How does C, N and P inputs in the soil affect soil carbon stocks?5 answersSoil carbon stocks are influenced by inputs of carbon (C), nitrogen (N), and phosphorus (P) in the soil. The addition of nitrogen and phosphorus alone has minimal impact on soil carbon storage. However, when these nutrients are added in combination with potassium and micronutrients, there is a considerable increase in soil carbon stocks. The priming effect, which is a short-term change in organic matter decomposition, can also affect soil carbon stocks. Residue additions with high C:N ratios can accelerate decomposition and release carbon, while additions with low C:N ratios can immobilize carbon in the soil. Additionally, plant carbon inputs through shoot, roots, and mycorrhizal fungi pathways contribute to soil organic carbon turnover. Higher soil fertility leads to greater contributions of shoot, root, and mycorrhizal-derived carbon to soil carbon stocks. Land-use type and soil erosion can also affect soil C, N, and P stoichiometry patterns, with differences observed in woodland, upland, and paddy soils. Overall, the inputs of C, N, and P in the soil can have significant effects on soil carbon stocks.
What are the effects of biochar on soil properties?5 answersBiochar application has positive effects on soil properties such as pH, surface area, cation exchange capacity, and nutrient content, leading to improved soil fertility and crop productivity. It has been found to have significant effects on available K, P, CEC, EC, and N in soils contaminated with heavy metals like chromium (Cr), indicating its potential for soil health improvement and remediation of polluted soils. Biochar also reduces the concentrations of exchangeable metals in the soil, including Al, Fe, Ni, Cd, Pb, and Zn, thereby reducing the risk of metal contamination in agricultural products. Additionally, biochar can alter soil thermal conductivity, capacity, and diffusivity, with a significant reduction in thermal conductivity and diffusivity observed under consistent bulk-density conditions. The effects of biochar on soil thermal properties are influenced by factors such as biochar particle size, application rate, and soil moisture content.
How carbon stability elvolves with soil depth?4 answersCarbon stability in soil evolves with depth, with different patterns observed in different studies. In drained peatlands, deeper soil layers were found to be more sensitive to plant carbon, particularly complex or recalcitrant carbon, than surface soil layers. In pasture soils, the fine fraction soil in the topsoil was found to have a larger stable carbon fraction, while plant material in the coarse fraction was less stable. In forest soils, significant amounts of organic carbon were found to accumulate in subsoil layers below 30 cm, with the stability of soil carbon varying between different subsoil depth increments. In chronosequences along a climate gradient, the stability of soil organic matter generally increased with depth in fluvial terraces, while it remained constant in fluvio-glacial terraces. In deep-rooted crops, carbon input through rhizodeposition declined with depth, but even small amounts of carbon allocated to deep soil layers became microbially stabilized.
How does corn stover affect soil carbon?5 answersCorn stover removal can negatively impact soil carbon stocks, leading to a decrease in soil organic carbon levels over time. Stover removal resulted in a decrease in soil organic carbon content after 6 years of consecutive treatment. In contrast, stover incorporation after corn harvest was found to enhance soil carbon pools and maintain soil organic carbon levels. Stover retention increased average soil organic carbon stocks over time, with a sequestration rate of 0.41 Mg C ha-1 year-1. Additionally, the incorporation of stover into soil stimulated microbial communities, leading to an increase in soil quality. Overall, the management of corn stover, whether through removal or incorporation, has significant implications for soil carbon dynamics and should be carefully considered to maintain soil health and fertility.
How carbon in soil is messured?5 answersCarbon in soil is measured using various methods. One commonly used method is loss-on-ignition, which involves heating the soil sample to determine the amount of carbonaceous components. Another method is thermogravimetric analysis (TGA), which uses precise and variable heating programs to separate carbon and other components in the soil. Additionally, soil carbon can be measured by determining the soil organic carbon (SOC) concentration. SOC is influenced by factors such as land use, soil management, and farming systems. The total soil carbon stock comprises of the soil organic carbon (SOC) and the soil inorganic carbon (SIC) components. The SOC stock can be sequestered through processes such as photosynthetic fixation of atmospheric CO2, deposition, and the accumulation of stabilized SOC fractions. Overall, measuring carbon in soil involves analyzing the carbonaceous components, determining the SOC concentration, and considering the total carbon stock in the soil.
What are the negative impacts of CCS on soil?5 answersCCS can have negative impacts on soil. Increased soil CO2 concentrations resulting from CCS leakage can decrease the crude fat content of sunflowers, reducing their commercial value. However, the elevated CO2 in soil can also improve the quality of sunflower oil by increasing the crude protein and linoleic acid contents. Soil particle size distribution and heavy metal concentrations do not show significant impacts with elevated CO2 concentration. Soil type and structure may play a minor role in mitigating or amplifying plant stress in response to CO2 leakage from CCS infrastructure. Switchgrass cultivation under CCS does not show short-term changes in soil organic carbon, but after 10 years, soil organic carbon is higher compared to fallowed soil. The design and operation of onshore pipelines for CCS should consider the heat transfer and thermal resistance in buried pipelines to prevent heat loss from the dense phase CO2 fluid.