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Kabita Ghimire Mike W. Dulin Robert L. Atchison Douglas G. Goodin J. M. Shawn Hutchinson 《Agroforestry Systems》2014,88(5):865-875
Windbreaks are valuable resources in conserving soils and providing crop protection in Great Plains states in the US. Currently, Kansas has no up-to date inventory of windbreaks. The goal of this project was to assist foresters with future windbreak renovation planning and reporting, by outlining a series of semi-automated digital image processing methods that rapidly identify windbreak locations. There were two specific objectives of this research. First, to develop semi-automated methods to identify the location of windbreaks in Kansas, this can be applied to other regions in Kansas and the Great Plains. We used a remote sensing technique known as object-based image analysis (OBIA) to classify windbreaks visible in the color aerial imagery of National Agriculture Imagery Program. We also combined GIS techniques and field survey to complement OBIA in generating windbreak inventory. The techniques successfully located more than 4500, windbreaks covering an approximate area of 2500, hectares in 14 Kansas counties. The second purpose of this research is to determine how well the results of the automated classification schemes match with other available windbreak data and the selected sample collected in the field. The overall accuracy of OBIA method was 58.97 %. OBIA combined with ‘heads up’ digitizing and field survey method yielded better result in identifying and locating windbreaks in the studied counties with overall accuracy of 96 %. 相似文献
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The use of improved high yielding crop varieties is an important avenue for reducing hunger and food insecurity in developing countries. Using cross-sectional data obtained from a survey conducted during 2013 crop season, we performed a probit model(plot-level analysis) to determine the probability of adopting new improved rice varieties(NIRVs) by smallholder farmers particularly from two main agro-ecological regions(hills and tropical plain terai regions) of Central Nepal. The results revealed that education, extension services and seed access play significant roles in adoption decisions.Additionally, farm and field characteristic variables such as farm size, endowment of favorable land type(e.g. lowlands), and animal power(e.g. oxen) are the key factors influencing the probability of adopting NIRVs. The results showed that technology specific variables(e.g. yield potential and acceptability) are significant for explaining adoption behavior, implying that it is important to take farmers' preferences to varietal characteristics into consideration in the design of a research and development program. Given the significant role played by extension and access related variables, increased emphasis on information dissemination, field demonstration, and farmers' participatory research and training programs to popularize new rice varieties and enhance their adoption rate are required. This also suggests that policy intervention should be made on improving the educational status of farming households, and developing programs on varietal package of rice seed which offer farmers a variety of choices among the appropriate pools of germplasm. Such programs ultimately help farmers develop more profit-oriented behavior which are necessary to enhance adoption rate, production and food security in the long run. 相似文献
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Community forest management helps in mitigating deforestation and forest degradation by addressing the negative aspects of rural livelihoods such as poverty and social exclusion. It is important in regulating global climate by encouraging sequestration of carbon in shoots, roots and soils. We studied the status of community forest management, forest resource harvest and carbon stocks in two community forests of the mid hill region of central and western Nepal. The study was based on primary and secondary data collected through carbon stock measurement from field visits and allometric equations, household surveys, focus group discussions, key informant interviews, and review of past studies. Socioeconomic variables such as gender, age group, livestock and landholding status were related to resource utilization, conservation, and management of community forest. Forest resources such as timber, firewood, fodder and leaf litter were harvested in sustainable ways. People were involved in forest thinning, co-management meetings, guarding and planting trees for forest conservation and management. Density and carbon stock of trees increased gradually in comparison to a previous study. We recommend further research on other community forests for more accurate and better results. 相似文献
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Binod Prasad Luitel Na-Young Ro Ho-Cheol Ko Jung-Sook Sung Ju-Hee Rhee On-Sook Hur 《Journal of Crop Science and Biotechnology》2018,21(5):499-506
A total of 47 core collections of pepper (Capsicum chinense Jacq.) conserved in National Agrobiodiversity Center (NAC) were studied under field condition at Jeonju over two consecutive years (2015 and 2016). All accessions were characterized for their 14 qualitative and 16 quantitative characters. Results revealed that both qualitative and quantitative characters exhibited wide variation among the studied germplasm. Distribution of fruit characters (fruit length, width, and fruit wall thickness) among the accessions was positively skewed. Of the 47 accessions evaluated, 38.3% accessions had conical shaped fruits and mature fruit color was predominantly red (51.1%), orange (21.3%) and yellow (14.9%). Principal component analyses revealed that (i) 56.64% of the qualitative (fruit shape, color and fruit surface) variation and (ii) 89.42% of the quantitative (plant width, height and fruit maturity days) variation were explained by the first two components. Clustering revealed two groups and dendrogram revealed morphological variation among accessions. The phenotypic diversity exists in this core collections provide valuable information to improve agronomic traits in pepper breeding program. 相似文献
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Background
Community recovery following primary habitat alteration can provide tests for various hypotheses in ecology and conservation biology. Prominent among these are questions related to the manner and rate of community assembly after habitat perturbation. Here we use space-for-time substitution to analyse frog and lizard community assembly along two gradients of habitat recovery following slash and burn agriculture (jhum) in Mizoram, Northeast India. One recovery gradient undergoes natural succession to mature tropical rainforest, while the other involves plantation of jhum fallows with teak Tectona grandis monoculture.Results
Frog and lizard communities accumulated species steadily during natural succession, attaining characteristics similar to those from mature forest after 30 years of regeneration. Lizards showed higher turnover and lower augmentation of species relative to frogs. Niche based classification identified a number of guilds, some of which contained both frogs and lizards. Successional change in species richness was due to increase in the number of guilds as well as the number of species per guild. Phylogenetic structure increased with succession for some guilds. Communities along the teak plantation gradient on the other hand, did not show any sign of change with chronosere age. Factor analysis revealed sets of habitat variables that independently determined changes in community and guild composition during habitat recovery.Conclusions
The timescale of frog and lizard community recovery was comparable with that reported by previous studies on different faunal groups in other tropical regions. Both communities converged on primary habitat attributes during natural vegetation succession, the recovery being driven by deterministic, nonlinear changes in habitat characteristics. On the other hand, very little faunal recovery was seen even in relatively old teak plantation. In general, tree monocultures are unlikely to support recovery of natural forest communities and the combined effect of shortened jhum cultivation cycles and plantation forestry could result in landscapes without mature forest. Lack of source pools of genetic diversity will then lead to altered vegetation succession and faunal community reassembly. It is therefore important that the value of habitat mosaics containing even patches of primary forest and successional secondary habitats be taken into account. 相似文献8.
Champa P. Wijekoon Binod B. Pageni Melanie L. Kalischuk Newton Z. Lupwayi Lawrence M. Kawchuk 《American Journal of Potato Research》2017,94(3):251-257
Late blight, caused by the oomycete Phytophthora infestans (Mont.) de Bary, is a devastating disease in potato and tomato and causes yield and quality losses worldwide. The disease first emerged in central America and has since spread in North America including the United States and Canada. Several new genotypes of P. infestans have recently emerged, including US-22, US-23 and US-24. Due to significant economic and environmental impacts, there has been an increasing interest in the rapid identification of P. infestans genotypes. In addition to providing details regarding the various phenotypic characteristics such as fungicide resistance, host preference, and pathogenicity associated with various P. infestans genotypes, information related to pathogen movement and potential recombination may also be determined from the genetic analyses. Restriction fragment length polymorphism (RFLP) analysis with the RG57 loci is one of the most reliable procedures used to genotype P. infestans. However, the RFLP procedure requires propagation and isolation of the pathogen and relatively large amounts of DNA. Isolation of the late blight pathogen is sometimes impossible due to the poor condition of the infected tissues or the presence of fungicide residues. In this study, we describe a procedure to identify P. infestans at the molecular level in planta using terminal restriction fragment length polymorphism (T-RFLP) of the RG57 loci. This T-RFLP assay is sufficiently sensitive to detect and differentiate P. infestans genotypes directly in planta without propagation and isolation of the pathogen, to facilitate the timely implementation of best management practices. 相似文献
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Parishmita Handique Hemanta Pokhrel Binod Kalita Raktim Sarmah Abdul Malik Ahmed Kaustabh Bhagawati Arnab Narayan Patowary 《Aquaculture Research》2020,51(5):1973-1979
The present study was conducted to evaluate the …effect of dietary selenium on growth performance and antioxidant enzymes activity in Cirrhinus mrigala for a period of 45 days. Four numbers of experimental diets were prepared, Tc for Control (0 mg organic selenium/kg of diet), T1 (2.5 mg organic selenium/kg of diet), T2 (5.0 mg organic selenium/kg of diet) and T3 (10 mg organic selenium/kg of diet). The water quality parameters (temperature, DO, pH, conductivity, hardness, ammonia, nitrate and nitrite) were found to be insignificant (p > .05) among all the treatments. Superoxidase dismutase (SOD) was found to be significantly highest in T2 (6.10 ± 0.07) when compared with the other treatments. Similarly, catalase (CAT) activity in T1 (13.21 ± 0.13) was significantly (p < .05) different with that of Control, T2 and T3. Present study also revealed that 2.5mg organic selenium/kg supplemented diet (T1) showed highest results in net weight gain (15.55 ± 1.36 g), net weight gain percentage (185.88 ± 8.98%) and SGR (2.35 ± 0.06 g) compared with other experimental diet. 相似文献
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beta-Lactams are among the most clinically important antimicrobials in both human and veterinary medicine. Bacterial resistance to beta-lactams has been increasingly observed in bacteria, including those of animal origin. The mechanisms of beta-lactam resistance include inaccessibility of the drugs to their target, target alterations and/or inactivation of the drugs by beta-lactamases. The latter contributes predominantly to beta-lactam resistance in Gram-negative bacteria. A variety of beta-lactamases have been identified in bacteria derived from food-producing and companion animals and may further serve as a reservoir for beta-lactamase-producing bacteria in humans. While this review mainly describes beta-lactamases from animal-derived Escherichia coli and Salmonella spp., beta-lactamases from animal-derived Campylobacter spp., Enterococcus spp., Staphylococcus spp. and other pathogens are also discussed. Of particular concern are the increasingly-isolated plasmid-encoded AmpC-type CMY and extended-spectrum CTX-M beta-lactamases, which mediate acquired resistance to extended-spectrum beta-lactams. The genes encoding these enzymes often coexist with other antimicrobial resistance determinants and can also be associated with transposons/integrons, increasing the potential enrichment of multidrug resistant bacteria by multiple antimicrobial agents as well as dissemination of the resistance determinants among bacterial species. Characterization of beta-lactam-resistant animal-derived bacteria warrants further investigation of the type and distribution of beta-lactamases in bacteria of animal origin and their potential impact on human medicine. 相似文献