Soil Organic Carbon in Forest and Other Land Use Types at Bengkulu City, Indonesia

Conversion of natural forest into agricultural land uses has decreased soil organic carbon (SOC) and increased carbon emission into the atmosphere, but proper management of agricultural land can sequester carbon from the atmosphere and increase the SOC. This study was conducted to estimate the SOC content and storage in a forest, agroforestry land, oil palm plantation, and agricultural experimental field and to analyze the correlation between the SOC and other soil characteristics at Bengkulu City, Indonesia. Soil were sampled from the following depths: 0–10 cm, 10–20 cm, and 20–30 cm. The biomass of litter and ground cover was also sampled. This study found that the forest had the highest average SOC content from the three depths, and 0–30 cm depth SOC storage, while the agroforestry system had the lowest of both SOC content and storage. The 0–10 cm depth had the highest SOC content and storage, while the 20–30 cm depth had the lowest of both variables. The SOC was positively correlated with litter biomass, field capacity, exchangeable potassium, cation exchange capacity, and negatively correlated with bulk density and exchangeable calcium, but not correlated with total nitrogen and available phosphorus. High litter biomass input is the key to the maintenance of high SOC.

Study of changes in carbon stock in primary and secondary forest in protection forest of Soya Village, Ambon City

This study aimed to determine changes in litter biomass and the effect of changes in litter biomass on carbon stock changes in Permanent Sample Plots of primary and secondary forest in the Protection Forest of Soya Village, Ambon City, for three years of measurement. This study used a sampling method with harvesting/collection and using laboratory analysis, where the working procedure used the SNI: 7724 guidelines. The data taken includes the water content of litter, total wet weight, dry weight of the sample, and wet weight of the sample to calculate the range of biomass or organic matter and carbon content of litter organic matter. The results showed that the average value of water content in both primary and secondary forests decreased. The depletion degree was higher in the first year than the second and third year. The biomass content of litter in primary forests decreased from year to year for three years of measurement. It causes a decrease in the carbon content in the primary forest. In contrast, the biomass content in secondary forests increased from year to year and increased carbon content from year to year for three years of measurement.

Effects of Fencing on Vegetation and Soil Nutrients of the Temperate Steppe Grasslands in Inner Mongolia

Grazing exclusion has been widely implemented in degraded grassland. However, the changes of plant communities and soil nutrients in response to fencing are still controversial. Thus, the effects of free grazing, 17 and 36 years of fencing on the plant biomass and litter biomass, carbon (C), nitrogen (N) and phosphorus (P) concentrations and stocks of plant, litter and soil were investigated in the temperate steppe grasslands of northern China. The results indicated that fencing increased the aboveground live biomass and litter biomass. In addition, fencing increased C, N and P stocks of aboveground live biomass, litter biomass and soil. Although root biomass and its nutrient stocks were also significantly increased by 17 years of fencing, they were decreased with fencing extending from 17 to 36 years. Moreover, there were no significant differences in aboveground live biomass and soil N and P stocks between 17 and 36 years of fencing. Litter biomass and its C, N and P stocks were positively correlated with soil C, N and P stocks. Our results demonstrated that 17 years of fencing is an effective way to restore vegetation and soil nutrients in the temperate steppe of Inner Mongolia, but a longer fencing duration has no further positive effects on biomass production and soil nutrients accumulation.

Responses and mechanisms of soil greenhouse gas fluxes to changes in precipitation intensity and duration: a meta-analysis for a global perspective

Although extensive manipulative experiments have been conducted to study the effects of altered precipitation intensity and duration on soil greenhouse gas (GHG; carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)) fluxes, the general patterns of GHGs to altered precipitation have not been globally described across biomes. Thus, we performed a meta-analysis of 84 published studies to examine the general responses of CO2, CH4, and N2O fluxes to altered precipitation. Our results indicated that increased precipitation significantly increased N2O emissions (+154.0%) and CO2fluxes (+112.2%) and significantly decreased CH4uptake (−41.4%); decreased precipitation significantly decreased N2O emissions (−64.7%) and CO2fluxes (−8.6%) and significantly increased CH4uptake (+32.4%). Moreover, increased precipitation significantly increased litter biomass and microbial biomass and decreased root biomass and the root:shoot ratio. However, decreased precipitation significantly decreased litter biomass and root biomass and significantly increased root:shoot ratio. These results suggest that precipitation changes could alter the carbon distribution patterns in plants. In addition, the CO2, CH4, and N2O fluxes exhibited diverse responses to different ecosystems, durations of precipitation changes, and changes in precipitation intensity. These results demonstrate that there are many factors that regulate the responses of GHG to precipitation changes.

Ancillary vegetation measurements at ICOS ecosystem stations

The Integrated Carbon Observation System is a Pan-European distributed research infrastructure that has as its main goal to monitor the greenhouse gas balance of Europe. The ecosystem component of Integrated Carbon Observation System consists of a multitude of stations where the net greenhouse gas exchange is monitored continuously by eddy covariance measurements while, in addition many other measurements are carried out that are a key to an understanding of the greenhouse gas balance. Amongst them are the continuous meteorological measurements and a set of non-continuous measurements related to vegetation. The latter include Green Area Index, aboveground biomass and litter biomass. The standardized methodology that is used at the Integrated Carbon Observation System ecosystem stations to monitor these vegetation related variables differs between the ecosystem types that are represented within the network, whereby in this paper we focus on forests, grasslands, croplands and mires. For each of the variables and ecosystems a spatial and temporal sampling design was developed so that the variables can be monitored in a consistent way within the ICOS network. The standardisation of the methodology to collect Green Area Index, above ground biomass and litter biomass and the methods to evaluate the quality of the collected data ensures that all stations within the ICOS ecosystem network produce data sets with small and similar errors, which allows for inter-comparison comparisons across the Integrated Carbon Observation System ecosystem network.