Effect of foliar application of nano urea under different fertility levels on the yield and economics of rice (Oryza sativa L.)

Introduction

Rice (Oryza sativa L.) is one of the most important cereal crops. It is a plant of South East Asia origin. It belongs to family Poaceae (Gramineae). The genus Oryza includes 24 species, of which 22 are wild and two species namely Oryza sativa and Oryza glaberrima are cultivated. All the varieties found in Asia, America and Europe belong to Oryza sativa and varieties found in West Africa belong to species Oryza glaberrima. Rice is primarily a highenergy or high calorie food. The protein content of milled rice is usually 6 to 7 per cent. Rice is enriched in the vitamin's thiamine, riboflavin and niacin. The amino acid profile of rice reveals that it is high in glutamic and aspartic acid (FAO, 2004) [4] . Rice contains 80% carbohydrates, 7-8% protein, 3% fat and 3% fiber. Globally, rice is cultivated in 165.25 million ha area with an annual production of around 787.30 million tonnes with yield of 4.76 tonnes ha -1 [Anonymous. 2021(a)] [1] . In India, cultivated area about 45.07 million hectares with an annual production of about 122.27 million tonnes and productivity of 2713 kg ha -1 [Anonymous. 2021(b)] [2] . In the Chhattisgarh state, Paddy cultivated area is 3.79 million hectares with production of 7.1 million tonnes and yield of paddy is 1889 kg ha -1 [Anonymous. 2021(c)] [3] . Increasing farmers' incomes is the primary task in agriculture. Reducing cultivation costs or raising crop yields are two ways we can help farmers make more money. Improved crop yields are dependent on appropriate nutrient management, or the administration of the right kind and quantity of fertilizers at the right time (dosage). The cost of cultivation and crop output are directly impacted by varying nitrogen sources and dosages. By reducing the money needed to purchase additional fertilizer and apply it, the precise amount of nitrogen from the right sources can help lower the cost of cultivation. Therefore, choosing the right nitrogenous fertilizer and making adjustments to fertilizer application or nutrient management techniques can be crucial to boosting rice production and ensuring that future generations' rice demands are met. Large amounts of fertilizers are currently used to produce food, as they are essential for crop productivity. However, sometimes their high cost, which is beyond the reach of marginal farmers, particularly in developing countries becomes a challenge to be faced by farmers. The application of nano-fertilizers (NFs) is an emerging research field in agriculture. These substances, which range in size from 1 to 100 nm, aid in the plants nutrition. As an alternative to traditional urea fertilizer, nano urea is a liquid formulation of urea based on nanotechnology that supplies nitrogen to plants. According to IFFCO guidelines, a 500 ml bottle of nano urea is sufficient for one Foliar application of nano urea (Liquid) at critical crop growth stages of a plant effectively fulfils its nitrogen requirement and leads to higher crop productivity and quality in comparison to conventional urea. It is a sustainable solution for plant nutrition with higher nutrient use efficiency and reduces soil, water, and air pollution. It was also reported for substantial increase in farmers income.

Materials and Methods

The present investigation was conducted at Instructional Farm, DKS College of Agriculture and Research Station, Bhatapara, Chhattisgarh during the Kharif season 2023 to find the effect of foliar application of nano urea under different fertility levels on rice (Oryza sativa L.)". The typical climatic condition of Bhatapara is hot and humid and the soil texture at the field experiment site is clayey. The total rainfall received during crop growth period was 1339.4 mm. Relative humidity ranged between 92% to 83.1%. The mean weekly maximum and minimum temperature during the crop growth period ranged between 28.8 to 33.7 o C and 11.8 to 25.7 o C respectively. Wind speed varied from 1 to 6.4 km hr -1 . The average and cumulative open pan evaporation during study period was 14.6 and 29.6 mm respectively. The bright sunshine varied from 0.8 to 9.2 hrs day -1 . Sixteen treatment combinations comprising of four differnent fertility levels as main plot viz., N 1 -Control, N 2 -50% RDF, N 3 -75% RDF and N 4 -100% RDF with foliar application of nano urea treatment as sub plot viz., S 1 -Nano urea spray one time (20-25 DAT @ 5 ml L -1 water), S 2 -Nano urea spray two times (20-25 DAT & 40-45 DAT @ 5 ml L -1 water), S 3 -Urea spray one time ( 20-25 DAT @ 20 g L -1 water) and S 4 -Urea spray two times (20-25 DAT & 40-45 DAT @ 20 g L -1 water) were replicated thrice in Split Plot Design taken under study to estimate response in yield and economics of rice. The rice variety mahamaya were transplanted at spacing 20 cm × 10 cm (row × plant). The gross and net plot size was 4 m × 4 m and 3.2 m × 3.2 m, respectively. The Recommended dose (100 kg N + 60 kg P 2 O 5 + 40 kg K 2 O ha -1 ) was provided as urea, diammonium phosphate and muriate of potash, in that order. Weed control practices were done by hand weeding at 30 DAT and 60 DAT. Although there were adequate amounts of rainfall during the testing period, the crop received two irrigations during the blossoming and grain filling stages. At physiological maturity, the grains were harvested under sufficiently harsh conditions, with less than 16 percent moisture content. Each net plot's harvested bundle was weighed after it had been exposed to the sun in order to record grain yield and straw yield following winnowing. The unit of measurement for both grain and straw yield was kg ha -1 . Harvest index and economics were worked out using the following formulas: a) HI (%) = Economic yield (kg ha -1 ) Biological yield (kg ha -1 ) × 100 b) Net returns (₹ ha -1 ) = Gross returns (₹ ha -1 ) -Cost of cultivation (₹ ha -1 )

Cost of cultivation (₹ ℎ𝑎 -1 )

Result and Discussion Yield

The fertility levels and foliar application of nano urea both exerted significant effect on grain yield and straw yield. The results revealed that the maximum grain and straw yield was recorded under N 4 -100% RDF which was followed by N 3 -75% RDF > N 2 -50% RDF > N 1 -Control. The control treatment yielded the lowest since it did not apply fertilizer. These results emphasise how important it is to apply fertilizer correctly in order to maximise rice output. The results obtained in the present study are supported by the works of Valojai et al. (2021) [6] . Also, the maximum grain and straw yield was recorded under S 2 -Nano urea spray two times (20-25 DAT & 40-45 DAT @ 5 ml L -1 water) followed by S 4 -Urea spray two times (20-25 DAT & 40-45 DAT @ 20 g L -1 water) > S 1 -Nano urea spray one time (20-25 DAT @ 5 ml L -1 water) > S 3 -Urea spray one time ( 20-25 DAT @ 20 g L -1 water). The findings highlight how crucial it is to apply nano urea for appropriate nutrient management in order to maximise rice yield and improve harvest quality. The finding of present study is in accordance with those of Midde and ferumal (2021) [5] and Valojai et al. (2021) [6] . Significantly, highest harvest index was recorded in treatment N 4 -100% RDF followed by N 3 -75% RDF > N 2 -50% RDF > N 1 -Control. Significant increases in yield parameters were also observed in treatment N 4 -100% RDF as compared to the Control treatment, emphasising the crucial importance of applying a sufficient amount of fertiliser. The research conducted by Valojai et al. (2021) [6] provides support for the findings of the current investigation. Also, the maximum harvest index recorded under S 2 -Nano urea spray two times (20-25 DAT & 40-45 DAT @ 5 ml L -1 water) followed by S 4 -Urea spray two times (20-25 DAT & 40-45 DAT @ 20 g L -1 water) > S 3 -Urea spray one time (20-25 DAT @ 20 g L -1 water) > S 1 -Nano urea spray one time (20-25 DAT @ 5 ml L -1 water). The relevant data of grain yield, straw yield and harvest index were presented in Table 1.

Economics

The fertility levels and foliar application of nano urea both exerted significant effect on economics of rice. The results revealed that the maximum cost of cultivarion, gross returns (₹ ha -1 ) and net returns (₹ ha -1 ) were recorded under N 4 -100% RDF which was followed by N 3 -75% RDF > N 2 -50% RDF > N 1 -Control. Also, the maximum cost of cultivarion, gross returns and net returns were recorded under S 2 -Nano urea spray two times (20-25 DAT & 40-45

References

1. Anonymous. Area, production and yield of world FAO [Internet]. c2021 [cited 2024 Aug 15]. Available from: https://www.fao.org/faostat/en/#data/QCL
2. Anonymous. Area, production and yield of India and state Agricultural Statistics at a Glance [Internet]. Government of India, Ministry of Agriculture and Farmers Welfare, Department of Agriculture, Cooperation and Farmers Welfare, Directorate of Economics and Statistics; c2021 [cited 2024 Aug 15].
3. Anonymous. Directorate of Economics and Statistics, DAFW (Department of Agriculture and Farmer Welfare), Ministry of Agriculture and Farmer Welfare, Government of India [Internet]. c2021 [cited 2024 Aug 15].
4. FAO. Rice is life [Internet]. Rome: FAO; c2004 [cited 2024 Aug 15]. Available from: http://www.fao.org/rice2004/en/f-sheet/factsheet3.pdf
5. Midde SK, Ferumal MS. Evaluation of nano urea on growth and yield of rice (Oryza sativa L.). Chem Sci Rev Lett. 2021;10(1):123-132.
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