Geo-spatial analysis of the temporal trends of kharif crop phenology metrics over India and its relationships with rainfall parameters

The Global Inventory Modeling and Mapping Studies bimonthly Normalized Difference Vegetation Index (NDVI) data of 8?×?8 km spatial resolution for the period of 1982–2006 were analyzed to detect the trends of crop phenology metrics (start of the growing season (SGS), seasonal NDVI amplitude (AMP), seasonally integrated NDVI (SiNDVI)) during kharif season (June to October) and their relationships with the amount of rainfall and the number of rainy days over Indian subcontinent. Direction and magnitude of trends were analyzed at pixel level using the Mann–Kendall test and further assessed at meteorological subdivision level using field significance test (α?=?0.1). Significant pre-occurrence of the SGS was observed over northern (Punjab, Haryana) and central (Marathwada, Vidarbha and Madhya Maharashtra) parts, whereas delay was found over southern (Rayalaseema, Coastal Andhra Pradesh) and eastern (Bihar, Gangetic West Bengal and Sub-Himalayan West Bengal) parts of India. North, west, and central India showed significant increasing trends of SiNDVI, corroborating the kharif food grain production performance during the time frame. Significant temporal correlation (α?=?0.1) between the rainfall/number of rainy days and crop phenology metrics was observed over the rainfed region of India. About 35–40 % of the study area showed significant correlation between the SGS and the rainfall/number of rainy days during June to August. June month rainfall/number of rainy days was found to be the most sensitive to the SGS. The amount of rainfall and the number of rainy days during monsoon were found to have significant influence over the SiNDVI in 24–30 % of the study area. The crop phenology metrics had significant correlation with the number of rainy days over the larger areas than that of the rainfall amount.     

Understanding clay minerals with fuzzy mathematics

A long-existing geochemical problem is the lack of a means of chemically defining non-stoichiometric complex minerals such as clays, which have no distinct composition and no clear compositional boundaries. We propose here a novel approach for describing the chemical nature of clay minerals using fuzzy logic. This non-conventional mathematical approach allows us to quantify compositional vagueness in such systems. We show that a clay mineral can be described in terms of how compositionally representative it is, of its own type ('belonging-ness') and to what extent it resembles other types (compositional overlap). Many clay minerals are seen to be far from the ideal, and most minerals are also to a lesser (and sometimes greater) extent, close to types other than their own. This has provided a means of grading such minerals, evaluating how 'good' a sample is, and defining the extent of transition to other phases. We have derived here the fundamental methodology for such computations, which could be a framework for the analysis of other complex chemical systems, especially in the fields of geology and metallurgy.     

Breakthrough adsorption study of migratory nickel in fine-grained soil.

The present study was conducted to evaluate the breakthrough curve for nickel adsorption in fine-grained soil from a nearby ash pond site of a thermal power plant. Nickel was found to be the major polluting solute in the ash sluicing wastewater. The adsorption of nickel by vertical soil column batch test and horizontal migration test was carried out in the laboratory. Field investigation was conducted also, by installing test wells around the ash pond site. Experimental results showed a good adsorptive capacity of soil for nickel ions. The breakthrough curves showed a reasonable fitting with a one-dimensional mathematical model. The breakthrough curves yielded from field test results showed good agreement with a two-dimensional mathematical model.     

Physico-chemical and bacteriological investigation on the River Torsa of North Bengal

A few physico-chemical and bacteriological parameters on certain locations of the river Torsa was studied. The major characteristics of Torsa river water were high alkalinity, high concentration of free ammonia with respect to albuminoid ammonia and the presence of bacteria of fecal origin. Marked seasonal variations of the parameters were also observed.     

Sewage fluxes and seasonal dynamics of physicochemical characteristics of the Bhagirathi-Hooghly River from the lower stretch of River Ganges,India

ABSTRACT

To understand the temporal variations of the physicochemical characteristics of the Bhagirathi-Hooghly River (BHR), three locations representing three districts of West Bengal were selected. The material fluxes from 34 drains during pre-monsoon season was quantified. The analysis of variance (ANOVA) revealed that no significant spatial variations were observed for the physicochemical parameters, whereas seasonal variations were significant. The mean discharge was found to be highest (247.2?×?10³?m³?d^?1) in the midstream drains. Highest mean concentrations of dissolved oxygen (DO) (7.35?mg?L^?1) and nitrate (0.81?mg?L ^?1) were observed during the post-monsoon season followed by the monsoon and pre-monsoon. According to the BIS, WHO and the European standard of water quality (pH, 6.5–8.5; Nitrate, 0–2.5?mg?L^?1;DO, ≥5?mg?L^?1), the results of the respective parameters revealed the BHR system is maintained at high to good water quality, meaning that the BHR system is slightly altered from its pristine environment. The mean concentrations of biological and chemical oxygen demands were found to be high during the monsoon season, revealing that a large quantity of refractory organic matter is transported to the eastern Bay of Bengal from the Ganges.     

Magnitude of anthropogenic phosphorus storage in the agricultural production and the waste management systems at the regional and country scales

Based on a systematic review of 17 recent substance flow analyses of phosphorus (P) at the regional and country scales, this study presents an assessment of the magnitude of anthropogenic P storage in the agricultural production and the waste management systems to identify the potential for minimizing unnecessary P storage to reduce the input of P as mineral fertilizer and the loss of P. The assessment indicates that in case of all (6) P flow analyses at the regional scale, the combined mass of annual P storage in the agricultural production and the waste management systems is greater than 50 % of the mass of annual P inflow as mineral fertilizer in the agricultural production system, while this is close to or more than 100 % in case of half of these analyses. At the country scale, in case of the majority (7 out of 11) of analyses, the combined mass of annual P storage in the agricultural production and the waste management systems has been found to be roughly equivalent or greater than 100 % of the mass of annual P inflow as mineral fertilizer in the agricultural production system, while it ranged from 30 to 60 % in the remaining analyses. A simple scenario analysis has revealed that the annual storage of P in this manner over 100 years could result in the accumulation of a massive amount of P in the agricultural production and the waste management systems at both the regional and country scales. This study suggests that sustainable P management initiatives at the regional and country scales should put more emphasis on minimizing unwanted P storage in the agricultural production and the waste management systems.     

Variations of bed elevations due to turbulence around submerged cylinder in sand beds

This paper presents the spatio-temporal variations in bed elevations and the near-bed turbulence statistics over the deformed bed generated around the submerged cylindrical piers embedded vertically on loose sediment bed at a constant flow discharge. Experiments were carried out in a laboratory flume for three blockage ratios in the range of 0.04–0.06 using three different sizes of submerged cylinders individually placed vertically at the centerline of the flume. Clear-water experimental conditions were maintained over the smooth sediment bed surface with a constant flow discharge (\(Q = 0.015\,{\rm m}^3/{\rm sec}\)), thereby giving three different cylinder Reynolds numbers \(Re_{D_c} = \frac{U_mD_c}{\nu }\) (=10200, 12750, 15300) away from the cylinder locations, where \(U_m\) is the maximum mean velocity, \(D_c\) is the cylinder diameter and \(\nu\) is the kinematic viscosity of fluid. Instantaneous sand bed elevations around the cylinders were recorded using a SeaTek 5MHz ultrasonic ranging system of net 24 transducers to estimate bed form migration, and the near-bed velocity data at transducer locations over the stable deformed bed around the pier-like structures were collected using down-looking three-dimensional (3D) Micro-acoustic Doppler velocimeter to estimate the bottom Reynolds shear stresses and the contributions of bursting events to the dominant shear stress component. The flow perturbation generated due to relatively lower flow blockage ratio favored to achieve the stable bed condition more rapidly than the others, and larger upstream scour-depth and deformed areas were noticed for greater flow blockage ratio due to larger cylinder diameter. For larger blockage ratio in the upstream of scour-hole near the bed, occurrences of probabilities of both boundary-ward interactions (Q1 and Q3) were the dominant; whereas in the downstream of the scoured region, occurrences of probabilities of second and third quadrant events (Q2 and Q4) were dominant. On the other hand, for the lower blockage ratio, quadrant (Q2) was dominant over Q4 in the downstream of scour-hole, and in the upstream of scour-hole, quadrant Q4 was the dominant.     

A comparative study on valuable products: bio-oil,biochar, non-condensable gases from pyrolysis of agricultural residues

Journal of Material Cycles and Waste Management - In this study, pyrolysis of agricultural residues, such as rice straw (RS), wheat straw (WS), and sugarcane bagasse (SB), was performed in a...