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European Journal of Applied Sciences – Vol. 10, No. 3
Publication Date: June 25, 2022
DOI:10.14738/aivp.103.12405. El-Ghazouani, O., Bouamri, R., & Ibijbijen, J. (2022). The Kinetics of Carbon and Nitrogen Mineralization of Different Organic
Amendments in the Soil. European Journal of Applied Sciences, 10(3). 318-331.
Services for Science and Education – United Kingdom
The Kinetics of Carbon and Nitrogen Mineralization of Different
Organic Amendments in the Soil
Ouiam EL-GHAZOUANI
Environment and Valorization of Microbial and Plant Resources Unit,
Faculty of Sciences, Moulay Ismail University, Meknes, Morocco
Rachid BOUAMRI
Department of Environment and Plant Protection
Plant Ecology Unit, national school of agriculture, Meknes, Morocco
Jamal IBIJBIJEN
Environment and Valorization of Microbial and Plant Resources Unit,
Faculty of Sciences, Moulay Ismail University, Meknes, Morocco
ABSTRACT
The exploitation of exogenous organic matter from fresh or composted livestock
manure in agriculture is an effective source that addresses the problem of soil
depletion and provides essential nutrients to plants. It can also cause worry about
environmental degradation, such as CO2 emissions and nitrate leaching. The
rational use of these organic soil amendments requires additional research, which
still remains limited in terms of articles and books in Morocco. The objective of our
research is to study the kinetics of carbon and nitrogen mineralization of the
different organic amendments, sheep manure (SM), cattle manure with straw (CM),
two composts (CA, CF) and poultry manure laying hen (PL), by an incubation
method under controlled laboratory conditions, and characterize the organic
matter (OM) by biochemical fractionation. In the light of these results obtained, it
can be seen that laying hen droppings induced the highest level of carbon and
nitrogen mineralization, followed by sheep manure and cattle manure with straw
which recorded an intermediate rate of carbon mineralization. And high nitrogen
immobilization, these two materials are considered to be a transition point
between the manure and the two compost, which recorded slow and low carbon and
nitrogen mineralization. Statistical analysis endorsed a correlation between the
kinetics of carbon mineralization and biochemical fractionations of organic matter
in EOMs.
Keywords: kinetics of mineralization, organic matter, mineral nitrogen, organic carbon,
and biochemical fractionation.
INTRODUCTION
Exogenous organic matter (EOM), such as poultry manure, animal manure, and composts is
frequently used in Moroccan soils. The application of these organic amendments (OA) can have
a strongly ecological and environmental value, making it possible not only to limit the use of
very expensive chemical fertilizers but also to enrich the soil with organic matter, generally to
rehabilitate degraded soils. Accordingly, to supply plants with the nutrients necessary for their
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El-Ghazouani, O., Bouamri, R., & Ibijbijen, J. (2022). The Kinetics of Carbon and Nitrogen Mineralization of Different Organic Amendments in the
Soil. European Journal of Applied Sciences, 10(3). 318-331.
URL: http://dx.doi.org/10.14738/aivp.103.12405
growth (Stratton et al., 1995; Marmo et al., 2004). These organic amendments are very rich in
carbon and nitrogen with high agricultural value and an important fertilizing potential
stimulating the microbial activity of the soil.
The decomposition of exogenous organic matter in the soil is dependent on their soluble
compounds namely carbohydrates, fatty acids, amino acids, cellulose, lignin, etc. In addition,
several studies have shown that the release of CO2 and the availability of inorganic nitrogen are
closely related to the properties of materials applied to the soil (Lashermens et al., 2009;
Hassani et al., 2017; Noirot-cosson et al., 2017). The degradation of exogenous organic matter
rich in unstable organic carbon in the soil leads to high production of CO2. In addition, these
unstable organic amendments also cause a decrease in oxygen concentration and
immobilization of mineral nitrogen in the soil (Diacono and Montemurro., 2010).
For rational use of the various exogenous organic materials in agricultural soil, several studies
are carried out in order to study the dynamics of carbon and nitrogen mineralization brought
to the soil (Kaboré et al., 2011; Antil et al., 2011; Zhang et al., 2017; Noirot-Cosson et al., 2017;
Chen et al., 2018). Other indicators have also made it possible to predict the evolution of organic
matter in the soil, such as the Organic Matter Stability Indicator (IROC) which determines, on
the one hand, the potential of organic matter remaining stable. In soil after application of MOEs,
including biochemical fractionations characterizing the OM of organic amendments
(Lashermes et al., 2009). On the other hand, it predicts the potential for carbon mineralization
in the soil under controlled laboratory conditions (Clément Peltre et al., 2012; Noirot et al.,
2017).
This present work aims to study the dynamics of carbon and nitrogen mineralization from
various exogenous organic materials in the soil under controlled laboratory conditions, to
illustrate the kinetics of carbon and nitrogen mineralization, as well as determine the level of
stable organic matter in the soil amended with MOE. Also, to highlight the relations between
the biochemical fractionations of the organic materials tested and the dynamics of carbon
mineralization.
MATERIALS AND METHODS
Soil and organic amendment
a. Soil collection and analysis
The incubated soil was collected at a depth of 0-15 cm in several points of a farm in BRIDIA
located 3 km from the city of Meknes (Fès-Meknes region).
The soil collected in December 2019 has a particle size distribution of 800 g / kg of sand, 80 g
/ kg of silt, and 120 g / kg of clay. The soil sample was dried at room temperature and sieved at
4mm.
All analyses were carried out at the Analysis and Quality Control Laboratory of the Green
Elephant Group and the Soil and Environmental Microbiology Laboratory of the Faculty of
Sciences, Moulay Ismail de Meknes. These analyses focused on: the particle size
distribution (AFNOR 2003), the pH in water (AFNOR 2005b), the carbonate contents (AFNOR
2014), the total organic carbon (AFNOR 1995), and mineral nitrogen sample of the soil, it was
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European Journal of Applied Sciences (EJAS) Vol. 10, Issue 3, June-2022
Services for Science and Education – United Kingdom
stirred for one hour with a solution of potassium chloride (100 ml of potassium chloride
solution for 25 g of dry equivalent soil at 103 C ° +/- 2 °) (table 1).
Table 1: Physico-chemical characteristics of the soil used
Texture TOC N-NO3 N-NH4 pH Calcareous
content
Clay Silt sand
g/kg g/kg mg/kg mg/kg g/kg
120 80 800 5 17,1 9,95 7,3 2
b. Organic amendments
Five organic amendments were used in the laboratory incubation experiment for 91 days. They
are designated by cattle manure with straw (CM), sheep manure (SM), poultry manure laying
hen (PL), and two types of compost (CA and CF) certified NF U 44-051 and developed within
the Green Elephant group.
The organic amendments were dried at 38 ° C to constant weight then crushed and sieved to 1
mm. A mineral nitrogen extraction (NH4 + and N-NO3-) of 60 g for each type of amendment
was made using 600 ml of 1 mol / l KCl (w / v factor: 1/10). The extract was assayed by
colorimetry on a continuous flow analyzer according to standards (AFNOR 1996) and (AFNOR
2005a). The determination of total Kjeldahl nitrogen is carried out according to the
standard (AFNOR 2002), the total organic matter was measured on the basis of the loss of mass
after calcination at 550 ° C (AFNOR 2011), the elemental organic carbon was measured
according to the standard (AFNOR 1995), the pH was measured according to the
standard (AFNOR 2012) and the C / N ratio was then calculated for all the organic amendments.
Characterization of the organic matter by biochemical fractionation of the soluble fractions
(SOL), hemicellulose (HEM), cellulose (CEL), and lignin (LIG) were determined by treatment
with neutral detergents, acid, and sulfuric acid as described in section standard (AFNOR 2009a)
NF ISO 44-162 (table 3). The organic fractions and the percentage of carbon mineralization
after 3 days (C3d) of laboratory incubation (NF XP 44-163) were used for the calculation of
indicator stability of organic matters (IROC), as described in the NF standard. XP 44-162: IROC =
44.5 + (0.5 x SOL) - (0.2 x CEL) + (0.7 x LIG) - (2.3 x cd3) 1
INCUBATION EXPERIMENTS
The carbon mineralization potential of organic amendments (of a soil/product mixture) was
determined in 4 repetitions for each treatment under controlled laboratory conditions
according to the standard (AFNOR 2009) NF XP U 44-163. The fresh soils (equivalent to 25g of
dry soil at 103 ° C +/- 2 ° C) were placed in airtight 500ml jars at a soil water content equivalent
to the water holding capacity (pF 2.5) and incubated at a temperature of 28 ° C +/- 2 ° C in the
dark for 91 days. The organic amendments were carefully mixed with the soil so that the
organic carbon of the added product represents 2 ‰ by mass of the dry soil (50 mg C). The soil
no amended was used as a control and four soilless jars were considered blanks. A 1 ml of
KNO3 was added to the treatments and to the control soil so that the mineral nitrogen of the
soil reached 35 mg per kg of dry soil at 103 ° C, to avoid that the decomposition of the MOE was
limited by the availability of mineral nitrogen (Recous et al., 1990).
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El-Ghazouani, O., Bouamri, R., & Ibijbijen, J. (2022). The Kinetics of Carbon and Nitrogen Mineralization of Different Organic Amendments in the
Soil. European Journal of Applied Sciences, 10(3). 318-331.
URL: http://dx.doi.org/10.14738/aivp.103.12405
Carbon mineralization
The pots of amended soil and control soil containing a 10 ml vial of 0.5 mol / l NaOH to trap the
mineralized CO2. The vial was replaced with a new freshly prepared NaOH at 1, 3, 7, 14, 21, 28,
49, 70, and 91 days after incubation. The CO2 trapped was dosed by titration with 0.5 mol / l
hydrochloric acid. The soil moisture was checked and readjusted by distilled water at 14, 28,
49, and 70 days, by weighing the flasks as described in standard NF XP U 44-163.
Nitrogen mineralization
The jars incubated to extract mineral nitrogen were covered with a perforated film to maintain
good oxygenation and by opening the jars at 1, 3, 7, and 14 days of incubation, then every 14
days checking the humidity by weighed the vials of soil.
An extraction of NH4 + and NO3- was measured on the first day of incubation, then after 7, 14,
28, 49, 70, and 91day incubation. Each day of extraction, the soil samples were stirred for one
hour with 100 ml of potassium chloride (KCl 1 mol / l), filtered, and assayed by continuous flow
colorimetry according to standard NF EN ISO 11732 & NF EN ISO 13395.
The percentage of mineralized nitrogen in the product was calculated as described in standard
NF XP U 44-163.
STATISTICAL ANALYSIS
The statistical analysis was carried out using the SPSS 19 software, the cumulative data of the
mineralized carbon and the mineralization kinetics were calculated by analytical mathematical
equations (according to standard NF 44-162 and NF 44-163). The comparison between the
results was made by the Pearson correlation coefficient.
RESULTS
Physico-chemical characteristics of applied organic amendments
The physicochemical characteristics of the organic amendments used in the experiment are
listed in Table 2. Exogenous organic matter, such as PL, CM, and SM recorded high organic
carbon content (> 31% / DM). While the two composts CA and CF have a lower content of 19%
and 25% respectively by dry matter (DM).
The PL is also characterized by a very high total organic nitrogen value (5% / DM), and a lower
C/N ratio, while other materials have lower total organic nitrogen content (<2% / DM). The
highest C/N ratio was recorded in MS and CM. These results are within the range of analysis
published by Noirot-Cosson et al. (2017).
Table 2: Physico-chemical characteristics of EOM
Exogenous organic matter (EOM) CEOM NTEMO C/N
%
Compost CA 18,9 1,8 10,5
Compost C F 24,5 2 12,3
cattle manure with straw (CM) 33,3 1,8 18,5
sheep manure (SM) 31,2 1,5 20,8
poultry manure laying hen (PL), 35,4 5,1 6,9