Effect of biofertilizer and organic manure on the growth and yield of rice (Oryza sativa L.)

Introduction

Rice (Oryza sativa L.) is one of the world's most vital staple food crops, serving as a primary source of sustenance for nearly two-thirds of the global population. India plays a key role in rice cultivation and production. As a staple, rice is rich in carbohydrates-mainly in the form of starch-which makes it a quick source of energy. It contributes approximately 27% to the global dietary energy intake, 20% to dietary protein, and around 3% to dietary fat. In addition to macronutrients, rice also offers notable nutritional benefits by supplying essential micronutrients such as thiamine, riboflavin, niacin, and zinc, though it contains only smaller quantities of other vitamins and minerals. According to the U.S. Department of Agriculture (USDA), India's paddy production for 2024-2025 is estimated at 220.52 million metric tons (rough rice), with a milled rice output of 147 million metric tons. This marks a significant increase from the previous year's production of 206.76 million metric tons of rough rice and 137.83 million metric tons of milled rice. The Food and Agriculture Organization (FAO) also forecasts India's paddy production at a record 214.2 million metric tons, attributing the rise to favourable monsoon rains and expanded planting areas. The Indian government's second advance estimates report a combined Kharif and Rabi rice production of approximately 1,364.37 lakh metric tons (136.44 million metric tons), with Kharif rice at 1,206.79 lakh metric tons and Rabi rice at 157.58 lakh metric ton. more than 90% of the world's rice is both grown and consumed in Asia, particularly in six countries: China, India, Indonesia, Bangladesh, Vietnam, and Japan (Kumar et al., 2017) [5] . Globally, In the 2024-25 Kharif season, Uttar Pradesh (UP) is projected to produce approximately 265.54 lakh metric tonnes of paddy, cultivated over an area of 61.24 lakh hectares, with an average yield of 43.36 quintals per hectare.

Azotobacter is a nitrogen-fixing bacterium capable of contributing up to 20 kg of nitrogen per hectare in nonleguminous crops. It transforms atmospheric nitrogen into an ammoniacal form (NH₄⁺), which plants can readily absorb and utilize. Beyond nitrogen fixation, Azotobacter also produces auxins, vitamins, growth-promoting substances, and antifungal compounds, which enhance its effectiveness. The nitrogen it fixes in the rhizosphere-the soil surrounding plant roots-is readily taken up by the roots, potentially leading to improved growth and development of the crop (Rathore and Gautham, 2003; Kumar et al., 2012) [8,4] . Historically, Indian agriculture has relied on natural manure, as the addition of FYM influences nutrient absorption, crop production, and soil health, leading to a synergistic impact (Yadav and Kumar, 2002) [18] . The application of vermicompost, wheat residue, and farm yard manure in a favorable environment may have led to balanced nutrition by enhancing the release of macro and micro nutrients, facilitating greater nutrient uptake. This hastened the formation of new tissues and the emergence of new shoots, which have ultimately enhanced the plants' height, dry matter accumulation, chlorophyll levels, and total tillers per meter of row length (Togas et al., 2007) [16] . Vermicompost is the compost produced using earthworms, and the method of employing nearby earthworm species for composting or sustaining life is referred to as vermi tech. Vermicompost typically has a finely textured, peat-like consistency that boasts excellent structure, porosity, aeration, drainage, and moisture retention capabilities. Vermicompost enhances the physical, chemical, and biological properties of soil. There is strong evidence that vermicompost enhances plant growth and positively impacts all yield metrics of crops such as wheat, rice, and sugarcane. The addition of Azolla in rice paddies enhanced the weight of grains, length of panicles, percentage of grain filling, and overall grain yield. This finding shows that adding Azolla boosts rice yield by 5-42% compared to the control; Azolla can serve as green manure prior to rice transplanting. Azolla is cultivated 15-20 days before rice transplanting in a properly prepared field using 500 kg to 1 ton of fresh inoculum per hectare. Biofertilizers, containing helpful microorganisms, provide an environmentally friendly and affordable substitute. They enhance plant growth by facilitating nutrient availability (such as nitrogen, phosphorus, and potassium) and promoting the production of phytohormones. These microbial inputs establish symbiotic relationships with plants, improving soil fertility and crop productivity. This study investigates the influence of various biofertilizers such as Azolla, Azotobacter, on the growth and yield of rice variety Uma under field conditions. The research aims to evaluate whether integrating biofertilizers with recommended agricultural practices can sustainably enhance rice production and reduce dependence on chemical inputs.

Materials and Methods

A field experiment took place during the Kharif season of 2024 at the Crop Research Farm (CRF), Department of Agronomy, Naini Agricultural Institute, SHUATS, Prayagraj (U.P.), to investigate the "Impact of biofertilizer and organic manure on the growth and yield of rice (Oryza sativa L.)." The experimental field's soil had a sandy loam texture, with a pH of 7.1, a low organic carbon content (0.452%), available nitrogen (178.48 kg/ha), available phosphorus (23.6 kg/ha), and available potassium (231.4 kg/ha). The study was designed using a Randomized Block Design featuring nine treatments and three replications. The treatment combinations are as follows: T1: Azotobacter 6 kg/ha with FYM 12 t/ha, T2: Azotobacter 6 kg/ha with vermicompost (VC) 5 t/ha, T3: Azotobacter with poultry manure (PM) 4 t/ha, T4: Azolla 500 kg/ha with FYM 12 t/ha, T5: Azolla 500 kg/ha with VC 5 t/ha, T6: Azolla 500 kg/ha with PM 4 t/ha, T7: Azotobacter 3 kg/ha combined with Azolla 500 kg/ha and FYM 12 t/ha, T8: Azotobacter 6 kg/ha combined with Azolla 500 kg/ha and VC 5 t/ha, and T9: Azotobacter 6 kg/ha combined with Azolla 500 kg/ha and PM 4 t/ha.

Chemical analysis of soil:

A composite soil sample was collected before laying out the experiment to determine the initial soil characteristics. The soil sample was taken from a depth of 0-15 cm, air-dried in the shade, ground with a wooden pestle and mortar, filtered through a 2 mm sieve, and used for analysis. Organic carbon availability and the black technique were according to Jackson (1973) [3] ; available nitrogen was determined by the alkaline permanganate method by Subbiah and Asija (1956) [13] , and phosphorus availability was measured using Olsen's colorimeter method as described by Olsen et al.

Statistical analysis:

The experimental data gathered underwent a statistical analysis of variance (ANOVA) as described by Gamez and Gomez (2010). Critical Difference (CD) values were computed, and the 'F' test was significant at the 5% level.

Result and Discussion

Growth and Yield attributes 1. Plant height (cm) Significant differences were recorded among the treatments. However, significantly higher plant height (57.07 cm) was recorded with the application of Azotobacter 6 kg/ha along with Azolla 500 kg/ha and PM 4 t/ha. Whereas, the application of Azotobacter 6 kg/ha along with Azolla 500 kg/ha and VC 5 t/ha (56.46 cm), and Azotobacter 6 kg/ha along with Azolla 500 kg/ha and FYM 12 t/ha (53.80 cm) were statistically at par with the application of Azotobacter 6 kg/ha along with Azolla 500 kg/ha and PM 4 t/ha. According [11] emphasized the importance of using organic sources like Farm Yard Manure, Poultry Manure, and full doses of mineral fertilizers for improved crop growth. The highest plant height was observed with the cumulative application of organic manures and biofertilizers, followed by their direct and residual effects. Applications to both rice and preceding wheat crops were more effective than applications to rice alone. While Dwivedi and Thakur (2000) also noted stronger cumulative than direct effects, differences among cumulative, direct, and residual effects were not statistically significant. Interaction effects between organic manures, biofertilizers, and their application modes significantly influenced rice plant height in both years.

Number of tillers/hills

The significantly highest number of tillers per hill (11.94) was recorded under the treatment with Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and PM at 4 t/ha. This treatment was significantly superior to all others, except Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and VC at 5 t/ha (11.80), and Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and FYM at 12 t/ha (10.80), which were statistically at par. Tigangam and George (2017) [14] reported that the highest tillering occurred when farmyard manure (FYM) was combined with inorganic fertilizers. This was attributed to enhanced nitrogen availability, which promoted vegetative growth, and increased phosphorus solubility, which supported better root development and tiller formation. According to Yuan et al., (2010), the improved nutrient uptake facilitated by arbuscular mycorrhizal fungi (AMF) also stimulates the production of important biological metabolites and enzymes. These contribute to better water and nutrient balance within the plant, enhancing photosynthetic performance and the accumulation of assimilates-factors that ultimately support higher tiller production.

Application of Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and PM at 4 t/ha the maximum plant dry weight (42.44 g) was recorded in which was significantly higher than all other treatments. However, the combinations of Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and VC at 5 t/ha (41.61 g), as well as Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and FYM at 12 t/ha (41.20 g), were statistically comparable to the PM-based treatment. As noted by Singh et al. (2013) [12] , bio-organic inputs greatly influenced yield characteristics, with the integration of FYM at 5 t/ha and BGA achieving the maximum effective tillers/m², filled grains per panicle, and 1000-grain weight, which were considerably superior to using either FYM at 5 t/ha or BGA alone. Upendra Rao et al., (2014) [17] reported that organic farming practices-comprising one-third of the recommended nitrogen dose (RDN) supplied through farmyard manure (FYM), vermicompost (VC), and neem cake, along with Azotobacter -led to significantly higher root dry weight and root volume in rice at the flowering stage.

Number of Effective Tillers per m²

The number of effective tillers per square meter showed a significant difference among all treatments. The maximum number of effective tillers (421.67/m²) was recorded with the application of Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and poultry manure (PM) at 4 t/ha. This was statistically at par with the treatment involving Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and vermicompost (VC) at 5 t/ha (410.33/m²), as well as Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and farmyard manure (FYM) at 12 t/ha (408.33/m²).

Number of Panicles per Spike

Significantly highest number of panicles per spike (17.47) was recorded with the application of Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and poultry manure at 4 t/ha. This was statistically at par with the treatments that received Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and VC at 5 t/ha (16.27), and Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and FYM at 12 t/ha (17.00).

Number of Grains per Panicle

The number of grains per panicle was found to be significantly higher (187.27) in the treatment with Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and poultry manure at 4 t/ha. This treatment was statistically at par with Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and FYM at 12 t/ha (186.00), and Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and VC at 5 t/ha (185.07).

Test Weight

The test weight was found to be non-significant among the treatments. However, the highest test weight (25.95 g) was recorded with the application of Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and poultry manure at 4 t/ha.

Grain Yield

Significantly higher grain yield (3.39 t/ha) was recorded with the application of Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and poultry manure at 4 t/ha. This treatment was statistically at par with Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and VC at 5 t/ha (3.10 t/ha), and Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and FYM at 12 t/ha (2.93 t/ha).

Straw Yield

The Significantly maximum straw yield (6.92 t/ha) was recorded with the application of Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and poultry manure at 4 t/ha. This treatment was statistically at par with Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and VC at 5 t/ha (6.85 t/ha), and Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and FYM at 12 t/ha (6.80 t/ha).

Harvest Index

The harvest index was found to be significant. The highest harvest index (30.31%) was recorded with the treatment involving Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and poultry manure at 4 t/ha, as compared with other treatments. Shanmugan et al. (2003) [9] reported beneficial effects of FYM and Mann et al. (1999) [6] and Aulakh et al. (2000) reported beneficial effects of GM application on yield parameters and yield of rice. GM + FYM + Biofertilizer and GM + FYM were statistically at par and significantly increased grain yield over GM and FYM alone.

Economic Analysis

Analyzing the economic impact of treatments is essential for identifying the most cost-efficient choice that enhances revenue and is feasible for implementation. Information on cultivation expenses, total revenues, net profits, and benefit-cost (B:C) ratios is affected by various treatments. The cultivation expenses differed across treatments due to the application of various slowrelease biofertilizers and organic manures, ranging from INR 96,800 to INR 1,06,800 per hectare. The treatment with Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and poultry manure (PM) at 4 t/ha resulted in the highest gross return (INR 2,86,447), net return (INR 1,89,647), and benefit-cost ratio (2.40). Similarly, the application of Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and farmyard manure (FYM) at 12 t/ha yielded a gross return of INR 2,34,893, a net return of INR 1,66,093, and a benefit-cost ratio of 2.32, which were relatively superior to the other treatments. Sharma et al. (2012) [10] indicated that the greatest net return and benefit-cost ratio occurred with N90 P45 kg ha⁻¹. The rise in net return and B:C with the application of N90 P45 kg may result from superior yields in these treatments, leading to a greater return compared to the control. Banerjee and Pal (2012) [1] showed that the net return and B:C ratio were 13,425 ha and 0.61, respectively, for 100% RDF. NPK at 80-40-40 kg ha was the highest compared to the other treatments. Shahbaz (2015) noted that Basmati 515 produced the greatest profit (48,951) and marginal rate of return (1.83) with fertilizer application of NPK 150-88-58 kg ha⁻¹.

Conclusion

The use of Azotobacter at 6 kg/ha, Azolla at 500 kg/ha, and poultry manure at 4 t/ha resulted in improved growth parameters, yield attributes, and a higher benefit-cost ratio for rice.

Acknowledgement

AcknowledgementThe authors express gratitude to Dr. Umesha C., Assistant Professor, Department of Agronomy, Naini Agricultural Institute, Prayagraj, Sam Higginbottom University of Agriculture Technology and Sciences, (U.P) India for offering essential resources to conduct the research.

References

1. Banerjee S, Pal S. Effects of humic acid on the growth and yield of transplanted summer rice. Environ Ecol. 2012;21(3):680-3.
2. Davari MR, Sharma SN. Effect of organic manures and biofertilizers on basmati rice (Oryza sativa L.) under organic farming of rice-wheat cropping system. Indian J Agron. 2012;55(4):290-4.
3. Jackson ML. Soil Chemical Analysis. New Delhi: Prentice Hall of India Pvt. Ltd.; 1973. p. 56.
4. Kumar P, Hooda RS, Kumar S, Singh K. Effect of nitrogen levels and biofertilizer strains on dry matter production and attraction index in pearl millet. Haryana J Agron. 2012;28(1-2):34-7.
5. Kumar V, Singh OP. Effect of organic manures, nitrogen and zinc fertilization on growth, yield, yield attributes and quality of rice (Oryza sativa L.). Int J Plant Sci. 2017;1(2):311-4.
6. Mann RN, Singh SP, Singh K. Effect of organic nitrogen nutrition on yield, quality, nutrient uptake and economics of rice (Oryza sativa L.)-table pea (Pisum sativum var. hortense)-onion (Allium cepa) cropping sequence. Indian J Agric Sci. 1999;80(1):1003-6.
7. Olsen SH, Cole VV, Watanabe FS, Dean LA. Estimation of available phosphorus in soil by extraction with sodium bicarbonate. USDA Circular. 1954;939:1-9.
8. Rathore SS, Gautam RC. Response of direct seeded and transplanted pearl millet (Pennisetum glaucum L.) to nitrogen, phosphorus and biofertilizers in intercropping system. Indian J Agron. 2003;48(3):153-5.
9. Shanmugan K, Rao KV, Sam TK. Improving productivity and nitrogen use efficiency through integrated nutrient management in irrigated rice (Oryza sativa). Indian J Agric Sci. 2003;78(2):173-6.
10. Sharma RA, Singh YV, Singh S. Response of rice to biofertilizers and nitrogen levels in system of rice intensification. Indian J Agron. 2012;56(3):254-8.
11. Singh NP, Singh MK, Tyagi S, Singh SS. Effect of integrated nutrient management on growth and yield of rice (Oryza sativa L.). Int J Curr Microbiol Appl Sci. 2002;7(1).
12. Singh YN, Singh KK, Sharma SK. Influence of crop nutrition on grain yield, seed quality and water productivity under two rice cultivation systems. Rice Sci. 2013;20(2):129-38.
13. Subbiah BV, Asija GL. A rapid procedure for estimation of available nitrogen in soils. Curr Sci. 1956;25:259-60.
14. Tigangam PG, George PJ. Black rice CV. 'Chakhao Amubi' (Oryza sativa L.) response to organic and inorganic sources of nutrients on growth, yield and grain protein content. J Pharmacogn Phytochem. 2017;6(4):550-5.
15. Toth SJ, Prince AL. Estimation of cation exchange capacity and exchangeable calcium, potassium and sodium contents of soils by flame photometer techniques. Soil Sci. 1949;67(6):439-46.
16. Toth SJ, Prince AL. Estimation of cation exchange capacity and exchangeable calcium, potassium and sodium contents of soils by flame photometer techniques. Soil Sci. 2007;67(6):439-46.
17. Upendra A, Murthy KMD, Sridhar TV, Raju SK. Studies on performances of organic and chemical farming in rainy season rice. Int J Pure Appl Sci. 2014;4:2231-90.
18. Yadav DS, Kumar A. Long-term effects of organic manures on productivity and soil fertility in rice-wheat cropping system. In: Extended Summaries, Second International Agronomy Congress. 2002;1:51-3.