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In this work, we have successfully developed novel silver nanoconjugates of pyrazolone analogue and screened its chemosensing potential in aqueous medium. Bispyrazolone silver nanoparticles (Bispyra-AgNPs) were synthesised and characterised through FTIR, UV-visible spectroscopy and atomic force microscopy. The sensing ability was explored towards Ca2+, Cd2+, Co2+, Cu2+, Fe2+, Li+, Pb2+, La3+, Hg2+, Mg2+, Ni2+ and Ba2+ metal ions, respectively. Bispyra-AgNPs showed a highly quenching potential in selective recognition of Cu2+and colour of the solution immediately turned from yellow to purple, after the addition of Cu2+ in to the solution. The developed method also displayed a remarkable selectivity for Cu2+ over others interfering metal ions. The binding ratio and stoichiometry of host-guest complex was found to be 1:1 and determined by Job’s method. The propose method is facile and sensitive to detect Cu2+ with detection limit of 10 µM. [ABSTRACT FROM AUTHOR]

The rate and timing of manure application when used as nitrogen (N) fertilizer depend on N-releasing capacity (mineralization) of manures. A soil incubation study was undertaken to establish relative potential rates of mineralization of three organic manures to estimate the value of manure as N fertilizer. Surface soil samples of 0-15 cm were collected and amended with cattle manure (CM), sheep manure (SM), and poultry manure (PM) at a rate equivalent to 200 mg N kg-1 soil. Soil without any amendment was used as a check (control). Nitrogen-release potential of organic manures was determined by measuring changes in total mineral N [ammonium-N+nitrate-N (NH4+-N+NO3--N)], NH4+-N, and accumulation of NO3--N periodically over 120 days. Results indicated that the control soil (without any amendment) released a maximum of 33 mg N kg-1soil at day 90, a fourfold increase (significant) over initial concentration, indicating that soil had substantial potential for mineralization. Soil with CM, SM, and PM released a maximum of 50, 40, and 52 mg N kg-1 soil, respectively. Addition of organic manures (i.e., CM, SM, and PM) increased net N released by 42, 25, and 43% over the control (average). No significant differences were observed among manures. Net mineralization of organic N was observed for all manures, and the net rates varied between 0.01 and 0.74 mg N kg-1 soil day-1. Net N released, as percent of organic N added, was 9, 10, and 8% for CM, SM, and PM. Four phases of mineralization were observed; initial rapid release phase in 10-20 days followed by slow phase in 30-40 days, a maximum mineralization in 55-90 days, and finally a declined phase in 120 days. Accumulation of NO3--N was 13.2, 10.6, and 14.6 mg kg-1 soil relative to 7.4 mg NO3--N kg-1 in the control soil, indicating that manures accumulated NO3--N almost double than the control. The proportion of total mineral N to NO3--N revealed that a total of 44-61% of mineral N is converted into NO3--N, indicating that nitrifiers were unable to completely oxidize the available NH4+. The net rates of mineralization were highest during the initial 10-20 days, showing that application of manures 1-2 months before sowing generally practiced in the field may cause a substantial loss of mineralized N. The rates of mineralization and nitrification in the present study indicated that release of inorganic N from the organic pool of manures was very low; therefore, manures have a low N fertilizer effect in our conditions. [ABSTRACT FROM AUTHOR]