Effect of organic materials and rice cultivars on methane emission from rice field

A field experiment was conducted for two years on a sandy loam (Typic Ustochrept) soil of Punjab to study the effect of organic materials and rice cultivars on methane emission from rice fields. The methane flux varied between 0.04 and 0.93 mg m(-2) hr(-1) in bare soil and transplanting of rice crop doubled the methane flux (0.07 to 2.06 mg m(-2) hr(-1)). Among rice cultivars, significantly (p < 0.05) higher amount of methane was emitted from Pusa 44 compared to PR 118 and PR 111. Application of organic materials enhanced methane emission from rice fields and resulted in increased soil organic carbon content. The greatest seasonal methane flux was observed in wheat straw amended plots (229.6 kg ha(-1)) followed by farmyard manure (111.6 kg ha(-1)), green manure (85.4 kg ha(-1)) and the least from rice straw compost amended plots (36.9 kg ha(-1)) as compared to control (21.5 kg ha(-1)). The differential effect of organic materials in enhancing methane flux was related to total carbon or C:N ratio of the material. The results showed that incorporation of humified organic matter such as rice straw compost could minimize methane emission from rice fields with co-benefits of increased soil fertility and crop productivity.     

Methane emission from rice fields in relation to management of irrigation water

A field experiment was conducted for two years to find out best water management practice to mitigate methane emission from the rice-fields. Continuously flooded conditions yielded two major flushes of methane emission and on an average resulted in relatively higher rate of methane emission (2.20 and 1.30 mg m(-2) hr(-1), respectively in 2005 and 2006) during the kharif season. The methane flux was reduced to half (1.02 and 0.47 mg m(-2) hr(-1), respectively in 2005 and 2006) when rice fields were irrigated 2-3 days after infiltration of flood water into the soil. Irrigating the field at 0.15 bar matric potential reduced seasonal methane flux by 60% (0.99 and 0.41 mg m(-2) hr(-1), respectively in 2005 and 2006) as compared to completely flooded conditions, without any decline in grain yield (60 q ha(-1)).     

Evaluation of genotoxic potential of industrial waste contaminated soil extracts of Amritsar, India

The rapid increase in population together with unplanned disposal of effluents from various industries has resulted in accumulation of various heavy metals like As, Cr, Cu, Hg, Ni, Pb and Zn in soil ecosystem which ultimately causes DNA damage in living systems. Considering this, the present study was designed to evaluate the content of various heavy metals (Cu, Cr, Co, Hg, Mn, Ni, Zn) and genotoxicity/mutagenicity of soil samples collected from the outskirts of two industries viz. zinc coating industry (SI) and copper sulphate manufacturing industry (SII) employing Allium root anaphase aberration assay (A/RAAA) and Ames assay. The physicochemical parameters like bulk density, water holding capacity, moisture content, pH, nitrates, phosphates and potassium were also estimated. It was observed that SI sample contained Ni (6.86 mg g-1), Zn (6.53 mg g-1), Co (5.05 mg g-1) and Cr (4.49 mg g-1), while SII contained Cu (32.86 mg g-1), Ni (9.66 mg g-1), Co (6.85 mg g-1) and Zn (5.41 mg g-1). In A/RAA assay, the percentage of cells with anaphase aberrations ranged from 3.63 to 10.67 and 0.38 to 4.83% for samples SI and SII, respectively. In Ames test, sample SII was found to be lethal to Salmonella tester strains at all concentrations used, while sample SI was found to be mutagenic in TA100 strains of Salmonella typhimurium. Sample SII was found to be strongly acidic with pH 3.46. The present study focuses on the increasing heavy metal pollution in Amritsar city due to industrial discharges over lands and also infers that both bioassays Ames and A/RAAA can serve as first alert indication of pollution.     

Volatile chemicals from leaf litter are associated with invasiveness of a neotropical weed in Asia

Some invasive plant species appear to strongly suppress neighbors in their nonnative ranges but much less so in their native range. We found that in the field in its native range in Mexico, the presence of Ageratina adenophora, an aggressive Neotropical invader, was correlated with higher plant species richness than found in surrounding plant communities where this species was absent, suggesting facilitation. However, in two nonnative ranges, China and India, A. adenophora canopies were correlated with much lower species richness than the surrounding communities, suggesting inhibition. Volatile organic compound (VOC) signals may contribute to this striking biogeographical difference and the invasive success of A. adenophora. In controlled experiments volatiles from A. adenophora litter caused higher mortality of species native to India and China, but not of species native to Mexico. The effects of A. adenophora VOCs on seedling germination and growth did not differ between species from the native range and species from the nonnative ranges of the invader. Litter from A. adenophora plants from nonnative populations also produced VOCs that differed quantitatively in the concentrations of some chemicals than litter from native populations, but there were no chemicals unique to one region. Biogeographic differences in the concentrations of some volatile compounds between ranges suggest that A. adenophora may be experiencing selection on biochemical composition in its nonnative ranges.     

Comparing the nutrient changes,heavy metals,and genotoxicity assessment before and after vermicomposting of thermal fly ash using Eisenia fetida

Environmental Science and Pollution Research - Fly ash (FA) is available in an unstable state and can be ameliorated by vermicomposting. The different ratios of FA viz (FA10, FA15, FA20, FA25,...     

Implications of endocrine-disrupting chemicals on polycystic ovarian syndrome: A comprehensive review

Environmental Science and Pollution Research - Polycystic ovarian syndrome (PCOS) is a complex multifactorial disorder of unknown pathogenesis in which genetic and environmental factors contribute...     

Recycling/reuse of plastic waste as construction material for sustainable development: a review

Environmental Science and Pollution Research - The exponential rise in the production of plastic and the consequential surge in plastic waste have led the scientists and researchers look out for...     

Studies on the role of six enzymes in the metabolism of kinetin in mustard aphid, Lipaphis erysimi (Kalt.)

The activity of catalase, glutathione peroxidase, superoxide dismutase, O-demethylase, ATPase and succinate dehydrogenase, belonging to two main classes of detoxification enzymes (i.e. hydrolases and oxido-reductases), mostly involved in metabolism and degradation of xenobiotics in insects, were assessed under the influence of kinetin, a plant growth regulator (PGR). The nymphs (48-52 hr old) of Lipaphis erysimi (Kalt.) were permitted to feed on radish plant, Raphanus sativus L. treated with kinetin (400 ppm) for 13, 25 and 37 hr. It was found that the activity of catalase, glutathione peroxidase and superoxide dismutase increased significantly when compared with the control of the same age group, which indicated that these enzymes might be playing a significant role in the metabolism of kinetin in this insect. The activity of O-demethylase showed an increase up to 25 hr of the treatment but it decreased under prolonged treatment whereas the activity of succinate dehydrogenase fluctuated insignificantly. ATPase showed a decrease in the activity with the treatment suggesting kinetin's interference in synthesis of ATPase.     

Role of ion track filters in environmental surveillance.

Ion track filters (ITFs) are produced by physiochemical treatments to thin films of polymers and mica irradiated by heavy ions. These ITFs have many applications in the fields of science and technology. In the present investigation, the developed ITFs from polycarbonate films have been used to filter bacteria of various types in water. It is observed that the electric conduction through these filters depends upon the concentration of contaminants and pore diameter of filters. Filtration experiments were carried out using both single and multipore filters. Other applications related to environment surveillance have also been reported.     

Agroecotoxicological Aspect of Cd in Soil–Plant System: Uptake,Translocation and Amelioration Strategies

Environmental Science and Pollution Research - Cadmium (Cd) is considered to be one of the most toxic pollutants persistent in soil for thousands of years and is ranked on seventh position among...