Browsing by Author "Naukkarinen, Veera"

Soil carbon (C) is a key part of the global C cycle. Agricultural soils can be both source and sink of the atmospheric carbon dioxide (CO2). In the Mid-Hill region of Nepal, a lot of the historical soil C has been lost in consequence of the conversion of forests into agricultural lands. However, there is huge potential to increase the soil C sink through appropriate farming practices. The region is characterized by mountainous topography with various microclimates found within a short distance. Thus, also the farming systems differ from each other, which further contributes to the altering soil C accumulation in the region. This Master's thesis is linked to the project Building Climate Resilience in Farming Systems in Sloping Lands of South Asia, supported by Asia-Pacific Network for Global Change Research (APN). The aim of the study was to find out what is the present soil carbon status in two predominant farming systems in the study site in Kavre, located in the Mid-Hill region, and what are the farming practices contributing to soil C. Soil samples from upland and lowland were taken into the analysis complemented with the interviews of the farmers and the field observations. The effect of the farming practices was investigated in three systems, including the both farming systems, upland solely, and lowland solely. The analysis of variance (ANOVA) was applied for studying the effects of the categorically measured farming practices. The effects of the farming practices classified as continuous variables were measured with the analysis of covariance (ANCOVA). The results showed that the soil C content was significantly higher in the upland system compared with lowlands. Vegetation cover, agroforestry, and the weed management with weed residues left to the fields were associated with higher soil C stocks. Negative relationship between the chemical fertilizer use and soil C sequestration was found. The use of organic fertilizers, tillage method, tilling intensity, crop residue management and irrigation did not show significant effect on soil C. This study suggests that the aboveground vegetation cover is an integral part of the soil C sequestration in the sloping agricultural lands in the Mid-Hill region of Nepal. Nonetheless, further research with replication and a larger sample size is needed in order to fully investigate the farming practices contributing to the greater soil C contents in the region.