Fertilization and Colors of Plastic Mulch Affect Biomass and Essential Oil of Sweet-Scented Geranium

Hindawi Publishing Corporation e Scientific World Journal Volume 2014, Article ID 828259, 7 pages http://dx.doi.org/10.1155/2014/828259 Research Article Fertilization and Colors of Plastic Mulch Affect Biomass and Essential Oil of Sweet-Scented Geranium Anderson de Carvalho Silva,1 Arie Fitzgerald Blank,1 Wallace Melo dos Santos,1 Paloma Santana Prata,2 Péricles Barreto Alves,2 and Maria de Fátima Arrigoni-Blank1 1 Department of Agronomic Engineering, Federal University of Sergipe, Avenida Marechal Rondon s/n, 49100-000 Sao Cristovao, SE, Brazil 2 Department of Chemistry, Federal University of Sergipe, Avenida Marechal Rondon s/n, 49100-000 Sao Cristovao, SE, Brazil Correspondence should be addressed to Maria de Fátima Arrigoni-Blank; Received 4 December 2013; Accepted 3 February 2014; Published 16 March 2014 Academic Editors: P. B. Andrade and R. M. Mian Copyright © 2014 Anderson de Carvalho Silva et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Sweet-scented geranium (Pelargonium graveolens L’Hér), a plant belonging to the Geraniaceae family, has medicinal and aromatic properties and is widely used in the cosmetic, soap, perfume, aromatherapy, and food industries. The aim of this study was to evaluate the influence of fertilization and the use of different colors of plastic mulch on sweet-scented geranium biomass and essential oil. Three colors of plastic mulch (black, white, and silver-colored) and a control without plastic mulch were assessed along with three fertilizers (20,000 L⋅ha−1 of cattle manure; 1,000 kg⋅ha−1 of NPK 3-12-6; and 20,000 L⋅ha−1 of cattle manure + 1,000 kg⋅ha−1 of NPK 3-12-6 fertilizer) and a control without fertilizer. The absence of a soil cover negatively influenced the agronomical variables, while coverage with plastic mulch was associated with increased biomass. The use of fertilizer had no effect on the evaluated agronomic variables. When cattle manure and NPK 3-12-6 were used together, combined with white or black plastic mulch, the highest yields of essential oil were obtained. For the silver-colored plastic mulch, higher amounts of essential oil (6,9-guaiadien) were obtained with mineral fertilizer. 1. Introduction The Pelargonium (Geraniaceae) genus contains around 280 herbaceous, shrub, and subshrub species, including annuals and perennials that typically originated from southern Africa [1]. Pelargonium graveolens L’Hér is one of the most important species in this genus and is an aromatic shrub species that can reach up to 1.3 m in height. This geranium is native to Cape Province, South Africa, and is grown in many regions worldwide, including the Reunion Islands, Algeria, southern France, Spain, Morocco, Madagascar, Congo, and Russia, for the production of its essential oil [2–6]. The geranium essential oil is an important material for the cosmetic, soap, perfume, aromatherapy, and food industries [2, 7–10]. It is also used in popular medicines against dysentery, diarrhea, colds, and lung infections [3, 11]. The production of essential oils in plants may be altered by environmental or ontogenic factors, such as the physicalchemical characteristics of the soil, moisture, temperature, developmental stage, and phenology [12]. These factors have therefore been evaluated to determine how they influence the production of volatile compounds in medicinal and aromatic species [8, 13–15]. Soil composition is one of the determining factors for crop establishment and may be altered to meet the nutritional needs of plants. Agricultural inputs, namely, chemical or organic fertilizers, can be used for this purpose. Organic fertilizers naturally reset nutritional characteristics and rely on the production of organic matter by decomposition, which is an important source of nutrients for plants, microflora, and terrestrial fauna. In the soil, organic matter provides nutrients and has an important role as a conditioner of the physical, chemical, and biological properties of the soil [16]. The traditional cultivation of geranium combines chemical fertilizer and organic matter inputs. With respect to essential oil production, the cultivation of P. graveolens is more profitable when the crop is grown in soils rich in organic matter [17]. 2 For the use of proper growth conditions and increase of the production of active constituents it is necessary to develop agricultural technologies for a correct cultivation of aromatic plants [16, 18]. Mulching is a common technology used in the cultivation of medicinal and aromatic species to increase the production of active ingredients [19]. Among other benefits, the use of mulch regulates surface radiation, promotes vegetative growth and productivity, increases insect repellence, controls weeds, decreases water loss by evaporation, and facilitates harvesting [20]. The aim of this study was to evaluate the effect of organicmineral fertilizers and soil coverage with plastic mulch on sweet-scented geranium (P. graveolens) biomass and essential oil. 2. Materials and Methods 2.1. Plant Materials. Plants of sweet-scented geranium (Pelargonium graveolens L’Hér) genotype UFS-PEL001 were propagated by cuttings. The plants were maintained in 1500 cm3 plastic bags containing a 1 : 1 mixture of soil and sand as substrate for 30 days and then transplanted to the field. Genotype exsiccates were deposited in the ASE Herbarium of the Federal University of Sergipe (UFS), under the record number ASE-14844. 2.2. Experimental Procedure. The assay was conducted at the “Campus Rural da UFS” Research Farm, located in São Cristóvão, Sergipe State, Brazil, from 2008 to 2009. The climate of the region is tropical semiarid, and the soil is classified as Red-Yellow Argisol with low fertility. The chemical characteristics of the soil are as follows: pH = 5.4 in water; 𝑃 = 2.3 mg⋅dm−3 ; K (Mehlich 1) = 0.09 cmolc⋅dm−3 ; Ca + Mg [21] = 2.70 cmolc⋅dm−3 ; and organic matter = 21.1 g⋅dm−3 . A randomized block design was used for the experiment, with three replicates in a split-plot design. In the plots, three different colored plastic mulches (black, white, and silver-colored) were tested in addition to the control with no plastic mulch. In the subplots, three fertilizer treatments (20,000 L⋅ha−1 of cattle manure; 1,000 kg⋅ha−1 of NPK 3-12-6; and 20,000 L⋅ha−1 of cattle manure + 1,000 kg⋅ha−1 of NPK 312-6) were tested in addition to the control without fertilizer. Fertilizer was applied 15 days before transplantation of the plants to the field. The spacing between rows and between plants was 50 cm. The beds were 90 cm wide, and each plot contained four plants cultivated in two rows. A drip irrigation system was used. Planting in the field was performed on May 28, and the first harvest was realized on August 26. Subsequent harvests were realized 90 days apart. At (...truncated)