Question

Carbon sequestration and plants: What aspects of plant biology could you change to make plants more effective at carbon capture? It is an equation so think about fixing carbon, and carbon banking both. What different types of crops fix more carbon? How can the agricultural system and the soil be managed differently to lock in more carbon?

Answer 1

Carbon fixation is te assimilation of CO2 to carbohydrates by the green plants that constitutes the biosynthetic phase of photosynthesis taking place in the stroma of chloroplast. The process of CO2 fixation is more effficient and effective in tropical plants like Sorghum, Maize, sugarcane, etc that constitute the C4 plants as compared to C3 plants. They have a special leaf anatomy and can tolerate higher temperatures. Because they lack a wasteful process called photorespiration, they show greater productivity and higher yield as compared to C3 plants. The C4 plants have a mechanism that increases the concentration of CO2 at the enzyme site. During the C4 pathway, when the C4 acid from the mesophyll cells is broken down in the bundle sheath cells, it releases CO2- this results in increasing the intracellular concentration of CO2. This in turn, ensures that the RuBisCO functions as a carboxylase minimising the oxygenase activity. Thus to ensure effective carbon capture, the wasteful process i.e photorespiration must be absent and enzyme RuBisCO must function as carboxylase and there should be a compartmentalisation of different specialized cells in order for efficient carbon capture.

The C4 plants like Sorghum, Maize, sugarcane, etc can fix more carbon as they have a mechanism that increases the concentration of CO2 at the enzyme site.

Carbon is constituent of almost all organic compounds of the cell and thus may be considered basis of life. Soil organic carbon is the basis of soil fertility and is a part of soil organic matter. The content of organic carbon in soil is balanced between its input and output and can be increased by increasing the organic matter in soil that raises soil fertility, reduce erosions, and flourish soil microorganisms. The soil organic carbon forms the basis of sustainable agriculture. But several factors may contribute to soil carbon loss that includes decomposition, soil erosion, etc. The organic carbon content can be locked in the soil by the following measures:

(i) Elimination or avoiding unnecessary cultivation. (ii) Rotation of pasture by growing high yield, high biomass crops and pastures in continuous cropping systems to maximize crop frequency and increasing organic matter in soil. (iii) Adopting proper grazing management strategies that minimize impact of grazing on soil structure and maximize soil organic carbon content. (iv) Maximizing and maintaining ground cover with proper conservation goals. (v) Maintaining soil fertility by introducing inorganic and organic fertilizers and implementing manure and compost to maximize the production. (vi) Monitoring the effectiveness of management system to assess and control the depletion or retsoring the carbon resource.