Pramanick, BiswajitB R, Rakesh2023-01-132023-01-132022M/AGRO/128/2020–21https://krishikosh.egranth.ac.in/handle/1/5810192196The research-work was conducted in the rainy season of 2021 (Kharif-2021), at Research-Farm RPCAU-Pusa, Bihar to study the “Effect of nano- nitrogenous fertilizer on growth, yield and nitrogen use efficiency of transplanted rice”. Experimental-soil was sandy-loam in nature having low in SOC (0.39%), available N (210 kg ha-1) and K (109 kg ha-1), medium available-P (12.0 kg ha-1) with alkaline soil pH of 8.81. The research work was with the following objectives, viz., to assess the effect of nano-N fertilizer on growth and yield of rice; to evaluate the effect of nano -N fertilizer on nitrogen use efficiency; & to evaluate the economics of different treatments. The study consisted of 7 various nutrient management options for rice (variety, Rajendra Bhagwati) with or without nano-N+various levels of recommended N (RDN). Treatments details as follows, T1: 100% RDN; T2: 50% RDN+2 nano-N sprays; T3: 75% RDN+2 nano-N sprays; T4: 100% RDN+2 nano-N sprays; T5: 125% RDN+2 nano-N sprays; T6: 150% RDN+2 nano-N sprays; T7: Control (no N-application). Statistical design was randomised complete block design (RCBD) with three replications. For all the treatments, recommended P and K fertilizers were given. From the one-year long study, it was observed that the application of 125% RDN+2 nano-N sprays (T5) resulted in the best attainments of growth viz. plant height (cm), dry-matter accumulation (g m-2), crop-growth rate (g m-2 d-1), tiller numbers m-2; yield attributing characters and yield of rice and this treatment was found at-par with application of 150% RDN+2 nano-N sprays (T6) and 100% RDN+2 nano-N sprays (T4). Interestingly, it was also observed that the application of 75% RDN+2 sprays of nano-N (T3) and application of 100% RDN (T1) was found at-par concerning almost all the growth and attributes and yield of the crops. It was observed that the application nano-N resulted in higher growth and yield when applied with RDN. Comparing T1 with T4 where addition 2-sprays of nano-N was administered, resulted in about 7.3% increment in tiller numbers m-2. T4 also resulted in about 10% and 5% more grain and straw yield of rice, respectively comparing those under T1. Concerning nutrient content in plants, it was observed that the application of varied nano-N significantly influenced the grain and straw N content (%) of rice. However, the P and K content in plants were not varied widely. T5 again showed the maximum values of N-content (%) in rice being at par with T4 and T6. N, P and K-uptake by the plants were found to be significantly varied with the different treatments. T5 exhibited the maximum attainment of N, P and K uptake by the plants. Concerning nitrogen use-efficiency (NUE), it was observed that application of 75% RDN+2 nano-N (T3) sprays resulted in the maximum value of NUE (20 kg kg-1) being closely followed by T4 (19.6 kg kg-1). It was also found that the application of RDN beyond 100% reduced the NUE as higher amount of N-application did not found to increase the yield at the same-tune. From the economic point of view, it was observed that the application of 125% RDN+2 nano-N sprays (T5) resulted in the maximum values of gross returns (Rs. 97981 ha-1), net returns (Rs. 52133 ha-1) and B:C ratio (1.14) and this treatment was found at-par with T4 and T6. Application nano-N over 100% RDN (T4) showed Rs. 7032 ha-1 more net returns comparing applying only 100% RDN without nano-N (T1). From this one-year study, it can be concluded that the application of 125% recommended N through urea+2 sprayings of nano-N at active tillering and panicle initiation stages resulted in the maximum growth, yield and economics of the rice cultivation. However, the maximum nitrogen use-efficiency was observed with 75% recommended N through urea+2 sprayings of nano-N.EnglishThesis