Soil carbon is one of the most affected variables to land-use change in tropics. The soil carbon ... more Soil carbon is one of the most affected variables to land-use change in tropics. The soil carbon flux plays a major role in regulating microbial activities and nutrient distribution in soil. This study aimed to evaluate the soil carbon stock in various land uses at different depths in the hilly terrain of Mizoram, Northeast India. Soil samples at 0-10 cm, 10-20 cm and 20-30 cm soil depths were collected from Rubber plantation (RP), Oil palm plantation (OPP), Teak plantation (TP), Bamboo Forest (BF), 5 years fallow (5YF), 10 years fallow (10YF), Tephrosia candida plantation (TCP), Horticulture garden (HORT), Homegarden (HG) and Natural forest (NF). Soil carbon stock varied significantly (p <0.05) across the land uses and depths. The soil under Tephrosia candida stand had significantly (p <0.05) higher values of C stock (73.66 Mg ha-1) which may be due to high biomass, dense vegetative cover and high C in root exudates. The minimum C stock estimated in Horticulture garden (43.28...
Nitrogen (N) dynamics during changes in land use patterns in tropical forests may profoundly affe... more Nitrogen (N) dynamics during changes in land use patterns in tropical forests may profoundly affect fine root dynamics and nutrient cycling processes. Variations in fine root biomass and soil N dynamics were assessed in developing stands of increasing ages following shifting agriculture in Mizoram, Northeast India, and comparisons were made with a natural forest stand. Concentrations of soil available N (NH4-N and NO3-N) and the proportion of NH4-N in total available N increased with stand age. The N-mineralization rate also increased with stand age whilst the proportion of nitrification relative to ammonification declined during succession. Fine root biomass and N-mineralization increased, and available N decreased during the monsoon season while this pattern was reversed during the winter season. A greater proportion of fine roots were <0.5 mm diameter in the younger sites, and turnover of fine roots was more rapid in the developing stands compared to the natural forest. Fine r...
In the present study we investigated the production and decomposition of leaves, branches and roo... more In the present study we investigated the production and decomposition of leaves, branches and roots in two moist regenerating tropical forests (5 and 15 years old; RF-5 and RF-15 respectively) and a natural forest (NF) in north-east India. Total litter input increased during vegetation succession (759, 1089 and 1284 g m–2 year–1 in RF-5, RF-15 and NF respectively), whereas the contribution of soft litter decreased sharply. Decomposition over 450 days indicated significant seasonal (P < 0.001) patterns in mass loss of litter components, with greater rates during the wet period. Soil CO2 efflux was strongly seasonal. C stock loss followed patterns similar to those of mass loss, whereas N increased initially, followed by its gradual release. Rainfall explained 74–90% of the variability in mass loss rates. Concentrations of cellulose and N were significantly positively correlated with mass loss at an early stage of decomposition (r = 0.54–0.65, P < 0.05), whereas lignin : N and C ...
Analysing phenological diversity of tropical trees provides a potential tool to detect climate ch... more Analysing phenological diversity of tropical trees provides a potential tool to detect climate change effects and devise forest management options. In this study, the leaf phenological activity of 28 dominant tree species in a moist sub-tropical hill forest of north-eastern India was examined for a period of 2 years and related to functional traits (i.e. leaf mass per area (LMA) and wood density (WD)). The peak phase of leaf fall occurred in the cool dry period (November to January) with leaf flush peaking in the pre-monsoon period (February to March), but variation was found between species as influenced by their phenological strategy, i.e. evergreen, leaf-exchanging or deciduous (<4 months leafless). Photoperiod and minimum temperature were the environmental factors most strongly correlated with phenological activity, and the synchrony index within species for both phenophases was 0.81. LMA was less in the deciduous species compared with the evergreen species, whereas WD did no...
ABSTRACT Temporal changes in soil CO 2 efflux rates were measured in a subtropical natural mixed ... more ABSTRACT Temporal changes in soil CO 2 efflux rates were measured in a subtropical natural mixed oak forest and managed oak plantation in the northeastern Himalayan region. Soil CO 2 efflux rates in two ecosystems were correlated with key soil biotic (e.g. fungal, bacterial and actinomycetes populations) and abiotic (e.g. soil moisture, temperature, pH and organic carbon concentration) variables. Rate of CO 2 efflux (mg CO 2 m -2 h -1) at forest and plantation sites varied between 102 -320 and 99 -543, respectively. The concentration of soil organic carbon was higher at plantation than natural forest. Bacteria and actinomycetes were dominant species at plantation, whereas, the fungi were dominant at forest. CO 2 efflux at both sites was significantly positively correlated with the populations of these three microbial groups. Among abiotic variables, soil temperature and pH played significant positive role on the rates of soil CO 2 efflux in forest while variables like soil moisture and organic carbon were least accountable. In contrast, at plantation soil CO 2 efflux was significantly positively correlated with soil moisture, temperature and pH. In the present study, CO 2 efflux was not influenced by the organic C concentration, however, it was affected by the other abiotic and biotic variables. CO 2 efflux rates at plantation was regulated by the presence of bacteria and actinomycetes, whereas, it was controlled by the population of fungi in the natural forest. Management practices operated in plantation appears to affect the group of microbial populations that further affect the soil CO 2 efflux rates.
This paper aims to represent the performance analysis of various error correcting techniques-Reed... more This paper aims to represent the performance analysis of various error correcting techniques-Reed Solomon (RS) code, Bose-Chaudhari-Hocquenghem (BCH) code & Low density parity check (LDPC) code in transmitting data over noisy channel for different parameters.Our main results are as follows: 1) RS correcting code is good as random binary linear codes.And its Frame error rate performance shown. 2) Comparative performance analysis of BCH and LDPC codes are shown. The simulated output is worthwhile to analyze the performance of communication system before physical implementation of the system.
Parkia timoriana, a leguminous tree, is an important multipurpose species growing over the northe... more Parkia timoriana, a leguminous tree, is an important multipurpose species growing over the northeastern part of India. The species has been closely associated with the livelihood of the society for its beneficial attributes, and therefore, besides its occurrences in the wild, the species also been commonly raised in the home gardens. However, the ecology of the species i.e., phenology, biomass and carbon sequestration potential has not been studied. Girth class distribution indicated the species exhibit more number of individuals in the midsize girth compare to the smaller and larger girth classes. The species showed maximum leaf flushing at the onset of rainy season (Apr–May), whereas, maximum leaf fall occurred during Nov–Jan. Flowering and fruiting was maximum during dry months. The individuals with 30–45 cm girth size and above showed flowering and fruiting and the individuals below this girth do not exhibit flowering and fruiting tendency. The total biomass of P. timoriana was 2.24 t ha−1 and magnitude of carbon sequestration potential was 0.23 t ha−1 year−1. The study suggests that a threshold level of girth size 30 cm and above would be required for the fruiting and flowering. In addition to its multiple uses, the species has a good potential to sequester carbon.
Soil carbon is one of the most affected variables to land-use change in tropics. The soil carbon ... more Soil carbon is one of the most affected variables to land-use change in tropics. The soil carbon flux plays a major role in regulating microbial activities and nutrient distribution in soil. This study aimed to evaluate the soil carbon stock in various land uses at different depths in the hilly terrain of Mizoram, Northeast India. Soil samples at 0-10 cm, 10-20 cm and 20-30 cm soil depths were collected from Rubber plantation (RP), Oil palm plantation (OPP), Teak plantation (TP), Bamboo Forest (BF), 5 years fallow (5YF), 10 years fallow (10YF), Tephrosia candida plantation (TCP), Horticulture garden (HORT), Homegarden (HG) and Natural forest (NF). Soil carbon stock varied significantly (p <0.05) across the land uses and depths. The soil under Tephrosia candida stand had significantly (p <0.05) higher values of C stock (73.66 Mg ha-1) which may be due to high biomass, dense vegetative cover and high C in root exudates. The minimum C stock estimated in Horticulture garden (43.28...
Nitrogen (N) dynamics during changes in land use patterns in tropical forests may profoundly affe... more Nitrogen (N) dynamics during changes in land use patterns in tropical forests may profoundly affect fine root dynamics and nutrient cycling processes. Variations in fine root biomass and soil N dynamics were assessed in developing stands of increasing ages following shifting agriculture in Mizoram, Northeast India, and comparisons were made with a natural forest stand. Concentrations of soil available N (NH4-N and NO3-N) and the proportion of NH4-N in total available N increased with stand age. The N-mineralization rate also increased with stand age whilst the proportion of nitrification relative to ammonification declined during succession. Fine root biomass and N-mineralization increased, and available N decreased during the monsoon season while this pattern was reversed during the winter season. A greater proportion of fine roots were <0.5 mm diameter in the younger sites, and turnover of fine roots was more rapid in the developing stands compared to the natural forest. Fine r...
In the present study we investigated the production and decomposition of leaves, branches and roo... more In the present study we investigated the production and decomposition of leaves, branches and roots in two moist regenerating tropical forests (5 and 15 years old; RF-5 and RF-15 respectively) and a natural forest (NF) in north-east India. Total litter input increased during vegetation succession (759, 1089 and 1284 g m–2 year–1 in RF-5, RF-15 and NF respectively), whereas the contribution of soft litter decreased sharply. Decomposition over 450 days indicated significant seasonal (P < 0.001) patterns in mass loss of litter components, with greater rates during the wet period. Soil CO2 efflux was strongly seasonal. C stock loss followed patterns similar to those of mass loss, whereas N increased initially, followed by its gradual release. Rainfall explained 74–90% of the variability in mass loss rates. Concentrations of cellulose and N were significantly positively correlated with mass loss at an early stage of decomposition (r = 0.54–0.65, P < 0.05), whereas lignin : N and C ...
Analysing phenological diversity of tropical trees provides a potential tool to detect climate ch... more Analysing phenological diversity of tropical trees provides a potential tool to detect climate change effects and devise forest management options. In this study, the leaf phenological activity of 28 dominant tree species in a moist sub-tropical hill forest of north-eastern India was examined for a period of 2 years and related to functional traits (i.e. leaf mass per area (LMA) and wood density (WD)). The peak phase of leaf fall occurred in the cool dry period (November to January) with leaf flush peaking in the pre-monsoon period (February to March), but variation was found between species as influenced by their phenological strategy, i.e. evergreen, leaf-exchanging or deciduous (<4 months leafless). Photoperiod and minimum temperature were the environmental factors most strongly correlated with phenological activity, and the synchrony index within species for both phenophases was 0.81. LMA was less in the deciduous species compared with the evergreen species, whereas WD did no...
ABSTRACT Temporal changes in soil CO 2 efflux rates were measured in a subtropical natural mixed ... more ABSTRACT Temporal changes in soil CO 2 efflux rates were measured in a subtropical natural mixed oak forest and managed oak plantation in the northeastern Himalayan region. Soil CO 2 efflux rates in two ecosystems were correlated with key soil biotic (e.g. fungal, bacterial and actinomycetes populations) and abiotic (e.g. soil moisture, temperature, pH and organic carbon concentration) variables. Rate of CO 2 efflux (mg CO 2 m -2 h -1) at forest and plantation sites varied between 102 -320 and 99 -543, respectively. The concentration of soil organic carbon was higher at plantation than natural forest. Bacteria and actinomycetes were dominant species at plantation, whereas, the fungi were dominant at forest. CO 2 efflux at both sites was significantly positively correlated with the populations of these three microbial groups. Among abiotic variables, soil temperature and pH played significant positive role on the rates of soil CO 2 efflux in forest while variables like soil moisture and organic carbon were least accountable. In contrast, at plantation soil CO 2 efflux was significantly positively correlated with soil moisture, temperature and pH. In the present study, CO 2 efflux was not influenced by the organic C concentration, however, it was affected by the other abiotic and biotic variables. CO 2 efflux rates at plantation was regulated by the presence of bacteria and actinomycetes, whereas, it was controlled by the population of fungi in the natural forest. Management practices operated in plantation appears to affect the group of microbial populations that further affect the soil CO 2 efflux rates.
This paper aims to represent the performance analysis of various error correcting techniques-Reed... more This paper aims to represent the performance analysis of various error correcting techniques-Reed Solomon (RS) code, Bose-Chaudhari-Hocquenghem (BCH) code & Low density parity check (LDPC) code in transmitting data over noisy channel for different parameters.Our main results are as follows: 1) RS correcting code is good as random binary linear codes.And its Frame error rate performance shown. 2) Comparative performance analysis of BCH and LDPC codes are shown. The simulated output is worthwhile to analyze the performance of communication system before physical implementation of the system.
Parkia timoriana, a leguminous tree, is an important multipurpose species growing over the northe... more Parkia timoriana, a leguminous tree, is an important multipurpose species growing over the northeastern part of India. The species has been closely associated with the livelihood of the society for its beneficial attributes, and therefore, besides its occurrences in the wild, the species also been commonly raised in the home gardens. However, the ecology of the species i.e., phenology, biomass and carbon sequestration potential has not been studied. Girth class distribution indicated the species exhibit more number of individuals in the midsize girth compare to the smaller and larger girth classes. The species showed maximum leaf flushing at the onset of rainy season (Apr–May), whereas, maximum leaf fall occurred during Nov–Jan. Flowering and fruiting was maximum during dry months. The individuals with 30–45 cm girth size and above showed flowering and fruiting and the individuals below this girth do not exhibit flowering and fruiting tendency. The total biomass of P. timoriana was 2.24 t ha−1 and magnitude of carbon sequestration potential was 0.23 t ha−1 year−1. The study suggests that a threshold level of girth size 30 cm and above would be required for the fruiting and flowering. In addition to its multiple uses, the species has a good potential to sequester carbon.
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