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Guhathakurta, P.
- Some Physiological Aspects of Development and Growth of Eucalyptus tereticornis SM (Syn Eucalyptus hybrid)
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Indian Forester, Vol 104, No 1 (1978), Pagination: 19-31Abstract
Some of the physiological qualities of Eucalyptus tereticornis (Syn. E. hybrid) namely, that of reproduction and seeding, moisture relations, nutrition, etc., have been characterised in this paper. The propagation is carried out through seeds. Out crossing may be common, but it is also not self-incompatible. The time of flowering and innate genetical trait rule out outcrossing with every other species of the same genus. The impurity in Eucalyptus tereticornis seeds is considered mostly a mechanical mixture and hybridisation, if at all, is nominal. The germinative capacity cannot be rated high. Viability appears to be lost gradually. The important concern for seedlings and seeds in the nursery is the damping off disease attributed to excessive watering, high relative humidity and temperature and poor light. For planting, the desiccation of the nursery stock is prevented by putting them in the polythene containers. But ischolar_main pruning Or knotting, as practised, tends to upset the internal water balance. This species develops ischolar_main system rapidly. The species grows well in soils with good physical characteristics. The laterite or kankar pan limits ischolar_main growth as also strong alkaline and saline conditions. The critical PH is UO. High water table causes inhibited ischolar_main growth, chlorosis, poor crOwn development and paucity of leaves. The limit for soluble salt stands at 0.7%. The addition of organic matter results in greater growth. The effects of various macro nutrients on the growth are still uncertain, except tor organic C, N and P. It is more important to determine the levels of these fertilizers in mixture with one another for optimum results. E. tereticornis not as cosmopolitan as made out initially through it can grow in divergent habitats. Its physiological behaviour and requirements need a more correct assessment.- Ailanthus grandis Prain-its Prospect in Forestry
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Indian Forester, Vol 98, No 5 (1972), Pagination: 261-270Abstract
Ailanthus grandis, Prain wlth several desirable characters in external form and behavior, namely, quicker rate of growth relative to others in association, a straight cylindrical bole without unwanted flares at the base and not too great a taper at the top, a restricted crown enabling a greater economy of the aerial space, habit of natural pruning, apical dominance of shoots and a thin back, has become eminently suitable for maximising production within a short span of time. The wood too can be put to several uses including box planking, match making and newsprint grade of pulp. From plantations raised since 1921 a relationship of the age wlth girth, height and volume of individual trees and some crop data bave been established. Some basic information too bas been gathered from current trials. Erratic in flowering and fruiting, Ailanthus has a long period of dormancy breaking with the onset of monsoon and a low viability; in a good seed year seed dibbling and in poor years, one-year old oursery stock outplanting in containers are the best methods of raising a successful plantatin. Naked ischolar_main or ball of earth planting is not as efficient. Stumping has failed so far though it does not seem to be totally impossible. A taungya with a low vegetabie crop in the first year makes invaluable assistance io establlsbing young plantations. An early planting in favourable weather results in superior height growth. The greatest obstacle to extension of Ailanthus grandis in the duars is its aversion to excess moisture in the seedling stage. In these areas, the micro-relief produces zones of impeded drainage. To combat this, the ridge planting has been found to be successful. At present, large areas in the bhabar where draiilage poses no problem are beinagbrought under Ailanthus grandis with Bombax ceiba Linn. And it seems to be possible to harvest such a crop at 35-40 years and the final crop from principal species, Ailanthus alone will yield 20 m2 per hectare per annum. This plus out-turn from intermediate thinnings and final harvest of Bombax ceiba should go to qualify the crop as economically viable. In the duars where the species bad setbacks, Ailanthus is being mixed with Michelia champaca, Linn. And Bombax ceiba. Here the question of predominant role of Ailamhus Is uncertain, and unlike, in the bhabar where it Is possible to manage a crop of predetermined composition, tbe strategy of management at present is highly flexible.- Effect of Antitranspirant Phenylmercuric Acetate on some Conifer Seedlings-a Preliminary Study
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Indian Forester, Vol 99, No 8 (1973), Pagination: 499-504Abstract
Excessive transpiration and resultant mortality of seedlings at the time of planting is one of the most important physiological problems associated with afforestation. An anti-transpirant, Phenylmercuric acetate which acts as a metabolic inhibitor and preveats stomatal opening has thrown up promise of maintaining a favourable water balance in transplant seedlings. The present study investigates the effect of Phenylmercuric acetate on transpiration in 11 month old nursery seedlings of Pinus patula Schidede and Deppe and Pinus taeda Linn. dripped in the chemical for 1 hour. In the case of conifers, the stomata being sunken, it is extremely difficult to observe the efficacy of this chemical in relation to stomatal opening. In an indirect method, the weight of seedlings was measured al percentage of initial green weight and expressed as a function of time upto the 6th day. In Pinus patula the rate of loss of water in 5000 ppm treated seedlings has been the least. In 500 ppm the response has appeared late, but the trend of drying out has heen slower than 5000 ppm. There was no effect with 100 ppm. In Pinus taeda both 100 ppm and 500 ppm treated seedlings have shown a slower rate of loss of water than the control. With 5000 ppm treatment the rate of loss of water has been faster than either control or other treatments. This high concentration treatment had adverse side effects in both Pinus patula and P. taeda but in a more pronounced way in the latter.- Pinus patula Schl. and Cham.-its Problems and Prospects in West Bengal
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Indian Forester, Vol 99, No 6 (1973), Pagination: 337-348Abstract
Acclaimed as a reliable species for high production Pinus patula has been widely planted in its native country, Mexico and also, in Soulh Afriqa, Rhodesia, Tansania, Kemfa, Malawi, Uganda, Malagasy etc. In India too, the species has of late, come into prominence and several states have adopted it for large scale plantation. Pinus patula is a native of Mexico where it grows on a wide range of sites in the southern region. In this region, three thermal zones can be clearly defined, viz. (a) temperate colder, (b) temperate warmer and subtropical-determined by altitude within the limits 19°21° north latitudes. Good growth of the species is however restricted to certain typical moist tracts. It is abundant in the warmer and colder temperate zone where dense and pure stand naturally occur at elevations ranging from about 1500 to 3000 with an annual rainfall of 700 to 2000 mm and frequent mists. The crop is superior in quality in the valleys and on the flats with deep, moist, well drained loamy solis. It is diluted with several associates of Pines in the marginal areas and on the poor, gravely and shallow solis with a lower rainfall and on the edge of escarpment it is usually replaced mainiy by P. teocote and Oak scrubs. Pinus patula often grows into a denseiy packed crop-about 1500 to 2500 stems can occur on a he ctare of land at the middle ages i.e. 30-40 years. On good sites, the trees show rapid growth in the early stages and in certain areas the species can attain a diameter of 25 cm at about 10 years. This extraordinary growth rate accounted for extensive trial plantations of P. patul in different parts of the world. The Silvicultural characteristic of P. patula should not vary fundamentally from those growing in its native habitat, and it should not be difficult to select suitable sites in this country.- Impact of Observed Climate Change on the Classification of Agroclimatic Zones in India
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Authors
N. Chattopadhyay
1,
A. K. Sahai
1,
P. Guhathakurta
1,
S. Dutta
1,
A. K. Srivastava
1,
S. D. Attri
2,
R. Balasubramanian
1,
K. Malathi
1,
Swati Chandras
1
Affiliations
1 India Meteorological Department, Shivajinagar, Pune 411 005, IN
2 India Meteorological Department, New Delhi 110 003, IN
1 India Meteorological Department, Shivajinagar, Pune 411 005, IN
2 India Meteorological Department, New Delhi 110 003, IN
Source
Current Science, Vol 117, No 3 (2019), Pagination: 480-486Abstract
The classification of agroclimatic zones in India was made in the 1990s for identifying priorities and developing strategies for location-specific and need-based research as well as overall agricultural development in the country. Long-term climatic parameters, particularly temperature and rainfall along with soil and crop information were used for the classification of agroclimatic zones. It has been documented with a fair degree of accuracy that overall climate is changing, particularly with respect to temperature over the Indian region. Thus it is anticipated that in the recent past, climate change may be reflected in the agroclimatic zones as well and ultimately affect the criteria of their classification based on climatic parameters. The objective of the present study is to examine the trends and spatial/temporal variability of temperature, rainfall, rainy days, and heavy rainfall in different agroclimatic zones of the country, which may help in better understanding of the further initiatives on reclassification of agroclimatic zones, if required. Using various long-term gridded data from 1985 and instrumental datasets starting from 1951 to 1980, studies have been made to observe changes in different components of the climatic variables, i.e. temperature and rainfall. It has been observed that there are significant changes in temperature and rainfall, both temporally and spatially, across India and there is a definite shift in temperature and rainfall patterns in the recent past compared to 1951–1980. It has also been inferred that there is a need to reconsider the classification of agroclimatic zones in India under the scenario of observed climate changes in the country.Keywords
Agroclimatic Zones, Classification, Climatic Parameters, Climate Change.References
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- Srivastava, A. K., Kothawale, D. R. and Rajeevan, M. N., Variability and long-term changes in surface air temperatures over the Indian subcontinent. In Observed Climate Variability and Change over the Indian Region, Springer, Singapore, 22 November 2016, 2017, 1st edn, pp. 17–36.
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- Chung, C. E. and Ramanathan, V., Weakening of North Indian SST gradients and the monsoon rainfall in India and the Sahel. J. Climate, 2006, 19, 2036–2045.
- Parthasarathy, B. and Dhar, O. N., Climate fluctuations over Indian region – rainfall: a review. Research Report No. RR-025. Indian Institute of Tropical Meteorology, Pune, 1978, p. 14.
- Rupa Kumar, K., Pant, G. B., Parthasarathy, B. and Sontakke, N. A., Spatial and sub-seasonal patterns of the long-term trends of Indian summer monsoon rainfall. Int. J. Climatol., 1992, 12, 257–268.
- Guhathakurta, P. and Rajeevan, M., Trends in rainfall pattern over India. Int. J. Climatol., 2008, 28, 1453–1469.
- Vijay Kumar, S. and Jain, K., Trends in rainfall amount and number of rainy days in river basins of India (1951–2004). Hydrol. Res., 2011, 42(4), 290–306; doi:10.2166/nh.2011.067.