1 Introduction

The tomato is an edible berry that is widely cultivated as an annual plant all over the world. It is one of the major income generating vegetable crops of Nepal in terms of production and cultivated area (Prativa and Bhattarai, 2012). There are abundant evidences that concludes inorganic fertilizers can improve yield of crop significantly (Sharma, 2017). Although chemical fertilizers majorly contribute for sufficient crop production for rising world population, its overuse is dragging serious challenges to the present and future generations like air, water and soil pollution, land degradation, soil depletion and increased emissions of greenhouse gases (Kumar et al., 2019). Constant use of chemical fertilizer can alter the pH of soil, increase pests infestation and cause acidification, which results in decreasing organic matter load, humus load, useful organisms, stunting plant growth, and which even become responsible for emission of greenhouse gases (Pahalvi et al., 2021). 

Organic fertilizer used in rotational cropping systems increased crop output by at least 40%, also improved soil nutrient pools, relative fraction of soil decomposers, and stability and diversity of bacterial and fungal networks (Jiang et al., 2022). The incorporation of organic matter in soil is controlled to avoid excessive release of soluble nutrients such as nitrogen and phosphorus thereby reducing N leaching loss and P fixation; they can also supply micronutrients subsequently leading to better crop growth and production (Abbott et al., 2015).

Integrated Nutrient Management (INM) is an advanced concept of modern agriculture. Application of chemical fertilizers provides a good yield but soil properties are badly affected. Keeping in mind the bad impact of chemical fertilizers uses, the concept of integrated nutrient management is taken under consideration to obtain a higher yield and good quality. INM provides organic and inorganic nutrient components to the plant for sustainable crop production as it maintains the soil health as well as soil fertility in long term (Pandey and Chandra, 2013). INM is eco-friendly, and when used in crops, has no negative effects on the ecology and human health. Adaptation of INM practices besides increasing productivity, also improves soil health. INM has also been reported to correct micronutrient deficiency (Ramesh et al., 2023).

Plant yield is a very complicated trait that depends on many different factors. As a result, understanding the degree to which yield and its characteristics are correlated is extremely useful in the field of crop improvement (Naveen et al., 2017). Assessing the interrelationships among a variety of component characters is a necessary step toward achieving the desired outcome (Sinha et al., 2020).

2 Materials and Methods

2.1 Experimental site

The research was conducted in Dhulikhel municipality, Karve. This region lies in temperate mid hill of Nepal situated within 27°37’ North latitude to 85°32’ longitude with an altitude of 1,550 meter above sea level. The experimental site lies in the subtropical zone of Nepal. It is characterized by three distinct seasons: rainy season (June to October), winter season (November to Feb), and spring season (March to April). The maximum temperature during winter season rises up to 25 °C (end of February) whereas during the hottest months (May-June) it reaches up to 35 °C. The Rainy season starts from June and lasts up to October, June -July receives the highest amount of rainfall.

2.2 Experimental design

The research was carried out in Randomized Complete Block Design (RCBD) with eight treatments each having three replications. The field area was divided into 24 plots. Space between plots within one replication was maintained at 0.50 m and the space between replications was maintained at 1 m. Each plot was planted with 20 tomato plants containing a total of 480 tomato plants in 24 plots. The spacing between row-to-row and plant-to-plant was maintained at 0.75 m and 0.45 m respectively. Five plants were chosen from each replication for data collection. The sample plants were chosen from among the plants that remained after the border plants were excluded. The required data were collected from the sample plants at required time intervals.

2.3 Treatment details

The experiment comprised eight different nutrient management treatments designed to evaluate the effect of integrated nutrient management on the growth and yield of tomato (Table 1). These treatments included the application of various organic and inorganic fertilizers, both individually and in combination, along with a control (no nutrient input). The organic sources consisted of well-decomposed farmyard manure (FYM), vermicompost, and poultry manure, while the inorganic source was the recommended dose of chemical fertilizers (NPK at 200:180:80 kg/ha). Some treatments involved combinations of organic and inorganic fertilizers to assess their synergistic effects.

Table 1 Description of nutrient management treatments applied in the experiment

3 Results and Analysis

3.1 Growth parameter

At 60 days after transplanting, plant height was measured and found significantly higher in T7 (7.5 t/ha of well-decomposed FYM + 25% of recommended NPK +5 t/ha of vermicompost + 2.5 t/ha poultry manure) with 116.46 cm, which is statistically higher than other treatments (Table 2). While the minimum height was recorded with control (101.66 cm) which is due to the application of major and minor nutrients, through different organic manure and bio fertilizers, which increased the photosynthetic activity, chlorophyll formation, nitrogen metabolism, and auxin contents in the plants which ultimately improved the plant height.

Table 2 Mean performance of yield attributing traits of tomato under different treatments Note: LSD= Least Significant Difference, SEM=Standard Error of Mean, CV= Coefficient of Variation, GM= Grand Mean, PH= Plant height, NF= Number of flowers, FC/P= Number of fruit cluster per plants, F/C= Fruits per cluster, FL= Fruit length, FD= Fruit diameter, FW= Fruit weight, Y/P= Yield per plot, Y/H= Yield per harvest

3.2 Flower, fruit characteristics and yield

Number of flowers were significantly influenced by different types of nutrients (Table 3). The average number of flowers were found to be 54.91. The highest number of flowers (84.33) were observed in T7 followed by T5 (58.33). The lowest number of flowers were recorded in control (43.00). The average number of fruit clusters/plants was 6.41. The highest number of fruit clusters/plant was recorded in T7 (8.33) followed by T6 (7.33) and the minimum number of fruit clusters/plant was found in control (3.00). The mean number of fruits/clusters was 6.79 and the highest was observed with T7 (9.66) and the lowest was found in control (4.00). 

Table 3 Mean performance of yield attributing traits of tomato under different treatments Note: LSD= Least Significant Difference, SEM=Standard Error of Mean, CV= Coefficient of Variation, GM= Grand Mean, PH= Plant height, NF= Number of flowers, FC/P= Number of fruit cluster per plants, F/C= Fruits per cluster, FL= Fruit length, FD= Fruit diameter, FW= Fruit weight, Y/P= Yield per plot, Y/H= Yield per harvest

The average fruit length was found to be 4.13 cm with highest in T7 (4.64 cm). The highest fruit diameter was obtained from T7 with 56.08 mm, which is significantly at par with T6. The lowest diameter was obtained from the control with 45.22 mm. The average fruit diameter was 50.03 mm. The average fruit weight was calculated to be 52.23 g. The highest fruit weight was obtained from T7 with 62.25 g followed by T3 and the lowest was found in the control. And the highest yield/hectare was obtained from T7 (186.05 mt/ha) which is followed by T5 (148.25 mt/ha) and T6 (132.79 mt/ha) and the lowest was found in control with 70.07 mt/ha.

3.3 Correlation between different plant parameters

The study showed that the traits plant height and yield were positively and significantly correlated (r=0.77) which means an increase in plant height increase the yield of tomato significantly (Table 4). Number of branches and yield were found significantly and positively correlated. Similar findings were reported for number of branches and plant height by Naveen et al. (2017).

Table 4 Correlation between different plant parameters Note: ** Correlation is significant at the 0.01 level; *Correlation is significant at the 0.05 level; YPP= Yield / plot, PH= Plant height, NOB= No. of branches, NOF= No. of flowers, NOFCP=No. of fruit clusters/plant, NOFC=No. of fruit / clusters, FL= Fruit Length, FD= Fruit Diameter, FW= Fruit Weight

Similarly, number of flowers, number of fruits cluster per plant, number of fruits per cluster, and yield were found positively and significantly correlated with correlation coefficient r=0.82, r=0.65 and r=0.70, respectively, which means increase in number of flowers, number of fruits cluster per plant, and number of fruits per cluster significantly increase the yield of tomato. Sinha et al. (2020) has also reported that fruit per cluster, fruit cluster per plant and plant height significantly influence the fruit yield in tomato. Furthermore, fruit length (r=0.79), fruit diameter (r=0.77) and fruit weight (r=0.81) were also found positively significant with the yield indicating their contribution to the yield.

4 Discussion

The experimental findings showed that among the eight treatments used in the experiment, the integrated nutrient combination (7.5 t/ha of well-decomposed FYM + 25% of recommended NPK + 5 t/ha of vermicompost + 2.5 t/ha of poultry manure) was found to be superior in terms of plant growth and performance including fruit yield. The enhanced growth can be attributed to the synergistic effects of organic and inorganic nutrient sources, which improved soil structure, microbial activity, and nutrient availability, thereby promoting better physiological responses in tomato plants. Correlation study revealed that yield per plot of tomato was positively correlated and highly significant with number of fruits followed by fruit weight, fruit length, fruit diameter, plant height, number of fruits per cluster and number of fruit cluster per plant. Thus, yield can be further improved by improving these traits.

A study conducted in Lalitpur also revealed that the integration of organic manures with inorganic fertilizers significantly improved overall plant growth, yield, and soil macronutrient status compared to the sole application of either nutrient (Prativa and Bhattarai, 2012). Another study conducted at Rajasthan, India, also suggested that the combination of biofertilizer, farm yard manure, vermicompost and poultry manure is the best nutrient combination for enhancing crop yield (Sharma et al., 2023). The findings suggest that use of integrated nutrient management should be adopted for tomato cultivation in the Kavrepalanchok district. Furthermore, the use of organic amendments like vermicompost and poultry manure contributes to long-term soil fertility and reduces dependency on synthetic fertilizers.

While the study presents promising results, some limitations must be acknowledged. The experiment was conducted in a specific agro-climatic region, and findings may not be applicable to all locations. Thus, trials in different climatic zones and soil conditions can help validate the broader applicability of the results. Moreover, future research should explore long-term soil health impacts and economic feasibility of this nutrient combination.

Authors’ contributions

NA develop the concept of the experiment, design the experiment and involved in data interpretation and report draft review. RS involved in data collection, analysis and content writing. HPG also engaged in data collection, analysis and content writing. Likewise, SD, SA and PG all involved in data collection, analysis and content writing. All authors read and approved the final manuscript.

Conflict of Interest Disclosure

The authors affirm that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

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