Iron making in ancient India - a critical assessment

It is a well known fact, that Indian craftsman produced quality iron products much earlier than the developed countries, making use of local reserves of iron ore. Iron produced in ancient India was mostly wrought iron. The metal was obtained in the form of a pasty mass and then shaped under hammer. Today, when India is producing several million tons of iron, primitive iron making is still exists in some parts of India. The primitive iron making furnaces declined in numbers gradually from about 500 in the beginning of 20'h century to about 150 by the middle of the century. Their present number is not known. Such furnaces are in operation deep into the forests and the tribal areas of India. The paper discusses briefly the history of iron making along with the critical assessment of the ancient processes. Some of the important measures absolutely. essential to upgrade the processes have also been discussed. Several pertinent modifications have been proposed in the design of these furnaces to make them more energy efficient and economically viable 'for tribal and rural populace

Methane and nitrous oxide emissions from an integrated rainfed rice–fish farming system of Eastern India

Integration of fish stocking with rice (Oryza sativa L.) cultivation promises an ecologically sound and environmentally viable management of flooded ecosystem. Rice agriculture contributes to the emission of greenhouse gases CH4 and N2O, but little is known on the effect of fish rearing in fields planted to rice on the emission of these two greenhouse gases. In a field study, CH4 and N2O fluxes were measured from a sub-humid tropical rice field of Cuttack, eastern India, as affected by integrated rice–fish farming under rainfed lowland conditions. Three Indian major carps, Catla catla H., Labeo rohita H. and Cirrhinus mrigala H., and Puntius gonionotus B. were stocked in rice fields planted to two rice cultivars in a split-plot design with no fish and fish as the main treatments and two rice varieties as sub-treatments with three replicates each. Fish rearing increased CH4 emission from field plots planted to both the rice cultivars with 112% increase in CH4 emission in cv. Varshadhan and 74% in case of cv. Durga. On the contrary, fish stocking reduced N2O emission from field plots planted to both the rice varieties. Movement of fish and associated bioturbation coupled with higher dissolved organic-C and CH4 contents, and lower dissolved oxygen could be the reasons for release of larger quantities of CH4 from rice + fish plots, while higher dissolved oxygen content might have influenced release of more N2O from the rice alone treatment. The total greenhouse gas emission, expressed as CO2 equivalent global warming potential (GWP), was considerably higher from rice + fish plots with CH4 contributing a larger share (91%) as compared to rice alone plots (78–81%). On the contrary, N2O had a comparatively lesser contribution with 19–22% share in rice alone plots that was further reduced to 9% in rice + fish plots. However, considering the profit-loss analysis based on the market price of the produce, rice–fish system provided a net profit of $453.36 ha−1 over rice alone system in spite of higher carbon credit compliance of a rice–fish ecosystem due to larger cumulative GWP