Effect of potassium on soil conservation and productivity of maize/cowpea based crop rotations in the north-west Indian Himalayas     

Birendra Nath Ghosh  Om Pal Singh Khola  Ranjan Bhattacharyya  Kuldeep Singh Dadhwal  Prasant Kumar Mishra 《山地科学学报》2016,13(4):754-762

Plots under conservation tillage may require higher amount of potassium (K) application for augmenting productivity due to its stratification in upper soil layers, thereby reducing K supplying capacity in a medium or long-term period. To test this hypothesis, a field experiment was performed in 2002-2003 and 2006-2007 to study the effect of K and several crop rotations on yield, water productivity, carbon sequestration, grain quality, soil K status and economic benefits derived in maize (Zea mays L)/cowpea (Vigna sinensis L.) based cropping system under minimum tillage (MT). All crops recorded higher grain yield with a higher dose of K (120 kg K₂O ha^-1) than recommended K (40 kg K₂O ha^-1). The five years’ average yield data showed that higher K application (120 kg K₂O ha^-1) produced 16.4% (P<0.05) more maize equivalent yield. Cowpea based rotation yielded 14.2% (P<0.05) higher production than maize based rotation. The maximum enhancement was found in cowpea-mustard rotation. Relationship between yield and sustainable indices revealed that only agronomic efficiency of fertilizer input was significantly correlated with yield. Similarly, higher doses of K application not only increased the water use efficiency (WUE) of all crops, but also reduced runoff and soil loss by 16.5% and 15.8% under maize and 23.3% and 19.7% under cowpea cover, respectively. This study also revealed that on an average 16.5% of left over carbon input contributed to soil organic carbon (SOC). Here, cowpea based rotation with the higher K application increased carbon sequestration in soil. Potassium fertilization also significantly improved the nutritional value of harvested grain by increasing the protein content for maize (by 9.5%) and cowpea (by 10.6%). The oil content in mustard increased by 5.0% and 6.0% after maize and cowpea, respectively. Net return also increased with the application of the higher K than recommended K and the trend was similar to yield. Hence, the present study demonstrated the potential yield and profit gains along with resource conservation in the Indian Himalayas due to annual additions of higher amount of K than the recommended dose. The impact of high K application was maximum in the cowpea-mustard rotation.  相似文献   

Size matters: experimental partitioning of the strength of fish herbivory on a fringing coral reef in Moorea,French Polynesia          下载免费PDF全文

Peggy Fong  Nicholas M. Frazier  Cameron Tompkins‐Cook  Ranjan Muthukrishnan  Caitlin R. Fong 《Marine Ecology》2016,37(5):933-942

While the importance of top‐down control by grazers in maintaining tropical reef community structure is well known, the effect of ‘fishing down the food web’, which simultaneously changes the abundance and size of herbivorous fishes, has received less attention. As many fishing practices target the biggest fish and regulations often set minimum size limits, understanding size‐dependency of this controlling force is important. We evaluated the hypothesis that reduction in the abundance and size of fish, regardless of species identity, reduces the role of herbivory in controlling algal abundance on reefs and assessed variation in efficacy of this top‐down control on different types of common macroalgae. We quantified herbivory rates within cages of differing opening sizes on assemblages of four common algal species (Padina boryana, Dictyota bartayresiana, Halimeda opuntia and Galaxaura fasciculata) on two fringing reefs in Moorea, French Polynesia. Small acanthurids (<15 cm length) were the dominant herbivorous fish while other herbivorous fish were rare. For the two most palatable algae, the majority of herbivory occurred in open plots, with herbivory reduced by >50% in the largest opening cages (6 × 6 cm) where the maximum size fish entering was 12 cm in length (mean = 7.6, SE = 0.4). Fish entering medium (4.5 × 4.5 cm openings, maximum fish length = 8 cm, mean = 6.3, SE = 0.4) and small (3 × 3 cm openings, no fish observed entering) cages had herbivory rates approximately equal to the control treatment (1 × 1 cm openings). Consumption varied among algal species, with minimal consumption of physically and chemically defended algae and no pattern across treatments. Our results demonstrate a need for management plans to not only maintain the overall abundance of herbivorous fish but to protect the largest sizes for effective top‐down control of algal communities.  相似文献   

Study of variation of aerosol optical properties over a high altitude station in Indian Western Himalayan region,palampur using raman lidar system     

Singh  Shishir Kumar  Radhakrishnan  S. R.  Jaswant  Mishra  Sumit Kumar  Shukla  Devesh Kumar  Ranjan  Ashish  Sharma  Chhemendra 《Journal of Atmospheric Chemistry》2022,79(2):117-139

A Raman lidar system was operated along with the Microtops sunphotometer measurements to carry out the study of the variation of the optical properties of aerosols over Palampur (32.11° N and 76.53° E), India from 17th April to 11th May 2019. The lidar system is furnished with Raman (N₂) channel and depolarization channel allowing independent measurement of Lidar Ratio (LR) and linear depolarization ratio. The study reveals that the majority of the aerosols approximately were restricted within the planetary boundary layer (PBL) and very less loading was present in the free troposphere over the study location. The particle loading over the study period was found to be very less with aerosol backscatter coefficient (at 355 nm) ranging from ～0.13 Mm^?1sr^?1 to ～7.25 Mm^?1sr^?1 with mean value of 2.67?±?0.82 Mm^?1sr^?1 and it is well supplemented by the mean aerosol optical depth (AOD) of 0.37?±?0.13 obtained from Microtops Sunphotometer. The average lidar ratio values for 0-1 km altitude (L1) 72?±?13sr, for 1-2 km (L2) altitude 55?±?8sr, for 2-3 km (L3) 54?±?15sr were observed as suggesting dominance of the biomass burning aerosols and anthropogenic aerosols. The particle depolarization ratio (355 nm) values were found from approximately 4.8?±?2.7% to 11.5?±?1.9% with the mean value of 7?±?1.3% suggesting the presence of non-spherical particles. To trace the sources of the pollution, we derived the HYSPLIT trajectory which shows the majority of the movement was from local sources.

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A proposed new approach for groundwater resources assessment in India     

Rana Chatterjee  Ranjan Kumar Ray 《Journal of the Geological Society of India》2016,88(3):357-365

Assessment of groundwater resources in India is guided by National Water Policy (1987, 2002) which states that groundwater resources can be exploited only up to its recharge limit. The methodology for groundwater resources assessment in India is broadly based on Ground Water Resources Estimation Methodology, 1997 and it involves assessment of annual replenishable groundwater resources (recharge), annual groundwater draft (utilization) and the percentage of utilization with respect to recharge (stage of development). The assessment units (blocks/watersheds) are categorized based on stage of groundwater development (utilization) and the long term water level trend. The present methodology though useful in identification and prioritization of areas for groundwater management, falls short of addressing several critical issues like spatial and temporal variation of groundwater availability within the aquifer, accessibility of groundwater resources and quality of groundwater. This paper introduces a new categorisation scheme considering the above issues. The proposed scheme takes into account four criteria, viz. (i) stage of exploitation, (ii) extractability factor, (iii) temporal availability factor and (iv) quality factor. In comparison to the existing method used for categorisation, the proposed approach is more inclusive. The methodology is also equally suitable for both alluvial and hard rock terrain since it takes into consideration the variable characteristics of different types of aquifers and convergence of quantitative and qualitative assessment. The categorisation proposed here involves GIS based integration of different parameters/ themes. This allows better representation of spatial variability. The proposed methodology is demonstrated in this paper taking a case study from a hard rock terrain in central India.  相似文献   

Evaluation of groundwater resources in wide inundation areas of the Mekong River basin   总被引：2，自引：0，他引：2  

So Kazama  Terumichi Hagiwara  Priyantha Ranjan  Masaki Sawamoto 《Journal of Hydrology》2007,340(3-4):233-243

Severe floods can have disastrous impacts and cause wide ranging destruction in the Mekong River basin. At the same time groundwater resources are significantly influenced and extensively recharged by flood water in inundation areas of the basin. This study determines the variation of groundwater resources caused by flooding over inundated areas located in lower part of the Mekong River basin using numerical modeling and field observations. The inundation calculations have been evaluated using satellite image outputs. Comparing large, medium and small flood events, we conclude that flood control which reduces the area of inundation, results in a reduction of groundwater resources in the area. In 1993, a 19% reduction in inundation areas resulted in a 31% reduction in groundwater storage. In 1998, a 44% reduction in inundation areas led to a 42% reduction in groundwater storage. Thus, while flood control activities are vital to reduce negative flood impacts in the Mekong River basin, they also negatively impact groundwater resources in the area.  相似文献   

Wavelet-ANFIS models for forecasting monsoon flows: Case study for the Gandak River (India)   总被引：2，自引：0，他引：2  

Rajeev Ranjan Sahay  Vinit Sehgal 《Water Resources》2014,41(5):574-582

WANFIS, a conjunction model of discreet wavelet transform (DWT) and adaptive neuro-fuzzy inference system (ANFIS) was developed for forecasting the current-day flow in a river when only available data are historical flows. Discreet wavelet transform decomposed the observed flow time series (OFTS) into wavelet components which captured useful information on three resolution levels. A smoothened flow time series (SFTS) was formed by filtering out the noise wavelet components and recombining the effective wavelet components. WANFIS model is essentially an ANFIS model with SFTS hydrograph as the input, while ANFIS and autoregression (AR) models, developed for comparison purpose, use OFTS hydrograph as input. For performance evaluation, the developed models were utilized for predicting daily monsoon flows for the Gandak River in Bihar state of India. During monsoon (June–October), this river carries large flows making the entire North Bihar unsafe for habitation or cultivation. Based on various performance indices, it was concluded that WANFIS models simulate the monsoon flows in the Gandak more reliably than ANFIS and AR models. The best performing WANFIS model, with four previous days’ flows as input, predicted the current-day Gandak flows with 80.7% accuracy while ANFIS and AR models predicted it with only 71.8 and 51.2% accuracies.  相似文献   

Bioremediation Potential of Arthrospira platensis (Spirulina) against Chromium(VI)          下载免费PDF全文

Sundaramoorthy Balaji  Thiagarajan Kalaivani  Chandrasekaran Rajasekaran  Ramamoorthy Siva  Mohan Shalini  Ranjan Das  Varun Madnokar  Prajakta Dhamorikar 《洁净——土壤、空气、水》2015,43(7):1018-1024

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Seismic strengthening of RC columns using external steel cage     

Pasala Nagaprasad  Dipti Ranjan Sahoo  Durgesh C. Rai 《地震工程与结构动力学》2009,38(14):1563-1586

Steel caging technique is commonly used for the seismic strengthening of reinforced concrete (RC) columns of rectangular cross‐section. The steel cage consists of angle sections placed at corners and held together by battens at intervals along the height. In the present study, a rational design method is developed to proportion the steel cage considering its confinement effect on the column concrete. An experimental study was carried out to verify the effectiveness of the proposed design method and detailing of steel cage battens within potential plastic hinge regions. One ordinary RC column and two strengthened columns were investigated experimentally under constant axial compressive load and gradually increasing reversed cyclic lateral displacements. Both strengthened columns showed excellent behavior in terms of flexural strength, lateral stiffness, energy dissipation and ductility due to the external confinement of the column concrete. The proposed model for confinement effect due to steel cage reasonably predicted moment capacities of the strengthened sections, which matched with the observed experimental values. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Errata to “Representative rainfall thresholds for landslides in the Nepal Himalaya” [Volume 100 (3–4), 429–443]     

Ranjan Kumar Dahal  Shuichi Hasegawa 《Geomorphology》2009,105(3-4)

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Estimation of lateral force contribution of boundary elements in steel plate shear wall systems          下载免费PDF全文

Abhishek Verma  Dipti Ranjan Sahoo 《地震工程与结构动力学》2017,46(7):1081-1098

Steel plate shear walls (SPSWs) are used as lateral force‐resisting systems in new and retrofitted structures in high‐seismic regions. Various international codes recommend the design of SPSWs assuming the entire lateral load to be resisted by the infill plates. Such a design procedure results in significant overstrength leading to uneconomical and inefficient use of materials. This study is focused on the estimation of contribution of boundary elements in resisting the lateral force considering their interaction with the web plates of SPSW systems. Initially, the relative contribution of web plates and boundary frames is computed for a single‐bay single‐story frame with varying rigidity and end connections of boundary elements. Nonlinear static analyses are carried out for the analytical models in OpenSees platform to quantify this contribution. Later, this study is extended to the code‐based designed three‐story, six‐story, and nine‐story SPSWs of varying aspect ratios. Based on the results obtained, a new design procedure is proposed taking the lateral strengths of the boundary frames into account. Nonlinear time‐history analyses are conducted for 40 recorded ground motions representing the design basis earthquake and maximum considered earthquake hazard levels to compare the interstory and residual drift response and yield mechanisms of SPSWs designed as per current practice and the proposed methodology. Finally, an expression has been proposed to predict the lateral force contribution of the infill plate and the boundary frame of SPSWs. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献