Influence of foliar spray of Terresol biostimulant on growth and development of tomato (Solanum lycopersicum L.)

Introduction

Tomato (Solanum lycopersicum L.) is an important vegetable crop belonging to the family Solanaceae and is widely cultivated for its nutritional and economic importance. Globally, tomato is grown over an area of about 5 million hectares with a production of around 189-190 million tonnes. In India, it contributes significantly to vegetable production, with major growing states including Maharashtra, Karnataka and Andhra Pradesh. Tomato is highly sensitive to environmental factors, particularly water and nutrient management, which greatly influence its growth and yield. Proper irrigation and nutrient supply during critical stages such as flowering and fruit development are essential for achieving optimum productivity. In recent years, biostimulants have gained considerable attention in sustainable agriculture due to their ability to enhance plant growth, nutrient uptake and stress tolerance (Calvo et al., 2014; du Jardin, 2015; Ruzzi et al., 2024) [2,5,9] . Biostimulants are known to improve physiological processes such as photosynthesis, enzyme activity and nutrient assimilation, leading to improved crop performance (Colla et al., 2015; Garg et al., 2024) [3,6] . Terresol, a commercially available biostimulant, contains bioactive compounds such as amino acids, humic substances and micronutrients that stimulate metabolic activities in plants. Studies have shown that biostimulants can significantly enhance growth, yield and quality of tomato under different environmental conditions (Dasgan et al., 2024) [4] . Furthermore, the combined application of biostimulants with fertilizers has been reported to improve nutrient use efficiency and yield under stress conditions (Benito et al., 2025) [1] . However, information on the combined effect of different fertilizer levels and Terresol application on morphophysiological traits and yield of tomato under field conditions is limited. Hence, the present investigation was undertaken.

Materials and Methods

A field experiment was conducted at the Experimental Farm, College of Agriculture, B'gudi, during the cropping season to study the influence of foliar application of Terresol biostimulant on growth, morphophysiological traits and yield of tomato (Solanum lycopersicum L.). The experimental site is located in the Northern Dry Zone of Karnataka, characterized by semi-arid climatic conditions. The experiment was laid out in a Randomized Block Design (RBD) with 11 treatments and three replications. The treatments consisted of different levels of recommended dose of fertilizers (RDF) in combination with varying concentrations of Terresol biostimulant applied as foliar spray, viz., T₁ (100% RDF without Terresol), T₂ (100% RDF + Terresol @ 2 mL L⁻¹), T₃ (100% RDF + Terresol @ 3 mL L⁻¹), T₄ (100% RDF + Terresol @ 4 mL L⁻¹), T₅ (75% RDF + Terresol @ 2 mL L⁻¹), T₆ (75% RDF + Terresol @ 3 mL L⁻¹), T₇ (75% RDF + Terresol @ 4 mL L⁻¹), T₈ (50% RDF + Terresol @ 2 mL L⁻¹), T₉ (50% RDF + Terresol @ 3 mL L⁻¹), T₁₀ (50% RDF + Terresol @ 4 mL L⁻¹) and T₁₁ (absolute control: no fertilizer and no Terresol). Tomato seedlings were raised in a nursery and transplanted to the main field at appropriate spacing of 75-90 cm × 45-60 cm. Recommended agronomic practices were followed uniformly for all treatments except for the imposed fertilizer and biostimulant treatments. The recommended dose of fertilizers (RDF) was applied as per the package of practices of the University of Agricultural Sciences, Raichur. Foliar application of Terresol biostimulant was carried out at three stages, namely at 3-5 leaf stage, 25 days after sowing (DAS) and 50 days after the first application, using a hand sprayer to ensure uniform coverage. Observations on growth parameters such as plant height, number of branches and leaf area were recorded at different growth stages. Physiological parameters including photosynthetic rate were measured using standard procedures. Yield attributes such as number of flowers, fruit setting percentage and number of marketable fruits per plant were recorded at harvest. The data collected were subjected to statistical analysis following the analysis of variance (ANOVA) technique appropriate for Randomized Block Design as described by Panse and Sukhatme (1967). The significance of treatment differences was tested using the critical difference (CD) at 5 percent level of significance.

Results and Discussion

The results of the present study revealed that significant variation among treatments with respect to growth, physiological parameters and yield of tomato. Among the treatments, T₄ (100% RDF + Terresol @ 4 mL L⁻¹) recorded superior growth parameters such as plant height, leaf area and total dry matter, along with higher photosynthetic rate at 45 DAS. The enhancement in growth may be attributed to improved nutrient availability and stimulation of metabolic activities by the biostimulant. Biostimulants are known to enhance cell division, elongation and chlorophyll synthesis, thereby improving plant growth (Henderson et al., 2025) [7] . The enhanced growth and physiological performance may be attributed to improved metabolic activity and nutrient use efficiency induced by biostimulants, which is in agreement with earlier findings (Colla et al., 2015) [3] . The increased photosynthetic rate observed under Terresol application could be due to improved chlorophyll content and enzyme activity, leading to enhanced carbon assimilation. Similar findings were reported by Dasgan et al. (2024) [4] , who observed improved physiological performance in tomato with biostimulant application. Yield parameters were also significantly influenced by treatments, with T₄ recording the highest yield (17.0 q ha⁻¹).

The improvement in yield may be attributed to better source-sink relationship, enhanced assimilate production and efficient translocation to developing fruits. The role of biostimulants in improving yield through enhanced physiological efficiency has been well documented (Ruzzi et al., 2024) [9] . The untreated control recorded the lowest values for all parameters, indicating the importance of nutrient and biostimulant application in crop production. The results also suggest that partial reduction in fertilizer levels, when combined with biostimulant application, can maintain reasonable productivity, which is in agreement with earlier findings (Benito et al., 2025) [1] .

References

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