Browsing by Author "Saranath Singh"

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Effect of soil nitrogen, carbon and moisture on methane uptake by dry tropical forest soils
(1997) J.S. Singh; Smita Singh; A.S. Raghubanshi; Saranath Singh; A.K. Kashyap; V.S. Reddy
Methane uptake was measured for two consecutive years for four forest and one savanna sites in a seasonally dry tropical region of India. The soils were nutrient-poor and well drained. These sites differed in vegetational cover and physico-chemical features of the soil. There were significant differences in CH4 consumption rates during the two years (mean 0.43 and 0.49 mg m-2 h-1), and at different sites (mean 0.36 to 0.57 mg m-2 h-1). The mean uptake rate was higher (P < 0.05) in dry seasons than in the rainy season at all the sites. There was a significant season and site interaction, indicating that the effect of different seasons differed across the sites. There was a positive relation between soil moisture and CH4 uptake rates during summer (the driest period) and a negative relation during the rest of the year. The results suggested that seasonally dry tropical forests are a strong sink for CH4, and C and N status of soils regulates the strength of the sink in the long term.
Methane flux from rice/wheat agroecosystem as affected by crop phenology, fertilization and water level
(Kluwer Academic Publishers, 1996) J.S. Singh; Smita Singh; A.S. Raghubanshi; Saranath Singh; A.K. Kashyap
Methane flux was measured for a rice/wheat agroecosystem of Gangetic Plains, with and without application of chemical fertilizer and wheat straw (WS). Three treatments of control, fertilizer application and fertilizer + WS application, were established in a completely randomized block design trod measurements were made for two consecutive years (1993 and 1994). CH4 measurements during growth of the rice crop period showed that there were significant difference in flux rates during the two years. Maximum emission occurred at the time of anthesis and minimum at the seedling stage. The flux rates were significantly higher for fertilizer or fertilizer + WS treatments. The effects of the treatments were similar across phenological stages and years. In the subsequent wheat crop and fallow period, the soils consumed CH4. There were significant differences in CH4 uptake rates between the two years. Fertilizer treatments reduced CH4 uptake in both the years. The results suggested that tropical agroecosystems may consume substantial amounts of CH4 and that the methane output can be reduced by lowering the submergence level in rice paddies.
Microbial biomass associated with water-stable aggregates in forest, savanna and cropland soils of a seasonally dry tropical region, India
(1995) Saranath Singh; J.S. Singh
The distribution of microbial biomass associated with water-stable macro- and microaggregates in soils was studied along a forest-savanna-cropland gradient. In both macro- and microaggregates, mean microbial biomass C, N and P were maximum in forest and minimum in cropland soils. At all the sites microbial C was greater in the macroaggregate than the microaggregate size class, whereas microbial biomass N and P were greater in the microaggregates. The microbial C-to-nutrient ratios were lower for the microaggregates compared to macroaggregates. It is possible that these two size classes support two different types or components (fungi-dominated and bacteria-dominated) of the food web in soil. There was a decrease in the amount of microbial C, N and P in both macro- and microaggregates along the forest-savanna-cropland gradient, which was due to the reduction of total soil organic matter. Total soil organic C and total N showed significant positive relations with both macro- and microaggregate microbial C and N, indicating that the latter are limited by the quantity of soil organic matter. © 1995.