Impact of fertigation on growth, yield and economic returns in rose scented geranium (Pelargonium graveolens L.)

Introduction

Pelargonium graveolens, an evergreen shrub with woody basal branches, is technically a perennial but often treated as an annual due to its high aromatic qualities. It typically grows to heights of approximately 4.9 feet (1.5 m) with a spread of about 3.3 feet (1 m). China and Egypt lead global production and export of rose scented geranium oil, with a combined output exceeding 641.38 US tons annually. In contrast, India produces only 20 tons per year, a fraction of the global demand estimated at over 600 tons. Currently, production occurs on a small scale across North Indian states such as Uttar Pradesh, Uttarakhand and Himachal Pradesh, as well as in South Indian states including Andhra Pradesh, Karnataka and Tamil Nadu (Kulkarni et al., 1997) [ 10] . In the family of rose scented geranium varieties, while historical roots suggest hundreds of types, the essential oil market primarily recognizes two main types: "Egyptian" and "Bourbon." Each type offers distinct scents and therapeutic benefits. Notably, M/S SH Kelkar and Co. in Mumbai has introduced a new cultivar known as Kelkar/Egyptian, cultivated on a small scale. In India, drip irrigation holds immense potential, estimated at 35,340 hectares (Annual report 2022-23, Department of Horticulture, KSDH). This method has proven superior to traditional irrigation techniques due to its ability to deliver water and nutrients directly to the plant root zone. Moreover, drip irrigation systems facilitate fertigation, the simultaneous application of fertilizers and irrigation water. Today, fertigation is gaining popularity worldwide with over 75% of the drip irrigated area being fertilized through this method. Fertigation is the practice of delivering dissolved fertilizers directly through an irrigation system, offering considerable benefits for agricultural productivity. The productivity gains from fertigation can vary widely across different vegetable crops, typically ranging from 20% to 80%. These improvements are largely due to the precise application of nutrients to the plant root zone at critical growth stages, which contrasts with the more significant nutrient losses (40-45%) typically seen in traditional fertilization methods. In addition to boosting crop productivity, fertigation contributes to environmental sustainability by reducing fertilizer losses. This method enables a reduction in fertilizer use by 25-50%while maintaining or even increasing nutrient efficiency.

This reduction not only lowers production costs but also minimizes the environmental impact, particularly by decreasing nutrient runoff into water bodies. In summary, the adoption of fertigation is a crucial step toward more efficient and sustainable agricultural practices, benefiting both farmers through cost savings and improved crop yields, as well as the environment by reducing pollution and resource waste. (Sathya et al., 2017) [9] . Hence, present study is taken up with the objective to estimate the effect of fertigation on economics of herbage and oil yield.

Materials and Methods

The present experiment was conducted during Rabi season of 2023-23 at The Department of PSMA field research block in Kittur Rani Channamma College of Horticulture, Arabhavi (16° 15' North latitude and 94° 45' East longitude) in University of Horticultural Sciences, Bagalkot, Karnataka, India. Rose scented geranium variety i.e. Kelkar was selected for the experiment and cuttings were prepared in August. 30 days old rooted cuttings were planted at spacing 1.2 m x 0.6m in experiment plot. The experiment consists of 6 treatments with 5 replication was Randomized Complete Block Design (RCBD). Fertigation commenced in the second week after transplanting and continued for four months for the main crop in weekly interval. For the ratoon crop, it started in the first week after the main crop harvest and lasted three months, utilizing only nitrogen fertilizer. In the main crop, a full dose of phosphorus and potassium was applied as a basal dose. Water-soluble fertilizers, including Urea, 12:61:0 (MAP) and 0:0:50 (SOP), were used for fertigation, administered at weekly intervals. Additionally, farmyard manure (FYM) was applied at a rate of 10 tonnes per hectare, ensuring even distribution and thorough mixing across all plots. This integrated nutrient management approach optimized nutrient availability and enhanced overall plant growth. The treatments details were, T 1: RDF (210:35:35 kg/ha) was given through conventional method of fertilizer application T 2: 100% RDF (210:35:35 kg/ha) through fertigation T 3: 50% RDF (105:17.5:17.5 kg/ha) through fertigation T 4: 75% RDF (157.5:26.5:26.5 kg/ha) through fertigation T 5: 125% RDF (262.5:43.75:43.75 kg/ha) through fertigation T 6: 150% RDF (315:52.5:52.5 kg/ha) through fertigation

Cultural practices

After transplanting the crop was watered immediately. Daily irrigation was provided for a month post-transplantation. Subsequently, irrigation frequency reduced to once a week, contingent upon soil moisture levels. Drip irrigation was employed for watering. Gaps between seedlings of identical age were filled 15 days post-transplanting. Hand weeding was undertaken to maintain weed-free plots at 30, 60 and 90 days post-transplantation for main crops and immediately after and 60 days later for ratoon crops.

Harvesting of crop

Harvesting was carried out manually during the morning hours on sunny days, typically 4 to 5 months after transplanting, depending on the growth of the foliage. The ideal time for harvest was marked by the appearance of sparse flowering, the yellowing of the basal leaves and a noticeable change in aroma from a lemon-like scent to a more rose-like fragrance. When the leaves were gently pressed between the fingers, they released a delicate rosy aroma. To harvest, the portion of the plant about 15 to 20 cm above the ground was carefully cut, including both the young, tender branches and leaves, using secateurs or a sharp sickle.

Distillation of herb

To reduce the moisture content, fresh geranium herbage samples were partially dried under shaded conditions. The herbs were left to wilt or partially dry overnight in the shade. The essential oil was then extracted using the steam distillation method. Any remaining trace amounts of water in the oil were removed by adding anhydrous sodium sulphate. The percentage of essential oil was calculated using a specific formula.

Final weight of essential oil in bottle (g) -Initial empty bottle weight (g) × 100 Weight of wilted herbage (g)

Results and Discussion Growth

In this experiment maximum plant height was recorded in T 2 :100% of RDF at main crop and first ratoon harvest (82.25 and 80.23 cm), number of leaves per plant (1564.00 and 1110.23), number of branches per plant (51.50 and 35.26) as presented in table 1. This is due to fertigation releasing the nutrients at active root zone of the plant which increases maximum nutrient uptake. Taller plants typically exhibit more leaves, branches and an expanded plant spread which is crucial for maximizing photosynthesis. This is due to fertigation releasing the nutrients at active root zone of the plant which increases maximum nutrient uptake. Similar results were mentioned by Akash et al. (2023) [7] in fennel, Zehra et al. (2014) [8] in Gerbera and Behera et al. (2014) [1] in mint. Likewise, due to the effect of different fertigation doses significantly maximum fresh herbage yield per hectare (22.58 and 18.31) at main and first ratoon crop were recorded in T 2: 100% of RDF as presented in Table 2. Yield increased due to better water utilization and uptake of nutrients and an excellent soil-water air relationship with higher oxygen concentration in root zone. Another reason might also be due to the optimum moisture conditions in the entire root zone. A higher yield per hectare may result from increasing the fresh weight of individual plants particularly in crops produced for their above ground biomass i.e. economic part ofrose scented geranium is above ground portion. Moti et al. (2020) [6] and Bairwa and Bhunia (2023) [5] both supported these findings.

The yield obtained under different fertigation treatments are presented in table2. From this, it is clear that maximum essential oil yield was obtained in T 2: 100% of RDF (27.09 and 20.14 kg/ha) which was followed by T 4: 75% of RDF (22.17 and 17.20 kg/ha) at main crop and first ratoon harvest. Average essential oil yield under conventional method of fertilizer application (T 1 ) was 15.72 and 12.25 kg per ha, respectively. 117333.00) and returns per rupee of expenditure (2.32 and 2.58) also obtained in treatment T 2 which was followed by T 4 (2.05 and 2.31) as presented in Table 3. By optimizing nutrient management, fertigation proves to be a viable strategy for rose scented geranium growers, offering higher yields, superior quality of essential oil and increased profitability. It leads to the higher returns per rupee by boosting crop production and net income. Behera et al. (2014) [1] in mint, Shigvan et al. (2023) [4] , Vaidehi et al. (2017) [2] and Sanjit and Patra (2015) [3] observed similar outcomes.

Conclusion

Based on the experiment, it can be concluded that T 2: 100% of RDF (210:35:35 kg/ha) recorded maximum fresh herbage yield (22.58 and 18.31 t/ha) and returns per rupee of expenditure of 2.32 and 2.58, respectively for main and ratoon cropwhich was performed better over the treatment T 1 (Conventional method of fertilizer application) and helps to increase yield and economic level. Hence, T 2 100% of RDF will be the best treatment in turn it will be recommended to get higher yield and returns

References

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