1 
 

 American Scientific Research Journal for Engineering, Technology,  and Sciences  (ASRJETS) 
ISSN (Print) 2313-4410, ISSN (Online) 2313-4402 

© Global Society of Scientific Research and Researchers  
http://asrjetsjournal.org/  

 

Development of Compost from Agro-food Residues: 

Analysis of the Crop Nutrients and Trace Elements 

Zanguina Adamoua*, Mella M. Tchicamab, Addam kiari Saidouc, Ousmane 

Garbad 

a,bFaculty of Science Université Abdou Moumouni, BP: 656 Niamey 
cInstitut National de la Recherche Agronomique du Niger, BP : 429Niamey 

dFaculty of Science University of Zinder BP: 237Zinder 
aEmail: adazangui@yahoo.fr 

bEmail: marouma2009@yahoo.fr 
cEmail: kaddam2001@yahoo.fr 

dEmail: ousmgb@yahoo.fr 

 

 

Abstract 

A composting study of agro-food residues was conducted to evaluate the nutrient content of plants. Three types 

of composts were made: compost C1 based on organic matter; compost C2 based on organic matter and Tahoua 

rock phosphate and compost C3 based on organic matter, cow manure and Tahoua rock phosphate. During 

composting, the pH reached 9.60; 8.93 and 8.88 respectively for composts C1, C2 and C3 before falling 

respectively to 9.15; 7.90 and 7.83 at the end of composting. The temperature reached 57 ° C for all composts 

during composting before stabilizing at 31 ° C after composting. The analysis of the physicochemical 

parameters of the composts obtained reveals that they contain carbon contents (23.01%, 14.625% and 16.575% 

for C1, C2 and C3 respectively) and nitrogen (2.63%; 34% and 1.62% for C1, C2 and C3 respectively) and C / N 

ratios (8.74, 10.91 and 10.83 for C1, C2 and C3 respectively) and nutrients: available phosphorus (186.2, 399.70, 

695.8 mg / kg for C1, C2 and C3 respectively), potassium (3389.97, 1127; 1313.30 for C1, C2 and C3 

respectively), calcium (12000, 42800, 64000 mg / kg for C1, C2 and C3 respectively) and magnesium (18936.77, 

15946.62, 16346.47 mg / kg for C1, C2 and C3 respectively). 

Keywords: composting; agro-food residues; crop nutrients. 

------------------------------------------------------------------------ 

* Corresponding author.  

http://asrjetsjournal.org/


American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2018) Volume 43, No 1, pp 1-12 

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1. Introduction 

Nowadays, the cities of Niger, like the other African cities, are confronted to a problem of purification due to an 

important stock of strong garbage. This garbage is produced daily by the populations whose quantity passes the 

capacities of hold currently in charge of the townships. It proves to be then necessary to think about a method of 

sustainable management of this garbage. 

An ecological, economic and beneficial solution yet exists for the man and for the environment, a mineralization 

process called composting. An adequate solution that allows to overcome the environmental problems with a 

non costly and yet valorizing the garbage.   

Composting presents some interests as the improvement of fertility and the quality of soil, health by hygiene and 

the increase of the agricultural production [1] encouraging an increase of the agricultural productivity, a better 

biodiversity of soil, a reduction of the ecological risks and a more favorable environment [2]. Composting 

allows adding value to garbage while manufacturing from these organic manure.   

In substitution to the manures of synthesis, many researchers recommended the use of compost produces 

especially by composting of the strong garbage, the agro-food residues.  This work appears in the setting of a 

thematic of research developed in our laboratory on the treatment of the urban strong garbage by composting.  

The objective of this work is to elaborate composts, from the agro-food residues. It adds value to crop nutrient 

elements in the soil. Work is aimed at the valorization of this garbage in compost added value to fertilizing 

improved material by addition of manure and Tahoua rock phosphate.  

2. Materials and methods 

2.1. Materials  

The agro-food garbage: the residues of agro-food cut in small pieces as source of nitrogen; dried millet stems 

and ground as source of carbon; dry cow manure as source of nitrogen and potassium; Tahoua rock phosphate as 

source of  phosphorus; used domestic garbage are largely from the kitchen activities of the university restaurant 

of Niamey.   Before loading the composting pit, a sorting of the garbage as well as a reduction must be to 

operate. The sorting will permit to isolate the non biodegradable matirials as the plastic bags, the tins of canned 

food etc and the reduction will permit to refine the granulometry of the garbage to make them more accessible to 

the micro-organisms responsible for the mineralization of the organic matter. 

2.2. Experimental Site 

Works are conducted at botanical garden of the faculty of sciences of the Abdoul-Moumouni University in 

Niamey during the period of August 2017 to December 2017. 

2.3. Methods of compost development   



American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2018) Volume 43, No 1, pp 1-12 

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The method in an aerobic pit has been used for the development of composts. Composts are elaborated in vats 

pit that measures 1, 04 x m 0, 67 x m 0, 68 m, covered by a plastic material, under a shelter in order to protect 

composts against the strong rains, the excess of sun and waters flooding. In order to respect the C/N ratio in 

every pit, compost has been prepared through a mixture of raw materials as follows: C1 compost, 100% of the 

organic matter containing 72% of the agro-food garbage plus 28% dried millet stems. C2 compost, 95% of the 

organic matter (70% of the agro-food garbage plus 25% dried millet stems) and 5% of the Tahoua rock 

phosphate. C3 compost, 95% of the organic matter (50% of the agro-food garbage plus 25% dried millet stems 

plus 20% of the cow dung manure) and 5% of the Tahoua rock phosphate. To assure a good aeration of the 

watered mixture, some agitations have been done every two (2) weeks with the help of a fuck. The first agitation 

intervened after 15 days of experimentation, and then the agitation continued every week and during the whole 

time of the experimentation that lasted 5 months. We also controlled humidity in order to check and maintain 

the content of water in the proportions of 50 to 60% of the weight of the mixture; The main physico-chemical 

features have been determined appropriately on samples of compost after 2, 3, 4 and 5 months of incubation. 

The chemical content of different composts has been determined at the end of the composting process. In the 

first month of composting, the temperature is taken every day with a digital thermometer, EUROLAB to probe 

then every 3 day after the 50th day of the process.    

In a biker, 10 g of compost ground and sieved to 2 mm are mixed to 100 ml of distilled water. The measure of 

the pH is done after ten (10) minutes of homogenization and after thirty (30) minutes of rest to ambient 

temperature with the help of a pH meter HANNA type. 

The total organic carbon is determined by the Walkley and Black method [3].   

The total organic carbon, expressed in percentage of dry matter, is given by the following relation: %𝐂𝐂𝐂𝐂𝐂𝐂 =

NFe𝟐𝟐+×(𝐕𝐕𝐕𝐕−𝐕𝐕𝐕𝐕)
𝐏𝐏

𝐱𝐱 𝟎𝟎,𝟑𝟑𝟑𝟑 

COT : carbone organique total en percentage of dry matter.  

Vt : titration volume of the check in ml.  

Ve : titration volume of the sample in ml.  

P : weight of the sample in g.  

NFe2+ : ions normality Fe2+ du sel de Mohr 

Total nitroge is determined by Kjeldahl method de  

Total nitrogen Kjeldahl is given by : 

 %𝑵𝑵𝑵𝑵𝑵𝑵 = (𝑽𝑽−𝑽𝑽𝟎𝟎)×𝑵𝑵×𝟎𝟎,𝟎𝟎𝟎𝟎𝟎𝟎𝐱𝐱𝟎𝟎𝟎𝟎𝟎𝟎
𝑷𝑷

  



American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2018) Volume 43, No 1, pp 1-12 

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V : volume of H2SO4 that serve for sample titration ; 

V0 : volume of H2SO4 that serve for blank titration; 

N : H2SO4 normality for ammonia titration ; 

P : sample weight in g.  

     Available phosphorus is determined by Bray 1method. 

Exchangeable cations (K+, Ca2+, Mg2+, Na+) have been determined on the elaborated composts. End product 

served to measure out exchangeable K+ and Na+ by flame absorption spectrophotometry in flame and Ca2+ and 

Mg2+ by flame atomic absorption spectrophotométry.  

3. Results and discussions   

The raw materials constitute the source of mineral elements of the prepared composts.    

The results show that manure is a lot of richer in total nitrogen (2.30%) than the milet dry stems (0.99%) that, 

them, are richer in total carbon (40.73) against (17.55%) for manure. The PNT is source of the 

Phosphorus, P2O5. 

One notices an increase of the temperature until maximal values being located between 50 and 57°C(fig.4a, b, 

c).. These values are reached after 2 days of composting for compost 3 (55,2°C), 5 days of composting for 

compost 2 (50,4°C) and 15 days of composting for compost 1 (57°C). This tendency is maintained until the 50th 

day of dating. The elevation of the temperature in the beginning of the process explains itself by a microbial 

activity (Thermopile) due to the presence of organic matters easily biodegradable. These elevated temperatures 

could lead to the reduction of the pathogenic agents and the elimination of the seeds of adventitious plant [4]. 

One notes that the temperature evolved practically in the same way in all composts studied from the 15th day of 

composting process.   

After 50 days of composting, the temperature begins to lower and come closer of the ambient temperature 

(30°C). This decrease of temperature can be explained easily by a slowing of the activity of the micro-organisms 

due to the weariness of the organic matters degradable. The evolution of the temperature is characterized by four 

phases.   

One notes a brief evolution of the active temperature of the ambient temperature to 45°C for all active studied 

composts of the 1st on the 2nd day of composting for composts 2 and 3 and of the 1st on the 13rd day of dating 

for compost 1.            What corresponds to the mesophile phase provoked by the bacteria of this group raising 

the temperature of 25-45° C. To this phase mésophile a phase thermophile follows for a length of 48 days for 

composts 2 and 3. And of 37 days for compost 1 characterized by elevated temperatures with a maximum of 

57°C.    



American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2018) Volume 43, No 1, pp 1-12 

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After 50 days of composting, one notes that the temperature lowered 47°C to the ambient temperature for all 

studied composts corresponding to the phase of cooling and the beginning of the maturation phase. One noticed 

an elevation of the temperature after every agitation, then again a fall of temperature. 

 

Figure 4a, b, c : Courbe d'évolution des Thermophiles et Mésophiles au cours du compostage 

The evolution of the pH during the process is represented on the face 5. The pH of C1 composts, C2 and C3 

constantly remained basic during the composting. This increase of the pH would be due to the nature of the 

garbage used composed largely of oranges rich in potassium (151 mg/100g) [5]. The addition of the powder of 

the Tahoua rock phosphate in C2 and C3 decreased the pH of these composts. This reduction would be due to 

the complex binding power of metallic cation of the phosphate ore by the carboxyliques groupings and 

hydroxyles of the acidic present humiques in the middle with liberation of the H+ protons [6]. Some similar 

results have been returned by [7]. 

One notes that the quantity of the organic carbon decreased in the elaborated composts (figure. 6) passer-by of 

51,87% to the 2nd month to 23,01% at the end of the dating for the C1 compost. She/it decreases from 40, 56% 

to the 2nd month to 14,62% at the end of the composting for the C2 compost. And finally it decreases from 36, 

27% to the 2nd month to 16, and 57% at the end of the process for the C3 compost. One also notices that the 

quantity of the organic carbon is raised more in the C1 compost where there was not addition of the Tahoua rock 

phosphate.  

This decrease of the content in organic carbon explains itself by a fast decomposition of the biodegradable 

compounds as sugar. This decomposition of the organic matter can be translated by the following oxidization 

reaction:    

20

30

40

50

60

0 15 30 45 60 75 90

te
m

pé
ra

tu
re

 e
n 

°C
 

Durée de compostage 
(jrs) 

C1

20

30

40

50

60

0 15 30 45 60 75 90

te
m

pé
ra

tu
re

 e
n 

 °C
  

Durée de compostage 
(jrs) 

C2

20

30

40

50

60

0 15 30 45 60 75 90

te
m

pé
ra

tu
re

 e
n 

 °C
 

Durée de compostage 
(jrs) 

C3

a b c 



American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2018) Volume 43, No 1, pp 1-12 

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𝐌𝐌𝐌𝐌𝐕𝐕𝐌𝐌è𝐫𝐫𝐕𝐕 𝐨𝐨𝐫𝐫𝐨𝐨𝐌𝐌𝐨𝐨𝐌𝐌𝐨𝐨𝐨𝐨𝐕𝐕 +  𝐂𝐂𝟐𝟐    →  𝐂𝐂𝐂𝐂𝟐𝟐  + 𝐇𝐇𝟐𝟐𝐂𝐂      (1) 

Indeed, similar reductions of the content in organic carbon, during the composting process, have been returned 

and have been assimilated to the mineralization of the organic matters by the micro-organisms by [1]. 

 

Figure 5: pH status during composting 

 

Figure 6: Carbone fate during composting, C1, C2 and C3 

One notices that the quantity of total nitrogen decreased in the prepared composts (figure. 7). This effect is due 

to the immobilization of nitrogen by the micro-organisms to oxidize the carbon. The nitrogen that disappears in 

this case is the most often free as NH3. The decomposition of the nitrogenous organic matter can be translated 

by the following reaction: 

𝐌𝐌𝐌𝐌𝐕𝐕𝐌𝐌è𝐫𝐫𝐕𝐕 𝐨𝐨𝐫𝐫𝐨𝐨𝐌𝐌𝐨𝐨𝐌𝐌𝐨𝐨𝐨𝐨𝐕𝐕 𝐌𝐌𝐚𝐚𝐨𝐨𝐕𝐕é𝐕𝐕 +  𝐌𝐌𝐌𝐌𝐌𝐌𝐫𝐫𝐨𝐨 − 𝐨𝐨𝐫𝐫𝐨𝐨𝐌𝐌𝐨𝐨𝐌𝐌𝐨𝐨𝐨𝐨𝐕𝐕𝐨𝐨 → 𝐍𝐍𝐇𝐇𝟎𝟎
+    (2) 

6

7

8

9

10

15 30 45 60 75 90 105 120 135 150 165

pH
 

Durée de compostage (jrs) 
 

compost 1

compost 2

compost 3

15

25

35

45

55

65

75

60 90 110 120 150 

T
en

eu
r 

en
 c

ar
bo

ne
 e

n 
%

 

 
Nombre de jours de 

compostage 

C1 

10

20

30

40

50

60 90 110 120 150 

T
en

eu
r 

en
 c

ar
bo

ne
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n 
%

 

Nombre de jours de 
compostage 

C2 

10

20

30

40

50

60 90 110 120 150 

T
en

eu
r 

en
 c

ar
bo

ne
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n 
%

 

Nombre de jours de 
compostage 

C3 



American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2018) Volume 43, No 1, pp 1-12 

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𝐍𝐍𝐇𝐇𝟎𝟎
+ + 𝐇𝐇𝟐𝟐𝐂𝐂 → 𝐍𝐍𝐇𝐇𝟑𝟑 (𝐨𝐨) +  𝐇𝐇𝟑𝟑𝐂𝐂+  (3) 

One also notices that the content in nitrogen decreases when one adds the natural phosphate in the mixture 

(figures 7b and 7c). The decrease of the content in nitrogen with the addition of the phosphate is to the reduction 

of the quantity of the organic matter in the C2 miscellanies and C3.  This reduction of the content in nitrogen 

could also be explained by the formation of the ammonium phosphates in the medium.  Indeed the phosphorus 

of P2O5 formula coming from the Tahoua rock P turns in the medium into phosphoric acid according to the 

following reaction:  

𝐏𝐏𝟐𝟐𝐂𝐂𝟓𝟓 + 𝟑𝟑𝐇𝐇𝟐𝟐𝐂𝐂 → 𝟐𝟐𝐇𝐇𝟑𝟑𝐏𝐏𝐂𝐂𝟎𝟎 (4) 

Then next gave  H2 PO4
−, HPO4

2−  and  PO4
3− as follows :   

 𝐇𝐇𝟑𝟑𝐏𝐏𝐂𝐂𝟎𝟎 + 𝐇𝐇𝟐𝟐𝐂𝐂 →  𝐇𝐇𝟑𝟑𝐂𝐂+ + 𝐇𝐇𝟐𝟐 𝐏𝐏𝐂𝐂𝟎𝟎
− (5) 

  𝐇𝐇𝟐𝟐 𝐏𝐏𝐂𝐂𝟎𝟎
− + 𝐇𝐇𝟐𝟐𝐂𝐂 →  𝐇𝐇𝟑𝟑𝐂𝐂+ + 𝐇𝐇𝐏𝐏𝐂𝐂𝟎𝟎

𝟐𝟐− (6) 

𝐇𝐇𝐏𝐏𝐂𝐂𝟎𝟎
𝟐𝟐− + 𝐇𝐇𝟐𝟐𝐂𝐂 →  𝐇𝐇𝟑𝟑𝐂𝐂+ + 𝐏𝐏𝐂𝐂𝟎𝟎

𝟑𝟑−    (7) 

These ions are going to react with the ions NH4
+ ammonium descended of the mineralization of the organic 

matter to form the phosphates of formula ammonium (NH4)3PO4, (NH4)2HPO4 and NH4H2PO4 according to the 

following reactions:  

 𝟑𝟑𝐍𝐍𝐇𝐇𝟎𝟎
+ + 𝐏𝐏𝐂𝐂𝟎𝟎

𝟑𝟑−  → (𝐍𝐍𝐇𝐇𝟎𝟎)𝟑𝟑𝐏𝐏𝐂𝐂𝟎𝟎            (8) 

𝟐𝟐𝐍𝐍𝐇𝐇𝟎𝟎
+ + 𝐇𝐇𝐏𝐏𝐂𝐂𝟎𝟎

𝟐𝟐− →  (𝐍𝐍𝐇𝐇𝟎𝟎)𝟐𝟐𝐇𝐇𝐏𝐏𝐂𝐂𝟎𝟎       (9) 

 𝐍𝐍𝐇𝐇𝟎𝟎
+ + 𝐇𝐇𝟐𝟐 𝐏𝐏𝐂𝐂𝟎𝟎

− →  𝐍𝐍𝐇𝐇𝟎𝟎𝐇𝐇𝟐𝟐𝐏𝐏𝐂𝐂𝟎𝟎             (10) 

Similar reductions of the content in total nitrogen, during the composting process, have been returned and have 

been assimilated to the oxidization of the organic carbon by the micro-organisms by [8] and by [1]. 

C/N report is the most commonly parameter measured to determine the maturity of a compost. According to [9], 

the optimum for a C/N of departure must be located between 25 and 30. For [10], the optimum is located 

between 30 and 35.   

One notes that the C/N report decreased in the elaborated composts (figure. 8) passer-by of 30,4 at the beginning 

of the process to 8,74 at the end of the process for the C1 compost; of 29,47 at the beginning of the process to 

10,91 at the end of the composting for the C2 compost and 30,5 in the beginning of the dating to 10,23 at the 

end of the dating for the C3 compost. Because of the consumption of nitrogen and the mineralization of the 

carbon, the C/N report decreases during the dating.   

At the end of the process of the composting the C/N reports of the different composts products are in between 8 



American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2018) Volume 43, No 1, pp 1-12 

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and 11 that  according to [10] characterize a mature compost. 

 

Figure 7: Fate of nitrogen during composting C1, C2 et C3. 

 

Figure 8: Ratio C/N during composting C1, C2 et C3. 

4. Fertilizing elements  

The dosage of the different fertilizing elements in composts at the end of the process of composting allowed us 

to get results consigned in table 1. 

The aP has been multiplied by 3, 73 in the C3 compost in relation to the Compost C1 and by 2,14 in the C2 

compost in relation to the Compost C1. This increase of the content in phosphorus is due to the presence of the 

P from manure of cow and the dissolution of Tahoua rock phosphate.  Indeed the availability of the P would be 

assigned to the mcrobiological oxidization of the organic matter and the process of humification that encourage 

the dissolution of the natural phosphates [11].  Of works achieved on the composting of lawn mowing in 

1.5

2

2.5

3

60 90 110 120 150 

T
en

eu
r 

en
 a

zo
te

 to
ta

l e
n 

%
 

Nombre  de jours de 
compostage 

C1 

0.5

1.5

2.5

60 90 110 120 150 

T
en

eu
r 

en
 a

zo
te

 to
ta

l e
n 

%
 

Nombre  de jours de 
compostage 

C2 

1

1.5

2

2.5

60 90 110 120 150 

T
en

eu
r 

en
 a

zo
te

 to
ta

l e
n 

%
 

Nombre  de jours de 
compostage 

C3 

5

15

25

35

45

1 60 90 110 120 150 

R
ap

po
rt

 C
/N

 

Nombre  de jours 
de compostage 

C1 

5

15

25

35

1 60 90 110 120 150 

R
ap

po
rt

 C
/N

 

Nombre  de jours 
de compostage 

C2 

5

15

25

35

1 60 90 110 120 150 

R
ap

po
rt

 C
/N

 

Nombre  de jours 
de compostage 

C3 



American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2018) Volume 43, No 1, pp 1-12 

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presence of Tahoua rock phosphate by [8] showed that the addition of the phosphate in the mixture permitted to 

improve the content of composts in phosphorus. One notice that the content in total potassium (figure 9) is 

raised more in the C1 compost than in C2 composts and C3.  Indeed the content of potassium in the C1 compost 

is equal to 3 times the one in the C2 compost and 2,6 times the one in the C3 compost. It is due to the nature of 

the garbage used that are composed largely of oranges rich in potassium [5] (151 mg/100g, 

www.lesfruitsetlégumesfrais.com). The reduction of the content in potassium with the addition of the phosphate 

could be explained by the formation of the phosphates of K_(3 potassium) PO4, KH2 PO4 and K2 resulting in 

HPO4 of the attack of the potassium hydroxide (KOH) by the phosphoric acid following these reactions:    

𝟑𝟑𝟑𝟑+ + 𝐏𝐏𝐂𝐂𝟎𝟎
𝟑𝟑−     → 𝟑𝟑𝟑𝟑 𝐏𝐏𝐂𝐂𝟎𝟎         (11) 

𝟐𝟐𝟑𝟑+ + 𝐇𝐇𝐏𝐏𝐂𝐂𝟎𝟎
𝟐𝟐−  →  𝟑𝟑𝟐𝟐𝐇𝐇𝐏𝐏𝐂𝐂𝟎𝟎      (12) 

𝟑𝟑+ + 𝐇𝐇𝟐𝟐𝐏𝐏𝐂𝐂𝟎𝟎
−   →  𝟑𝟑𝐇𝐇𝟐𝟐𝐏𝐏𝐂𝐂𝟎𝟎      (13) 

Table 1: Chemical composition of C1, C2 and C3 

Compost 
 

pH C N C/N  aP K Ca Mg Na Cl 

  %  mg/kg 

1 
 

 
9,15 

 
23,01 2,63 8,74  186,2 3389,97 12000 18936,77 62,1 207,67 

2 
 

 
7,90 

 
14,62 1,34 10,91  399,70 1127 42800 15946,62 34,5 138,45 

3 
 

 
7,83 

 
16,57 1,62 10,83  695,8 1313,30 64000 16346,47 110,4 108,27 

 

aP = available P 

So the main source of potassium in our miscellanies is the organic matter.    

The phosphate is not a good source of potassium (% K2O = 0,12, [12]. Of works achieved on the dating of lawn 

mowing in presence of the phosphate natural of Tahoua by [8] showed that the content in potassium of composts 

decreases with the addition of the phosphate in the mixture. One notices that the content in total calcium (figure. 

9b) is raised more in C2 composts and C3 that in the C1 compost. The content of the calcium in the C3 compost 

is equal to 5,3 times the one in the C1 compost and the content in calcium , C2 compost is equal to 3,56 times 

the one in the C1 compost. It explains itself at a time by the contribution of the calcium by the garbage used 

composed largely of oranges that are rich in calcium [5](29,7 mg/g, www.lesfruitsetlégumesfrais.com), of the 

manure of cow and the phosphate natural of Tahoua rich in calcium. (% CaO = 43,12) [12].   



American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2018) Volume 43, No 1, pp 1-12 

10 
 

 

Figure 9ab: Content in calcium(a) and in magnesium(b) in the composts 

One notices that the content in total magnesium is raised more (figure.12) in C1 composts and C3 that in the C2 

compost.  It is due to the nature of the garbage used that is composed largely of oranges rich in magnesium [5] 

(12,4 mg/100g, www.lesfruitsetlégumesfrais.com) and of the cow manure. The reduction of the content in 

magnesium with the addition of the phosphate natural of Tahoua in C2 and C3 could be explained by the 

formation of the magnesium phosphates in the middle according to the reactions: 

𝟑𝟑𝐌𝐌𝐨𝐨𝟐𝟐+ + 𝟐𝟐𝐏𝐏𝐂𝐂𝟎𝟎
𝟑𝟑−     →   𝐌𝐌𝐨𝐨𝟑𝟑(𝐏𝐏𝐂𝐂𝟎𝟎)𝟐𝟐    (14) 

  𝐌𝐌𝐨𝐨𝟐𝟐+ + 𝐇𝐇𝐏𝐏𝐂𝐂𝟎𝟎
𝟐𝟐−      →   𝐌𝐌𝐨𝐨𝐇𝐇𝐏𝐏𝐂𝐂𝟎𝟎           (15) 

 𝐌𝐌𝐨𝐨𝟐𝟐+ + 𝟐𝟐 𝐇𝐇𝟐𝟐𝐏𝐏𝐂𝐂𝟎𝟎  
−  → 𝐌𝐌𝐨𝐨(H2PO4)𝟐𝟐        (16) 

 

These results show that the main source of magnesium in our miscellanies is the organic matter and that the 

phosphate natural of Tahoua is poor in magnesium. (% MgO = 0, 20), [12].  The results gotten after analysis of 

composts showed that the elaborate composts have contents raised in P, K, That and Mg. These contents can 

explain themselves between other by the nature of the garbage used. Indeed, the fertilizing value of the compost 

of the agro-food residues depends on the initial content in major elements of the garbage. The composts of 

studied garbage are therefore rich in fertilizing elements can be used then like fertilizing. 

4. Trace elements    

Two trace elements have been determined (Sodium and chlorine). Sodium (Na) and the chlorine (Cl) are present 

in all three elaborate composts with weak contents (Picture 4). One notices otherwise that the content in sodium 

is raised more in the C3 compost that in the C1 compost (fig. 10). One also notices that the addition of the 

phosphate natural of Tahoua decreased the content in sodium. This decrease of the content in sodium could be 

explained by the formation in the middle of the sodium phosphates according to the reactions: 

5000
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𝟑𝟑𝐍𝐍𝐌𝐌+ + 𝐏𝐏𝐂𝐂𝟎𝟎
𝟑𝟑−         → 𝐍𝐍𝐌𝐌𝟑𝟑𝐏𝐏𝐂𝐂𝟎𝟎       (17) 

𝟐𝟐𝐍𝐍𝐌𝐌+ + 𝐇𝐇𝐏𝐏𝐂𝐂𝟎𝟎
𝟐𝟐−  →  𝐍𝐍𝐌𝐌𝟐𝟐𝐇𝐇𝐏𝐏𝐂𝐂𝟎𝟎        (18) 

𝐍𝐍𝐌𝐌+ + 𝐇𝐇𝟐𝟐𝐏𝐏𝐂𝐂𝟎𝟎
−   →  𝐍𝐍𝐌𝐌𝐇𝐇𝟐𝟐𝐏𝐏𝐂𝐂𝟎𝟎        (19) 

One also notes that the content in chlorine decreased with the addition of the phosphate in the middle. (fig14). 

This reduction could be explained by the formation of the calcium chloride according to the reaction: 

𝐂𝐂𝐌𝐌𝟐𝟐+ + 𝟐𝟐𝐂𝐂𝐂𝐂− → 𝐂𝐂𝐌𝐌𝐂𝐂𝐂𝐂𝟐𝟐     (20) 

 

Figure 10a et b: Content in sodium and in chlorine in the composts 

 

Other trace elements as iron, boron, manganese, the molybdenum, copper, zinc, silicon and cobalt…, that have 

not been measured out exist and contribute to crop growth.  

5. Conclusion  

Composting of agro-food garbage permits to get compost for the fertilization of soils.  The sought-after 

nutriments notably nitrogen, potassium, phosphorus, calcium, magnesium and the trace elements (sodium and 

chlorine) are present in the prepared composts. The pH of elaborated composts is basic (9, 15; 7, 90 and 7, 83 

respectively for C1, C2 and C3). C/N report of elaborated composts ranged between 8 and 11 (8, 74; 10,91 and 

10,83 for C1, C2 and C3 respectively). It has been established that the incorporation of Tahoua rock phosphate  

in the development of compost allowed to improve the contents and in available phosphorus in composts.  

According to the results of this survey, it is established that compost gotten with a mixture of garbage, manure 

of cow and Tahoua rock phosphate (C3 compost) has content in major elements superior to the one gotten from 

garbage without or with Tahoua rock phosphate.   

20

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References 

[1].SANONKA TCHEGUENI, 2011.  Contribution à la valorisation des déchets agro-alimentaires en 

compost: Caractérisation physico-chimique des composts et étude de leur minéralisation dans deux sols 

agricoles du Togo, Thèse de Doctorat, Université de Lomé TOGO, pp1-13. 

[2]. R.V. MISRA, 2005. Méthodes de compostage au niveau de l’exploitation agricole FAO, p16  

[3]. Walkley A. Black, C.A, 1934: An examination of the degtjareff method for determining soil organic 

matter and a proposal modification of the chromic acid titration method. Soil Sci., 37 (1): 29-38. 

[4].NDEGWA, P.M., THOMPSON, S.A., 2001. Integrating composting and vermicomposting in the 

treatment and bioconversion of biosolids. Bioresource Technology. 76 (2), 107-112. 

[5]. www.lesfruitsetlégumesfrais.com consulté le 24/12/17. 

[6]. M. KORIKO, A. ZANGUINA, G. TCHANGBEDJI, M. EL MERAY, I. NATATOU, M. HAFIDI, M. 

SARAKHA, J. Soc. Ouest-Afr. Chim., 030 (2010) 41 - 47  

[7].MAHAMANE SANI OUSMANE , ADAMOU ZANGUINA , SANONKA TCHEGUENI , SIDI 

LAOUALI , NOMAO DAN LAMSO  ET IBRAHIM NATATOU, (2017).  Étude de la solubilisation 

des phosphates naturels de Tahoua (Niger) au cours de la biodégradation des résidus agroalimentaires 

Afrique SCIENCE 13(2) (2017) 179 - 189. 

[8].ZANGUINA ADAMOU, 2011. Contribution à la caractérisation physico-chimique et à la  mise en 

valeur agronomique du phosphate naturel de Tahoua (Niger) : rt Université de Niamey Niger, pp9-11. 

[9]. GODDEN B. (1995). La gestion des effluents d’élevage. Techniques et aspect du compostage dans une 

ferme biologique. Revue de l’Ecologie. No 13.p37. 

[10].MUSTIN, M. 1987. Le Compost, Gestion de la Matière Organique, F. Dubusc eds, pp. 957, Paris. 

[11].M. KORIKO, (2010)  Extraction, caractérisation, réactivité chimique des substances humiques 

naturelles avec les phosphates de Hahotoe-Kpogamé et leurs propriétés photodégrantes, Thèse, 

Université de Lomé, Togo. 

[12]. I. NATATOU, Z. ADAMOU, K. IKHIRI, A. BOOS, J. GUILLE, F. RASTEGAR, M. BURGARD, 

Ann. Chim. Sci. Mat., 30 (1) (2005) 67 - 76  

 

http://www.lesfruitsetl%C3%A9gumesfrais.com/

	Exchangeable cations (K+, Ca2+, Mg2+, Na+) have been determined on the elaborated composts. End product served to measure out exchangeable K+ and Na+ by flame absorption spectrophotometry in flame and Ca2+ and Mg2+ by flame atomic absorption spectroph...
	The raw materials constitute the source of mineral elements of the prepared composts.
	The results show that manure is a lot of richer in total nitrogen (2.30%) than the milet dry stems (0.99%) that, them, are richer in total carbon (40.73) against (17.55%) for manure. The PNT is source of the Phosphorus, P2O5.
	Figure 5: pH status during composting
	Figure 6: Carbone fate during composting, C1, C2 and C3
	Figure 7: Fate of nitrogen during composting C1, C2 et C3.
	Figure 8: Ratio C/N during composting C1, C2 et C3.
	4. Fertilizing elements
	Table 1: Chemical composition of C1, C2 and C3

	Figure 9ab: Content in calcium(a) and in magnesium(b) in the composts
	Figure 10a et b: Content in sodium and in chlorine in the composts
	5. Conclusion