Different Agro-climatic Regions Of India Research Articles

Molecular Diversity of Seed-borne Fusarium Species Associated with Maize in India.

A total of 106 maize seed samples were collected from different agro-climatic regions of India. Sixty-two Fusarium isolates were recovered, 90% of which were identified as Fusarium verticillioides based on morphological and molecular characters. Use of the tef-1α gene corrected/refined the morphological species identifications of 11 isolates, and confirmed those of the remaining isolates. Genetic diversity among the Fusarium isolates involved multilocus fingerprinting profiles by Inter Simple Sequence Repeats (ISSR) UPGMA and tef-1α gene phenetic analyses; for which, we observed no significant differences among the isolates based on geographic origin or fumonisin production; most of the subdivision related to species. Genotyping was performed on the F. verticillioides isolates, using 12 primer sets from the fumonisin pathway, to elucidate the molec-ular basis of fumonisin production or non-production. One fumonisin-negative isolate, UOMMF-16, was unable to amplify nine of the 12 fumonisin cluster genes tested. We also used the CD-ELISA method to confirm fumonisin production for our 62 Fusarium isolates. Only 15 isolates were found to be fumonisin-negative. Interestingly, genotypic characterization re-vealed six isolates with various gene deletion patterns that also tested positive for the production of fumonisins via CD-ELISA. Our findings confirm the importance of molecular studies for species delimitation, and for observing genetic and phenotypic diversity, among the Fusaria.

Conservation of threatened goat breeds in India

India is a rich repository of goat genetic resources having 23 well-recognized goat breeds. These breeds have evolved through natural selection and selective breeding by rearers for adaptation to specific agro-ecological conditions. As the indigenous goat breeds of India display great variation in adaptability, productivity, feed utilization, disease resistance, etc. so conservation for unique characteristics of indigenous breeds are of great importance. The recognized breeds of Indian goat population are facing a greater threat due to lack of enforcement of proper breeding policy, inadequate number of breeding bucks, indiscriminate crossbreeding and intermixing among breeds with local animals etc. Considering the current population size, declining rate of population, loss of habitat and introduction of other breeds in the area, the threatened goat breeds are Jamunapari, Beetal, Jakhrana and Surti in the northwestern region, Sangamneri, Osmanabadi, Malabari and Attappady Black in the southern region, Ganjam in the eastern region, and Chegu and Changthangi in the temperate Himalayan region. Furthermore, the positions of several breeds are more or less vulnerable in their breeding tracts. Now, efforts have been made to conserve the indigenous goat breeds for their unique characteristics in their home tracts through in-situ and ex-situ conservation in different agroclimatic regions of India.

Energy Balance of Rural Ecosystems In India

Abstract. India is predominantly an agricultural and rural country. Across the country, the villages vary in geographical location, area, human and livestock population, availability of resources, agricultural practices, livelihood patterns etc. This study presents an estimation of net energy balance resulting from primary production vis-a-vis energy consumption through various components in a "Rural Ecosystem". Seven sites located in different agroclimatic regions of India were studied. An end use energy accounting "Rural Energy Balance Model" is developed for input-output analysis of various energy flows of production, consumption, import and export through various components of crop, trees outside forest plantations, livestock, rural households, industry or trade within the village system boundary. An integrated approach using field, ancillary, GIS and high resolution IRS-P6 Resourcesat-2 LISS IV data is adopted for generation of various model inputs. The primary and secondary field data collection of various energy uses at household and village level were carried out using structured schedules and questionnaires. High resolution multi-temporal Resourcesat-2 LISS IV data (2013–14) was used for generating landuse/landcover maps and estimation of above-ground Trees Outside Forests phytomass. The model inputs were converted to energy equivalents using country-specific energy conversion factors. A comprehensive geotagged database of sampled households and available resources at each study site was also developed in ArcGIS framework. Across the study sites, the estimated net energy balance ranged from −18.8 Terra Joules (TJ) in a high energy consuming Hodka village, Gujarat to 224.7 TJ in an agriculture, aquaculture and plantation intensive Kollaparru village, Andhra Pradesh. The results indicate that the net energy balance of a Rural Ecosystem is largely driven by primary production through crops and natural vegetation. This study provides a significant insight to policy relevant recommendations for Energy Sustainable Rural India.

BOX-PCR- and ERIC-PCR-based genotyping and phylogenetic correlation among Fusarium oxysporum isolates associated with wilt disease in Psidium guajava L.

Abstract Fusarium oxysporum f. sp. psidii is a soilborne fungal pathogen that causes wilt disease in guava. There is an urgent need to establish a sensitive and specific molecular assay to diagnose the disease. A genetic fingerprint of the guava wilt pathogen also needs to be established. We isolated and identified 21 isolates of F. oxysporum f. sp. psidii from soil and infected roots of wilted guava, from different agro-climatic regions of India. We used BOX-PCR and enterobacterial repetitive intergenic consensus (ERIC)-PCR for generating a genetic fingerprint of F. oxysporum f. sp. psidii that ranged from 150 to 2500 bp in size. A dendrogram was constructed for the isolates on the basis of both the fingerprint patterns and the highest and lowest similarity values. The latter were observed for Fop123–Fop127 (at 94.0%) and Fop18–Fop24 (at 18.0%), respectively. Molecular data were derived from an analysis of the internal transcribed spacer sequences of 38 isolates belonging to 19 taxa within the species F. oxysporum. In this study, F. oxysporum f. sp. psidii was grouped in a single cluster that represented a different genetic structure. This study suggests that BOX-PCR and ERIC-PCR could be suitable, rapid, reproducible, and useful techniques for the discrimination of F. oxysporum f. sp. psidii, to better manage guava wilt disease.

Diversity in leaf morphology and physiological characteristics among mango (Mangifera indica) cultivars popular in different agro-climatic regions of India

The present study was aimed to characterize eight different mango cultivars, viz., ‘Alphonso’, ‘Borsha’, ‘Himsagar’, ‘Fazli’, ‘Langra’, ‘Dashehari’, ‘Totapuri’ and ‘Neelum’ popularly grown in different agro-climatic regions in India. Significant differences in gas exchange and leaf morphological characters were observed among cultivars. Higher photosynthesis rate (PN) was recorded in ‘Borsha’, ‘Himsagar’, ‘Langra’ and ‘Neelum’. Across the cultivars PN and CE (carboxylation capacity) were highest in ‘Neelum’ followed by ‘Borsha’. ‘Langra recorded highest WUE and WUEi. The SLA and SLW were maximum in ‘Totapuri’ and ‘Dashehari’ respectively. Maximum epicuticular wax content (ECW) was observed in ‘Totapuri’. The content of Chl a, Chl b, total chlorophyll and carotenoids was highest in ‘Alphonso’. Adaxial and abaxial stomatal numbers were highest in ‘Totapuri’ and ‘Langra’, respectively. The variations in leaf morphology, gas exchange and related traits may be linked to genotypic variation suitable for different agro-climatic regions in India.

Detection of Ralstonia solanacearum from Asymptomatic Tomato Plants, Irrigation Water, and Soil Through Non-selective Enrichment Medium with hrp Gene-Based Bio-PCR

Bacterial wilt of tomato caused by Ralstonia solanacearum (Smith) Yabuuchi et al. (Microbiol Immunol 39:897-904, 1995) is a serious disease, which causes losses up to 60 % depending on environmental conditions, soil property, and cultivars. In present investigation, nucleotide sequences of virulence, hypersensitive response and pathogenicity (hrp) gene were used to design a pair of primer (Hrp_rs 2F: 5'-AGAGGTCGACGCGATACAGT-3' and Hrp_rs 2R: 5'-CATGAGCAAGGACGAAGTCA-3') for amplification of bacterial genome. The genomic DNA of 27 isolates of R. solanacearum race 1 biovar 3 & 4 was amplified at 323 bp. The specificity of primer was tested on 13 strains of R. solanacearum with other group of bacteria such as Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, and X. citri subsp. citri. Primer amplified DNA fragment of R. solanacearum at 323 bp. The sensitivity of the primer was 200 cfu/ml and improved further detection level by using non-specific enrichment medium casamino acids-pepton-glucose broth followed by PCR (BIO-PCR). Out of 130 samples of asymptomatic tomato plants, irrigation water, and soil collected from bacterial wilt infested field in different agro-climatic regions of India, R. solanacearum was detected from 86.9, 88.5, and 90.9 per cents samples using BIO-PCR, respectively. The primer was found specific for detecting viable and virulent strains of R. solanacearum and useful for the diagnosis of R. solanacearum in tomato seedlings and monitoring of pathogen in irrigation water and soil.

Mould incidence and mycotoxin contamination in freshly harvested maize kernels originated from India

In this study, mould incidence and mycotoxin contamination were determined in freshly harvested maize samples collected from different agroclimatic regions of India. A total of 150 freshly harvested maize samples from major maize-growing areas of India (Karnataka, Andhra Pradesh and Tamilnadu) were collected during winter seasons 2010-2011 and 2011-2012 to determine their toxigenic fungal incidences, and mycotoxins were analyzed and quantified by high-perfomance liquid chromatography. A total of 288 fungal isolates comprising Fusarium, Aspergillus and Penicillium species were tested for aflatoxin B1 (AFB1), ochratoxin A (OTA), trichothecenes (deoxynivalenol (DON) and T-2 toxin) and fumonisin B1 (FB1). Chemotype determination of fungal isolates was carried out by molecular and chemical analysis through polymerase chain reaction (PCR) and high-performance thin layer chromatography respectively. The diversity and distribution of the mycoflora among the studied samples were recorded in terms of frequency, density, importance value index and diversity indices. A total of 288 fungal isolates were recovered from the 150 maize samples, of which 28 were positive for AFB1, 20 for OTA, 58 for FB1, 23 for DON and 11 for T-2 toxin chemotypes by PCR. Species-specific PCR assays were in line with morphological analysis. Toxigenic fungal incidences were found throughout the study region, and most of the toxins under study exceeded the maximum legal limits. The range of observed toxin concentrations were 48-58 µg AFB1, 76-123 µg FB1, 38-50 µg T-2, 72-94 µg DON and <5 µg OTA kg⁻¹ grain sample. Owing to the high incidences of toxigenic moulds and mycotoxins in the study area, there is a need for the creation of mycotoxin awareness among maize farmers of India to control the chronic adverse health effects on humans and livestock due to mycotoxins.

Effect of feeding a balanced ration on milk production, microbial nitrogen supply and methane emissions in field animals

Dairy animals in developing countries produce more methane (CH4), primarily on account of feed rations imbalanced in nutrients. A field study on early lactating cows (n = 80) and buffaloes (n = 82) was conducted to evaluate the effect of feeding a balanced ration on milk production, microbial nitrogen (N) supply and CH4 emissions in different agroclimatic regions of India. CH4 emissions was measured using the sulfur hexafluoride tracer technique, before and after feeding a balanced ration. Feeding practices revealed that intake of protein was adequate in the ration of experimental animals in most of the regions, except for the buffaloes of the western region. Metabolisable energy (MJ/cow.day) intake was higher by 7.6% and 13.6% in cows of western and northern regions, respectively. In buffaloes, energy intake (MJ metabolisable energy/buffalo.day) was higher by 11.5% in the western region but lower by 17.7% in the central region. Average calcium intake was deficient by 23.5% and 35.1%, whereas phosphorus intake was deficient by 33.2% and 56.2% in cows and buffaloes, respectively. Feeding a balanced ration increased (P &lt; 0.05) average daily milk production by 6.7% and 7.6%, whereas cost of production decreased by 13.7% and 9.9% in cows and buffaloes, respectively. Fat-corrected milk increased from 9.1 to 9.8 kg/cow.day and from 6.9 to 7.7 kg/buffalo.day. Intestinal flow of microbial N improved significantly by 25.5% and 26.7% in cows and buffaloes, respectively. Balanced feeding reduced CH4 emissions (g/kg milk yield) by 17.3% (P &lt; 0.05) in cows and 19.5% (P &lt; 0.01) in buffaloes. The present study indicates that feeding a balanced ration improves milk production and microbial N supply, and reduces CH4 emissions in field animals.

English

Bacillus spp. is a potential bacterial antagonist to manage bacterial wilt disease of tomato incited by Ralstonia solanacearum, which is one of the most threatening diseases of tomato in India. Genetic diversity of Bacillus strains and their potentiality to control bacterial wilt of tomato isolated from rhizospheric soil and endophytic tomato plants from different agro-climatic regions of India were studied. Rhizospheric soil and plants of tomato were pasteurized at 80&deg;C for 15 min before dilution and then inoculated onto the Petri plates containing tryptic soy agar medium and incubated at 28&plusmn; 2&deg;C. Out of 250 isolates of Bacillus species, 47 strains showed antagonistic ability against R. solanacearum. Maximum growth of R. solanacearum was inhibited by strain DTBS-5 to form inhibition zone of 5.5 cm2 in vitro and lowest wilt incidence of 14.3 and 7.6 % in Pusa Ruby and Arka Abha cultivars under glass house conditions, respectively. Plants treated with strain JTBS-9 had maximum fresh weight of 42.0 and 49.0 g and dry weight 6.1 and 6.6 g in tomato cultivars Pusa Ruby and Arka Abha after 45 days of transplanting, respectively. Out of 47 strains, 11 strains of Bacillus spp. were detected as iturin antibiotic producing strains by using iturin gene based marker. Genetic variability was found in Bacillus spp., which was made 5 clusters at 50% similarity coefficient. However, iturin producing and iturin non-producing strains as well as rhizospheric and endophytic Bacillus spp. could not be distinguished by using 16S rRNA sequence analysis and genetic fingerprinting. Key words: BOX-PCR, Bacillus spp., iturin, Ralstonia solanacearum, phylogenetic analysis, tomato.

Natural occurrence of aflatoxin, aflatoxigenic and non-aflatoxigenic Aspergillus flavus in groundnut seeds across India

A survey across different agro-climatic regions of India was done and 38 groundnut seed samples were collected from various sources. Upon analysis, all samples were found infected with Aspergillus flavus ranging from 2 to 50% incidence with aflatoxin content of 0.0 to 28 ppb. Greenhouse studies revealed no correlation between incidence of A. flavus and aflatoxin content on seedling emergence, root length, shoot length and dry weight. Seeds were predominantly contaminated with aflatoxin B1 followed by aflatoxin B2. Among the tested A. flavus isolates, 31 were found aflatoxigenic and seven were nonaflatoxigenic when analyzed through cultural, thin layer chromatography, competitive direct enzyme linked immunosorbent assay and multiplex polymerase chain reaction. Present study reveals the current scenario of aflatoxin contamination, and aflatoxigenic and non-aflatoxigenic fungal infection in groundnut seeds collected across India. Keywords: Polymerase chain reaction (PCR), Aspergillus flavus , aflatoxin, enzyme-linked immuno sorbent assay (ELISA), groundnut African Journal of Biotechnology Vol. 12(19), pp. 2587-2597

Virulence analysis and genetic diversity of Xanthomonas campestris pv. campestris causing black rot of crucifers

Xanthomonas campestris pv. campestris (Xcc) is a devastating bacterium to cause black rot disease in crucifers. To study the genetic diversity and virulence analysis, 24 isolates of Xcc were collected from cole crops including cauliflower, cabbage, broccoli and knol khol from different agro-climatic regions of India ranging from temperate to subtropical climates. For virulence analysis, 24 isolates of Xcc were tested on 27 cultivars of crucifers including seven species of Brassica spp. (B. campestris, B. carinata, B. juncea, B. napus, B. nigra, B. oleracea and B. rapa), Sinapsis alba, Eruca sativa and Raphanus sativus under field conditions at IARI, New Delhi, during November 2010–March 2011. Maximum disease incidence 85.15% was found in the cultivars of crucifers caused by strains Xcc-C124, Xcc-C6, Xcc-C125, Xcc-C111 and Xcc-C131 after 15 days of inoculation and significantly increased after 30 days. Black rot severity in cultivars of crucifers varied from 0 to 6.9 and 0 to 7.9 out of 9 scale after 15 and 30 days of inoculation, respectively. But, no disease incidence was recorded on all the tested cultivars of B. juncea (Pusa Bold, Varuna, Pusa Mustard-21 and Pusa Vijay) against all the strains of Xcc after 15 days. Genetic diversity of 24 strains of Xcc was studied using REP- and BOX-PCR, indicating the existence of wide range of genetic diversity among the strains. The strains were clustered into two groups at 50% similarity coefficient and designated as Group 1 and Group 2. The majority of the strains (23 strains) were clustered under Group 1 except Xcc-C120, which formed separate group (Group 2). In the present study, genetic diversity and virulence pattern in Indian strains of Xcc were established, which will be helpful in the development of resistant genotypes against this bacterial pathogen.

Detection of Fusarium wilt pathogens of Psidium guajava L. in soil using culture independent PCR (ciPCR)

Traditional culturing methods take a long time for identification of pathogenic isolates. A protocol has been developed for the detection of Fusarium from soil samples in the early stage of infection. Seventeen soil samples from different locations were collected before the onset of rains to find out the presence of Fusarium spp. population present in the soil of guava orchards and to correlate its presence with incidence of wilt. A PCR based method was developed for the molecular characterization of Fusarium using Fusarium spp. specific primer. DNA extracted by this method was free from protein and other contaminations and the yield was sufficient for PCR amplification. The primer developed in this study was amplifying ∼230bp in all infected samples while not in healthy soil. The specificity and sensitivity of primer were tested on several Fusarium spp. and found that this primer was amplifying 10−6 dilution of the fungal DNA. The present study facilitates the rapid detection of Fusarium spp. from infected soil samples of guava collected from different agroclimatic regions in India. A rapid detection method for pathogens and a diagnostic assay for disease would facilitate an early detection of pathogen and lead to more effective control strategies.

EFFECTIVENESS OF CULTURAL PARAMETERS ON THE GROWTH AND SPORULATION OF &lt;i&gt;COLLETOTRICHUM GLOEOSPORIOIDES&lt;/i&gt; CAUSING ANTHRACNOSE DISEASE OF MANGO (&lt;i&gt;MANGIFERA INDICA&lt;/i&gt; L.)

Colletotrichum gloeosporioides causing anthracnose which is a serious post harvest disease in mango accounting for 15-20% loss. The variation in nutritional and physiological characteristics among five isolates of C. gloeosporioides collected from different agro-climatic regions of India was investigated. All the isolates showed differential response in requirements of media, temperature and media pH for growth and sporulation. Malt Extract Agar (MEA) medium was best suited for growth in terms of radial mycelial diameter for all the isolates. Among the studied isolates, Cg 72 (from Maharashtra) showed more virulence and maximum sporulation (137.5×103 mL-1) at 28°C and media pH 6. Maximum growth and virulence at 28°C was observed with Cg 62 isolate. Media of pH 6 was found to be most suitable for the growth of respective isolates (s), but Cg 62 which was collected from Bihar found most virulent in this experiment.

Potentiality for value-added technical use of Indian sisal

India is one of the major exporters of sisal ropes and cordages but the raw fibres are imported from Africa and some other places. Import of sisal fibre in India is increasing at the rate of 25% per year for last few years. Sisal is grown in randomly distributed pockets all over Indian sub-continent mainly for some other purpose without giving any attention to the selective variety or species of Agave family. It is commonly stated that quality of Indian sisal fibre is not up to the mark of making standard quality of ropes, binder, twines, etc. The paper reports the textile related structure and properties (viz. tensile behavior, bending rigidity, thickness, coefficient of friction, moisture, thickness, surface appearance, transversal structure) of Indian variety of sisal fibres grown in two different agro-climatic regions in India to find out its suitability for producing standard quality products. The properties of Indian sisal fibres have also been compared to the imported one to explore the potentiality of the Indian fibres for making standard international quality products. The present work reveals that it is possible to grow sisal fibre of specified variety/species (Agave sisalana) having much balanced property parameters for producing international quality products (viz., ropes, cordages agricultural binders). Agave sisalana grown in certain agro-climatic regions (viz., Orissa) in India showed much comparable property parameters, even sometimes better, to the fibres imported from Tanzania.

Molecular diversity in Indian isolates of Fusarium oxysporum f.sp. lentis inciting wilt disease in lentil (Lens culinaris Medik)

For integrated management of wilt disease, foolproof knowledge about the genetic diversity among the prevalent isolates is very important. One hundred (100) isolates of Fusarium oxysporum f. sp. lentis, causing agent of vascular wilt in lentil were collected from different agro-climatic regions of India. Finally, fifteen distinct F. oxysporum f. sp. lentis isolates were selected for molecular characterization by three molecular markers. Twenty randomly amplified polymorphic DNA (RAPD)primers produced a total of 105 reproducible bands, out of which 81 (77.14%) were polymorphic and 24 (22.85%) were monomorphic. Nine simple sequence repeats (SSR) primer pairs amplified 21 alleles with 2.33 alleles per primer. Considerable length variations (561 to 668 bp) in rDNA regions were found and restriction digestion of amplified rDNA region produced forty eight different DNA bands. Three molecular markers revealed varying degree of genetic diversity in the selected isolates ranging from 54% in case of RAPD to up to 35% with ITS markers. Based on the coefficient of similarity, the isolates grouped into two major clusters in the dendrogram. Isolates from North Indian regions grouped in same cluster, whereas isolates from north east regions and eastern region fell in another cluster. This information will be helpful for pathologists and plant breeders to design effective resistance breeding programs in lentil taking into account the diversity in wilt pathogen. Key words: Indian isolates, Fusarium oxysporum f.sp. lentis, vascular wilt, molecular diversity.

Diazinon resistant status in Rhipicephalus (Boophilus) microplus collected from different agro-climatic regions of India

The resistance status of Rhipicephalus (Boophilus) microplus to “Diazinon” was evaluated in 20 locations situated at various agro-climatic regions of India. Adult immersion test (AIT) was optimized using laboratory reared acaricide susceptible IVRI-I strain of R. (B.) microplus and minimum effective concentration of Diazinon was determined as 635.2ppm. The discriminating dose (DD) was worked out as 1270.4ppm and was tested on female ticks collected from organized and unorganized farms located at different agro-climatic regions of India. On the basis of the data generated on three variables viz., mortality, egg masses and reproductive index, the resistance level was categorized as I, II, III and IV. The average resistance factor (RF) of 6.1 (level II) was recorded in the ticks collected from the northern sub-temperate trans-gangetic plains while high average RF values of 26.65 (level III) was recorded in the ticks collected from tropical middle-gangetic plains. The tropical middle gangetic plain has a very high density of animal populations where farmers use Diazinon for tick control, for agricultural practices and for mosquito control. Due to the continuous use of OP compounds the environmental load of Diazinon has become high in the area. This is the first experimental data generated on Diazinon resistant status in ticks of India.

Genotypic variability in maize for aflatoxin contamination

A total of 60 maize genotype samples from different agroclimatic regions of India were collected. Fresh harvest of these maize samples comprising some commercial maize genotypes and some land races were kept under ambient storage conditions for 9 months duration at grain moisture ranges from 14% to 10.5% with a view to identifying the least contaminated maize genotype with aflatoxin. The purpose of this study was to identify the maize genotypes which can survive in ambient storage conditions with minimum spoilage. The response of various maize genotypes for AFB1 accumulation was variable in similar storage conditions. Promising genotypes which showed lower accumulation of AFB1 were identified: Shaktiman-1 (A QPM variety) by showing the lowest concentration of AFB1 (0.30 ppb) followed by KMH-1701 (0.40 ppb); HQPM-1 (0.50 ppb); and QPM-2-136 (0.60 ppb), whereas the most highly toxic sample was Mon - 4 (62.42 ppb) at grain moisture ranges from 12.6 to 11.1%. During the study it has been observed that Shaktiman-1 and other QPM genotypes showed minimum levels of AFB1. Further, it was confirmed by western blot analysis by comparing the resistant and susceptible genotype under artificially inoculated grains with Aspergillus flavus and uninoculated maize grains. It was observed that more chitinase activity was found in shaktiman-1, when the grains were artificially inoculated with A. flavus. The thickness of the seed coat and Aleuron layer was maximum in (90–100 μm) in Shaktiman compared to that of Pro-311 (80–85 μm). It was observed that the thickness of seed coat may act as a barrier for mold contamination and as a result the storage spoilage is minimised.

Sorption and desorption behavior of lead in four different soils of India

Sorption and desorption mechanisms of lead (Pb) were determined in four different soils collected from different agro-climatic regions of India. The soils were classified as: fine loamy mixed Typic- Dystrudepts, fine sandy loam Typic Ustochrepts, fine loamy Typic Ustochrept, and fine sandy loam Udic Haplustalfs. Seven different Pb solutions [Pb(NO3)2 dissolved in 0.01M Ca(NO3)2] in a range of 400 to 2000µgL-1 were applied to study the sorption amounts at 25(±2)oC and 45(±2)oC temperatures. With the increase in application rate and tempera-ture, sorption amounts of Pb increased; however, percentages of sorption of applied Pb were decreased. Sorptions were positively and significantly (p≤0.01) correlated with Langmuir adsorption isotherm. Thermodynamic parameters of sorption (i.e. Ko, ?Go, ?Ho, and ?So) were also determined at two tempera-tures, 25(±2)oC and 45(±2)oC. Increase in Ko with the increase in temperature indicated positive effect of temperature on Pb sorption. High absolute values of ?Go, and positive values of ?Ho, and ?So suggested that the sorption reaction was spontaneous and en-dothermic. Sorbed Pb were desorbed in Pb free 0.01M Ca(NO3)2 solutions at 25(±2)oC and 45(±2)oC. Desorption amounts increased with increase in the Pb application rate, but not always with the increase in temperature.

Changes in dry land agriculture in the semi-arid tropics of India, 1975–2004

This paper examines the changes in dry land agriculture between 1975 and 2004, drawing both from macro-level data as well as the Village Level Studies (VLS) data of ICRISAT from six villages in Maharashtra and Andhra Pradesh. The long-term panel data facilitate an indepth analysis of cropping patterns, productivity levels, costs and returns of crop enterprises over time. The contrasting findings about increasing asset prices and declining returns to land and management puzzle the analysts. Equally implausible are the non-viability of agricultural enterprises on one hand and increasing incomes and living standards of the farm house holds on the other. Yet the SAT areas record highest incidence of poverty among the different agroclimatic regions of India. There is a clear dividing line between dry land agriculture and irrigated agriculture in terms of productivity levels, viability, indebtedness and poverty incidence. The government has come out with relief packages for farmers and employment guarantee programmes for the agricultural labourers in these areas. Besides such temporary palliatives, long-term policy biases which caused them need to be set right to make dry land agriculture in the SAT areas viable and competitive.

Modeling Event-Based Temporal Variability of Flow Resistance Coefficient

During the storm duration, the effects of surface resistance on the developing and receding overland flow depths (hj) on different flow parameters like the overland flow resistance coefficient (Nj), flow velocities (vj), Reynolds number (Rj), and Froude number (Fj) have been studied for the six natural catchments (0.012–92.5 km2) located in different agroclimatic regions of India. The kinematic wave (KW) equations are used for simulation of overland and channel flows using explicit methods for developing numerical solutions for the estimation of flow parameters at short durations. For the complete storm duration hj-Nj relationships have been found to form hysteresis loops. To predict resistance coefficients, simple hj-Nj relationships have been worked out separately for the rising and depleting overland flow conditions. Computed hydrographs simulated by incorporating these equations in the KW model agree well with the observed ones. The overall applicability of the suggested approach is successfully demon...