Effects of land-use change on soil microbial C, N and P in a Himalayan watershed   总被引：8，自引：0，他引：8  

P. Sharma  S. C. Rai  R. Sharma  E. Sharma 《Pedobiologia》2004,48(1):83-92

Soil microbial C, N and P as affected by land-use change were studied in a Himalayan watershed at Sikkim, India. The major land-uses considered were forests (dense and open), agroforestry types (large cardamom and mandarin), open cropped and wasteland areas covering subtropical and temperate zones. Across the land-use, microbial C ranged from 219 to 864 μg g⁻¹, microbial N from 30 to 142 μg g⁻¹, and microbial P from 12 to 43 μg g⁻¹ soils. The microbial C, N and P were positively related to each other. The microbial C:N ratio in these soils ranged from 6 to 11 and the microbial C:P ratio from 18 to 27. The conversion of forests into other land-uses resulted in a remarkable decline in the amounts of soil nutrients and microbial C, N and P. The microbial nutrients in the Himalayan region are very sensitive to land-use/cover changes. Therefore, the conversion of forest to agricultural land should be reversed. Agroforestry systems should be included in agricultural land in mountainous regions.  相似文献   

Commercial viability of alternative cytoplasmic-nuclear male-sterility systems in pearl millet     

K.N. Rai  K. Anand Kumar  D.J. Andrews  A.S. Rao 《Euphytica》2001,121(1):107-114

Commercial viability of three cytoplasmic-nuclear male sterility (CMS) systems (A₄, A₅ and A_v) as potential alternatives to the most widely used A₁ system in pearl millet (Pennisetum glaucum (L.) R.Br.) was evaluated in terms of stability of complete male sterility of four isonuclear A-lines (81A₁, 81A₄, 81A₅ and 81A_v) and the level and stability of male fertility restoration of their 44 single-cross hybrids. Lines 81A₄ and 81A₅ had no pollen shedders (PS), and there were very low frequency of non-PS plants of these A-lines that had a maximum of 1–5% selfed seedset (SSS). In 81A₁ and 81A_v,there were, albeit low frequency (<1%) of PS plants, and relatively higher frequency of the non-PS plants in these two lines, the more so in 81A_v,had 1–5% and even greater SSS. Some hybrids made on each of the three A-lines (81A₁, 81A₄ and 81A_v) had high and stable male fertility, while others made on the same three A-lines displayed large variation in SSS across the environments, the more so in case of hybrids made on 81A_v. These results indicate that the A₄ CMS system provides a better alternative to the A₁ CMS system, while the A_v system does not. On the basis of highly stable male sterility and the highest frequency of pollinators behaving as maintainers, the A₅ CMS system appeared to be the best for A-line breeding. The commercial viability of this CMS system in breeding R-lines of grain hybrids, however, still remains to be ascertained as no hybrid on it was fully male fertile in any environment. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

The Characterization of Infectious Bursal Disease Virus Strains/Isolates from Field Outbreaks in India     

Pahar  B.  Rai  A. 《Veterinary research communications》1997,21(4):289-301

Pahar, B. and Rai, A., 1997. The characterization of infectious bursal disease virus strains/isolates from field outbreaks in India. Veterinary Research Communications, 21 (4), 289-301Three infectious bursal disease virus (IBDV) isolates were adapted to culture in chick embryo fibroblast cells in which they produced a cytopathic effect. The isolates were identified as IBDV by virus neutralization tests using a standard hyperimmune serum against infectious bursal disease, physicochemical properties and their pathogenicity in chick embryos and chicks. The IBDV S394 strain was antigenically different from IBDV S194/IBDV S494 as well as from the IBDV Intermediate Georgia strain, one of the vaccine strains in use in India.  相似文献   

‘Neodomesticates’ of the Himalayan allium spices (Allium species) in Uttarakhand,India and studies on eco-geography and morphology     

Pandey  Anjula  Malav  Pavan Kumar  Rai  Madhav K.  Ahlawat  S. P. 《Genetic Resources and Crop Evolution》2021,68(5):2167-2179

Genetic Resources and Crop Evolution - The study on Himalayan allium spices was undertaken with specific reference to commercially important taxa belonging to the genus Allium viz. A. stracheyi...  相似文献   

Tolerance to excess moisture in maize (Zea mays L.): susceptible crop stages and identification of tolerant genotypes     

Pervez H. Zaidi  S. Rafique  P. K. Rai  N. N. Singh  G. Srinivasan 《Field Crops Research》2004,90(2-3):189-202

Excess moisture (water-logging) during the summer–rainy season is one of the major production constraints for maize (Zea mays L.) in a large area of Southeast Asia. Identification and development of genotypes capable of withstanding the stress conditions could be an ideal and affordable approach suitable for resource poor maize-growing farmers of such areas. We attempted to identify the most susceptible/critical crop stage(s) of maize for excess moisture stress, and to develop a screening technique and selection strategies for identification of germplasm tolerant to excess moisture stress. Among the four crop stages, i.e. early seedling (V2), knee-high (V7), tasseling (VT) and milk stage (R1), V2 was found to be highly susceptible, followed by the V7 stage. A screening technique (cup method) was developed/standardized, and was found to be an efficient technique for large-scale screening of maize genotypes against excess soil moisture stress. Germplasm was screened using this technique followed by field evaluation at the V7 growth stage (seventh leaf visible). Excess soil moisture stress severely affected various growth and biochemical parameters, impaired anthesis and silking, and eventually resulted in poor kernel development and yield. However, remarkable variability was found among the genotypes studied. Genotypes with good carbohydrate accumulation in stem tissues, moderate stomatal conductance, <5 days ASI, high root porosity, and early brace root development ability have been found to have good tolerance against the hypoxia/anoxia caused by excess soil moisture conditions.  相似文献   

Effect of SO2 and NH3 on growth behavior of some phylloplane fungi of wheat in in vitro     

A. K. Singh  Bharat Rai 《Water, air, and soil pollution》1990,49(3-4):343-347

The colony growth of some phylloplane fungi of wheat viz. Alternaria alternata, Aspergillus favus, Amiger, Cladosportium cladosporioides, Curvularia lunata, Drechslera australiensis, Epicoccum purpurascens, Fusarium oxysporum, Penicillium chrysogenum and P. citrinum were studied in chamber fumigation experiments exposed to 2669 ± 105 μg SO₂ m^?3 and 708.33 ± 55 μg NH3 m^?3 air, separately, for 10, 30 and 60 min. The colony growth of all the test fungi was significantly (P=0.01/0.005) inhibited on prolonged period of SO₂/NH₃ exposure. However, some of the test fungi namely A. favus, A. niger, E. purpurascens and F. oxysporum showed growth stimulation after 10 min exposure of SO₂. Similarly, the growth of C. lunata and F. oxysporum increased only after 10 min exposure of NH3. The inhibitory effect of SO₂/NH₃ was directly correlated with the exposure times.  相似文献   

An assessment on CRISPR Cas as a novel asset in mitigating drought stress     

Ali  Zafar  Rai  S. K.  Jan  Sami  Raina  Kavita 《Genetic Resources and Crop Evolution》2022,69(6):2011-2027

Genetic Resources and Crop Evolution - Drought stress is currently one of the major threats to the global food security as it primarily is the main cause behind yield loss and hence overall...  相似文献   

Identification of ‘Ca. Phytoplasma asteris’, banana bunchy top virus and banana streak MY virus associated with Champa and Sabri banana cultivars in Tripura,a North Eastern state of India     

Mitra  Surabhi  Debnath  Prasenjit  Rai  Richa  Srivastava  Nishant  Rao  Govind Pratap  Baranwal  Virendra Kumar 《European journal of plant pathology / European Foundation for Plant Pathology》2022,163(4):907-922

European Journal of Plant Pathology - Symptoms of bunchy top, little leaf, leaf chlorosis with chlorotic streaks, leaf necrosis and stunted growth were noticed in two banana cultivars, Champa and...  相似文献   

Microclimate modifications,growth and yield of intercrops under Hardwickia binata Roxb. based agroforestry system     

Arun K Shanker Scientist  Ram Newaj  P Rai  KR Solanki  K Kareemulla  R Tiwari 《Archives of Agronomy and Soil Science》2013,59(3):281-291

An experiment was conducted by planting Hardwickia binata Roxb. at 200, 400 and 800 trees ha^???1, intercrops viz., Brassica campestris (mustard) and Glycine max (soybean) were sown from the second year onwards in winter and summer respectively at the National Research Centre for Agroforestry, Jhansi, U.P., India with the objectives of evaluating agrosilvicultural potential of the system and to study the effect of tree densities on ecophysiology of understorey crops. Tree growth was affected by both density and intercrop in the initial years of growth. Photosynthetic photon flux density (PPFD) available to the intercrops reduced with increasing densities. Transpiration rate and stomatal conductance in intercrops decreased due to the presence of trees. No significant changes in leaf temperature were observed till the fifth year of the growing season. Yield was significantly higher in pure crop in comparison with all the densities in mustard. Soybean yield under 200 trees ha^???1 was comparable to that of the pure crop. Trees at the density of 200 trees ha^???1 provided a conducive microenvironment to the intercrops.  相似文献   

Role of India's Anganwadi Center in Securing Food and Nutrition for Mothers and Children     

Sandhya Kumar  Rajesh Kumar Rai 《Journal Of Agricultural & Food Information》2013,14(2):174-182

India's 2013 National Food Security Act identifies Anganwadi centers (the courtyard shelter) as responsible for ensuring the food and nutrition for mothers and children. This article proposes four essential reforms that must take place to revitalize the languishing Anganwadi system: (a) strengthen implementation of the Integrated Child and Development Services (ICDS) through greater outreach and education; (b) boost incentives for Anganwadi workers and Anganwadi health workers; (c) bring together different government stakeholders to provide the integrative framework needed; and (d) improve monitoring and evaluation of Anganwadis so as to better gauge not just performance of workers, but also health and nutrition outcomes among women and children.  相似文献