S, Hickey, K.D., & Sams, C.E. (1997). The role of calcium and nitrogen in post harvest quality and disease resistance of apples. Hort Science, 32, 831-835. https://doi.org/10.21273/HORTSCI.32.5.831
18. Fernandez, V., Sotiropoulos, T., & Brown, P.H. (2013). Foliar fertilization: scientific principles and field practices. International Fertilizer Industry Association (IFA), France. p 140.
19. Gaaliche, B., Ladhari, A., Zarrelli, A., & Mimoun, M.B. (2019). Impact of foliar potassium fertilization on biochemical composition and antioxidant activity of fig (Ficus carica). Scientia Horticulturae, 253, 111-119. https://doi.org/10.1016/j.scienta.2019.04.024
20. Ghesmati, M., Moradinezhad, F., & Khayyat, M. (2017). Effects of foliar application of calcium nitrate and calcium chloride on antioxidant properties and quality of Ziziphus jujuba Iranian Journal of Medicinal and Aromatic Plants, 3(5), 871-881. (In Persian with English abstract). https://doi.org/10.22092/ijmapr.2017.111043.2059.
21. Ghesmati, M., Moradinezhad, F., & Khayyat, M. (2018). Efficacy of some calcium salts foliar spray on growth and biochemical parameters of jujube fruit (Ziziphus jujuba Mill.). Journal of Plant Productions (Scientific Journal of Agriculture), 41(3), 25-37. (In Persian with English abstract). https://doi.org/22055/ppd.2017.21173.1447.
22. Ghous, K., Pouyan, M., Ebrahimi, M., Hosseini, S., & Shahi, T. (2019). Jujube, from Planting to Processing.Tehran: Fekrebekr Publication. (In Persian)
23. Hafez, O.M., & EL-Metwally, I.M. (2007). Efficiency of zinc and potassium sprays alone or in combination with some weed control treatments on weeds growth, yield and fruit quality of washington navel orange orchads. Journal of Applied Sciences Research, 3(7), 613-621.
24. Hassan, H.S.A., Sarrwy, S.M.A., & Mostafa, E.A.M. (2010). Effect of foliar spraying with liquid organic fertilizer, some micronutrients, and gibberellins on leaf mineral content, fruit set, yield, and fruit quality of “Hollywood” plum trees. Agriculture and Biology Journal of North America, 1(4), 638-643.
25. Hegazi, E.S., Mohamed, S.M., EL-Sonbaty, M.R., Abd El-Naby, S.K.M., & El-Sharony, T.F. (2011). Effect of potassium nitrate on vegetative growth, nutritional status, yield and fruit quality of olive cv. Picual. Journal of Horticultural Science and Ornamental Plants, 3(3), 252-258.
26. Inglese, P., Barone, P., & Gullo, G. (1995). The effect of complementary irrigation on fruit growth, ripening pattern and oil characteristics of olive (Olea europaea) cv. Carolea. Journal of Horticultural Science, 71, 257-263. https://doi.org/10.1080/14620316.1996.11515404
27. Jifon, G.E., & Lester, J.L. (2007). Effects of foliar potassium fertilization on muskmelon fruit quality and yield. Annual Report for TX-52F, 1-5.
28. Kadir, S.A. (2005). Fruit quality at harvest of Jonathan apple treated with foliarly applied calcium chloride. Journal of Plant Nutrition, 27, 1991-2006. https://doi.org/1081/PLN-200030102
29. Kazemi, M. (2014). Effect of foliar application of humic acid and calcium chloride on tomato growth. Bulletin of Environment, Pharmacology and Life Sciences, 3(3), 41-46.
30. Khalili, H., & Naseri, L.A. (2015). Effect of foliar application of calcium chloride and gibberellic acid before harvesting and immersion after calcium harvesting on shelf life and quality properties of red gold nectarine fruit. The third international research conference on applied research in agricultural sciences (30 February 2014), The University of Applied Science and Technology. (pp. 33-39) (In Persian)
31. Khoshghalb, H., Arzani, K., Malakouti, M.J., & Barzegar, M. (2013). Effect of Ca, Zn and B spray application on preharvest fruit drop, sugar and nutrient contents and on some quantitative and qualitative fruit characterestics in some asian pear (Pyrus serotina) cultivars. Iranian Journal of Horticultural Science, 44(2), 149-159. (In Persian with English abstract).  https://doi.org/10.22059/ijhs.2013.35048
32. Khosravi Meshizi, M., & Sarcheshmehpour, M. (2015). Effect of calcium and potassium foliar application on plant growth, yield and post-harvest characteristics of two melon cultivars (Cucumis melon). Journal of Crop Production and Processing, 5(17), 295-310. (In Persian). https://doi.org/10.18869/acadpub.jcpp.5.17.295
33. Lalonde, S., Tegeder, M., Throne‐Holst, M., Frommer, W.B., & Patrick, J.W. (2003). Phloem loading and unloading of sugars and amino acids. Plant, Cell and Environment, 26(1), 37-56. https://org/10.1046/j.1365-3040.2003.00847.x
34. , G.E., Jifon, J.L., & Makus, D.J. (2010). Impact of potassium nutrition on postharvest fruit quality: melon (Cucumis melo L.) case study. Plant and Soil, 335, 117-131. https://doi.org/10.1007/s11104-009-0227-3
35. Li, J., Fan, L.P., Ding, S.D., & Ding, X. (2007). Nutritional composition of five cultivars of Chinese jujube. Food Chemistry, 103(2), 454-460. https://org/10.1016/j.foodchem.2006.08.016
36. Lichtenthaler, H.K. (1987). Chlorophylls and carotenoids: pigments of photosynthetic biomembranes. Methods in Enzymology, 148, 350-382. https://doi.org/10.1016/0076-6879(87)48036-1
37. Liu, M. (2010). Chinese Jujube: Botany and Horticulture. Horticultural Reviews, 32, 229–299. https://doi.org/1002/9780470767986.ch5
38. Liu, M., & Wang, J. (2019). Fruit scientific research in new China in the past 70 years: Chinese jujube. Journal of Fruit Science, 36, 1369–1381.
39. Mao, Y.M., Shen, L.Y., Wei, W., Wang, X.L., Hu, Y.L., Xu, S.S., & Mao, L.L. (2014). Effects of foliar applications of boron and calcium on the fruit quality of 'Dongzao' (Zizyphus jujuba), In XXIX International Horticultural Congress on Horticulture, Sustaining Lives, Livelihoods and Landscapes (IHC2014): III 1116, 105-108. https://doi.org/10.17660/ActaHortic.2016.1116.18
40. Marschner, P. (2012). Mineral nutrition of higher plants 3rd edition. 3rd (ed). Academic Press, 651 p.
41. Mohammed, S., Singh, D., & Ahlawat, V.P. (1993). Growth, yield and quality of grapes as affected by pruning and basal application of potassium. Journal of Horticultural Science and Technology, 22, 79-182.
42. Moor, U., Karp, K., Põldma, P., Asafova, L., & Starast, M. (2006). Post-harvest disorders and mineral composition of apple fruits as affected by pre-harvest calcium treatments. Acta Agriculturae Scandinavica, 56(3), 179-185. https://doi.org/10.1080/09064710500303175
43. Moradinezhad, F., Hassanpour, S., & Sayyari, M.H. (2018). Influence of preharvest spray of calcium chlorideand salicylic acid on physicochemical and quality properties of fresh seedless barberry fruit. Journal of Horticultural Science, 32(1), 61-74. (In Persian with English abstract). https://doi.org/22067/JHORTS4.V32I1.60331
44. Morris, L.R., Sims, C.A., & Cawton, D.L. (1983). Effects of excessive potassium levels on pH, acidity and color of fresh and stored grape juice.American Journal of Enology and Viticulture, 34, 35-39.
45. Nguyen, P.M., Kwee, E.M., & Niemeyer, E.D. (2010). Potassium rate alters the antioxidant capacity and phenolic concenteration of basil (Ocimum basilicum) Leaves. Food Chemistry, 123, 1235- 1241. https://doi.org/10.1016/j.foodchem.2010.05.092
46. Nojavan, S. (2015). The effect of foliar feeding with potassium sulfate and zinc sulfate on fruit quality and resistance to winter cold of red quince variety grape buds. Master's Thesis in the Field of Horticultural Sciences. Faculty of Agriculture, Urmia University. (In Persian with English abstract)
47. Rajpal, S., Godara, N.R., & Ahlawat, V.P. (2002). Qualitative attributes affected by foliar spraying of nutrients and growth regulators in ber (Ziziphus mauritiana) cv. Umran. Haryana Journal of Horticultural Sciences, 31(1/2), 23-25.
48. Ramazanian, A., Rahemi, M., & Vazifeshenas, M.R. (2009). Effects of foliar application of calcium chloride and urea on quantitative and qualitative character eristics of pome granate fruits. Scientia Horticulturae, 121, 171-175. https://doi.org/10.1016/j.scienta.2009.01.039
49. Restrepo-Diaz, H., Benlloch, M., Navarro, C., & Fernandez Escobar, R. (2008). Potassium fertilization of rainfed olive orchards. Scientia Horticulturae, 116, 399-403. https://doi.org/1016/j.scienta.2008.03.001
50. Rouhi, V., Nikbakht, A., & Hooshmand, S. (2015). Effect of sodium chloride concentrations and Its foliar application time on quantitative and qualitative characteristics of pomegranate fruit (Punica granatum) cv. “Malas Saveh”. Journal of Horticultural Science, 29(2), 158-167. (In Persian with English abstract). https://doi.org/10.22067/JHORTS4.V0I0.26271
51. Salukha, D.K., Jadha, S.J., & Yu, M.H. (1974). Quality and nutritional composition of tomato fruits influenced by certain biochemical and physiological changes. Qualitas Plantarum Plant Foods for Human Nutrition, 24(1-2), 85-113. https://doi.org/10.1007/BF01092727
52. Sarikhani, H., Haghi, H., Ershadi, A., Esna-Ashari, M., & Pouya, M. (2014). Foliar application of potassium sulphate enhances the cold-hardiness of grapevine (Vitis vinifera). Journal of Horticultural Science and Biotechnology, 89(2), 141-146. https://doi.org/10.1080/14620316.2014.11513060
53. Sharafzadeh, Sh., Khoushkhoy, M., & Javidnia, K. (2008). Effects of nutrients on growth and active substances of thyme (Thymus vulgaris). Journal of Gardener's Science and Techniques, 9(4), 261-274. (In Persian)
54. Sharma, R.R., Singh, D., & Pal, R.K. (2013). Synergistic influence of pre-harvest calcium sprays and postharvest hot water treatment on fruit firmness, decay, bitter pit incidence and postharvest quality of royal delicious apples (Malus x domestica Borkh). American Journal of Plant Sciences, 4, 153-159. https://doi.org/4236/ajps.2013.41020
55. Singh, B. (2002). Effects of macro and micro nutrient spray on fruit yield and quality of grapes (Vitis vinifera) cv. Perlette. Acta Horticulturae, 594, 197-202. https://doi.org/10.17660/ActaHortic.2002.594.21
56. Singh, D.P., Beloy, J., McInerney, J.K., & Day, L. (2012). Impact of boron, calcium and genetic factors on vitamin C, carotenoids, phenolic acids, anthocyanins and antioxidant capacity of carrots (Daucus carota). Food Chemistry, 132(3), 1161-1170. https://doi.org/10.1016/j.foodchem.2011.11.045
57. Soares, A.G., Trugo, L.C., Botrel, N., & Souza, L.F. (2005). Reduction of internal browning of pineapple fruit (Ananas comusus) by preharvest soil application of potassium. Postharvest Biology and Technology, 35, 201-207. https://doi.org/10.1016/j.postharvbio.2004.07.005
58. Solhjo, S. (2015). The Effect of foliar application of calcium chloride and potassium sources on improvement of color, quality characteristics and storage life of delicious apple fruit. Master's thesis in the field of horticultural sciences. Faculty of Agriculture, Shiraz University. (In Persian with English abstract)
59. Souty, M., Reich, M., Breuils, L., Chambroy, Y., Jacquemin, G., & Audergon, J.M. (1995). Effects of postharvest calcium treatments on shelf-life and quality of apricot fruit. Acta Horticulturae, 384, 619-623. https://doi.org/17660/ActaHortic.1995.384.97
60. Taha, R., Rania, A.T., Hassan, H.S.A., & Shaaban, E.A. (2014). Effect of different potassium fertilizer forms on yield, fruit quality and leaf mineral content of Zebda Mango trees. Journal of Scientific Research, 21(1), 123-129. https://doi.org/10.5829/idosi.mejsr.2014.21.01.21451
61. Tehranifar, A., & Mahmooditabar, S. (2009). Foliar application of potassium and boron during pomegranate (Punica granatum) fruit development can improve fruit quality. Horticulture, Environment and Biotechnology, 3(50), 23-34.
62. Teixeira, A.F, Andrade, A.B., Ferrarese-Filho, O., & Ferrarese, L.L. (2006). Role of calcium on phenolic compounds and enzymes related to lignification in soybean (Glycine max) root growth. Plant Growth Regulation, 49, 69-76. https://doi.org/10.1007/s10725-006-0013-7
63. Viccente, A.R., Costa, M.L., Martinez, G.A., Chaves, A.R., & Civello, P.M. (2005). Effect of heat treatment on cell wall degradation and softening in strawberry fruit. Postharvest Biology and Technology, 38, 213-222. https://doi.org/1016/j.postharvbio.2005.06.005
64. Wang, M., Zheng, Q., Shen, Q., & Guo, S. (2013). The critical role of potassium in plant stress response. International Journal of Molecular Sciences, 14(4), 7370-7390. https://doi.org/3390/ijms14047370
65. Wójcik, P., Skorupińska, A., & Filipczak, J. (2014). Impacts of preharvest fall sprays of calcium chloride at high rates on quality and ‘Conference’pear storability. Scientia Horticulturae, 168, 51-57. https://doi.org/10.1016/j.scienta.2014.01.017
66. Yousefi, S., Amiri, M.E., Mirabdulbaghi, M., & Habibi, F. (2015). Effects of CaCl₂ concentration and spraying time on quality, mineral composition and shelf life of apricot fruit cv. ‘jahangiri’. Iranian Journal of Horticultural Sience and Technology, 16(1), 121-136. (In Persian)
67. Zangeneh, N., & Rasouli, M. (2017). Effect of potassium fertilizers and Humic acid on the Pigments and activity of antioxidants in grape 'Bidaneh Sefid'. Iranian Journal of Horticultural Science, 48(3), 701-714. (In Persian with English abstract). https://doi.org/10.22059/ijhs.2017.229264.1202
68. Zeraatgar, H., Davarinejad, Gh.H., Moradynejad, F., & Abedi, B. (2018). Effect of salicylic acid and calcium nitrate spraying on qualitative properties and storability of fresh jujube fruit (Ziziphus jujube). Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 46(1), 138-147. https://doi.org/10.15835/nbha46110743

Zivdar, Sh. (2015). Investigating the effect of potassium sulfate foliar application on some physiological and biochemical indicators of olive (Olea europaea L.) in the weather conditions of Ahvaz. Master's Thesis in the Field of Horticultural Sciences. Faculty of Agriculture, Shiraz Universi