EFFECTS OF FERTILIZER AND PLANT DENSITY ON YIELD AND QUALITY OF ANISE ( PIMPINELLA ANISUM L . )

Abstract: In order to understand the effect of organic fertilizer on yield of anise, an experiment was conducted in the form of split-plot in randomized complete block design with three replications in Mashhad, Khorasan Agriculture and Natural Resource Research Center. Four treatments of fertilization: the control, vermicompost – 5 t/ha, cow manure – 25 t/ha, and mineral fertilizer (NPK) – 60 kg/ha (the same rate of each nutrient) were applied as the main factor. The second factor was plant density, applied at three levels: 17, 25, and 50 plants/m. The results showed a significant effect of fertilizer on the number of umbels per plant, number of umbellets per umbel and canopy cover. Plant density had a significant effect on grain yield, biological yield, the number of lateral branches, essential oil percentage and yield of essential oil. Seed and essential oil yield were the highest in the case of the application of vermicompost and plant densities of 50 and 25 plants/m respectively.


Introduction
Anise (Pimpinella anisum L.) is one of the most important annual medicinal plants from Apiaceae family in the world.It is a dainty, white-flowered plant, about 44 cm high, native of Iran, Turkey, Egypt, Greece, Crete and Asia Minor.Its active substances are used in various pharmaceutical and food industries (Nabizadeh et al., 2012).It is widely distributed and mainly cultivated for the seeds.The seeds of anise contain an essential oil (1 to 4%) and active substances like anethole used in various pharmaceutical and food industries (Klaus et al., 2009).It is a folkloric remedy for seizures in traditional medicine (Pourgholami et al., 1999;Staub, 2008;Özel, 2009;Aćimović, 2013).
Fertilizers have played an effective role in increasing crop yield, and the indiscriminate use of chemical fertilizers can cause environmental and human Mahdi Faravani et al. 210 health problems, depletion of non-renewable resources, and make plants less resistant to pests and diseases (Jevdjović and Maletić, 2006;Mal et al., 2013).Environmental problems related to the use of synthetic fertilizers and to organic waste management have led to an increased interest in the use of organic materials as an alternative source of nutrients for crops, but this is also associated with N 2 O emissions (Aguilera et al., 2013).
The vermicompost is the product of composting using various worms, usually red wigglers, white worms, and other earthworms to create a heterogeneous mixture of decomposing vegetable or food waste, bedding materials, and vermicast.The vermicompost is a management practice that may contribute to sustainable agroecosystems by making them less dependent on inorganic fertilizers (Amossé et al., 2013).
The results from a study on anise (Pimpinella anisum L.) in Turkey showed that plant height, number of branches per plant, number of umbellets per plant, number of seeds per umbellet, seed yield and thousand seed weight were affected positively by organic fertilizer and organic-inorganic fertilizer combination application (Doğramaci and Arabaci, 2010).Nabizadeh et al. (2012) reported that the highest seed yield and the highest oil content were achieved (1,286 and 179 kg/ha) by fertilizer treatment using biological Nitroxin (3 l/ha) and chemical nitrogen (60 ha/kg) with the density of 25 plants/m 2 respectively.
Plant spacing is an important factor in determining the microenvironment in the anise field and can lead to a higher yield in the crop by favorably affecting the absorption of nutrients and exposure of the plant to the light.The current study was carried out to determine the effects of different plant densities and type of fertilizers on the yield of seed and its main components -the weight of 1000 seeds, the number of umbels per plant, the number of umbellets per umbel, the number of seeds per umbellet and yield of essential oil.

Material and Methods
This study was conducted at Khorasan Agriculture and Natural Resources Center with geographic coordinates of latitudes 36°13' N and longitudes 59°25' E at an average altitude of 985 m above sea level in 2011-2012.According to De Martonne climate classification, the areas of this province are located in arid or semi-arid climate.While, according to Emberger climate classification, most of areas of this province are located in cold-dry climate.In order to determine the physical and chemical properties of soil, soil sampling was done before planting.The results of soil analysis showed that the electrical conductivity of the saturation extract was 1.62 dS m -1 and pH value was 8. Seed planting was done in 36 plots with dimensions 3 m × 2 m with row spacing of 50 cm and seed planting depth of 3 cm on 21 April 2012.
The experiment was conducted by using the split-plot design which involved two experimental factors.The main factor was fertilization, applied in four treatments: control, vermicompost -5 t/ha, cow manure -25 t/ha, and full chemical fertilizer (NPK) -60 kg/ha (with the same rate of each nutrient).The second factor was plant density, applied at three levels: 17, 25, and 50 plants/m 2 .Levels of fertilizers and plant densities with the whole plots were arranged in a randomized complete block design.The vermicompost used in this study was produced by the activity of Eisenia foetida worm on manure.Irrigation was performed weekly.Thinning and weed control were done at growth stages of 4-6 leaves in order to get the desirable plant density and the best use of space and nutrient requirements.
Plants were harvested when leaf color changed to yellow.Different plant morphological characters as the number of umbels per plant, number of umbellets per umbel, plant height, internode distance, the number of lateral branches, grain number, grain weight and yield components were measured from five randomly selected plants.A ruler was applied to measure the length and the width of the canopy.Canopy area (S) was calculated by using the following formula: S = 3.14 × (x + y)/2, where: x is length of canopy, and y is canopy width.
The seed essential oil was measured by Clevenger hydro-distillation method.Calculations and statistical analysis were done by using SAS statistical software.Duncan's multiple range tests were used for means comparisons.

Results and Discussion
An analysis of variance showed that the anise plant height was not affected by applied treatments (p<0.05) but plant height was significantly (p<0.05)changed by the interaction between plant density and fertilizer (Table 1).The maximum plant height (42.83 cm) was observed in combination of 50 plants per square meter and application of vermicompost (Table 2).The maximum cover (1,442 cm 2 ) was obtained when using vermicompost (p<0.05) but it was not affected by plant density.Lateral branches were significantly (p<0.05)affected by plant density; as plant density increased, plants lateral branches decreased.The maximum number of branches was observed in plant density of 25 plants/m 2 .
Thousand kernel weight was not affected significantly (p<0.05) by applied treatments.However, the highest thousand kernel weight with 3.5 g was observed in plant density of 25 plants/m 2 .Number of umbels per plant and number of umbellets per umbel were affected (p<0.05) by fertilizers, but the effect of plant density and its interaction with fertilizer were not significant (p<0.05).The maximum number of umbels per plant -30.56 and 31.56 were found in the application of vermicompost and cow manure, respectively.No significant difference (p<0.05) was observed among the applications of the treatments, but their interaction was significant (p<0.01).The maximum number of seeds (8.66 seeds per umbellet) was obtained in application of cow manure and using plant density of 50 plants/m 2 .Both seed yield and biological yield were affected by plant density (p<0.05) and no difference was observed in the fertilizer consumption.When a density of 50 plants per square meter was used, the highest seed yield (552.26 kg/ha) and biological yield (876.67 kg/ha) were obtained in the field.The lowest yield was observed at plant density of 17 plants/m 2 (Table 2).
Results indicated significant differences (p<0.05) for harvest index in different levels of fertilizers without any differences in the level of plant density.The fertilizer caused a greater decrease in harvest index (HI) through an increased biological yield or vegetative growth than seed yield.The highest harvest index (23%) was observed in the control treatment.
The integrated use of plant density and fertilizer (cow manure) increased the percentage of essential oil to 6.18% in 25 plants per square meter and the essential oil yield to 20.19 kg/ha in 25 plants per square meter (Table 2).The application of organic fertilizer did not indicate any significant effect on the essential oil, but its interaction with plant density showed a significant (p<0.01)difference.Choosing an optimum plant density and fertilizer may improve soil physical and chemical properties, nutrient availability that might increase the quality of yield.It was also observed that at the same oil yield level of essential oil of Artemisia annua, increased 1.5, 2 and 2.5 fold when the plant densities increased about 2, 4, and 8 fold (Ram et al., 1997).Khorshidi (2009) in his research on Foeniculum vulgare Mill.var.'Soroksary' reported that the highest essential oil percentage (3.53%)was obtained when applying the lowest densities of planting.The highest percentage of anethole (83.07%), estragol (3.47%), fenchone (8.04%), p-cymene (4.45%), α-terpinene (0.54%), sabinene (0.51%), and α-pinene (0.48%) were obtained with the space between plants of 25, 10, 20, 20, 15, 20, and 25 cm, respectively.The yield and essential oil of aniseed are affected by the genotype, the ecological conditions and especially by agricultural practices, such as the sowing date, fertilizer and water application, and plant density (Nabizadeh et al., 2012).

Conclusion
The highest yields of seeds and essential oil of anise were obtained from the application of vermicompost and optimum plant density of 25 and 50 plants per square meter.Seedlings grown at the highest planting density (50 plants/m 2 ) and treated with vermicompost (5 t/ha) had better development than all groups without vermicompost, even at the lowest density.The application of organic fertilizers has great potential to accelerate growth development and increase germination, growth, flowering and fruit production when applying an optimum plant density.

Table 1 .
Mean squares from analysis of variance for morphological characters of anise at different plant densities and fertilizer treatments.

Table 2 .
Multiple comparisons of measured characters of anise at different plant densities and fertilizer treatments.the same letter are not significantly different at p<0.05 according to Duncan's multiple range test.