Thakur, S.K.Mallick, Jidan Ali2024-06-292024-06-292023M/SS/175/2021-22https://krishikosh.egranth.ac.in/handle/1/5810211194The use of nano-fertilizers in agriculture is expanding quickly as a strategy to increase crop yields, nutrient use efficiency and decrease the use of synthetic fertilizers. A novel agricultural input developed through nano technology is called nano urea which provides nitrogen to plants.Nano urea which contains 4% N by weight in nano form. Its use efficiency is higher than that of regular urea and most crops can be benefited from nano urea as a source of nitrogen. A field experiment was therefore, conducted in 2022–2023 at the Crop Research farm Kalyanpur, Dr. Rajendra Prasad Central Agricultural University, Bihar, with an objective to study the “Effect of nano urea on soil nitrogen status, uptake, yield and juice quality of Sugarcane in calcareous soil of Bihar”.The experiment was carried out in RBD design with 10 treatmentswith three replications comprising control, application of nitrogen @ 50, 75 &100 %recommended dose alone or in combination with spray of nano urea (NU) @ 1.0 &2.0% at tillering & grand growth stages. Spray of nano urea @ 2.5% was carried out only at tillering stage. The results revealed that the number of tillers increased significantly from 44.59 - 97.30×103 ha-1 and 62.36 - 110.53× 103 ha-1 at 90 and 120 days after planting with increasing levels of nitrogen. Significant increase in the number of millable cane (67.84 - 76.72 ×103 ha-1) over control was observed due to addition of different doses of nanourea. Applying nano urea had a positive effect on cane yield (61.24 to 79.24 t ha-1) and sugar yield (7.36 to 9.92 t ha-1) but highest cane and sugar yield (81.95 t ha-1 and 10.23 t ha-1 respectively) was observed due to application of recommended dose of nitrogen (RDN). The application of different doses of nano urea did not show significant variation in plant height, cane length, cane girth but single cane weight varied significantly (0.719-1.024 kg) across the different treatments. The application of nano urea in various combinations did not result in statistically significant improvements in cane juice quality parameters like brix, pol, purity, and commercial cane sugar. The highest available nitrogen content (246.14 kg ha-1) was observed in treatment received 100% recommended dose of nitrogen. The available nitrogen content in post-harvest soil varied 224.40 to 236.53 kg ha-1 due to application of nano urea @ 1.0, 2.0 & 2.5% along with 50% and 75% nitrogen fertilizer. Nano urea had no notable impact on the available phosphorus and potassium content of the post-harvest soil. The meanuptake of nitrogen (88.07 to 279.53 kg ha-1), phosphorus (12.4 to 15.36 kg ha-1) and potassium (113.07 to 154.75 kg ha-1) by sugarcane crop varied significantly across the treatments. The benefit-cost ratio in the treatments receiving 75% RDN along with spray of NU @ 1.0, 2.0 and 2.5% were found at par with the maximum BC ratio (1.89) observed in treatment receiving 100% RDN. Thus,application of 1% nano urea at tillering and grand growth stage along with 75% RDN may be used for sugarcane production in calcareous soil of Bihar.EnglishThesis