Carbon from organic matter

Both active and passive pools of carbon have their  own role to play in crop production ,soil quality, soil resilience and maintenance of soil biodiversity. Only thing  one has to take care is regular addition of organic matter in the form of manure, compost and crop residues etc.

As mentioned by Dr. Subba Rao, I do agree with him conceptually but LOC is considered as early indicator of land use/ treatment effect  on soil quality change so obviously crop productivity  and biodiversity.

Thanking you Drs Rao and Ghosh for your valuable suggestions, my submition is the active pool or LOC is same or not ?

Another one is if same the which form of LOC is an early indicator of soil quality and microbial diversity.

One thing more any other factor more responsible compared carbon, 

Thanks, 

VSM

Active pool and LOC are not exactly same.Active pool represents SOC  with a trun over period o 1-2 yrs. Sometimes active pool includes SMBC also. LOC determined with 333 um KMNo4 i sLOC.

Any ortherr means , all SQI parameters established through minimum data set determined through PCA.

Dr.Meena,labile organic carbon, active carbon and microbial biomass carbon belong to one category i.e. non-humic carbon.These on decomposition and mineralization provide nutrients to growing plants.So they have bearing on crop growth and productivity.When fresh organic materials are added to soil,they(especially manure compost, green manure) decompose fast  and  provide energy , carbon source and nutrients  to microorganisms for say,2-3 months.Added carbon becomes part of microbial bodies and also soil  organic carbon.Again some in active pool and some may start forming humus.Humus formation takes time and until such time carbon  may be in the labile or active form.When energy or carbon source is limited the microbial biomass may decompose and mineralize providing  nutrients  to plants.Microbial population may come down but certain minimum population will remain active in soil deriving food from labile and even from passive or slow pool of carbon.So the long term maintenance of soil populations of microbes may also depend on the so called slow pool or humic material.But humin or inert or aggregate protected carbon may not provide food or enegy to microbes.

Thanking you Dr. Rao for your valuable suggestions, I agree with all these point.

As mentioned above by others, soil organic carbon is the carbon associated with soil organic matter. Soil organic matter is the organic fraction of the soil which is made up of decomposed plant and animal materials and microbial biomass, but does not include fresh and un-decomposed plant materials, such as crop residues and litter being on the soil surface. Soil carbon can also be found in inorganic forms, e.g. lime or carbonates in some calcareous soils of drier areas.

Soil organic carbon can be divided into different pools dependent on their ease of decomposition, i.e. labile pool, slow pool and inert pool). The labile pool includes all the freshly added plant and animal materials and microorganisms. As these are easily decomposed, they are labile. The slow pool includes well- decomposed organic materials, the humus. The inert pool refers to the fraction that is old, resistant to further decomposition and represents the products of the last stage of decomposition, biochar. Generally, soil carbon is used directly or indirectly in improving soil fertility, that is by supplying nutrients and improving the nutrient retention and water holding capacity of soils. So soil organic carbon is the base for improving soil health and sustaining agricultural productivity..

I agree with Dr. Suba Rao.