SummarySix field experiments, three each during 1982–3 and 1983–4, were conducted on a sandy loam soil to study the effect of varying levels of nitrogen, phosphorus and potassium, in the absence and presence of farmyard manure (FYM) (30 t/ha), on the number of tubers and yield of potato in three grades. Increase in nitrogen, phosphorus and potassium application, in the absence or presence of FYM, did not significantly affect the total number of tubers/m2 but did affect the number of tubers in different grades. An increase in nitrogen and potassium significantly decreased the number of tubers/m2 in small (< 25 g) and increased in medium (25–75 g) and large (> 75 g) grades at 45, 60, 75 and 90 days after planting. Increase in the application of phosphorus increased the number of tubers/m2 in the small grade and decreased it in the large grade but did not affect the number in the medium grade. Increase in nitrogen and potassium application decreased the tuber yield in the small grade and increased it in the medium and large grades. Applied phosphorus increased the yield in the small and medium grades and decreased it in the large grade. The increase in the yield of tubers with increase in nitrogen and potassium application was found to be caused by an increase in the number of tubers in the medium and large grades at the expense of the small grade; however, with applied phosphorus the increase in yield was due to increase in the weight of individual tubers within the small and medium grades. FYM application decreased the number of tubers in the small grade and increased it in the medium and large grades. The response of potato to nitrogen increased and to phosphorus and potassium decreased with the application of FYM.

Incubation experiments were carried out to evaluate the feasibility of extracting phosphorus from soil by embedding iron oxide-impregnated filter paper strips (Pi strips) in soils having a wide range in pH, texture, and extractable-P contents. Under flooded conditions, the amount of P extracted by the P~ strips increased with the period of submergence and embedding time of the P~ strips. Under unsaturated conditions, the P~ strips were found to extract P from soils over a wide range in moisture conditions; however, keeping the soil at moisture level between saturation and field capacity was found to result in maximal sorption of P by the strips. An embedding time of 16 h was found to be adequate.Phosphorus extracted by embedding Pi strips in soil columns for 16 h at field capacity moisture level correlated significantly with P extracted by shaking the soil with 0.01 M CaC12 solution and a P~ strip for 16 h in the laboratory (r = 0.94**). The P extracted by embedding Pi strips correlated best with Bray 1 P in acid soils (r = 0.97**) and with Olsen P in alkaline and calcareous soils (r = 0.96**). The results of the studies demonstrate the feasibility of developing a nondestructive method of monitoring changes in plant-available P in situ under field conditions.

The present study aims to evaluate the inhibition effectiveness of titanium dioxide nanoparticles in combination with cell wall active antibiotics -ceftazidime and cefotaxime against the multi-drug resistant Pseudomonas aeroginosa isolated from pus, sputum, endo-tracheal tract and broncho-alveolar lavage. Commercial Degussa-P25 TiO 2 nanoparticle, antibiotics ceftazidime and cefotaxime were used in this study against multi-drug-resistant nosocomial pathogen. The nanoparticle shows antimicrobial effect on the pathogen at concentrations more than 350 mg/mL, when exposed to ultraviolet (UV) light for an hour. Minimum inhibitory concentration values obtained for the antibiotic cefotaxime were sixfolds higher than the antibiotic ceftazidime. When these antibiotics were used in combination with UV-irradiated metal nanoparticle, ceftazidime resulted in enhanced antimicrobial activity whereas cefotaxime does not show any change.

Distribution of different nitrogen and sulphur fractions and N:S ratios in alfalfa (Medicago sativa L. Pers.) without and with S fertilization has been studied with a green house experiment. With increasing rates of applied S, the concentrations of total N, protein N, total S, protein S and total soluble S in the plant increased but those of non-protein N fractions (total soluble N, amino acid N, amide N, nitrate N) decreased. Thus the adequate supply of S in alfalfa increases the protein synthesis by accelerating protein metabolism. Sulphur application narrowed total N :total S ratios and widened protein N:protein S ratios. The data indicate that one part sulphur was required for every 11 to 12 parts of nitrogen to insure maximum production of protein.