Browsing by Author "M. KAVITHA"

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    SYNTHESIS, CHARACTERIZATION AND EVALUATION OF THE EFFICACY OF BIOCHAR BASED NANO-PHOSPHORUS FERTILIZER ON GROUNDNUT PRODUCTIVITY IN ALFISOLS
    (Acharya N G Ranga Agricultural University, 2024-05-23) M. KAVITHA; Dr. T.N.V.K.V. PRASAD
    The present investigation entitled “Synthesis, characterization and evaluation of the efficacy of biochar based nano-phosphorus fertilizer on groundnut productivity in Alfisols” was carried out involving three experiments during 2020 and 2021 at S.V. Agricultural College, Tirupati campus of Acharya N.G. Ranga Agricultural University of Andhra Pradesh. Nanoscale phosphorus particles were prepared by the biological method by using Stevia leaf extract as reducing and stabilizing agent. Surface modification of biochar was done through acid wash and gum acacia was used as a binding agent for loading of nano-phosphorous particles. The techniques such as, UV-VIS spectroscopy, Fourier transform infrared spectroscopy (FT IR), Dynamic light scattering (DLS), Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to characterize the biochar based phosphorus fertilizer (BBPF), biochar based nano-phosphorus fertilizer (BBNPF) and nano phosphorous (NP). The synthesized BBPF, BBNPF and NP mean size was 110.8, 87.6 and 53.7 nm, respectively. A pot culture experiment was carried out to know the effect of different concentrations of BBPF and BBNPF on groundnut plants. Increased plant height, higher values of dry matter, leaf area, phosphorus content and phosphorus uptake and significantly higher yield parameters (number of pod plant-1 , number of kernels plant-1 , kernel weight plant-1 ) in groundnut were recorded with the application of BBPF and BBNPF. xxi Based on the results obtained from the pot culture experiment, the treatments viz., 100% RDP + BBPF @ 10 kg ha-1 , 75% RDP + BBPF @ 10 kg ha-1 and 75% RDP + BBPF @ 8 kg ha-1 , 100% RDP + BBNPF @ 4 kg ha-1 , 75% RDP + BBNPF @ 4 kg ha-1 and 100% RDP + BBNPF @ 6 kg ha-1 were identified as prominent doses and were taken up for field evaluation. The field experiments were conducted during two seasons viz., kharif 2020-21 and rabi 2020-21 in wetland farm, S.V. Agricultural College, Tirupati. The experiments were laid out in randomized block design (RBD) with three replications and ten treatments (with groundnut cultivar ‘Dharani’). BBPF and BBNPF were applied as per the treatments, while nitrogen and potassium were applied common to all the treatments and gypsum was applied (just before flowering stage) @ 500 kg ha-1 . BBPF and BBNPF levels significantly influenced the growth parameters, yield and yield attributes, phosphorus uptake, and post-harvest soil available phosphorus and overall economic returns of groundnut. Higher leaf area index was recorded with soil application 100% RDP + BBNPF @ 4 kg ha-1 (T7). The next best results were noticed with the 75% RDP + BBNPF @ 4 kg ha-1 (T8). At all the stages of observation, maximum dry matter was recorded with the application of 100% RDP + BBNPF @ 4 kg ha-1 (T7). However, nodule count was not significantly influenced by the treatments at different stages of sampling (30, 60, 90 DAS and harvest) during both seasons of experimentation except at 30 DAS during rabi season. With regard to the yield attributes viz., number of pods plant-1 , 100-pod weight, 100-kernel weight and shelling percentage were higher with the application of 100% RDP + BBNPF @ 4 kg ha-1 (T7). The next best treatment was 75% RDP + BBNPF @ 4 kg ha-1 (T8) and lower number of pods plant-1 , 100-pod weight, 100-kernel weight and shelling percentage of groundnut were recorded with the control, during both the instances of study. The pod yield and haulm yields of groundnut were significantly influenced by the soil application of BBPF and BBNPF. The higher pod yield was recorded with the application of 100% RDP + BBNPF @ 4 kg ha-1 (T7). The haulm yield of groundnut increased significantly with 100% RDP + Soil application of BBNPF @ 4 kg ha-1 (T7) which was however at par with 75% RDP + Soil application of BBNPF @ 4 kg ha-1 (T8) and statistically comparable with 100% RDP + BBPF @ 10 kg ha-1 (T6). Lower pod yield and haulm yields were noticed with the no application of fertilizers (T1). Similar trend was noticed during both the seasons of investigation. Soil application of biochar based phosphorus and nano-phosphorus significantly influenced phosphorus content and phosphorus uptake of groundnut at different stages during both seasons of study. The phosphorus content and phosphorus uptake were higher with the soil application of 100% RDP + BBNPF @ 4 kg ha-1 (T7). The lower phosphorus content and phosphorus uptake by groundnut were recorded with the control (T1). xxii BBPF and BBNPF levels failed to exert significant influence on the post harvest soil physical (soil texture, bulk density, porosity and maximum water holding capacity) and soil physico-chemical (soil pH, EC and OC) properties during both the seasons of study. Post-harvest available nitrogen and phosphorus status (soil) were significantly influenced by the applied levels of BBP and BBNP during both the seasons of the investigation. The higher available nitrogen and phosphorus were recorded with the application of 100% RDP + soil application of BBNPF @ 4 kg ha-1 (T7). The lower levels of available nitrogen and phosphorus were noticed with the control (T1), whereas, the effect on available potassium was not statistically significant by the imposed treatments. Post harvest available secondary (Ca, Mg and S) and micronutrients (Fe, Mn, Cu and Zn) in soil were found to be non-significant with the soil application of BBPF and BBNPF, during both the years of study. Among the different treatments, the higher gross returns, net returns and benefit-cost ratio were realized with the soil application of 100% RDP + BBNPF @ 4 kg ha-1 (T7) which was comparable with 75% RDP + soil application of BBNPF @ 4 kg ha-1 (T8). However, lower economic returns were recorded with the crop that has not received any application of nutrients (T1), during both seasons of experimentation. In conclusion, the results of the present study revealed that the soil application of 100% RDP + BBNPF @ 4 kg ha-1 recorded higher pod yield and economic returns in groundnut grown in red sandy loam soils. Further, loading of nano-phosphorus with biochar and the consequent application to the soil enhance the phosphorus availability with an extended period of time due to slow-release activity and thereby sustain the groundnut productivity