Effect of organic bio-stimulants on growth of Chinese cabbage under greenhouse conditions of Sikkim

Introduction

Chinese cabbage is an underutilized vegetable crop in India as well as in the state of Sikkim. It is scientifically called Brassica rapa var. pekinensis belonging to Brassicaceae family with a chromosome number of 2n=20. It is a winter leafy vegetable which is originated from the North China and is widely cultivated all across the Asia. The crop is grown as an annual crop for leaves and biennial for the seed production. It has a short vegetation period, and is considered as the fastest growing one among all leafy vegetables. In good conditions, its head can be cut at ten weeks after transplanting (El-Afifi et al., 2014) [1] . It grows well in loamy soil and sandy loam soils that are rich in organic matter and water. It contains around 5% of dry matter, 10 g/kg of dietary fiber, 2,520 mg/kg potassium, 1,050 mg/kg calcium, 190 mg/kg magnesium, 650 mg/kg sodium, and 450 mg/kg vitamin C of fresh matter (USDA, 2007) [2] . The usage of chemical nitrogen fertilizer application significantly improves the yield, but it also leads to the decline in the nutritional quality of the economic part, as well as, the increase in nitrate content and pollutes the environment (Rumsby, 2002) [3] , which paves way for the usage of organic amendments for the crop cultivation. The state of Sikkim after becoming organic state in 2016 restricts the synthetic agrochemicals for crop cultivation (Kumar et al., 2017) [4] . The farmers of the state are still following traditional farming practices and unaware of the scientific organic practices of vegetable farming. Bio-stimulants, which are new gen amendments for supplements of nutrients for the plants, are derived from living organisms such as plants, seaweeds, microbes, etc., and function similar to chemical fertilizers (Bhupenchandra et al., 2020) [5] . Besides supplying plant nutrients, certain bio-stimulants such as seaweed extract and humic acid derivatives support plants during the unexpected abiotic stresses, which are an added advantage of their usage in crop cultivation (Bhupenchandra et al., 2022) [6] . So, this study was undertaken to identify the suitable biostimulant and its dose for enhancing growth and yield of Chinese cabbage under low-cost polyhouse condition in mid-hills of Sikkim.

Materials and Methods

A pot experiment was carried out at the Experimental farm of College of Horticulture, Bermiok (Central Agricultural University, Imphal) in the Kharif season of 2025 to study the impact of different bio-stimulants spray in growth and yield of Chinese cabbage under low-cost polyhouse conditions in midhills of Sikkim. The experimental farm was located at 88˚ 46.8' 92.7'' E, 27˚ 23.2' 36.3'' N and 867 m MSL altitude. The pot experiment was laid out in completely randomized design (CRD) with seven treatments viz., namely T 1 (Controlwater spray), T 2 (3% Seaweed extract), T 3 (5% Seaweed extract), T 4 (3% Humic Acid), T 5 (5% Humic Acid), T 6 (3% Panchagavya), and T 7 (5% Panchagavya) and replicated thrice. Biostimulant and water sprays were done at 30 and 45 days after transplanting as per the treatment in all the pots. The soil used in the experiment was slightly acidic with 6.1 pH, and contained 190.3 kg/ha N, 3.5 kg/ha P 2 O 5 and 161.1 kg/ha K 2 O. The average maximum temperature during the study was ˚C in the month of and the minimum temperature was ˚C which was in the month of. A uniform dose of farm yard manure (0.72 kg/ pot) and rock phosphate (0.18 kg/pot) were supplied to all the pots, including the control as basal dose of organic manures. Chinese cabbage var. F 1 Yates was used as planting material in this study. Seeds were sown on 24 th May 2025 in protrays, and then 24 th day-old seedlings were transplanted in pots on 16 th June 2025 in polybags. Various growth and yield parameters such as leaf length (cm), leaf width (cm), number of leaves per plant, plant height (cm), and fresh weight plant yield (g) were measured on the day of harvest (9 th August 2025). The crop productivity (g/day) was estimated by dividing the fresh plant weight by the total crop duration. The total crop duration was 55 days during the investigation. All statistical analyses such as mean and Analysis of Variance were carried out using Microsoft Excel and OPSTAT of HAU, Hisar at 5% significance to draw a cogent inference.

Results and Discussion

Data presented in Table 1 indicated that the tallest plant was observed under T 7 (44.67 cm) which was at par with T 6 (43.67 cm) but was significantly taller than the rest of treatments. Significant enhancement in leaf length was found in the treatment T 6 (40.23 cm) which was on par with T 7 (38.85 cm) and T 5 (36.69 cm). The maximum value of leaf width was registered under T 6 (21.19 cm) which was at par with T 3 (21.18 cm), T 7 (20.73 cm), T 5 (20.50 cm) and T 2 (19.32 cm), and it showed a significant difference with T 4 (16.83 cm) and T 1 (12.56 cm). Number of leaves per plant was markedly improved due to the application of T 7 (30.67) which was significantly higher the rest of treatments, except T 6 . Similarly, the significantly highest total fresh plant weight was recorded under T 7 (1111.67 g/ plant) which was 10.15 times higher than T 1 (99.67 g). Consequently, the maximum value of crop productivity was noted under T 7 (20.21 g/day) which was significantly superior among all treatments. According to the results observed, the bio-stimulants were found to enhance the growth and yield of the Chinese cabbage with different mode of action and mechanisms. The humic acid may influence the membrane fluidity of the plant cells and the activity of the pyrophosphatase enzyme (H + -PPase), which in turn increase the uptake of macronutrients such as nitrogen, phosphorus and potassium and other secondary nutrients such as S, Ca, Mg, Mn, and Fe in crops (Bhupenchandra et al., 2022) [6] , which will obviously increase the yield of crop. The seaweed extract contains several micro and macronutrients required by the plants, along with amino acids, vitamins, and phytohormones such as auxins, cytokinins & abscisic acid, which has the potential of changing the metabolism in cellular level and impacts plant growth and yield (Khan et al., 2009) [7] . Panchagavya which contains essential microorganisms along with some required plant nutrients that improves plant growth increases metabolic activities of the crop and also gives certain resistance to pest and diseases (Rakesh et al., 2017) [8] . In Broccoli, which is a crop of same family, Panchagavya 5% spray had been reported as best treatment by Chongtham et al. (2025) [9] which supports the current finding. Panchagavya 3% along with 80% of RDF was found to be best treatment as per Chaudhari et al. (2024) [10] in the beetroot cultivar which also highlights the role of Panchagavya spray in yield enhancement. In Carrot cultivation under organic conditions, the treatment which found to give best quality characters is basal application of farm yard manure 20 t/ha and 3% Panchagavya spray at 45, 60 and 75 DAS (Das, 2020) [11] .

Conclusion

From this study, it is inferred that application of 5 percent Panchagavya foliar spray at 30 and 45 days after transplanting along with basal dose of 0.72 kg of farm yard manure/pot and 0.18 kg of rock phosphate/pot increased the growth and yield attributes of Chinese cabbage. Therefore, it can be recommended as an alternate source of nutrients for organic cultivation of Chinese cabbage under low cost poly-house conditions in the mid-hills of Sikkim.

References

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