Peoples’ Perception and Conservation of Dactylorhiza hatagirea (D. Don) Soóin Manaslu Conservation Area, Central Nepal

The present study analyzes the information and perception of the local community of Samagaun VDC, Manaslu Conservation Area Project (MCAP) regarding Dactylorhiza hatagirea (D. Don) Soó (Orchidaceae). We assessed the local peoples’ perception on its population status, its availability, factors causing its decline and management practices of this terrestrial orchids. A pre-designed questionnaire was used to gather information targeting the age group between 25 and 60 years (n = 75, 45 male and 30 female). Most of the informants (76%) believe that the abundance of this orchid is declining. Over grazing of domestic animals, over harvesting and lack of awareness among the local community were determined to be the major causes of decline of D. hatagirea in the study area. Protection measures as prescribed by the informants were control grazing, raising awareness among the individuals and sustainable harvestings for the long-term conservation of the species. Systematic management plans that incorporate the participation of local individuals and prioritization of their views will be applicable for the proper conservation of the species.

Saline-Sodic Soils:Potential Sources of Nitrous Oxide and Carbon Dioxide Emissions?

Increasing salt-affected agricultural land due to low precipitation,high surface evaporation,irrigation with saline water,and poor cultural practices has triggered the interest to understand the influence of salt on nitrous oxide(N_2O) and carbon dioxide(CO_2)emissions from soil.Three soils with varying electrical conductivity of saturated paste extract(EC_e)(0.44-7.20 dS m^(-1)) and sodium adsorption ratio of saturated paste extract(SARe)(1.0-27.7),two saline-sodic soils(S2 and S3) and a non-saline,non-sodic soil(S1),were incubated at moisture levels of 40%,60%,and 80%water-filled pore space(WFPS) for 30 d,with or without nitrogen(N)fertilizer addition(urea at 525 μg g^(-1) soil).Evolving CO_2 and N2 O were estimated by analyzing the collected gas samples during the incubation period.Across all moisture and N levels,the cumulative N_2O emissions increased significantly by 39.8%and 42.4%in S2 and S3,respectively,compared to S1.The cumulative CO_2 emission from the three soils did not differ significantly as a result of the complex interactions of salinity and sodicity.Moisture had no significant effect on N_2O emissions,but cumulative CO_2 emissions increased significantly with an increase in moisture.Addition of N significantly increased cumulative N_2O and CO_2 emissions.These showed that saline-sodic soils can be a significant contributor of N_2O to the environment compared to non-saline,non-sodic soils.The application of N fertilizer,irrigation,and precipitation may potentially increase greenhouse gas(N2O and CO_2) releases from saline-sodic soils.

Carbon Dioxide and Nitrous Oxide Emissions from Naturally Occurring Sulfate-Based Saline Soils at Different Moisture Contents

Soil salinization may negatively affect microbial processes related to carbon dioxide(CO_2) and nitrous oxide(N_2O) emissions. A short-term laboratory incubation experiment was conducted to investigate the effects of soil electrical conductivity(EC) and moisture content on CO_2 and N_2O emissions from sulfate-based natural saline soils. Three separate 100-m long transects were established along the salinity gradient on a salt-affected agricultural field at Mooreton, North Dakota, USA. Surface soils were collected from four equally spaced sampling positions within each transect, at the depths of 0–15 and 15–30 cm. In the laboratory, artificial soil cores were formed combining soils from both the depths in each transect, and incubated at 60% and 90% water-filled pore space(WFPS) at 25?C. The measured depth-weighted EC of the saturated paste extract(EC_e) across the sampling positions ranged from 0.43 to 4.65 dS m^(-1). Potential nitrogen(N) mineralization rate and CO_2 emissions decreased with increasing soil EC_e, but the relative decline in soil CO_2 emissions with increasing ECe was smaller at 60% WFPS than at 90% WFPS. At 60% WFPS, soil N_2O emissions decreased from 133 μg N_2O-N kg^(-1) soil at EC_e < 0.50 dS m^(-1) to 72 μg N_2O-N kg^(-1) soil at EC_e = 4.65 dS m^(-1). In contrast, at 90% WFPS,soil N_2O emissions increased from 262 μg N_2O-N kg^(-1) soil at EC_e = 0.81 dS m^(-1) to 849 μg N_2O-N kg^(-1) soil at EC_e = 4.65 dS m^(-1), suggesting that N_2O emissions were linked to both soil ECe and moisture content. Therefore, spatial variability in soil EC_e and pattern of rainfall over the season need to be considered when up-scaling N_2O and CO_2 emissions from field to landscape scales.