A company in soil carbon sequestration is involved in the process of capturing and storing carbon dioxide from the atmosphere in the soil. This is a key method for mitigating climate change since it reduces greenhouse gas emissions. The company might be involved in various activities such as researching and developing new technologies or methods for carbon sequestration, providing consultation services on sustainable land use practices, or even selling products that enhance the soil's ability to store carbon. They may also be involved in creating or trading carbon offset credits.

1. Agricultural Sequestration: Various farming practices can contribute to soil carbon sequestration. These include the use of cover crops, crop rotation, reduced tillage, and organic farming. These practices add organic matter to the soil, leading to increased carbon storage.  

2. Forest Sequestration: Forests naturally sequester carbon as trees absorb CO2 for photosynthesis. Practices like reforestation, afforestation, and sustainable forest management can increase the amount of carbon stored in the soil.  

3. Grassland Sequestration: Grassland ecosystems store a significant amount of carbon in their soil. By practicing sustainable grazing and pasture management, these lands can store even more carbon.  

4. Wetland Sequestration: Wetlands have a high capacity to store carbon due to the slow decomposition rate in these environments. Enhancing and restoring wetlands can increase soil carbon sequestration.  

5. Urban Sequestration: Urban soils have the potential to store carbon through the planting of green spaces and the use of biochar - a charcoal-like substance made from plant matter.  

6. Biochar Sequestration: Biochar is a form of charcoal that is applied to the soil to help improve soil conditions. Biochar can be an effective carbon sink because it is resistant to decomposition.  

7. Carbon Mineralization: It is a form of geological sequestration where carbon is stored in the form of carbonate minerals.  

8. Managed Grazing: Controlled grazing by livestock on grasslands can contribute to the accumulation of organic carbon in the soil, thereby promoting soil carbon sequestration.  

9. Reduced Tillage/No-Till Farming: This farming practice helps in retaining the organic matter in the soil surface, thereby reducing carbon emission and promoting carbon storage.  

10. Organic Waste Composting: Composting of organic waste and its application on soil helps in replenishing the organic carbon content of the soil, thereby promoting carbon sequestration.  Each of these types of soil carbon sequestration has differing potential for carbon storage, and are dependent on factors such as climate, soil type, land use, and management practices.

Soil carbon sequestration plays a key role in the process of decarbonization as it involves the capture and storage of atmospheric carbon dioxide in the soil. Here's how it helps:  

1. Carbon Capture: Plants absorb CO2 during photosynthesis and convert it into organic carbon, part of which is later transferred to the soil. This reduces the concentration of CO2 in the atmosphere, contributing to the slowdown of global warming.  

2. Carbon Storage: The organic carbon absorbed by the soil can remain there for hundreds to thousands of years if not disturbed, effectively serving as a carbon sink.  

3. Soil Health: Higher levels of organic carbon improve soil health by enhancing its structure, nutrient content, and ability to hold water. This, in turn, can increase productivity for crops and other vegetation, further promoting the absorption of CO2.  

4. Ecosystem Services: Improving soil health through carbon sequestration supports ecosystem services such as water filtration, pest control, and biodiversity, all of which are key to a healthy environment.  

5. Carbon Credits: Farming practices that promote soil carbon sequestration can be part of carbon offset programs, giving a financial incentive for societies to pursue this type of carbon dioxide removal method.  So, soil carbon sequestration not only works as a natural method of carbon storage to reduce CO2 levels in the atmosphere, it also improves soil health, promotes better farming practices, and supports ecosystems.

When seeking to work with a vendor in Soil Carbon Sequestration (SCS), you should evaluate specific factors to ensure the company meets your requirements:  

1. Expertise and Reputation: Choose companies with sufficient experience in SCS—those that have successfully completed similar projects. Check their client reviews, case studies and testimonials to gauge their performance.  

2. Methodology: Different companies might use different soil carbon sequestration techniques. The ideal company would utilize a combination of methods to treat your specific needs. They should be familiar with enhanced weathering, biochar addition, conservation agriculture, etc.  

3. Certifications & Standards: The vendor should comply with international and local environmental standards. Check if they have necessary certifications and permits for operations.  

4. Sustainability approach: Clarify their strategy for avoiding negative impacts like deforestation and biodiversity loss during the sequestration process.  

5. Monitoring and Verification: The vendor should provide services related to the monitoring and verification of the carbon sequestration process.  

6. Financial Viability: Assess the financial stability of the firm. They should be able to withstand fluctuations in the carbon price market and deliver on their long-term commitments.  

7. Services and Offerings: Be clear about the services you require: modelling and predicting soil carbon sequestration potential, satellite monitoring, testing the depth of carbon sequestration, data analysis etc., and ensure they can provide them.  

8. Technical Support: The vendor should be able to provide technical support when needed, answering questions and troubleshooting problems with the process.  

9. Communication: Communication goes two ways. The vendor should understand your requirements and keep you regularly updated on progress.  

10. Cost: Get quotes from potential vendors and compare them, factoring in the above points. Often, a lower cost may mean less comprehensive services or poor-quality results.  

11. Contract Terms: Examine contract terms carefully. You may want to confirm they include a clause for continuous improvement in terms of the technology used and the efficiency of the solutions provided.  Remember to make your selection based on your company's unique needs, budget, and long-term goals.