2007 vol. 66, 69-77 DOI: 10.2478/v10032-007-0009-5 ______

REACTION OF LEAF ( GRAVEOLENS L. VAR. SECALINUM) TO PLANTING DENSITY AND IRRIGATION

Ewa ROŻEK Agricultural University Department of Vegetable Crops and Medicinal St. Leszczyńskiego 58, 20-515 Lublin, Poland

Summary In experiments conducted in the years 2004-2005, effect of seedlings planting density and irrigation on yield of 2 cultivars of (Afina, Safir) was evaluated. Transplants were planted on 15 May 2004 and 12 May 2005 with spacing 25 x 20 cm and 15 x 20 cm. Harvest of celery leaves was carried out in three turns: on 15 July, 14-15 September and 27-28 October. It was shown that higher planting density significantly increases yield of leaves. Irrigation increased leaf yield, on average, by 55.9%. Depending on cultivar and planting density, leaf yield of non-irrigated plants was 5.29-6.34 kg.m-2, while for irrigated plants it ranged from 7.70 to 11.97 kg.m-2. key words: leaf celery, Apium graveolens L. var. secalinum, irrigation, spacing, yield

INTRODUCTION

Leaf celery is one of less popular vegetable plants. Its usable parts are dark-green, glossy leaves on long, thin leaf petioles, which may be eaten fresh or processed, mainly frozen or dried. Seasoning and flavor qualities of this vegetable depends on essential oils comprising mostly α and β-pinene, myrcene, limonene, humulene i apiol (Saleh et al. 1985). Gajc-Wolska et al. (2006) list leaf celery among vegetables with valuable antioxidative properties, reducing a risk for many civilization diseases. All currently cultivated botanical varieties of celery, due to shallow root system, are plants with high water requirements, and irrigation during periods of water deficit may significantly increase yield of these vegetables (Knaflewski 1982, Evers et al. 1997, Kaniszewski et al. 1999, Rumasz et al. 1999, Elkner & Kaniszewski 2001, Breschini & Hartz 2002, Pascale et al. 2003). Kaniszewski (2005) recommends starting celery irrigation at soil water potential of -30 – -40 kPa. Research of Feller et al. (2001) proved that leaf celery has very shallow root system and irrigation during drought periods strongly increases leaf yield.

Corresponding author: e-mail: [email protected] © Copyright by RIVC 70 VEGETABLE CROPS RESEARCH BULLETIN 66 ______

Leaf celery may be direct sown or grown by transplants. Direct sowing is cheaper but less reliable, just like for other vegetables, which seeds germinate slowly and are sensitive to soil crust (Rożek 2006). In contrast, cultivation of leaf celery from transplants is expensive because plants are planted at quite high density. Literature data does not specify optimal density for leaf celery production from transplants. It is why the aim of the study was evaluation of effect of different planting density and irrigation for yield and biometric char- acteristics of plants of 2 cultivars of leaf celery.

MATERIAL AND METHODS

The experiments were conducted in the years 2004-2005 at Felin Experi- mental Farm of Agricultural University in Lublin. The experiment was set in three-factor, randomized blocks design with 4 replicates. Factor I was plant cultivar (Afina, Safir), factor II – plant spacing (25x20 cm or 15x20 cm), factor III – irrigation of plants. Celery seeds were sown in mid-March. Transplants were produced in multipots with cell volume 54 cm3. Pre-planting fertilization -1 -1 -1 was 120 kg N ha , 100 kg P2O5 ha and 150 kg K2O ha . The transplants were planted into field on 15 May 2004 and 12 May 2005. The area of plots for har- vest was 4 m2. In each year harvests were carried out 3 times (15 July, 14-15 September and 27-28 October), cutting off leaves 2-3 cm above soil level. Har- vest of leaves of irrigated and non-irrigated plants was conducted at the same time. Directly before harvest, height of plants on a plot was measured and after harvest number of leaves per plant was counted for 10 plants from each repli- cate. After each harvest fertilization with 40 kg N per ha was applied. Plants were irrigated with drip lines. In 2004 year plants were irrigated 9 times, while in 2005 12 times. Irrigation was started at soil water potential –40 kPa. One-time water dose supplied to plants equaled 15-20 mm of rainfall at the beginning of plants growth (May - July) and 25 mm of rainfall later on. The obtained results were analyzed statistically with analysis of variance for k-fold classification. Statistical conclusions were drawn basing on multiple confidence intervals of T-Tukey at significance level P=0.05.

RESULTS AND DISCUSSION

Average multi-year sum of rainfall from May to October at Felin Experi- mental Farm is 359.7 mm. In 2004, during corresponding period a sum of rain- fall was 259.3 mm, being by 100.4 mm lower than multi-year average. In 2005 amount of rainfall was 39.4 mm higher than multi-year average, but in both years of experiments rainfall distribution over time was very uneven. In 2004, the strongest deficit of rain occurred in the first decade of June, second decade of August as well as September and October, when rainfalls reached only, re- spectively, 27.6% and 47.2% of multi-year average for these months. In 2005 significant rainfall deficit was noted in third decade of May, second and third decades of June, first decade of July and from second decade of August to the end of plants vegetation. Heavy rainfalls, much higher than multi-year sum of E. ROŻEK – REACTION OF LEAF CELERY ... 71 ______rainfall for the month, occurred in third decade of July (87.4 mm) and first dec- ade of August (103.9 mm). Such distribution of rainfall had substantial effect on yield of leaves of non-irrigated plants during consecutive harvests of leaf celery. First harvest of leaves was conducted on 15 of July. Non-irrigated plants of tested cultivars of leaf celery produced at this time 65.5 to 85.3 leaves per plant and reached mean height of 21.0 to 25.0 cm (Table 1 & 2).

Table 1. Effect of transplants planting density on mean height of non-irrigated plants for two cultivars of leaf celery (cm)

Planting Harvest Cultivar density Year (cm) IIIIII 2004 35.1 37.5 14.3 25x20 2005 14.8 37.8 13.8 Mean 25.0 b 37.8 a 13.8 c Afina 2004 27.3 31.3 13.7 15x20 2005 15.8 38.0 14.5 Mean 21.6 b 34.7 a 14.1 c 2004 34.1 37.5 14.6 25x20 2005 15.0 38.5 15.8 Mean 24.6 b 38.0 a 15.2 c Safir 2004 28.1 35.8 16.5 15x20 2005 14.3 37.0 14.8 Mean 21.2 b 36.4 a 15.7 c Note: Means with the same letter do not differ significantly at P=0.05

Table 2. Effect of planting density on mean number of leaves of non-irrigated plants for two cultivars of leaf celery

Planting Harvest Cultivar density Year (cm) IIIIII 2004 100.2 103.4 61.2 25x20 2005 70.3 92.3 63.5 Mean 85.3 b 97.9 a 62.4 c Afina 2004 83.0 107.8 51.3 15x20 2005 48.0 72.3 47.5 Mean 65.5 c 90.1 ab 48.9 d 2004 91.3 105.2 67.8 25x20 2005 77.5 100.5 62.0 Mean 84.4 b 102.9 a 64.9 c Safir 2004 85.5 97.1 56.1 15x20 2005 48.0 72.3 47.5 Mean 66.8 c 84.7 b 51.8 d Note: see Table 1 72 VEGETABLE CROPS RESEARCH BULLETIN 66 ______

On average, for both years of experiments, yield of non-irrigated plants at the first harvest was, depending on cultivar, from 1.47 kg.m-2 to 2.19 kg.m-2 (Table 3). Much higher yield of leaves, ranging from 3.07 to 4.13 kg.m-2, was obtained during second harvest carried out on 14-15 September. Non-irrigated plants reached by then mean height of 34.7-37.8 cm and developed 84.7-102.9 leaves. In third harvest (27-28 October) only small yield of leaves was collected (0.75-1.07 kg.m-2). Average plant height was 13.8-15.7 cm and leaf number 48.9-62.4.

Table 3. Effect of planting density on yield of leaves of non-irrigated plants for two cultivars of leaf celery (kg.m-2)

Planting Harvest Cultivar density Year Total yield (cm) IIIII 2004 1.95 2.57 0.88 5.39 25x20 2005 0.98 3.57 0.62 5.19 Mean 1.47 3.07 0.75 5.29 a Afina 2004 2.48 2.97 0.83 6.28 15x20 2005 1.32 4.11 0.96 6.39 Mean 1.9 3.54 0.86 6.13 b 2004 1.95 3.35 0.90 6.14 25x20 2005 1.30 4.13 0.68 6.11 Mean 1.63 3.74 0.79 6.12 ab Safir 2004 2.48 4.79 1.16 8.43 15x20 2005 1.89 3.47 0.98 6.31 Mean 2.19 4.13 1.07 7.36 c Note: see Table 1

Mean yield of irrigated plants for both experimental years, depending on cultivar and plant spacing was from 2.95 kg.m-2 to 4.69 kg.m-2 during first har- vest, 4.19-6.49 kg.m-2 during second one, and 0.57-0.90 kg.m-2 in the last har- vest (Table 6). Irrigated plants, during first harvest were, on average, 39.0-40.8 cm high and had from 82 to 101.8 leaves, while during second harvest their height was 41.8-47.2 cm and leaves number was 104.8 to 135, and during third harvest plant height and leaves number were, respectively, from 14.5 to 15.9 cm and 54.6 to 62.4 (Table 4 & 5). E. ROŻEK – REACTION OF LEAF CELERY ... 73 ______

Table 4. Effect of transplants planting density on mean height of irrigated plants for two cultivars of leaf celery (cm)

Planting Harvest Cultivar density Year (cm) IIIIII 2004 43.0 43.1 13.5 25x20 2005 36.5 41.8 15.5 Mean 39.8 b 41.8 b 15.5 c Afina 2004 43.6 48.9 14.0 15x20 2005 36.5 42.3 15.0 Mean 40.1 b 45.6 a 14.5 c 2004 42.0 48.9 15.5 25x20 2005 36.0 42.5 15.3 Mean 39.0 b 45.7 a 15.4 c Safir 2004 46.1 52.0 15.4 15x20 2005 35.5 42.3 16.3 Mean 40.8 b 47.2 a 15.9 c Note: see Table 1

Table 5. Effect of planting density on mean number of leaves of irrigated plants for two cultivars of leaf celery

Planting Harvest Cultivar density Year (cm) IIIIII 2004 113.5 102.1 64.7 25x20 2005 80.8 107.5 60.0 Mean 97.2 c 104.8 bc 62.4 e Afina 2004 89.5 112.4 59.2 15x20 2005 74.5 114.5 57.0 Mean 82.0 d 113.5 b 58.1 e 2004 110.0 107.1 63.9 25x20 2005 93.5 162.8 57.3 Mean 101.8 c 135.0 a 60.6 e Safir 2004 119.0 114.3 56.4 15x20 2005 57.3 109.3 52.8 Mean 88.2 d 111.8 b 54.6 e Note: see Table 1 74 VEGETABLE CROPS RESEARCH BULLETIN 66 ______

Table 6. Effect of planting density on yield of leaves of irrigated plants for two cultivars of leaf celery (kg.m-2)

Planting Harvest Cultivar density Year Total yield (cm) IIIIII 2004 3.18 2.55 0.55 6.28 25x20 2005 2.71 5.82 0.58 9.11 Mean 2.95 4.19 0.57 7.70 a Afina 2004 4.62 3.80 0.66 9.12 15x20 2005 3.44 7.11 0.93 11.48 Mean 4.03 5.46 0.71 10.30 c 2004 3.54 3.59 0.82 7.83 25x20 2005 3.50 6.37 0.72 10.49 Mean 3.52 4.98 0.77 9.16 b Safir 2004 5.45 6.27 0.83 12.55 15x20 2005 3.92 6.71 0.96 11.97 Mean 4.69 6.49 0.90 11.97 d Note: see Table 1

On average, across other experimental factors, yield of irrigated plants was 9.76 kg.m-2 (Fig. 1) and it was by 55.9% higher than in non-irrigated plants (6.28 kg.m-2).

-2 kg ⋅m 12 11.13a

10 9.79A 8.43b 8 6.75c 6 6.28B 5.70d 4

2

0 25x20cm 15x20cm mean

non-irrigated plants irrigated plants

Fig. 1. Effect of transplants planting density and irrigation (average for cultivars and experimental years) on total yield of leaves of leaf celery E. ROŻEK – REACTION OF LEAF CELERY ... 75 ______

Higher planting density of leaf celery transplants significantly increased yield of leaves of both cultivars (Table 3). For cultivar Afina, yield increased from 5.29 kg.m-2 to 6.34 kg.m-2 and for cv. Safir from 6.17 kg.m-2 to 7.22 kg.m-2. Similar reaction was observed for irrigated plants, but the yield obtained was much higher (Table 6). Total yield of leaf celery obtained in the experiment was close to the yield of celery presented in the papers of Kossowski et al. (1981 a,b), Dyduch et al. (1997), Michalik (2003) and Michalik & Szwejkowska (2005). According to Kaniszewski (2005), depending on rainfall deficit, irrigation may even double yield of some vegetable species. Author’s own experiments, conducted in the years 2001-2002 (Rożek 2005 b) and 2004-2005 (Rożek 2006) prove that irrigation significantly increases yield of leaf celery and much bigger difference in yield was observed between irrigated and non-irrigated plants for celery produced by direct sowing to the field. In previous experiment (Rożek 2005 b), average yield of non-irrigated plants, produced from transplants, was 6.8 kg.m-2 while for irrigated ones it was 8.13 kg.m-2. Yield of directly sown plants was 2.0 kg.m-2 and 10.2 kg.m-2, respectively (Rożek 2006). In currently presented research, irrigation increased yield of celery leaves by 55.9%, which was more that in previous experiments from the years 2001-2002 (Rożek 2005 b). Previous studies on optimal plant density and its influence on biometric parameters of leaf celery plants showed that increased planting density signifi- cantly reduces weight of a plant and number of harvested leaves per plant (Rożek 2005 a). Similar reaction in cultivation of celery was found by Michalik 2003 and Michalik & Szwejkowska 2005. Planting of leaf celery with spacing 40x30 and 40x20 cm (Rożek 2005 a) significantly affected yield per plant but differences in a yield per area were insignificant. In current experiment, in- creasing planting density from 25x20 to 15x20 cm resulted in significantly higher yield of both tested cultivars.

CONCLUSIONS

1. Irrigation of plants increased yield of leaves by 55.9%, on average. Plants irrigated were higher and produced more leaves per plant. 2. Increasing planting density of leaf celery transplants from 25x20 cm to 15x20 cm resulted in significant rise in yield of leaves from area unit and decrease in number of leaves per plant. 3. The highest yield of leaves was obtained during second harvest.

REFERENCES

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REAKCJA SELERA LISTKOWEGO APIUM GRAVEOLENS L. VAR. SECALINUM NA ZAGĘSZCZENIE I NAWADNIANIE

Streszczenie W latach 2004-2005 oceniono wpływ rozstawy sadzenia rozsady i nawadniania na plonowanie 2 odmian selera listkowego (Afina, Safir). Rozsadę posadzono 15 maja w 2004 roku i 12 maja w 2005 roku, w rozstawie 25x20 cm i 15x20 cm. Zbiór liści selera przeprowadzono trzykrotnie: 15 lipca, 14-15 września i 27-28 października. Wykazano, że zwiększenie gęstości sadzenia rozsady istotnie zwiększyło plon liści. Nawadnianie zwiększyło plon liści średnio o 55,9%. Zależnie od odmiany i rozstawy sadzenia rozsa- dy plon liści roślin nienawadnianych wynosił 5,29-6,34 kg . m-2, a nawadnianych 7,70- 11,97 kg . m-2.