Hi Avijit,

From many studies it is clear - even with high enough fertilization and water supplies -  that (tropical as well as temperate zone) agriculture depletes carbon in soils. Originally most of the actual cropping areas (globally) were (tropical) forests, also in India. A tropical forest ecosystem reaches maximal soil carbon amounts in tropical areas of all ecosystems possible in a tropical climate. Carbon storage in tropical soils however is (much) less than in temperate forests or highmoors where carbon is immobiized due to acidic soils. This soil typeleads to stabilized (sequestered) carbon in peat or forests soils (humus) over a relatively long period of centuries.

Some tropical forest types in Indonesia also form peat when precipitation is high enough. Howver with increasing drougt in such forests, the risc is high that peat catches fire and burns for months, emitting all carbon stored, as CO2 into the atmosphere. Indonesia has known this type of gigantic tropical forest fires of this type of which the fire plumes could be monitored with satellite remote sensing for months on a row, a few years ago.

If your unique objective is to increase carbon content in soils, then (try to) reforest te most marginal cropping areas as a starter! Evidently, a forest can only grow when protected (population pressure not too high) and when climate (or runoff from mountains etc,..) offers enough water resources.

Actually humanity has since more than 2000 years proven that it is more capable of creating deserts instead of forest. This trend is not finished yet - globally - on a few exceptions where reforestation takes place. Hence global carbon storage capacity (sequestration) of ecosystems still degrades as we speak. There are not many demographic elements - globally - which can convince me that this trend will change in the future of mankind, rather on the contrary.

Now if you would like to increase carbon in soils without reforestation and in tropical zones, I don't see many successful strategies. just have a look at the paper I added in this respect on Brazilian tropical ecosystems, agriculture and soil carbon. In Brazil conversion of forest into cropping systems reduces carbon in soils with more than 50%. And it is kown that after a rather small number of years, when cropping is performed on hilly terrains with rather steep slopes, erosion, pretty soon converts what originally was forest and converted to a non-fertilzed cropping system, transfroms into degraded wastelands inapt for agriclulture and very difficult to reforest.

But evidently India is not Brazil. Nonetheless both countries have a tropical climate and hence face the same problems I guess, when cropping is performed in hilly terrain. Even on non hilly terrain, when not enough natural water resources (precipitation, run-off), is available, aquifers are depleted rather fast by using them to irrigate the cropping area's. After depletion of an aquifer increasing soil carbon becomes a far away dream because desert will become the dominant land cover type. In India over 70% of the land cover is sub-humid to semi-arid and arid (desert). How come?  Read the evidence presneted in the paper here below

Hanqin Tiana, Kamaljit Bangera, Tao Boa, Vinay K. Dadhwal. History of land use in India during 1880–2010: Large-scale land transformations reconstructed from satellite data and historical archives. Global and Planetary Change Volume 121, October 2014, Pages 78–88.  doi:10.1016/j.gloplacha.2014.07.005)

It tells you in detail what I shortly outlined here.

Best regards and have a nice day,

Frank

Dear Avijit,

Increment in labile C in soil is only temporary, which can be easily achieved by adding organic matter in soils. As you point out this pool is liable to go away soon under the tropical climate conditions. It would interesting if you can increase C stock by improving a relatively non-labile pool in soils through the management practices (be it a tillage or any other management that adds organic matter to soils). However, I have strong reservations on the idea of C sequestration in soil as a means of climate mitigation, which does not have strong scientific data support, rather increasing C in soils should be encouraged as a means to improve the soil structure and subsequently to a healthy soil.

My good wishes

My Dear Avijit Ghosh,As per my opinion  it is not  possible to increase soil labile carbon in tropical India for longer period. I am totally in agreement of comment of @ Dr Debashish. Thanks

There are few  experimental results that show it is possible by adopting integrated nutrient management. Please refer to the attached review paper,which may be of some information to you.

Increase in labile carbon pools is a temporary phenomenon. We can not increase it continuously.  Irrespective of climate, labile pools will easily be oxidized, that is the reason it is called as labile. In tropical condition this oxidation will be faster. Now after adopting the different management practices, which could improve the carbon stock in soil definitely that have positive effects on the labile pools of carbon in soil. Hence in this context, the increment in labile carbon is highly site specific, depends upon the management practices, environmental  factors and so on, however we can not increase it continuously.

What about SRF in Inda?

Isn't that an option?

Frank

 Sir did you mean slow release fertilizer by SRF ?

What I mean  IS Short Rotation Farming (SRF). It is a forest harvested each 2 years . The wood is processed ito pellets adn these are used for heating appliances. Maybe in the tropics fast growing tree species which withstand regular cutting like wilows or poplar trees in temperate zones, might offer heating resources  and an increasde sequestration of carbon in soils. Maybe Eucaluptusoffers good species, It grows fast, withstands drought and can be used forpaper production as well. I have seen planraions in Spain used ofr paper production in bon dry Sierras. Not so bad when thinkng of marginal soils.

Cheers.

Frank

Thank you sir for your explanation.

But in India where population is a burden and food production is an urgent, there I think it will be criticized. 

Dear Avijit Ghosh,                                              Dated 14th March 2015-03-14

I must thank you for raising a pertinent question befitting to your age. Your question is related to many local and Global issues whether it is (i) carbon status & diversity, (ii) role of soil biodiversity & soil fertility, (iii) mineralisation and immobilization in tropical soil, (iv) role of agrochemicals in mineralisation of soil carbon stock, (v) Green revolution (by about 1950-60) turning brown (by 1970-80), (vi) factors relating to carbon storage (sequestration) in tropical countries like India, (vii) traditional technology of carbon storage, and lastly to (viii) Global warming mitigation.

Your question has been already addressed by experts and I think most important is by Frank Veroustraete. His approach has given lights to many issues that I have raised. My simplest answer to you that spoon feeding of simple food might support a baby for a short time but the adult needs full meal with carbon diversity (metabolic or labile, active, slow and passive). Same is the case for agriculture and agro forestry. A healthy soil, healthy crop and healthy environment is necessary for the Dear Earth Planet. Many of the conventional agrotechnology is now questioned in terms of crop quality, environmental health and Global warming. That is the reason organic farming, ecological agriculture, biodynamic agriculture, crop holyday, crop rotation practices are gaining importance. These techniques are ancient technologies developed in different parts of the world. Although conventional agriculture has helped grain production in India during the crisis period, perhaps it has also damaged equally or may be with multifold. Scientific attitude must change towards development of technology at local level instead of adapting copy & paste method. In India, issues of food shortage and promoting subsidy is perhaps more for the advantage of Chairman Scientists and Political people rather than marginal farmer. About 40% of India’s agro product is wasted because of lack of accountability. I hope sincerely that the present generation like you to be dedicated and accountable and prepare for both research & development for sustainable production.

Please read papers and books published by Prof. Rattan Lal on organic matter; D.C. Coleman and P. Lavelle on soil organism. Ref: P.Lavelle and A.V. Spain, Soil Ecology, 2nd Ed, Kluwer Scientific Publications, Amsterdam,2006

You can refer to the model pasted and to some papers which are attached

All the best,

B.K.Senapati

BBX*}

Labile carbon levels can be raised but not continually, the way that can be done is by continuous carbon applications (normally to expensive) and by changing to a perennial crop (plants release carbon through roots). Another way is by incorporation of biochar which apparently slows down the decomposition of labile carbon (but also increases priming on hi organic matter soils).

Also, some rotating grazing practices have shown to augment the organic matter levels and the depth of soil A horizon.

Since labile carbon decomposes by definition, the only way to augment it is by adding it at a faster rate than its decomposition (compost, cover crops, mulches, perennials) and by reducing influences in the soil that accelerate the decomposition rate (direct sunlight, tilling, chemical fertilizers, crop residue removal and burning, etc). Because of the fast tropical decomposition, one can not expect any good practice to work by itself on rising labile carbon levels.

Good luck