Effect of planting dates, bulb size and shading Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 25 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index EFFECT OF PLANTING DENSITY, DEPTH OF PLANTING AND CHEMICAL FERTILIZATION ON GROWTH AND FLOWERING OF Iris hollandica Abdulrahman A. AlSheikhly Assist. Prof., Horticulture & Landscape Dept., College of Agric., University of Diyala, Iraq E.mail: abdulrahmanraheem@uodiyala.edu.iq ABSTRACT The experiment was conducted at a nursery in the city of Baghdad, during the time 2013/2014 season. The objective of the experiment was to study the effects of four planting density (1, 2, 3 and 4 bulbs pot -1 ), three depth of planting (3, 6, and 9 cm) and two levels of NPK fertilization (0 and 100 mg L-1) on growth and flowering of Iris hollandica cv. Prof. Blaauw. The studied parameters included number of days to flowering, plant height, flower diameter, flowering stem diameter, flowering stem fresh weight, vase life, fresh weight of new bulbs and fresh weight of bulblets. Plant density at (one bulb pot -1 ) produced the highest plant, largest flower, best stem diameter and heaviest fresh weight of flowering stem, while it gave the lowest fresh weight of bulbs and bulblets per pot. Depth of planting had a significant effects in increasing the number of days to flowering and fresh weight of the new bulbs, while it significantly decreased the fresh weight of the flowering stem. Fertilization significantly increased stem diameter, fresh weight of flowering stem and fresh weight of bulblets, while it significantly decreased the number of days to flowering. Interaction between depth of planting and fertilization and between plant density and fertilization had a significant effect on number of days for flowering and fresh weight of flowering stem respectively. Key words: Iris hollandica cv. Prof. Blaauw, planting density, depth of planting, fertilization. INTRODUCTION Iris is a bulbous plant, its name used by Theophrastus which means the Greek goddess of rainbow, an apt name for a genus in which almost the entire color spectrum can be found, it contains more than 300 species all native to the northern hemisphere. Iris belongs to family Iridaceae, many species were found growing in north of Iraq such as I. persica, I. barnumae and I. aucheri (Bryan, 2002). Iris hollandica was developed from crosses between I.xiphium praecox, I.tingitana and I.Iusitanica, the most widely used cultivars are Wedgwood, Ideal, and Prof. Blaauw (Larson, 1992). Iris flower is one of the main exportable flowers and the foreign markets demands flowers with high quality, and must Received: 29/10/2017 Accepted: 1/3/2018 Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 26 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index match the international standers of exportable flowers (Mahgoub et al., 2006). The quantity as well as the quality of flowers depends on several factors like density, depth of planting and chemical fertilization, therefore the present study was undertaken to find out the optimum plant density, proper depth of planting and fertilization. MATERIAL AND METHODS The experiment was conducted at a nursery in the city of Baghdad, through 2013/2014. The study consisted of four planting densities (P) 1, 2, 3 and 4 bulbs pot -1 , and three depths of planting (D) 3, 6 and 9 cm and two levels of NPK fertilization (F) 0 and100 mg L -1 (To prepare 100 liter of 100 mg NPK fertilization solution we have to dissolve 50 gm of NPK (20:20:20) in 100 liter of water). Locally produced bulbs of Iris hollandica cv. Prof. Blaauw were planted on 1 st of November in 15 cm-diameter plastic pots filled with mixture of three parts loamy sand soil and 1 part sphagnum moss peat (Alsheikly, 2010). The analysis of the used medium is presented in Table 1. Max. and Min. air temperature was measured (Table 2). The routine agricultural practices were carried out as recommended for such plantation. Flowering time took place between 11 March and 5 April, the flowers were harvested in full opening stage and leaving 4 leaves on the plants as they were needed for development of the new bulb and bulblets. The following data were recorded: number of days to flowering, plant height (cm), flower diameter (cm), flowering stem diameter (mm), flowering stem fresh weight (g), vase life (day), fresh weight of new bulbs (g pot -1 ) and fresh weight of bulblets (g pot -1 ). The experiment layout was a randomized complete blocks design (RCBD) with three factors (4 planting densities, 3 depths of planting and 2 fertilization levels) with 24 treatments with three replicates every replicate contained 4 pots. All data were subjected to analysis of variance (ANOVA) and the means separated using Least Significant Difference test (LSD) (Gomez and Gomez, 1984). Table 1. Some physical and chemical properties of the used planting medium EC1:1 dS m -1 pH Sand Silt Clay Available N Available P Available K g kg -1 g kg -1 2.3 7.5 812 52 136 42.0 67.9 136.0 * Ministry of Agriculture/Agric. Res. Centre-Soil Res. Dep.-Laboratories. Table 2. The daily means of Maximum & Minimum temperature 2013-2014 season Month Temp. (°C) Oct. Nov. Dec. Jan. Feb. March April May Max. 31.6 23.8 18.8 19.5 20.6 25.1 35.3 39 Min. 18.2 6.1 1.8 2.2 3.4 6.3 17.4 22 Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 27 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index RESULTS AND DISCUSSION Number of days to flowering The means of analyzed data for number of days to flowering indicated that plant density had no significant effect on this character (Table 3) which was contrary to the findings of Mane et al., (2007). Deepest planting 9 cm recorded more numbers of days to flowering 126.9 days compared to the shallow depth of planting 125.25 days (Table 3). These results are in accordance with the findings of Mane et al., (2007) and Hatamzadeh et al., (2012) on tuberose, this might be due to the late emergence of plants. Table 3. Effect of plant density, depth of planting and fertilization on days to flowering of Iris hollandica Plant Density × Depth of Planting Fertilization Depth of Planting Plant Density F1 F0 126.16 126.33 126.00 D1 P1 128.16 126.33 130.00 D2 127.16 124.33 130.00 D3 124.66 123.66 125.66 D1 P2 125.00 124.00 126.00 D2 126.16 125.33 127.00 D3 125.00 127.oo 123.00 D1 P3 124.50 122.66 126.33 D2 128.00 128.00 128.00 D3 125.16 125.00 125.33 D1 P4 125.66 125.00 126.33 D2 126.50 124.33 128.66 D3 NS NS L.S.D. at 0.05 Effect of Plant Density Plant Density × Fertilization 127.16 125.66 128.66 P1 125.27 124.33 126.22 P2 125.83 125.88 125.77 P3 125.77 124.77 126.77 P4 NS NS L.S.D. at 0.05 Effect of Depth of Planting Depth of Planting × Fertilization 125.25 125.50 125.oo D1 125.83 124.50 127.16 D2 126.95 125.50 128.40 D3 1.34 1.9 L.S.D. at 0.05 125.16 126.86 Effect of Fertilization 1.09 L.S.D. at 0.05 Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 28 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index Data presented in Table 3 showed that fertilization led to a significant reduction in number of days to flowering 125.16 days compared to non- fertilized plants 126.86 day, these results are in line with the findings reported by sewedan (2012) on gladiolus. Interaction between depth of planting and fertilization had a significant effect on this character, 3cm depth combined with 100 mg L -1 NPK fertilization gave the minimum days to flowering 124.5 days whereas 9 cm with 0 mg L -1 NPK fertilization gave the maximum 128.41 days (Table 3). Plant height (cm) The mean values regarding plant height revealed that the different plant densities significantly affected the plant height, the maximum 44.44 cm was observed in those planted at 1 bulb pot -1 , while the shortest plants 36.00cm was in those planted at 4 bulbs pot -1 density (Table 4), these results were supported by Ahmed et al., (2010) who found that wider spaces allowed gladiolus cultivars to gain maximum plant height than narrow spaces. Depth of planting had no significant effects on plant height (Table 4). These results are in agreement with the findings of Rao et al., (1991) who reported that depth of planting had no significant effects on the growth and flowering characteristics of tuberose. Data in Table 4 shows no significant response to fertilization, these results are in accordance with the findings of Alsheikly (2013) who reported that fertilization with NPK elements had no significant effects on plant height of Iris hollandica, also supported by the findings of Butt (2005) on gladiolus. No significant effects were found due to interactions between the studied factors (Table 4). Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 29 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index Table 4. Effect of plant density, depth of planting and fertilization on Plant height (cm) of Iris hollandica Interaction between Plant Density and Depth of Planting Fertilization Depth of Planting Plant Density F1 F0 45.83 48.00 43.66 D1 P1 44.00 45.33 42.66 D2 43.50 42.66 44.33 D3 39.83 42.66 37.00 D1 P2 39.33 39.33 39.33 D2 41.16 41.00 41.33 D3 38.16 39.00 37.33 D1 P3 39.66 42.00 37.33 D2 38.66 39.33 38.00 D3 36.00 37.00 35.00 D1 P4 36.50 40.00 33.00 D2 35.50 36.66 34.33 D3 NS NS L.S.D. at 0.05 Effect of Plant Density Plant Density × Fertilization 44.44 45.33 43.55 P1 40.11 41.00 39.22 P2 38.83 40.11 37.55 P3 36.00 37.88 34.11 P4 1.92 NS L.S.D. at 0.05 Effect of Depth of Planting Planting depth × Fertilization 39.95 41.66 38.25 D1 39.87 41.66 38.08 D2 39.70 39.91 39.50 D3 NS NS L.S.D. at 0.05 41.08 38.61 Effect of Fertilization 1.35 L.S.D. at 0.05 Flower diameter (cm) The data presented in Table 5 revealed that decreased plant density led to a significant increase in the flower diameter, the maximum 9.68 cm was obtained at the density of 1 bulb pot -1 while the minimum 8.87cm was observed when planting at the density of 4 bulbs pot -1 . These results are supported by Bhat et al., (2010) who reported that wider spacing significantly increased floret diameter of gladiolus. No significant differences in flower diameter were found due to depth of planting (Table 5), these results are in harmony with those obtained by Rao et al., (1991) on tuberose. Fertilization had no significant effects on this character Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 30 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index (Table 5). These results are supported by the findings of Alsheikly (2013) who found no significant differences in flower diameter due to fertilization of Iris hollandica. No significant effects were found due to interactions between the studied factors (Table 5). Table 5. Effect of plant density, depth of planting and fertilization on flower diameter (cm) of Iris hollandica Plant Density × Depth of planting Fertilization Depth of Planting Plant Density F1 F0 9.68 9.86 9.50 D1 P1 9.71 9.90 9.53 D2 9.65 9.83 9.46 D3 9.25 9.26 9.23 D1 P2 9.50 9.50 9.50 D2 9.38 9.60 9.16 D3 9.06 9.16 8.96 D1 P3 9.20 9.23 9.16 D2 9.16 9.10 9.23 D3 8.76 8.73 8.80 D1 P4 9.06 8.93 9.20 D2 8.80 8.76 8.83 D3 NS NS L.S.D. at 0.05 Effect of Plant Density Plant Density×Fertilization 9.68 9.86 9.50 P1 9.37 9.45 9.30 P2 9.14 9.16 9.12 P3 8.87 8.81 8.94 P4 0.22 NS L.S.D. at 0.05 Effect of Depth of Planting Depth of Planting × Fertilization 9.19 9.25 9.12 D1 9.37 9.39 9.35 D2 9.25 9.32 9.17 D3 NS NS L.S.D. at 0.05 9.32 9.21 Effect of Fertilization NS L.S.D. at 0.05 Flowering stem diameter (cm) Planting density had a significant effect on the flowering stem diameter of Iris hollandica cv. Prof. Blaauw, the maximum flowering stem diameter was observed in those planted at a density of 1 bulb pot -1 6.90 mm, while the minimum was in those planted at density of 4 bulbs pot -1 5.75 mm (Table 6). Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 31 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index These results are in line with the findings of Khalaj and Edrisi (2012) on tuberose and Amjad and Ahmad (2012) on lilium. Depth of planting had no significant effects on flowering stem diameter (Table 6). These results are in harmony with those obtained by Rao et al., (1991) on tuberose. Fertilization with 100 mg L -1 (NPK) gave the maximum flowering stem diameter 6.51mm compared to 5.95mm for those non fertilized (Table 6). These findings are in agreement with those obtained by Alsheikly (2013) on Iris hollandica. No significant effects were found due to interactions between the studied factors (Table 6). Table 6. Effect of plant density, depth of planting and fertilization on flowering stem diameter (mm) of Iris hollandica Plant Density × Depth of Planting Fertilization Depth of Planting Plant Density F1 F0 7.01 7.33 6.70 D1 P1 6.81 7.33 6.30 D2 6.88 7.16 6.60 D3 6.50 6.50 6.50 D1 P2 6.50 6.83 6.16 D2 6.16 6.50 5.83 D3 6.08 6.50 5.66 D1 P3 6.00 6.33 5.66 D2 5.58 5.66 5.50 D3 5.50 6.00 5.00 D1 P4 5.83 6.00 5.66 D2 5.91 6.00 5.83 D3 Ns NS L.S.D. at 0.05 Effect of Plant Density Plant Density × Fertilization 6.90 7.27 6.53 P1 6.38 6.61 6.16 P2 5.88 6.16 5.61 P3 5.75 6.00 5.50 P4 0.347 NS L.S.D. at 0.05 Effect of Depth of Planting Depth of Planting × Fertilization 6.27 6.58 5.96 D1 6.28 6.62 5.95 D2 6.13 6.33 5.94 D3 NS NS L.S.D. at 0.05 6.51 5.95 Effect of Fertilization 0.245 L.S.D. at 0.05 Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 32 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index Fresh weight of flowering stem (gm) Planting density had a significant effect on this character, the maximum fresh weight of flowering stem 14.88 gm was obtained in those planted at a density of 1 bulb pot -1 , while the minimum 9.27 gm observed at 4 bulbs pot -1 (Table 7). This increase in weight was a reflection of increment in length and diameter of the flowering stem that obtained in low planting density, these results are supported by the findings of Amjad and Ahmad (2012) on lilium. Table 7. Effect of plant density, depth of planting and fertilization on fresh weight of the flowering stem (gm) of Iris hollandica Plant Density × Depth of Planting Fertilization Depth of Planting Plant Density F1 F0 15.50 17.00 14.00 D1 P1 15.66 17.33 14.00 D2 13.50 15.66 11.33 D3 12.16 11.66 12.66 D1 P2 11.33 12.33 10.33 D2 10.66 11.66 9.66 D3 10.33 11.66 9.00 D1 P3 10.00 10.33 9.66 D2 9.50 9.33 9.66 D3 9.50 10.33 8.66 D1 P4 9.33 9.00 9.66 D2 9.00 9.00 9.00 D3 NS NS L.S.D. at 0.05 Effect of Plant Density Plant Density×Fertilization 14.88 16.66 13.11 P1 11.38 11.88 10.88 P2 9.94 10.44 9.44 P3 9.27 9.44 9.11 P4 1.11 1.57 L.S.D. at 0.05 Effect of Depth of Planting Depth of Planting × Fertilization 11.87 12.66 11.08 D1 11.58 12.25 10.91 D2 10.66 11.41 9.91 D3 0.96 NS L.S.D. at 0.05 12.11 10.36 Effect of Fertilization 0.78 L.S.D. at 0.05 Fresh weight of flowering stem was influenced significantly by depth of planting, the shallow planting gave the highest fresh weight 11.87 gm compared to 10.66 gm produced by deep planting, these results are in agreement with the Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 33 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index findings of Hatamzadeh et al., (2012) who reported that the fresh weights of tuberose flowering stems were negatively correlated with the plant depth. Fertilization with 100 mg L -1 (NPK) significantly increased the fresh weight of the flowering stem 12.11gm compared to 10.63 gm produced by non-fertilized plants. These results are supported by the findings of Alsheikly (2013) on Iris hollandica. Interaction between planting density and fertilization had a significant effect on this character, 1 bulb pot -1 density combined with 100 mg L -1 NPK fertilization gave the maximum fresh weight of the flowering stem 16.66 gm while the minimum obtained by using 4 bulbs pot -1 density with 100 mg L -1 NPK fertilization 9.11 gm (Table 7). Vase life (day) Data presented in Table 8 shows no significant effects due to different planting densities. These results are in agreement with the findings of Khalaj and Edrisi (2012) who found that planting tuberose at a density of (10×10, 15×15, 20×20) cm had no significant effects on the flowers vase life. Different levels of planting depth had no significant differences on this character. These results were in line with the findings of Mane et al., (2007) on tuberose. Fertilization levels did not affect Iris vase life. Similar findings to these results have been reported by Alsheikly (2013). No significant differences were found due to interactions between the studied factors (Table 8). Fresh weight of new bulbs (gm) Planting density significantly increased the fresh weight of the new bulbs, the maximum 29.77 gm was obtained by a density of 4 bulbs pot -1 while the minimum 12.77 gm was obtained when planted at 1 bulb pot -1 density (Table 9). These results were in the same line with Bhat et al., (2010) who reported that high plant density produced the maximum yield of gladiolus corms per m 2 . Deep planting produced the maximum fresh weights of bulbs pot -1 23.75 gm compared to 19.45 gm produced by shallow planting (Table 9). These results are confirmed by the findings of Barbara et al., (2013) who reported a significant increase in bulbs fresh weights of tulip due to deeper planting, this could be refer to the fact that, the increasing of depth lead to the decrease in temperature which reduces the respiration rate which mean provision of stored food consequently high corms fresh weights produced. N P K Fertilization had no significant effects on this character (Table 9). Similar results were obtained by Alsheikly (2013) on Iris hollandica cv. Prof. Blaauw. No significant differences were found due to interactions between the studied factors (Table 9). Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 34 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index Table 8. Effect of plant density, depth of planting and fertilization on the vase life (day) of Iris hollandica plants Plant Density × Depth of Planting Fertilization Depth of Planting Plant Density F1 F0 5.50 5.66 5.33 D1 P1 5.66 6.00 5.33 D2 5.50 5.33 5.66 D3 5.33 5.33 5.33 D1 P2 5.33 5.33 5.33 D2 5.00 5.00 5.00 D3 5.33 5.33 5.33 D1 P3 5.50 5.33 5.66 D2 5.16 5.00 5.33 D3 5.00 5.00 5.00 D1 P4 5.00 5.00 5.00 D2 5.16 5.00 5.66 D3 NS NS L.S.D. at 0.05 Effect of Plant Density Plant Density × Fertilization 5.55 5.66 5.44 P1 5.22 5.22 5.22 P2 5.33 5.22 5.44 P3 5.05 5.00 5.11 P4 NS NS L.S.D. at 0.05 Effect of Depth of Planting Depth of Planting × Fertilization 5.29 5.33 5.25 D1 5.37 5.41 5.33 D2 5.20 5.08 5.33 D3 NS NS L.S.D. at 0.05 5.27 5.30 Effect of Fertilization NS L.S.D. at 0.05 Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 35 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index Table 9. Effect of plant density, depth of planting and fertilization on fresh weight of new bulbs (gm) of Iris hollandica plants Plant Density × Depth of Planting Fertilization Depth of Planting Plant Density F1 F0 11.50 12.00 11.00 D1 P1 13.16 13.66 12.66 D2 13.66 17.00 10.33 D3 17.33 16.66 18.00 D1 P2 20.33 21.33 19.33 D2 22.66 24.00 21.33 D3 23.00 24.00 22.00 D1 P3 27.00 27.00 27.00 D2 25.16 25.33 25.00 D3 26.00 24.00 28.00 D1 P4 31.33 30.66 32.00 D2 32.00 32.00 32.00 D3 NS NS L.S.D. at 0.05 Effect of Plant Density Plant Density × Fertilization 12.77 14.22 11.33 P1 20.11 20.66 19.55 P2 25.05 25.44 24.66 P3 29.77 28.88 30.66 P4 2.15 NS L.S.D. at 0.05 Effect of Depth of Planting Depth of Planting × Fertilization 19.45 19.16 19.75 D1 22.95 23.16 22.75 D2 23.37 24.58 22.16 D3 1.86 NS L.S.D. at 0.05 22.30 21.55 Effect of Fertilization NS L.S.D. at 0.05 Fresh weight of bulblets (gm) Data in Table 10 show that high plant density produced the maximum fresh weights of bulblets 11.61 gm compared to 7.27 gm produced by low plant density of 1 bulb pot -1 . Depth of planting had no significant effects on this character, while fertilization significantly affected the fresh weights of bulblets, no significant differences were found due to interactions between the studied factors (Table 10). Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 36 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index Table 10. Effect of plant density, depth of planting and fertilization on fresh weight of bulblets (gm) of Iris hollandica In general, flower quality improved when planting density decreased, this may probably be due to less competition between plants for water, nutrients, light, and more area for better root growth. Depth of planting show limited effects on the studied characters. These results confirmed by Rao et al., (1991) who reported that depth of plating have no significant differences on characteristics of growth and flowering. Some of the studied characters didn’t response significantly to fertilization, this may be explain that iris is a bulbous plant and has enough food materials to supply the growing plant with nutrients. Plant Density × Depth of Planting Fertilization Depth of Planting Plant Density F1 F0 7.66 8.66 6.66 D1 P1 7.33 8.33 6.33 D2 6.83 8.66 5.00 D3 9.00 10.66 7.33 D1 P2 9.16 9.00 9.33 D2 8.50 10.33 6.66 D3 10.33 12.33 8.33 D1 P3 9.33 10.33 8.33 D2 9.16 11.00 7.33 D3 12.33 12.66 12.00 D1 P4 10.66 11.66 9.66 D2 11.83 12.33 11.33 D3 NS NS L.S.D. at 0.05 Effect of Plant Density Plant Density × Fertilization 7.27 8.55 6.00 P1 8.88 10.00 7.70 P2 9.61 11.22 8.00 P3 11.61 12.22 11.00 P4 1.07 NS L.S.D. at 0.05 Effect of Depth of Planting Depth of Planting × Fertilization 9.83 11.08 8.58 D1 9.12 9.83 8.41 D2 9.08 10.58 7.58 D3 NS NS L.S.D. at 0.05 10.50 8.19 Effect of Fertilization 0.76 L.S.D. at 0.05 Diyala Agricultural Sciences Journal (DASJ), 11(2): 25-38, 2019 AlSheikly 37 https://journal.djas.uodiyala.edu.iq/index.php/dasj/index CONCLUSION 1- Reducing planting density improves flowers quality of Iris hollandica cv. 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Iris hollandica تأثير كثافة السراعة واعماقها والتسميذ الكيميائي في نمى االيرش الهىلنذي وإزهاره عبذالرحمن عبذالقادر الشيخلي ، انعساقجايعت دٌانى – كهٍت انصزاعت -لسى انبسخُت وهُدست انحدائكاسخاذ يساعد، صلخستمال ، انهدف يٍ انخجسبت هى 3102-3102ل انًىسى خال يشخم نهصهىز فً يدٌُت بغدادانخجسبت فً َُفرث أصٍص ( بصهت2، 2، 3، 0كثافاث شزاعت )دزاست حأثٍس ازبع -0 ( سى 9، 6، 2نهصزاعت ) أعًاقثالثت و ، ( يهغى نخس1 ،011)NPK انًسكب ويسخىٌٍٍ يٍ انخسًٍد انكًٍٍائً -0 فً صفاث انًُى واإلشهاز نُباحاث هاز، ازحفاع نغاٌت اإلش األٌاو، ولد اشخًهج انمٍاساث عهى: عدد Prof. Blaauwاالٌسض انهىنُدي صُف ، انىشٌ ، انعًس انًصهسينهساق انصهسي لطس انساق انصهسي، انىشٌ انطسي ،انُباث، لطس انصهسة أصٍص بصهت 0عت )كاٌ نكثافت انصزا نهبصٍالث. انطسي نهبصهت انجدٌدة وانىشٌ انطسي -0 حأثٌٍس يعُىيٌ ( ق نهسا وانىشٌ انطسي ،لطس انساقو ،انصهسةلطس وخائج نصفاث ازحفاع انُباث، فضم انُأعطاء إفً كاٌ نهبصٍالث. نصفخً انىشٌ انطسي نهبصهت انجدٌدة وانىشٌ انطسي بًٍُا اعطج الم انمٍى ،انصهسي انىشٌ ولهم يعُىٌا نألبصال انجدٌدة انىشٌ انطسي شٌادةو عت حأثٍسا يعُىٌا فً حأخٍس اإلشهازنعًك انصزا ،انىشٌ انطسي نهساق انصهسيولطس انساق، يعُىٌا يٍ انخسًٍد انكًٍٍائً شاد ،نهساق انصهسي انطسي وخفض يعُىٌا يٍ عدد األٌاو نغاٌت اإلشهاز. انخداخم بٍٍ عًك انصزاعت ،نهبصٍالث وانىشٌ انطسي حأثٍسا يعُىٌا فً عدد االٌاو وانخسًٍد انكًٍٍائً وكرنك بٍٍ كثافت انصزاعت وانخسًٍد انكًٍٍائً كاٌ نهًا .وانىشٌ انطسي نهساق انصهسي عهى انخىانً نغاٌت اإلشهاز ، كثافت انصزاعت، عًك انصزاعت، حسًٍد.شهسة انسىسٍ الكلمات المفتاحية: