Know more

Our use of cookies

Cookies are a set of data stored on a user’s device when the user browses a web site. The data is in a file containing an ID number, the name of the server which deposited it and, in some cases, an expiry date. We use cookies to record information about your visit, language of preference, and other parameters on the site in order to optimise your next visit and make the site even more useful to you.

To improve your experience, we use cookies to store certain browsing information and provide secure navigation, and to collect statistics with a view to improve the site’s features. For a complete list of the cookies we use, download “Ghostery”, a free plug-in for browsers which can detect, and, in some cases, block cookies.

Ghostery is available here for free: https://www.ghostery.com/fr/products/

You can also visit the CNIL web site for instructions on how to configure your browser to manage cookie storage on your device.

In the case of third-party advertising cookies, you can also visit the following site: http://www.youronlinechoices.com/fr/controler-ses-cookies/, offered by digital advertising professionals within the European Digital Advertising Alliance (EDAA). From the site, you can deny or accept the cookies used by advertising professionals who are members.

It is also possible to block certain third-party cookies directly via publishers:

Cookie type

Means of blocking

Analytical and performance cookies

Realytics
Google Analytics
Spoteffects
Optimizely

Targeted advertising cookies

DoubleClick
Mediarithmics

The following types of cookies may be used on our websites:

Mandatory cookies

Functional cookies

Social media and advertising cookies

These cookies are needed to ensure the proper functioning of the site and cannot be disabled. They help ensure a secure connection and the basic availability of our website.

These cookies allow us to analyse site use in order to measure and optimise performance. They allow us to store your sign-in information and display the different components of our website in a more coherent way.

These cookies are used by advertising agencies such as Google and by social media sites such as LinkedIn and Facebook. Among other things, they allow pages to be shared on social media, the posting of comments, and the publication (on our site or elsewhere) of ads that reflect your centres of interest.

Our EZPublish content management system (CMS) uses CAS and PHP session cookies and the New Relic cookie for monitoring purposes (IP, response times).

These cookies are deleted at the end of the browsing session (when you log off or close your browser window)

Our EZPublish content management system (CMS) uses the XiTi cookie to measure traffic. Our service provider is AT Internet. This company stores data (IPs, date and time of access, length of the visit and pages viewed) for six months.

Our EZPublish content management system (CMS) does not use this type of cookie.

For more information about the cookies we use, contact INRA’s Data Protection Officer by email at cil-dpo@inra.fr or by post at:

INRA
24, chemin de Borde Rouge –Auzeville – CS52627
31326 Castanet Tolosan CEDEX - France

Dernière mise à jour : Mai 2018

Menu Logo Principal

Home page

Change in C levels and stocks in soils

Organic C levels increase in soils that receive OWP and decrease in the control plots. The increases are largest for GWS compost and FYM, slightly lower for BIO compost and even lower for MSW compost. The input of mineral N acting on the biomass from crop residues also increases organic C levels in soils. The BSI appears to be a good indicator of the humic balance (increase in organic C measured in the soil, compared with the quantity of organic C input via OWP).

Organic C levels in soils

The organic C levels measured in the soils are shown in Figure 1.

Evolution stock C org sol_An_1998-2011_72 dpi
Figure 1. Change in organic C levels in the soils in the N fertilized plots since the begining of the experimentTable 1. Change in organic C levels in the surface levels of the different treatments (in % compared with the average initial levels in the treatments)
Augmentation C org sol_1998-2011_An_72 dpi

 

Organic C levels in the soils increased in all of the plots receiving OWP and decreased in the control plots. The export of wheat straws undoubtedly explains the decline in organic C levels in the control plots, as well as the fall in the production of biomass from crop residues in the section not complemented with mineral N.

In the section not receiving any mineral N, organic C concentrations in the surface level are significantly higher (than the 5% threshold) in all organic treatments compared with the control, from 2002, i.e. after two spreadings. In the section receiving mineral N, these differences are significant in 2004.

Organic C levels in the soils differ according to the OWP input, even though the OWP doses provide the same quantity of organic C (4 t/ha). Organic C levels in soils receiving GWS compost, BIO compost or FYM are significantly higher than those in soils receiving MSW compost, from 2004 in the section with no mineral N and in 2006 in the section of the system receiving mineral N. In the section complemented with mineral N, the input of organic C by crop residues temporarily conceals the effect of the input of OWP (input of 20 t C/ha in all treatments). 

MSW compost appears to be less effective than the other OWPs studied at increasing the organic C stock in the soil. This is linked with the biodegradeability of its organic matter, which is higher than that of the other OWP (see Characteristics of OWP).

The OWPs also act through their effect on the biomass from crop residues: 17 t C/ha (BIO compost), 18 t C/ha (GWS and MSW compost) and 19 t C/ha (FYM).

Calculation of humic performance based on the change in the organic C stock

The humic performance measured corresponds to the increase in organic C measured in the soils compared with the quantity of organic C input by the OWP. These coefficients are shown in Table 2 for each OWP and are compared with the BSI values. Their aim is to estimate the proportion of stable organic C liable to enrich the soil (for a definition of the BSI, see Characteristics of OWP). MSW compost appears to be the least effective at increasing the organic C stock in the soil.

 
Table 2. Average humic performances of OWPs and comparison with the BSI

C stock 1998

C stock 2011

Increase of C in soil from 1998 to 2011

C input by the 9 spreadings

Humus yield

Average yield

Average BSI

t C / ha

-

-

-

GWS + N

40,5

59,7

19,7

34,4

0,57

0,62

0,42

BIOW + N

41,2

58,3

18,4

30,7

0,60

0,66

0,50

MSW + N

39,7

49,1

9,1

29,3

0,31

0,36

0,37

FYM + N

40,7

55,1

15,1

32,9

0,46

0,52

0,44

CTR + N

40,9

40,0

-

-

-

-

-

GSW

39,4

58,6

22,8

34,4

0,66

-

-

BIOW

39,9

58,2

22,4

30,7

0,73

-

-

MSW

39,5

47,8

12,1

29,3

0,41

-

-

FYM

40,3

55,0

19,2

32,9

0,58

-

-

CTR

39,8

35,8

-

-

-

-

-

 

flèche précédent
RikikiBulleEfficacitéAgronomique
flèche suivant