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ThesisItem Open Access Strategies for nano-nitrogen use and scheduling to improve use-efficiency and minimize environmental losses in rice-wheat system(CCSHAU, Hisar, 2023-09-20) Manu Rani; Bhardwaj, Ajay KumarNitrogen (N) is the most frequently limiting plant nutrient for crop growth and yield. N fertilization is very important in crop production due to its requirement in high amount by plants for vital function in practically all metabolic activities, and also due to high losses linked with soil-plant system during cropping cycle. It needs to be applied in amounts more than the actual requirement of crop because of its low recovery (30-50%) and its losses in different forms. Therefore, there is an urgent need for improving N use efficiency in agricultural crop production. The existing strategy of fixed-rate, fixed-time (blanket) fertilizer application has proven ineffective for increasing NUE beyond certain limits. The enhanced efficiency fertilizers (EEFs) are being developed on a continual basis to manage the release of N from fertilizers, allowing for increased absorption and utilization by plants, minimizing losses and boosting crop output per unit of fertilizer. Nanofertilizer is one such type of EEFs wherein the nutrients are present in form of nanoparticles (0-100 nm). Nano-N is one of the first nanotechnology based fertilizers which was released by IFFCO (Indian Farmers Fertilizer Cooperative Limited) for agricultural application in India and worldwide. Conceptually, Nano-N can contribute to lessening the environmental N leakages from agricultural areas through reduced leaching and gaseous emissions, both of which contribute to pollution and climate change. Though preliminary studies suggest Nano-N to be very effective as it reduces the losses of N to environment due to its foliar application mode it may not suffice meeting the plant N requirement for protein synthesis if used alone. The precision and use efficiency apart a ottle of Nano-N contains only 20 g of N compared to a ag of prilled urea which has 20 kg N. Keeping these factors in view, a field experiment was initiated in 2020 at ICAR-Central Soil Salinity Research Institute (CSSRI), Karnal, India to develop strategies for Nano-N use and scheduling to improve use-efficiency and minimize environmental losses in rice-wheat system under different combination with prilled urea and precision application techniques. The present experiment was carried out with eight treatments in total: four treatments with replacement of prilled urea by nano-N namely, 33% replacement (R33), 50% replacement (R50), 66% replacement (R66), 100% replacement (R100); two precision-scheduling treatments namely, application of nano-N based on leaf colour chart (LCC) values after basal dose of prilled urea (M-LCC), and application of nano-N based on GreenSeeker (GS) values after basal dose of prilled urea (M-GS) and two control treatments included „100% recommended N through prilled urea‟ (R0; no replacement) and „no N fertilizer at all‟ (No-N) treatment to observe their impact on environmental loses, growth, physiology, yield parameters, and use efficiency of nitrogen under rice-wheat system. The findings showed that the incremental replacement of conventional urea with nano-N resulted in decreased environmental losses of reactive N (N2O and NO3). No decrease in the available soil N pool was noticed upto 33% replacement (1 split dose replacement) of urea with Nano-N. The available N in the soil showed a noticeable decrease when nano-N replaced conventional urea by 50% or more. Therefore, only one split dose replacement of conventional urea with nano-N would avoid N mining over time, unless N addition from any other source is provided. Upto 50% replacement of conventional urea with nano-N, the plant growth parameters were statistically at par with the treatment having 100% conventional urea. The overall assessment suggests that at least one dose of conventional urea (1 out of 3 splits) may be replaced with nano-N without a reduction in yield in basmati rice crop and upto 50% replacement with nano-N in wheat crop without yield loss yet significant gain in use efficiency.ThesisItem Open Access Influence of long-term nutrient management using Soil Test Crop Response approach on chemical and biological properties of soil under pearl millet-wheat cropping system(CCSHAU, Hisar, 2020-08) Manu Rani; Goyal, VishalThe present study was carried out on the ongoing long-term experiment of STCR initiated in 2009 at Research Farm, Department of Soil Science, CCSHAU, Hisar. The experiment was planned in a randomized block design with four replication and seven treatments viz. T1-control, T2- FYM @ 15 t ha-1, T3-RDN&P, T4-STCR with TY 3.0 t ha-1, T5-STCR with TY 3.5 t ha-1, T6- Integrated STCR with TY 3.0 t ha-1 + FYM and T7- Integrated STCR with 3.5 t ha-1 + FYM yield targets. FYM @ 15 t ha-1 was applied in rabi and kharif season in T2, T6 and T7 plots. Grain yield of pearl millet was significantly affected by use of fertilizers in combination with FYM after ten cycles of pearl milletwheat cropping system. Integrated treatment (T7) recorded the highest pearl millet grain and straw yield (3532 and 8937 kg ha-1) followed by chemical fertilizers alone and lowest in control (1662 and 4132 kg ha-1). The per cent deviations of grain yield in target yield (30 and 35 q ha-1) treatments with and without FYM vary from -2.2 to +1.0. Application of FYM along with chemical fertilizers enhanced total N, P and K uptake by 150.84, 192.56 and 150.75 % over the control. The long-term application of FYM alone (T2) or integrated with fertilizers (T6 and T7) increased the available N from initial value (2009) of 126 kg ha-1 to 168 kg ha-1 and available P from its initial value of 15 kg ha-1 to 27.10 kg ha-1. The soil organic carbon, EC and micronutrients increased significantly with application of FYM alone or in combination with chemical fertilizers. A decrease in soil pH was observed in the treatments where FYM was applied. Amongst the different treatments, application of FYM alone or integrated with chemical fertilizers showed higher microbial population, microbial biomass carbon and better enzymatic activities in the soil. Soil microbial population followed a trend of natural population (predominance of bacteria followed by actinomycetes and fungi). Integrated treatments (T6 & T7) showed highest bacterial population (7.91 to 8.14 log10 no. cfu g-1 soil), fungal population (4.41 to 4.60 log10 no. cfu g-1 soil) and actinomycetes population (5.85 to 6.03 log10 no. cfu g-1 soil). The application of FYM alone (T2) or with fertilizers (T6 and T7) continuously for a period of 10 years had increased the soil MBC by 71 to 89 % as compared to control (T1). The long-term nutrient management using STCR approach showed an increase of 16.30 to 93.79 % in dehydrogenase activity in soil in different treatments during the entire crop growth of the pearl millet over the control (T1). Further, the microbial population, soil microbial biomass carbon, enzymatic activities, soil organic carbon and available nutrients were found to be more at early developmental stages of the crop and decreased at maturity.