Water use, growth and yield of green gram under rainfed upland crop sequences in Gangetic Plains of Indian sub-tropics     

A.Zaman  S.K.Choudhuri 《地理学报(英文版)》2002,12(3)

A field experiment was conducted to study the effect of different crop sequences on water use, growth and yield of green gram (Vigna radiata (L) Wilezek) during 1992-93 and 1993-94 under rainfed upland condition in Indo-Gangetic plains of West Bengal. Green gram sown in the month of March as pre-rainy (summer) season crop, as and when the winter crops vacated the land, produced highest dry matter of 372 gm-2 which was significantly highest in black gram-yellow sarson sequence.The results of the field experimentation revealed that green gram gave highest grain yield to the extent of 10.80 q/ha when sown after black gram (rainy season) followed by yellow sarson (winter season) while the crop produced 10.63 q/ha under sesame-yellow sarson sequence. Highest water use of 267mm was achieved in green gram under black gram-yellow sarson sequence and the crop gave water use efficiency of 4.07 kg ha-1mm-1 under black gram-yellow sarson sequences.  相似文献   

Water use, growth and yield of green gram under rainfed upland crop sequences in Gangetic Plains of Indian sub-tropics     

A. Zaman  S.K. Choudhuri 《地理学报》2002,12(3):301-304

A field experiment was conducted to study the effect of different crop sequences on water use, growth and yield of green gram (Vigna radiata (L) Wilezek) during 1992-93 and 1993-94 under rainfed upland condition in Indo-Gangetic plains of West Bengal. Green gram sown in the month of March as pre-rainy (summer) season crop, as and when the winter crops vacated the land, produced highest dry matter of 372 gm-2 which was significantly highest in black gram-yellow sarson sequence. The results of the field experimentation revealed that green gram gave highest grain yield to the extent of 10.80 q/ha when sown after black gram (rainy season) followed by yellow sarson (winter season) while the crop produced 10.63 q/ha under sesame-yellow sarson sequence. Highest water use of 267 mm was achieved in green gram under black gram-yellow sarson sequence and the crop gave water use efficiency of 4.07 kg ha-1mm-1 under black gram-yellow sarson sequences.  相似文献   

Structural controls on gold mineralisation and the nature of related fluids of the Paiol gold deposit, Almas Greenstone Belt, Brazil     

Mrcio Anselmo Duarte Ferrari  Asit Choudhuri 《Ore Geology Reviews》2004,24(3-4):173

Chemical analyses suggest that the metavolcanic rocks of the Almas Greenstone Belt (AGB), Tocantins State, Brazil have a continental affinity, possibly related to a continental rift environment. They were metamorphosed to amphibolite facies during a regional tectono-metamorphic event (D_n), retrogressed to greenschist facies assemblages and then hydrothermally altered within dextral strike–slip shear zones (D_n+1). Fracture sets related to D_n+2 intersect S_n+1.The Paiol Gold Mine is one of several mineralised zones within metabasic and meta-intermediate rocks of the AGB. It exploits shoots of sulphide–Au–quartz mineralisation that occupy dilational zones approximately perpendicular to an elongation lineation (L_n+1) within mylonitic foliation S_n+1 (S_n+1=S within the S–C fabric). The dilational zones probably formed due to dextral displacement on sinistrally en echelon C surfaces. Minor amounts of gold may have been introduced or remobilised during D_n+2.Coexisting primary and pseudosecondary fluid inclusions in mineralised quartz veins from ore shoots comprise a high-salinity three-phase type (Type II) and a lower salinity two-phase type (Type I). Homogenisation temperatures for Type II inclusions range from 200 to 410 °C and Type I from 90 to 320 °C. The inclusions and their temperature ranges are believed to reflect heat exchange and some mixing between the two fluid types under relatively constant ambient temperatures, but variable (though broadly declining) fluid temperatures. This took place late in D_n+1 in conjunction with greenschist facies retrogression and localised hydrothermally induced metasomatism.  相似文献   

Radioactive element distribution in the Archean granulite terrane of Jequié — Bahia,Brazil     

S. S. Iyer  A. Choudhuri  M. B. A. Vasconcellos  U. G. Cordani 《Contributions to Mineralogy and Petrology》1984,85(1):95-101

The radioactive element distribution in the Archean granulite facies rocks of Jequié, Brazil, has been determined. The K/Rb ratios show a large spread with majority of the values falling within the normal field (K/Rb<300). The Th/U ratios fall into two groups, one group with values in the range of 1.7 to 2.6, whereas the other group show Th/U values greater than 7 (7 to 25). These distributions can be explained on the basis of the presence of accessory minerals apatite and zircon. The relatively high concentrations of the radioactive and other elements in Jequié granulites probably represents the relict primary geochemical character, little modified during metamorphism. The radiogenic heat production data for the area are calculated and using the measured regional heat flow value from nearby area an estimate of the relative thickness of the continental lithosphere is made using the model developed by Oxburgh (1981).  相似文献   

Water for food production in Sub-Saharan Africa     

Dr. Asit K. Biswas 《GeoJournal》1987,15(3):233-242

Water control is an essential requirement if food and energy crises in Africa are to be resolved on a sustainable basis. The paper reviews the problems and prospects associated with the expansion of irrigation in Africa, where experiences with large and medium scale water management have been of comparatively recent origin. The present status of water development and management issues are approached carefully and cautiously, they can make an important and lasting contribution to the resolution of Africa's food crisis.  相似文献   

Chloritoid from low-grade schists. Singhbhum,Eastern India     

A. Choudhuri 《Contributions to Mineralogy and Petrology》1970,29(2):116-122

Chloritoid-sericite schists from the chlorite zone of the regionally metamorphosed Singhbhum anticlinorium in Eastern India are described with regard to the formation of chloritoid during prograde metamorphism — the main stage of its crystallisation was coeval with the movement. The movements accompanying metamorphism have had a marked effect on the lattice orientation of this mineral, so that its crystallographic axis is roughly parallel to the regional fold axis. In one case chloritoid appears to be in stable association with hematite, i.e. it persists beyond the magnetite-hematite equilibrium, which is probably a local effect due to a slight rise in oxygen partial pressure in the last stages of metamorphism. The occurrence of phengitic mica in these schists is suggestive of high total pressures and high water pressures.  相似文献   

International Seminar on Climatic Fluctuations and Water Management     

Asit K. Biswas 《Climatic change》1991,19(3):345-348

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Prospects for predicting cycle 24     

Arnab Rai Choudhuri 《Journal of Astrophysics and Astronomy》2008,29(1-2):41-47

Although we have reliable data of solar polar fields only from the mid-1970s, it seems that the polar field at a minimum is well correlated with the next cycle, but the strength of the cycle is not correlated with the polar field produced at its end. We explain this by suggesting that the Babcock-Leighton mechanism of poloidal field generation from tilted active regions involves randomness, whereas the other aspects of the dynamo process are more ordered. To model actual cycles, we have to ‘correct’ our theoretical dynamo model by ‘feeding’ information about the polar field at the minima. Following this process, we find that our model fits the observed sunspot numbers of cycles 21–23 reasonably well and predicts that cycle 24 will be the weakest in a century.  相似文献   

The role of magnetic buoyancy in a Babcock-Leighton type solar dynamo     

Dibyendu Nandy  Arnab Rai Choudhuri 《Journal of Astrophysics and Astronomy》2000,21(3-4):381-385

We study the effects of incorporating magnetic buoyancy in a model of the solar dynamo&amp;#x2014;which draws inspiration from the Babcock-Leighton idea of surface processes generating the poloidal field. We present our main results here.  相似文献   

Probabilistic analyses of three-dimensional circular footing resting on two-layer c–ϕ soil system considering soil spatial variability     

Choudhuri  Kouseya  Chakraborty  Debarghya 《Acta Geotechnica》2022,17(12):5739-5758

Acta Geotechnica - The prime objective of this paper is to study the effect of soil spatial variability on the three-dimensional probabilistic bearing capacity of a circular footing resting on the...  相似文献