Role of blue green algae biofertilizer in ameliorating the nitrogen demand and fly-ash stress to the growth and yield of rice (Oryza sativa L.) plants

Rice is a major food crop throughout the world; however, accumulation of toxic metals and metalloids in grains in contaminated environments is a matter of growing concern. Field experiments were conducted to analyze the growth performance, elemental composition (Fe, Si, Zn, Mn, Cu, Ni, Cd and As) and yield of the rice plants (Oryza sativa L. cv. Saryu-52) grown under different doses of fly-ash (FA; applied @ 10 and 100 tha(-1) denoted as FA(10) and FA(100), respectively) mixed with garden soil (GS) in combination with nitrogen fertilizer (NF; applied @ 90 and 120 kg ha(-1) denoted as NF(90) and NF(120), respectively) and blue green algae biofertilizer (BGA; applied @ 12.5 kg ha(-1) denoted as BGA(12.5)). Significant enhancement of growth was observed in the plants growing on amended soils as compared to GS and best response was obtained in amendment of FA(10)+NF(90)+BGA(12.5). Accumulation of Si, Fe, Zn and Mn was higher than Cu, Cd, Ni and As. Arsenic accumulation was detected only in FA(100) and its amendments. Inoculation of BGA(12.5) caused slight reduction in Cd, Ni and As content of plants as compared to NF(120) amendment. The high levels of stress inducible non-protein thiols (NP-SH) and cysteine in FA(100) were decreased by application of NF and BGA indicating stress amelioration. Study suggests integrated use of FA, BGA and NF for improved growth, yield and mineral composition of the rice plants besides reducing the high demand of nitrogen fertilizers.     

Clear effects of soil organic matter chemistry, as determined by NMR spectroscopy, on the sorption of diuron

Organic matter has long been recognized as the main sorbent phase in soils for hydrophobic organic compounds (HOCs). In recent times, there has been an increasing realization that not only the amount, but also the chemical composition, of organic matter can influence the sorption properties of a soil. Here, we show that the organic carbon-normalized sorption coefficient (K(OC)) for diuron is 27-81% higher in 10 A11 horizons than in 10 matching A12 horizons for soils collected from a small (2ha) field. K(OC) was generally greater for the deeper (B) horizons, although these values may be inflated by sorption of diuron to clays. Organic matter chemistry of the A11 and A12 horizons was determined using solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. K(OC) was positively correlated with aryl C (r2=0.59, significance level 0.001) and negatively correlated with O-alkyl C (r2=0.84, significance level <0.001). This is only the second report of correlations between whole soil K(OC) and NMR-derived measures of organic matter chemistry. We suggest that this success may be a consequence of limiting this study to a very small area (a single field). There is growing evidence that interactions between organic matter and clay minerals strongly affect K(OC). However, because the soil mineralogy varies little across the field, the influence of these interactions is greatly diminished, allowing the effect of organic matter chemistry on K(OC) to be seen clearly. This study in some way reconciles studies that show strong correlations between K(OC) and the chemistry of purified organic materials and the general lack of such correlations for whole soils.     

Assessment of yield losses in tropical wheat using open top chambers

The present study deals with the evaluation of effects of ambient gaseous air pollution on wheat (Triticum aestivum L. var. HUW-234) growing in a suburban area situated in eastern Gangetic plain of India, using open top chambers. Eight hourly air monitoring was conducted for ambient concentrations of SO₂, NO₂ and O₃ in filtered chambers (FCs), non-filtered chambers (NFCs) and open plots (OPs). Various morphological, physiological and biochemical parameters were assessed during different developmental stages and finally yield parameters were quantified at the time of harvest.Mean concentrations of SO₂, NO₂ and O₃ were 8.4, 39.9 and 40.1 ppb, respectively during the experiment in NFCs. Concentrations of SO₂, NO₂ and O₃ reduced by 74.6%, 84.7% and 90.4%, respectively in FCs as compared to NFCs. Plants grown in FCs showed higher photosynthetic rate, stomatal conductance, chlorophyll content and Fv/Fm ratio as compared to the plants in NFCs and OPs. Lipid peroxidation, proline, total phenol and ascorbic acid contents and peroxidase activity were higher in plants grown in NFCs. There were improvements in morphological parameters of plants growing in FCs as compared to those in NFCs and OPs. Yield of plants also increased significantly in FCs as compared to those ventilated with ambient air (NFCs) or grown in OPs. During the vegetative phase, NO₂ concentrations were higher than O₃, but O₃ became dominant pollutant during the time of grain setting and filling. The study concludes that O₃ and NO₂ are the main air pollutants in the sub-urban areas causing significant yield reductions in tropical wheat plants.     

Vegetation pattern related tc grazing pressure in alpine meadows of Nanda Devi Biosphere Reserve

The present study aims to analyze the interaction of prevailing biotic pressure on plant species diversity in Nanda Devi Biosphere Reserve (NDBR) which lies in northern part of Uttaranchal hills between 79 degrees 40'E to 80 degrees 05'E longitude and 30 degrees 17' N to 30 degrees 41'N latitude and covers an area of 2236.7 km2. A total of 75 species has been found which included the herbaceous plants viz., grasses, sedges and forbs. Generally, the plants have a short life span of 3-4 months. However, few species persist throughout the growth period i.e. May-October. Phytosociological study performed in plots of varying slope and grazing pressure intensity revealed that the dominant grasses were Danthonia cachemyriana and Poa annua and dominant forbs were Trachydium roylei and Geum elatum in all the plots. Grasses were abundant on west facing slopes while forbs preferred the even topography of east facing meadows. The grasses and sedges together had optimum density during July and August. In general, short lived species exhibited more diversity for one or two months whilst the long lived species exhibited optimum diversity althrough the snow free period. The species diversity is maximum (100%) in moderately grazed bughiyals i.e. Pacchu and minimum in intensively grazed bughiyals i.e. Martoli. The species distribution among the plots was 60-90% contagious and 11.2-38.0% randomirrespective of grazing pressure, thus highlighting the significance of grazing pressure in management of alpine meadows.     

Fly-ash induced synthesis of phytochelatins in chickpea (Cicer arietinum L.) plants

Phytochelatins and related metabolites (cysteine and GSH) were found to be induced in the shoots of two varieties of Cicer arietinum viz., CSG-8962 and C-235 grown under different amendments of fly-ash with garden soil and press mud. Cysteine, GSH, PCs and its speciation were found in higher concentrations in amended fly-ash than in the control 100% soil. Two species of metal binding peptides i.e., PC2 and PC4 were found in both varieties and in amendments, however, their concentration varied depending upon the fly-ash concentrations in both amendments. Further, var. CSG-8962 was found more tolerant than var. C-235 because of higher concentrations of PCs and related metabolites.     

Assessment of the pulp and paper mill effluent on growth,yield and nutrient quality of wheat (Triticum aestivum L.)

Assessment of agropotentiality of the effluent coming out from century pulp and paper mill, Ghanshyamdham, Lalkua (Uttaranchal) has been made on wheat (Triticum aestivum var. UP-2329) crop grown in two soils differing in texture with different effluent concentrations. Diluted effluent increased the chlorophyll content, plant height, shoot and root biomass, grain yield, protein, carbohydrate and lipid contents in wheat grains, while undiluted effluent caused inhibition in plant growth resulting in a sharp decline of yield. Pure soil provided better growth and yield results than those soil mixed with sand.     

Investigating hydrochemistry of groundwater in Indo-Gangetic alluvial plain using multivariate chemometric approaches

Groundwater hydrochemistry of an urban industrial region in Indo-Gangetic plains of north India was investigated. Groundwater samples were collected both from the industrial and non-industrial areas of Kanpur. The hydrochemical data were analyzed using various water quality indices and nonparametric statistical methods. Principal components analysis (PCA) was performed to identify the factors responsible for groundwater contamination. Ensemble learning-based decision treeboost (DTB) models were constructed to develop discriminating and regression functions to differentiate the groundwater hydrochemistry of the three different areas, to identify the responsible factors, and to predict the groundwater quality using selected measured variables. The results indicated non-normal distribution and wide variability of water quality variables in all the study areas, suggesting for nonhomogenous distribution of sources in the region. PCA results showed contaminants of industrial origin dominating in the region. DBT classification model identified pH, redox potential, total-Cr, and λ ₂₅₄ as the discriminating variables in water quality of the three areas with the average accuracy of 99.51 % in complete data. The regression model predicted the groundwater chemical oxygen demand values exhibiting high correlation with measured values (0.962 in training; 0.918 in test) and the respective low root mean-squared error of 2.24 and 2.01 in training and test arrays. The statistical and chemometric approaches used here suggest that groundwater hydrochemistry differs in the three areas and is dominated by different variables. The proposed methods can be used as effective tools in groundwater management.     

Smart nanopackaging for the enhancement of food shelf life

Environmental Chemistry Letters - Food spoilage is a major global concern due to the lack of proper packaging technology. Nanotechnology is expected to improve food packaging. Indeed, novel...     

Desorption of cadmium from goethite: effects of pH, temperature and aging

Cadmium is perhaps environmentally the most significant heavy metal in soils. Bioavailability, remobilization and fate of Cd entering in soils are usually controlled by adsorption-desorption reactions on Fe oxides. Adsorption of Cd on soil colloids including Fe oxides has been extensively studied but Cd desorption from such soil minerals has received relatively little attention. Some factors that affect Cd adsorption on goethite include pH, temperature, aging, type of index cations, Cd concentrations, solution ionic strength and presence of organic and inorganic ions. This research was conducted to study the influence of pH, temperature and aging on Cd desorption from goethite. Batch experiments were conducted to evaluate Cd desorption from goethite with 0.01 M Ca(NO3)2. In these experiments Cd desorption was observed at 20, 40 and 70 degrees C in combination with aging for 16 h, 30, 90 and 180 d from goethite that adsorbed Cd from solutions containing initial Cd concentrations of 20, 80 and 180 microM. Following the adsorption step Cd desorption was measured by 15 successive desorptions after aging at various temperatures. At the lowest amount of initially adsorbed Cd and equilibrium pH 5.5, cumulative Cd desorption decreased from 71% to 17% with aging from 16 h to 180 d and the corresponding decrease at equilibrium pH 6.0 was from 32% to 3%. There was a substantial decrease in Cd desorption with increasing equilibration temperature. For example, in goethite with the lowest amount of initial adsorption at equilibrium pH 5.5, cumulative Cd desorption decreased from 71% to 31% with increase in temperature from 20 to 70 degrees C, even after 16 h. Dissolution of Cd adsorbed goethite in 1M HCl, after 15 successive desorptions with 0.01 M Ca(NO3)2, indicated that approximately 60% of the Cd was surface adsorbed. Overall, dissolution kinetics data revealed that 23% to 88% Cd could not be desorbed, which could possibly be diffused into the cracks and got entrapped in goethite crystals. At elevated temperature increased equilibrium solution pH favoured the formation of CaCO3 and CdCO3 which reasonably decreased Cd desorption. Cadmium speciation showed the formation of calcite and otavite minerals at 40 and 70 degrees C due to increase in pH (>9.5) during aging. X-ray diffraction analysis (XRD) of these samples also revealed the formation of CaCO3 at elevated temperatures with aging. While mechanisms such as Cd diffusion and/or entrapment into fissures and cracks in goethite structure with increase in temperature and aging are possible.     

Sorption of isoxaflutole diketonitrile degradate (DKN) and dicamba in unsaturated soil

When analyzing the sorption characteristics of weakly sorbing or labile pesticides, batch methods tend to yield a high margin of error attributable to errors in concentration measurement and to degradation, respectively. This study employs a recently developed unsaturated transient flow method to determine the sorption of isoxaflutole's herbicidally active diketonitrile degradate (DKN) and dicamba. A 20-cm acrylic column was packed with soils with varied texture that had been uniformly treated with 14C-labeled chemical.The antecedent solution herbicide in equilibrium with sorbed phase herbicide was displaced by herbicide-free water, which was infiltrated into the column. Sorption coefficients, Kd, were obtained from a plot of total herbicide concentration in the soil versus water content in the region where the antecedent solution accumulated. DKN Kd values were approximately 2-3 times (average Kd = 0.71 L kg-1) greater using the unsaturated transient flow method as compared to the batch equilibration method in clay loam (Kd = 0.33 L kg-1), but similar for the two methods in sand (0.12 vs 0.09 L kg-1) soils. Dicamba Kd values were 3 times greater using the unsaturated transient flow method as compared to the batch equilibration method in the clay loam soil (0.38 vs 0.13 L kg-1), however, the Kd values were the same for the two methods in the sand (approximately 0.06 L kg-1). This demonstrates that to determine sorption coefficients for labile hydrophilic pesticides, an unsaturated transient flow method may be a suitable alternative to the batch method. In fact, it may be better in cases where transport models have overpredicted herbicide leaching when batch sorption coefficients have been used.