Soil degradation due to heavy metal accumulation under long term fertilization of paddy (Oryza sativa L.)

Long term fertility experiment (LTFE) under double rice cropping system was investigated in Tamil Nadu Rice Research Institute, Aduthurai, India with two varieties (ADT 43 and ADT 45) in two seasons (Kharif and Rabi) under six fertilizer treatments to study the heavy metal accumulation in soil and its impact on paddy. There was a significant variation in physico-chemical properties of soil due to different fertilizer treatments. The surface soil (0-15cm soil depth) in all the treatments showed relatively higher heavy metal accumulation than subsurface. In thelong run, there was a build up in the total heavy metal content in soil and it was found to be relatively high in phosphatic fertilizer applied treatments than others. Total Cd and Pb was found high, but the availability was below detectable limit indicated that Cd and Pb were found in unavailable forms, while Cu and Zn were slightly in mobile forms which had been translocated into grain and straw of paddy. The DTPA (Diphenyl Triamine Penta Aceticacid) extractable Cd and Pb in the soil was low, but there was heavy increase in Cu and Zn comparing with initial period. The rate of increase in Cd and Pb content was lower in N alone and control plots. This might be due to the long term application of phosphotic and zinc sulphate fertilizers. Cd and Pb were evenly distributed at low concentrations in grain and straw under various treatments. In case of Cu and Zn, it was relatively higher in grains and paddy strawamong various fertilizer treatments. There was no significant difference among the varietal (seasons) treatments for the accumulation of heavy metals in grain and straw

Utilization of flower waste for the removal of chromium from tannery effluent

In this work we used flower waste biomass as a biosorbent to remove Cr from tannery effluent through column experiments. The sorption capacities of biosorbent (Fine, coarse and rough grades) were also evaluated by employing chemical pretreatments viz., sodium hydroxide, acetic acid, glutaraldehyde and hydrogen peroxide. The order of percentage removal of Cr using the above pretreatments was: 10% hydrogen peroxide < Raw powdered-FWB < 2% Gluteraldehyde < 10% Acetic acid < 0.1N sodium hydroxide. Among the different grades of biosorbents used, fine grade adsorbed more Cr (70 %) than that of coarse (64%) and rough (62 %) sorbents. The removal percentage of Cr from tannery was analyzed by using Atomic Absorption Spectroscopy, the functional groups which are responsible for adsorption was examined by Fourier Transform- Infrared Spectroscopy and the amorphous behaviour of FWB facilitating metal biosorption was indicated by the X-ray diffractogram. This study showed that pretreated flower waste biomass is a potential sorbent of Cr, which could be successfully used to reduce the Cr content in tannery effluent

Evaluation of localization of lead and nickel in plant cells of Amaranthus sp. and Brassica sp. absorbed from mine spoil waste

A detailed survey was undertaken in the sewage water contaminated areas of Coimbatore to select the natural hyper accumulators to rehabilitate the contaminated mine spoils. From this experiment the Pb and Ni accumulators, Amaranthus sp. and Brassica sp. were selected for further studies towards remediating the metal contaminated mine spoils. Microtomy of root, stem and leaf of Amaranthus sp. and Brassica sp. showed that the colour development in the plant species is evidence for accumulation of metals in different parts of plants and also tolerance mechanism employed by plant species under metal stress condition. The accumulation of heavy metals from soil to plant did not follow any particular pattern and varied with respect to metals, species and plant parts. However, the maximum Pb localization took place in root portion than in aerial parts. But the Ni accumulation was almost equal or higher in aerial parts (leaf and stem) compared to roots. This study revealed that the Amaranthus sp and Brassica sp stored lead and nickel in roots, leaves and stems. The roots showed more localization of metals followed by leaves and stems

Root canal irrigants influence the hydrophobicity and adherence of Staphylococcus epidermidis to root canal dentin: an in vitro study

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Influence of Nano Urea on Growth and Microbial Population in Paddy Ecosystem

Chemical fertilizer usage has been a long-drawn criticism because of its harmful effects on the environment and on the quality of agricultural produce. Researchers are continually looking for more productive, better solutions while retaining societal wellbeing. Effective use of nano fertilizers in place of chemical fertilizers is essential in reducing fertilizer overuse and also contribute in lowering the pollution and leaching which in turn increase the effectiveness of nutrient consumption and also increase the yield of the crop. An experiment was carried out in paddy to study the influence of Nano urea applications on growth and microbial populations in soil. The field trial used a Randomized Block Design (RBD) with eight treatment combinations and three replications. Results showed that application of STCR based N as Urea (50%) and Nano Urea (2 sprays) and Recommended dosage of N as Urea (50%) and Nano Urea (2 sprays) recorded higher plant height, Leaf Area Index (LAI), Dry matter accumulation in paddy. In addition, applications of Nano urea increased the microbial population including bacteria, fungi and actinomycetes. Combining recommended dosage of fertilisers with nano urea spray at critical stages of paddy crop increases the crop growth and microbial activity