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71.
Trisha Roy Samar Chandra Datta Abhijit Sarkar Siddhartha Sankar Biswas 《Archives of Agronomy and Soil Science》2018,64(11):1564-1581
Non-renewable nature of rock phosphate (RP) reserves coupled with open ended nature of P cycle makes it imperative for maximum utilization of available P resources. In this context, use of Indian RPs from Purulia and Udaipur along with citric acid loaded nanoclay polymer composite (CA-NCPC) as P source to costly diammonium phosphate (DAP) was investigated through an incubation experiment followed by a greenhouse experiment with wheat-rice cropping sequence in a Luvisol (pH 5.14, available P 13.5 mg kg?1). Soil available P, crop yield parameters and dynamics of soil P fractions were taken to judge the efficacy of CA-NCPC in solubilizing RPs. Application of CA-NCPC and DAP resulted in 82% and 69% increase in available P over control, respectively under incubation study. Direct effect of treatment receiving CA-NCPC + RP on yield and P uptake by wheat was comparable with DAP but residual impact of CA-NCPC + RP (16.7 g pot?1) was better than DAP (13.8 g pot?1) in rice. The changes in inorganic P fractions were also significant as inclusion of RP increased calcium-P from 16.1 to 61.5 mg kg?1. Results indicated potentiality of RPs treated with CA-NCPC as an alternate P source which could prove promising amidst P scarcity. 相似文献
72.
Uttam K. Saha Leticia Sonon Bipul K. Biswas 《Communications in Soil Science and Plant Analysis》2018,49(1):63-75
Soil mineral (or inorganic) nitrogen (SMN), which primarily exists as exchangeable and soluble ammonium (NH4+) and the nitrate (NO3?) ions, represents readily available nitrogen for plant growth. Over the years a 2M potassium chloride (KCl) solution has become the extraction solution of choice for extracting SMN. In the research and service laboratories, either distillation-titration method (DTM) or colorimetric method (CM) is virtually the standard to measure NH4+- and NO3?-N in the 2M KCl soil extracts. However, being a time-consuming and labor intensive method, DTM generally has a very low throughput. Likewise, CM is affected by interferences from pH variation, color, turbidity, presence of organic species, and some other constituents in the extracts. In contrast, diffusion conductivity method (DCM) is a less expensive and high throughput one, which is also relatively free from common interferences. In this study, we, therefore, compared the extraction efficiency of various KCl concentrations and performance of diffusion conductivity method (DCM) with DTM in measuring NH4+-N and NO3?-N in KCl extracts of 32 agricultural soils of Georgia. A 0.2M KCl solution extracted statistically similar amounts of NH4+-N and NO3?-N as did 2M KCl, suggesting that a 10-fold dilute KCl solution than the standard 2M KCl might be good enough to extract and estimate the most of SMN. For the analyses of NH4+- and NO3?-N in the KCl extracts, the DCM produced results statistically similar to those produced by DTM. The deviation between the results given by DCM and DTM was no more than ±10%. Thus, DCM appears to be an attractive alternative to the labor intensive and time-consuming DTM for measuring NH4+- and NO3?-N in the KCl extract of soils in the research and service laboratories. 相似文献
73.
The present study focuses on the transformations of nitrogen (N), phosphorus (P), and sulfur (S) in soil amended with rock phosphate (RP) enriched composts prepared using different crop residues under wheat-green gram sequence. Data emanated from the field study revealed that significant buildup in available pools of potassium permanganate (KMnO4-N), Olsen-P, and calcium chloride (CaCl2-S) as well as different fractions of N, P, and S were maintained higher under RP enriched composts treated plot than control. The total N, P, and S varied from 979 to 1776, 604 to 1165, and 273 to 464 kg ha?1, respectively in different treatments. The yield of wheat and green gram was significantly correlated with different fractions of N, P, and S in soil. Results conclude that RP enriched compost could be an alternative and cost-effective option for mitigating the shortage of chemical fertilizers for crop production. 相似文献
74.
Biswas A Sharma BK Willett JL Advaryu A Erhan SZ Cheng HN 《Journal of agricultural and food chemistry》2008,56(14):5611-5616
An environmentally friendly water-based pathway to form the azide derivatives of soybean oil and fatty esters is reported. This entails first the formation of epoxides and then the azidization of the epoxides. The azidization reaction is carried out at high yields in water with only a small amount of an ionic liquid as a catalyst. The distribution of azide and alcohol functionalities on the fatty acid moiety is approximately random. This reaction has been applied to methyl oleate, methyl linoleate, soybean oil, and methyl soyate. The resulting structures have been studied by NMR. 相似文献
75.
Abhijit Majumdar Anindya Ghosh Shib Sankar Saha Ayan Roy Subir Barman Dhrubajyoti Panigrahi Anjan Biswas 《Fibers and Polymers》2008,9(2):240-245
Aesthetic properties of fabrics have been considered as the most important fabric attribute for years. However, recently there
has been a paradigm shift in the domain of textile material applications and consequently more emphasis is now being given
on the mechanical and functional properties of fabrics rather than its aesthetic appeal. Moreover, in certain woven fabrics
used for technical applications, strength is a decisive quality parameter. In this work, tensile strength of plain woven fabrics
has been predicted by using two empirical modelling methods namely artificial neural network (ANN) and linear regression.
Warp yarn strength, warp yarn elongation, ends per inch (EPI), picks per inch (PPI) and weft count (Ne) were used as input
parameters. Both the models were able to predict the fabric strength with reasonably good precision although ANN model demonstrated
higher prediction accuracy and generalization ability than the regression model. The warp yarn strength and EPI were found
to be the two most significant factors influencing fabric strength in warp direction. 相似文献
76.
In eastern India, cultivation of winter maize is getting popular after rainy season rice and farmers practice irrigation scheduling
of this crop based on critical phenological stages. In this study, crop water stress index of winter maize at different critical
stages wase determined to investigate if phenology-based irrigation scheduling could be optimized further. The components
of the energy budget of the crop stand were computed. The stressed and non-stressed base lines were also developed (between
canopy temperature and vapor pressure deficit) and with the help of base line equation, [(T
c − T
a) = −1.102 VPD − 3.772], crop water stress index (CWSI) was determined from the canopy-air temperature data collected frequently
throughout the growing season. The values of CWSI (varied between 0.42 and 0.67) were noted just before the irrigations were
applied at critical phenological stages. The soil moisture depletion was also measured throughout the crop growing period
and plotted with CWSI at different stages. Study revealed that at one stage (silking), CWSI was much lower (0.42–0.48) than
that of recommended CWSI (0.60) for irrigation scheduling. Therefore, more research is required to further optimize the phenology-based
irrigation scheduling of winter maize in the region. This method is being used now by local producers. The intercepted photosynthetically
active radiation and normalized difference vegetation index over the canopy of the crop were also measured and were found
to correlate better with leaf area index. 相似文献
77.
Context
Ecological processes that shape diversity and spatial pattern of ecological communities are often altered by disturbance. Spatial patterns (spatial autocorrelation) in species diversity are thus expected to change with disturbance.Objective
When examining spatial patterns, ecologists traditionally lump positive and negative spatial autocorrelation into the overall spatial autocorrelation. By contrast, here we aim to understand disturbance effects on both positive and negative spatial autocorrelation of species richness and evenness, which may be related to environmental filtering and restricted dispersal, and to competition, respectively.Methods
For 8 years, we monitored the spatial autocorrelation in species richness and evenness of riparian plant communities in both uncut control and experimentally clearcut sites in the boreal forest of Alberta, Canada. The overall spatial autocorrelation for each of these two indices of diversity was separately decomposed into the components of positive and negative spatial autocorrelations through eigendecomposition of the spatial weighting matrix.Results
Negative spatial autocorrelation in richness and evenness were more pronounced in the clearcut than uncut sites, although positive spatial autocorrelations in all indices of diversity remained unchanged. Effect of disturbance was not detected on the overall spatial autocorrelation.Conclusions
Disturbance increases negative spatial autocorrelation in species richness and evenness, with a stronger increase in evenness than richness, which underscores the importance of competition in structuring post-disturbance riparian communities. Our results also highlight the need for assessing positive and negative spatial autocorrelation and different aspects of diversity separately in understanding disturbance effects on the spatial pattern, or identifying processes from patterns.78.
Adult red sea bream, Pagrus major (body weight, 1.0–2.0 kg) was exposed to three photoperiods [12 h light:12 h dark (12L:12D), 16 h light:8 h dark (16L:8D) and 24 h light:0 h dark (24L:0D)] from 2 months before spawning till the end of the spawning season to investigate growth, spawning and stress response. During the spawning season, tanks were checked every morning for spawned eggs. The growth performance in fish under 24L:0D was stimulated with significantly higher feed intake than those under other photoperiods (P<0.05). The number of eggs and gonadal histology confirmed that three and five females out of six in each of duplicate tanks of the 16L:8D treatment spawned. In contrast, only two out of six females in one tank of the 24L:0D treatment spawned, and no spawns were observed in the 12L:12D treatment. At the end of the spawning period, both 17β‐estradiol and testosterone levels were significantly higher in fish exposed to 16L:8D followed by 12L:12D and 24L:0D photoperiods (P<0.05). Photoperiod manipulation did not cause significant stress response in fish (P>0.05). The results suggest that stimulating the growth performance of red sea bream at reproductive stage with a 24L:0D photoperiod is possible if the fish are subjected to this photoperiod long before the onset of the spawning season. 相似文献
79.
Osamu Takaoka Seung‐Cheol Ji Katsuya Ishimaru Si‐Woo Lee Gwan‐Sik Jeong Junichi Ito Amal Biswas Kenji Takii 《Aquaculture Research》2011,42(12):1824-1829
The effects of the dietary medicinal herbs Massa medicata, Crataegi fructus (Cf), Artemisia capillaries, Cnidium officinale and their mixture (HM), on growth and resistance against Vibrio anguillarum were examined using larval red sea bream, Pagrus major. The methanol extracts of Cf and HM inhibited the proliferation of seven infectious bacterial strains including the genera Aeromonas, Edwasiella, Photobavterium, Pseudomonas and Vibrio. Rotifers enriched with emulsified bonito oil containing extracts of Cf and HM lowered the bacterial counts in their body on TCBS medium for the genus Vibrio in comparison with rotifers enriched by emulsified bonito oil alone. Although statistically not significant, larvae fed rotifer fortified with Cf from 3 to 20 days after hatching showed the best growth and final body weight followed by those given rotifer with HM and control enrichment. However, final body length of larvae fed rotifer with Cf was significantly larger than larvae fed on rotifers enriched with other herb extracts. After a challenge test with V. anguillarum, survival of larvae fed rotifer with Cf and HM was significantly higher than for the control treatment. These results revealed that Cf and HM in rotifer is useful to promote growth and resistance against V. anguillarum in red sea bream larvae, providing a new technology for mass production of disease‐resistant fry and fingerlings. 相似文献
80.
Md. Mozammel Haque Jatish Chandra Biswas Sang Yoon Kim Pil Joo Kim 《Paddy and Water Environment》2017,15(2):403-411
Intermittent drainage of rice fields alters soil redox potential and contributes to the reduction of CH4 emission and thus may reduce net global warming potential (GWP) during rice cultivation. Incorporation of green biomass helps maintaining soil organic matter, but may increase CH4 emission. We investigated net ecosystem carbon budget (NECB) and net GWP under two water management regimes—continuous flooding and intermittent drainage—having four biomass incorporation levels (0, 3, 6 and 12 Mg ha?1). Water management and biomass incorporation level demonstrated significant (P < 0.05) interaction effect on the NECB and GWP. Intermittent drainage decreased the NECB by ca. 6–46 % than continuous flooding under same rates of cover crop biomass (CCB) incorporation. Moreover, intermittent drainage reduced seasonal CH4–C fluxes by ca. 54–58 % and net GWP by 35–58 % compared to continuous flooding. There was also no significant reduction in rice yield because of intermittent drainage under similar CCB. This implies that incorporation of 3 Mg ha?1 CCB and intermittent drainage could be a good option for reducing net GWP and higher grain yield. 相似文献