Impact of Subsurface Drainage on Improvement of Crop Production and Farm Income in North-West India     

K.K. Datta  Laxmi Tewari  P.K. Joshi 《Irrigation and Drainage Systems》2004,18(1):43-56

The Indian Council of Agricultural research has given priority to control and manage salinity problems that have developed in north-west India. Multi-disciplinary taskforces have recommended installation of subsurface drainage for salinity control, based on design and management techniques developed by the Central Soil Salinity Research Institute (CSSRI), to rehabilitate lands with excess soil salinity. After small-scale studies, large-scale pilot projects were launched to install subsurface drainage in problem areas. One such attempt in was initiated in the north-west region of India where a large-scale drainage project was carried out with Dutch collaboration. We assessed the impact of investments in subsurface drainage in order to validate past funding on research of drainage in India. The important methods used for assessing the efficiency benefits of drainage investment were: to determine the impact of subsurface drainage in terms of net present value, internal rate of returns, consumers' surplus and producers' surplus; to assess the social welfare in terms of social equality and sustainability of the drainage system; and to examine the factors affecting the sustainability of the technology. The internal rate of return was computed to assess the efficiency parameter of subsurface drainage for salinity management. In order to measure the changes in inequality distribution of income, Gini concentration ratios were computed with and without installing sub surface drainage. The Radar Approach, a method based on a graphical display of differences between actual ideal performance, was used to quantify drainage sustainability in terms of optimizing gains and conserving, or improving the quality of soil and water resources. There were several farm-level benefits as a result of installing subsurface drainage: these included: (i) a substantial increase in farm income; (ii) cropping intensification and diversification toward high value crops; and (iii) generation employment. A high internal rate of return justified investment in subsurface drainage. Income inequalities across farms were reduced. The radar approach showed improvement in sustainability in terms of economic gains and resource conservation. Despite of these economic, social, and environmental benefits, the sustainability of subsurface drainage technology is questionable. The specific reasons include: (i) the nature of the technology; (ii) lukewarm collective action by the beneficiaries; (iii) conflicting objectives among beneficiaries; and (iv) growing numbers of free riders. To a large extent these were addressed in the study area by forming village committees. Without appropriate institutional arrangements, subsurface drainage may not yield the desired results, and in the long run may result in neglect of operation and maintenance needs and ultimately the abandonment of the technology.  相似文献   

Mycorrhizal and common root-rot infection,and nutrient accumulation in barley grown on breton loam using N from biological fixation or fertilizer     

S. P. Wani  W. B. McGill  J. P. Tewari 《Biology and Fertility of Soils》1991,12(1):46-54

Summary This paper presents soil biological data from a study on the functioning of three soil-plant systems on a Gray Luvisol in Cryoboreal Subhumid central Alberta. The systems were (1) an agroecological 8-year rotation, (2) a continuous grain system, both established in 1981, and (3) a classical Breton 5-year rotation established in 1930. The objectives were to (1) determine whether changes in vesicular-arbuscular mycorrhizae (VAM) populations occurred in soil under these cropping systems, (2) discover whether these cropping systems and/or VAM infection influenced the incidence of common root rot (Bipolaris sorokiniana), and (3) use nutrient translocation indices to test the hypothesis that soil quality influences non-specific physiological conditions in barley (Hordeum vulgare L.). VAM fungal propagules in soil samples and VAM infection under controlled conditions were significantly affected by the cropping system. VAM infection accounted for more than 85% of the variability in grain yield, plant biomass yield, and plant uptake of K, S, Ca, Fe, and Zn under controlled conditions. Backward-elimination regression analyses showed that under these conditions of high available P, plant P uptake was governed by the quantity of extractable P in the soil (r ²=0.82); the VAM infection contributed practically nothing when combined with available P (R ²=0.84). Neither VAM infection nor the cropping system were related to the B. sorokiniana infection in the barley. The growth of B. sorokiniana was equal, and its sporulation superior, when grown on residues of the non-host fababean (Vicia faba L.), compared with growth on residues of barley. Higher translocation of plant nutrients to the grain in the agroecological compared with the continuous grain treatments suggested that VAM and/or the soil history affected plant physiology, possible through hormonal effects. Superior barley yields in the agroecological compared with the continuous grain treatments were partly due to increased VAM colonization, greater nutrient accumulation and translocation to the grain, but not to a reduced disease incidence. These results demonstrate the benefits of a holistic systems approach while studying biological interactions involving plants and groups of soil microorganisms.(ICRISAT journal article number 1161)  相似文献   

Computer Simulation of Tractor Single-point Drawbar Performance     

C.S. Sahay  V.K. Tewari 《Biosystems Engineering》2004,88(4):419-428

A computer algorithm has been developed to predict single-point drawbar performance of a tractor taking into account all the necessary variables during field operation. The performance of tractor–implement system with a single-point hitch involves the effect of a number of variables on the whole tractor–implement–soil system. Considering all these, the developed computer algorithm is able to predict the performance of whole operation. This model is capable of determining the maximum pull available in the given field condition and matches the performance of trailed implements, such as a disc harrow and two-axle trailer. The model was able to predict maximum load and slope climbing ability of tractor with single- and two-axle trailers under different conditions. It was predicted by the model that the maximum pull developed by a tractor is limited by gross traction in the soft soil whereas it was limited by the power available from the tractor in hard soil. The longitudinal stability of the tractor taken for analysis varied with hitch point position. Appropriate determination of disc harrow performance was possible using the developed model.  相似文献   

Characterization and identification of leaf morphology of <Emphasis Type="Italic">Populus deltoides</Emphasis> Bartr. clones     

Ajaz LONE  Altamah BASHIR  Salil K. TEWARI  Mumtaz MAJEED 《中国林学(英文版)》2011,13(4):270-275

Leaves are of fundamental importance to plants, representing their facility to generate power and are the sensing units of plants towards the environment. An attempt was made to characterize and compare the variations of leaf morphology of various Populus deltoides Bartr. clones by studying the winter buds and other leaf parameters of fully developed leaves. To achieve these objectives, forty-three exotic and indigenous clones of P. deltoides Bartr. were evaluated for different parameters. On the basis of various morphological characteristics the results reveal that each clone has a distinct color pattern of leaves. Different colors observed in these clones varied from light green through green to dark green. Two distinct lengths of the leaf apex were found, i.e., short and long; as well both acuminate and acute apex types were found. Erratic distribution of serration of leaves was also found. In this study, the morphological traits of leaves provided discriminatory grounds for separating various populations of P. deltoides Bartr. clones. Winter bud studies indicate that different clones vary considerably with regard to shape, color, shape of leaf scars and exudation.  相似文献   

Influence of earthworm culture on fertilization potential and biological activities of vermicomposts prepared from different plant wastes     

Pankaj Kumar Srivastava  Poonam C. Singh  Manjul Gupta  Arpita Sinha  Aradhana Vaish  Ashish Shukla  Nandita Singh  Sri Krishna Tewari 《植物养料与土壤学杂志》2011,174(3):420-429

The present investigation was aimed to analyze influence of earthworm culture on nutritive status, microbial population, and enzymatic activities of composts prepared by utilizing different plant wastes. Vermicomposts were prepared from different types of leaves litter of horticulture and forest plant species by modified vermicomposting process at a farm unit. Initial thermophilic decomposition of waste load using cow‐dung slurry was done in the separate beds. The culture of Eisenia fetida was used for vermicomposting in specially designed vermibeds at the farm unit. The physico‐chemical characteristics, enzyme activities (oxido‐reductases and hydrolases), and microbial population (bacteria, fungi, free‐living nitrogen‐fixing bacteria, actinomycetes, Bacillus, Pseudomonas, phosphate‐solubilizing bacteria and fungi) of vermicomposts were found significantly higher (p < 0.05) than those of control (without earthworm inoculum). The study quantified significant contributions of earthworm culture to physico‐chemical, enzymatic, and microbiological properties of vermicompost and confirmed superior fertilization potential of vermicompost for organic farming. The agronomic utility of vermicompost was assessed on yellow mustard plant in a pot experiment. Pot soil was amended with different ratios (5%, 10%, 20%) of vermicompost and normal compost (without earthworm inoculum). Effects of these amendments on the growth of Brassica comprestis L. were studied. The significant differences (p < 0.05) in the growth of plant were observed among vermicompost‐, compost‐amended soil, and control. Vermicompost increased the root and shoot lengths, numbers of branches and leaves per plant, fresh and dry weights per plant, numbers of pods and flowers, and biochemical properties of plant leaf significantly, especially in 20% amendment. These results proved better fertilization potential of vermicompost over non‐earthworm‐inoculated compost.  相似文献   

Fatal pandemic (H1N1) 2009 influenza A virus infection in a Pennsylvania domestic cat     

Campagnolo ER  Rankin JT  Daverio SA  Hunt EA  Lute JR  Tewari D  Acland HM  Ostrowski SR  Moll ME  Urdaneta VV  Ostroff SM 《Zoonoses and public health》2011,58(7):500-507

We report the earliest recognized fatality associated with laboratory-confirmed pandemic H1N1 (pH1N1) influenza in a domestic cat in the United States. The 12-year old, indoor cat died on 6 November 2009 after exposure to multiple family members who had been ill with influenza-like illness during the peak period of the fall wave of pH1N1 in Pennsylvania during late October 2009. The clinical presentation, history, radiographic, laboratory and necropsy findings are presented to assist veterinary care providers in understanding the features of this disease in cats and the potential for transmission of infection to pets from infected humans.  相似文献   

Optimization of Size and Shape of Experimental Plots for Trials Against Eggplant Fruit Borer,Leucinodes orbonalis Guen 1     

G. S. Prasada Rao  G. C. Tewari 《Journal of Agronomy and Crop Science》1987,159(1):6-8

Studies were made to work out the optimum size and shape of the plots for conducting field trials against Leucinodes orbonalis Guen which is a serious pest of eggplant throughout South East Asia and Africa. A plot with 20 plant stand measuring 7.2 m² was found to be optimum size based on the cv.-% values. The shape of the plot was not considered to be important. The index of infestation heterogeneity (b) was high (> 2) indicating uniform spread of infestation throughout the field.  相似文献   

Neutralizing and Complement-fixing Monoclonal Antibodies as an Aid to the Diagnosis of Equine Herpesvirus-1 Infection     

Singh  B.K.  Yadav  M.P.  Tewari  S.C. 《Veterinary research communications》2001,25(8):675-686

One complement-fixing (C-MAb) and three complement-dependent neutralizing monoclonal antibodies (N-MAbs) were raised against Hisar-90-7 equine herpesvirus-1 (EHV-1) strain. The target antigen of the C-MAb (2A5) and two of the N-MAbs (1H6, 9C4) was identified as a 140 kDa polypeptide in Western blotting. The target antigen of N-MAb (9C6) could not be identified. Purified polypeptides of five EHV-1 strains isolated from different regions and at different times gave intense bands at 140 kDa when reacted with N-MAb (1H6) in Western blots. In sandwich ELISA, all four MAbs captured the viral antigen from clinical materials, giving a reliable and rapid diagnosis of EHV-1 infection in equines.  相似文献   

An analysis of the appropriateness of wind and other energy systems for irrigation water pumping in India     

Sharat K. Tewari 《Agricultural Water Management》1981,4(4):445-455

This study attempts to quantify a figure of merit (appropriateness) for various options of energy technologies feasible for a prespecified task. Within the framework of rural energy development, various attributes are identified, relatively weighted and quantified for a group of energy technologies including renewable energy sources. Based on the data for Indian conditions, it is found that windmills designed to respond to low wind speeds of the order of 12 km/h and very carefully optimised for cost reduction are likely to be most appropriate within the group of alternatives considered in this study. This conclusion, however, holds only for irrigation from shallow wells (10–15 m deep) in small farms (size 1–2 ha).  相似文献   

Total and Merchantable Volume Equations for Tectona grandis Linn. f. Plantations in Karnataka,India     

Vindhya Prasad Tewari  K. M. Mariswamy  A. N. Arunkumar 《Journal of Sustainable Forestry》2013,32(3):213-229

Tectona grandis (teak) is one of the most important timber species worldwide and India is one of the major teak growing countries. Though some volume equations were developed in the past in India, merchantable volume equations (any top diameter or bole length) are not available. Moreover, the models developed were neither quantitatively and qualitatively evaluated nor validated with independent data sets. Hence, the objective of this study was to develop appropriate volume equations to predict total tree volume and merchantable volume for teak in Karnataka.

Linear and non-linear equations were used to model the relationship of the volume with respect to diameter at breast height (dbh) and total height. Merchantable volume equations for estimating merchantable volume to any minimum top diameter or bole length have also been constructed. The equations tested mostly fitted well to the data. Other models developed elsewhere tended to underestimate the volume, especially at dbh ≥ 23 cm. The geometric cylinder volume equation, in combination with a stem form factor of .40, is widely used for teak in Karnataka but they were found to be less precise compared to regression equations when applied to the present data set. Model validation indicated that models should be calibrated with local data for greater accuracy in the prediction.  相似文献