# Effect of Mixed Biochar-Compost Based on Dead Biomasses of Prosopis juliflora and Eichhornia crassipes on the Productivity and Biodiversity of Arid Sandy Soils in the Sahelian Zone

Alexis Dzokom

► To cite this version:

Alexis Dzokom. Effect of Mixed Biochar-Compost Based on Dead Biomasses of Prosopis juliflora and Eichhornia crassipes on the Productivity and Biodiversity of Arid Sandy Soils in the Sahelian Zone. EQA -International Journal of Environmental Quality, In press. hal-04678280

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Submitted on 26 Aug 2024

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# Effect of Mixed Biochar-Compost Based on Dead Biomasses of *Prosopis juliflora* and *Eichhornia crassipes* on the Productivity and Biodiversity of Arid Sandy Soils in the Sahelian Zone

Alexis DZOKOM

Department of Environmental Sciences, National Advanced School of Engineering, University of Maroua, Cameroon

## Abstract

The Biochar-Compost mixture based on the dead biomass of *Prosopis juliflora* and *Eichhornia crassipes* can be used as an input in agricultural production. The objective of this study is to determine the capacity of the Biochar-Compost mixture based on the dead biomass of *Prosopis juliflora* and *Eichhornia crassipes* on the restoration and productivity of degraded arid soils in the Cameroonian Sahel. A randomized complete block design (RCBD) was used to test the effect of the Biochar-Compost mixture on a sandy-clay soil (95%-05%) with and without Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes*. The Berkley rapid composting method was used to produce the compost while the carbonization method developed by SAHEL NATURE CONSULTING FOR COMMUNITIES was used to produce the biochar. In this experiment, the Biochar-Compost mixture based on the dead biomass of *Prosopis juliflora* and *Eichhornia crassipes* was applied to the cultures of Zea mays and Solanum lycopersicum L. above at 5, 10, 15, and 20 t/ha with and without Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes*. The results showed a significant increase in seed germination percentage as we applied more of 15 t/ha of Compost_Biochar 2 (47.36-52.63)% based on *Prosopis juliflora_Eichhornia crassipes* to agricultural land abandoned due to its degradation due to aridity and silting. The study also showed an increase in crop biomass using Biochar (100%) based on *Prosopis juliflora_Eichhornia crassipes* alone and/or in combination with Compost based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T03 (95%-05%). The application of this Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T03 (95%-05%) also increases the growth of shoots and roots of crops, then improves crop yield by improving the physicochemical properties and biological soils, which is probably the reason why Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T03 (95%-05%) could contribute to plant productivity. In view of the percentage of leaching obtained due to runoff water, we conclude that, even in conditions of high precipitation (floods or irregular rainfall), leached soils from highlands for example could be sustainably improved by an amendment to Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes*. Based on the results of the study, it can be recommended that the application of Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* on a sandy clay soil T03 (95%-05%) with a view to restoring degraded agricultural soil and improve seed germination potential, crop growth performance and dry matter yield without chemical fertilizer.

**Keywords:** Compost, Biochar, degraded agricultural soil, Sahelian arid zones, *Prosopis juliflora*, *Eichhornia crassipes*

## 1. Introduction

The Intergovernmental Panel on Climate Change (IPCC, 2018) published in its report that modern agriculture is responsible for 10 to 12% of greenhouse gas emissions. Severe depletion of soil fertility and decline in agricultural productivity due to reduced soil organic matter (SOM) and nutrient imbalances are major constraints in most tropical agricultural soils (Lal, 2015; Pender, 2009). Soil nutrient depletion is a significant concern, directly linked to food insecurity due to intensified and unsustainable land use (Henao and Baanante, 1999). Total nutrient deficits globally have been estimated at 20 Teragram (Tg, 1012 g), of which 75% occurs in developing countries, 14% in developed countries, and 11% in least developed countries. Considering a total NPK deficiency for four crops (rice, wheat, corn and barley) with an individual nutritional deficit in the form of N represented 28% (5.5 Tg), P for 12% (2.3 Tg) and K for 60% (12.2 Tg) (Tan et al., 2005).

*Prosopis juliflora* is a dominant, invasive, drought-tolerant, evergreen, fast-growing tree widely distributed in arid and semi-arid regions (Sivakumar et al., 2018; Mohanraj et al., 2022). It is a unique plant found in varied climatic conditions around the globe (Kazmi et al., 2010). Species of the genus *Prosopis* and their hybrids are among the most aggressive invasive alien plant species in the world and are considered one of the 100 most dominant invasive trees in the world (Walter and

Armstrong 2014; Becker et al., 2016; Patnaik, 2017).

Biochar is a carbon-rich product obtained by thermal decomposition of organic matter under a limited supply of oxygen and at relatively low temperatures (Joseph et al., 2009; Lehmann and Joseph, 2009). The characteristics of biochars depend on the raw material, but also on the method of production of the material (Abenavoli et al., 2016). The carbon in biochar resists degradation and can retain carbon in soils for hundreds or even thousands of years (Kazmi et al., 2010). Due to its high carbon content, *Prosopis juliflora* wood biochar (PWB) is used either as biochar (Angaleeswari and Kamaludeen, 2017) or hydrochars (Shalini et al., 2018). According to a study conducted by Wu et al. (2012), the organic carbon content in biochars is between 40 and 50% for biochars coming from agricultural residues compared to 70 to 90% for biochars made from wood, hulls or bark. Chemically, biochar is not pure carbon, but rather a mixture of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), sulfur (S) and ashes in different proportions (Wang et al., 2020).).

Biochar improves soils and their productivity. It is a carbon-rich porous material with multifaceted physico-biochemical properties such as retention capacity and cation exchange capacity (Arroyo and Ryan, 2018). By converting agricultural waste into a powerful soil amendment that retains carbon and
makes soils more fertile, we can increase food security, discourage deforestation and preserve cropland diversity (Kazmi et al., 2010).

The burning and natural decomposition of trees and agricultural materials contributes to a large amount of CO₂ released into the atmosphere (Tomczyk, 2020). Biochar can store this carbon in the soil, potentially leading to a significant reduction in atmospheric levels of greenhouse gases; at the same time, its presence in the land can improve water quality, increase soil fertility, increase agricultural productivity and reduce pressure on old-growth forests (Lompo et al., 2021; Kazmi et al., 2010). Biochar as a soil amendment faces the challenge that it must be beneficial to soil health because it cannot in any way be separated from soils once added (Bodjona et al., 2023; Lone et al., 2015); soils can be considered as complex communities of organisms), which continually change in response to soil characteristics, climatic and management factors and especially in response to the addition of organic

matter (Chen et al., 2013; Thies and Rillig, 2009). However, the application of biochar to soils is subject to have different change effects on soil biota compared to the addition of fresh organic matter, which can affect the abundance, activity and diversity of soil biotic communities (Lehmann et al., 2011). The objective of this study is to determine the capacity of the Biochar-Compost mixture based on the dead biomass of *Prosopis juliflora* and *Eichhornia crassipes* on the restoration and productivity of degraded arid soils in the Cameroonian Sahel.

## 2. Material and Methods

### 2.1. Study Area

The study was carried out in the Lake Chad area, in the Far North of Cameroon, around 10 sites, including 5 sites which are affected by the invasion of water by *Eichhornia Crassipes* and 5 other sites on dry land which are concerned by the invasion by *Prosopis juliflora*.

<figure><img src="image_2.png" /><figcaption>Figure 1: Map of the Study Area</figcaption></figure>

### 2.2. Biomass sampling

The dry dead biomasses of *Prosopis juliflora* and *Eichhornia crassipes* were collected in bulk in nature. Then, via a manual selective sorting process described by (MEPN, 1998). They were separated then arranged into dry dead biomasses on the one hand and live biomasses on the other hand.

Using the methodologies developed by (ASTMD5142-02, 2002), (MEPN, 1998), (Benjamin, 1996), (Wenny et al., 2019), the very selective sorting of the raw material is preferably done manually, using individual protective equipment (nose covers, gloves, etc.). The fork, the pickaxe, the rakes, the garbage excavations, the

shovels were used to dig and separate the raw material from the organic deposits. Wheelbarrows and bags are tools that made it possible to collect, transport and store this raw material (MEPN, 1998), (Benjamin, 1996), (Wenny et al., 2019).

### 2.3. Preparation of biochar and germination test

The preparation of biochar was done by anaerobic pyrolysis of the biomass in a traditional pyrolization device. It consisted of heating the dry mixture of dry dead biomasses of *Prosopis juliflora* and *Eichhornia crassipes*, between 350°C and 600°C in a metallic medium in the absence of oxygen. The
biomass (Prosopis juliflora and Eichhornia crassipes) was introduced into a carbonizer consisting of two

metal drums intertwined one on top of the other following the diagram in Figure 2.

<figure><img src="image_3.png" /><figcaption>**Figure 2:** Traditional carbonizer</figcaption></figure>

The first metal drum is placed in another larger metal drum. The empty space (flame chamber) between the two metal barrels is the source of the pyrolysis flame powered by fuel (Wood) (Figure 2). The device is covered by a metal cover fitted with a chimney to allow the fumes to escape (Figure 2). The metal lid is of the same alloy as the barrel. Continuous pyrolysis for 5 hours made it possible to obtain biochar, samples of which were characterized (Figure 2).

## 2.4. Preparation of compost and germination test

The Berkley rapid composting method was used in the work. It involves shredding the materials to a Table 1: Characteristics of the pit composting site

size of 1.25 cm to 3.75 cm, with frequent turning which allows compost to be produced in three weeks following the steps:

- Cleaning the site which must be sheltered from wind and bad weather.

- Once the site was clean, a storage area for raw materials was demarcated.

- The composting zone being in dry Sahelian zones, the arrangement of the composting device is done according to the most suitable composting method which is pit composting, the characteristics of which are:

<table><thead><tr><td>Type of composting</td><td>Installation location</td><td>Number of pits/tank per locality</td><td>Device dimensions</td></tr></thead><tbody><tr><td>Ditch</td><td>Non-floodable soil</td><td>3</td><td>- length: 2 m;<br/>- width: 2 m;<br/>- depth: 1 m.</td></tr></tbody></table>

### 2.4.1. The community experimental system and preparation of Biochar

The community experimental device used for this work consists of a carbonizer, a crusher and sieves designed in a traditional way specifically for this

work. The carbonizer consists of two metal barrels which were used; one of 50 cm in diameter serving as the external walls of the pyrolyzer and the other of 25 cm serving as a carbonization chamber.

<figure><img src="image_4.png" /><figcaption>**Figure 3:** Biochar preparation device</figcaption></figure>
The device is equipped with a chimney and a sheet metal cover, allowing the channeling and escape of fumes.

## 2.4.2. Experimental Design and Treatments

The trial was conducted using a randomized Fisher block design comprising three (3) blocks and six (6) treatments which are:

T₀ = no biochar, no compost, no fertilizer;
T₁ = 50 kg/ha of NPK (15-15-15) (50%) at emergence + 100 kg/ha of compost 0 (33.33%) at tillering + 150 Kg/ha of Compost_Biochar 1 (16.67%) at the rise;
T₂ = 275 kg/ha of Compost_Biochar 1 (52.38%) at emergence + 125 kg/ha Compost_Biochar 2 (23.81%) at tillering + 125 Kg/ha Compost_Biochar 3 (23.81%) at emergence;
T₃ = 350 kg/ha of Compost_Biochar 1 (58.33%) + 125 kg/ha of Compost_Biochar 2 (20.83%) at bolting + 125 kg/ha of Compost_Biochar 3 (20.83%) at heading;
T₄ = 475 kg/ha of Compost_Biochar 1 (65.52%) + 125 kg/ha Compost_Biochar 2 (17.24%) at bolting + 125 Kg/ha of Compost_Biochar 3 (17.24%) at heading;

T₅ = 725 kg/ha of Compost_Biochar 1 (74.36%) + 125 kg/ha Compost_Biochar 2 (12.82%) at bolting + 125 Kg/ha of Compost_Biochar 3 (12.82%) at heading

The test was carried out over an area of 500 m² (50 m x 10 m) (Figure 2). Each elementary plot, measuring 10.85 m² (7.75m x 1.40m), included 2 ridges, each 7.25 m long and oriented widthwise (Figure 3).

Except for the T₂ modality which is the recommended practice in terms of dose and application period, the other modalities were determined by considering possible scenarios of use and application of fertilizers resulting from climatic and/or rainfall forecasts observed at the start of the campaign. Thus T₄ and T₅ type modalities could be practiced in the hypothesis (h1) where the forecasts are uncertain but where ultimately the season starts normally and seems to be good: in this case we do not add anything at the start, then we make adjustments. late contributions. For logistical reasons there was no modality tested corresponding to the opposite hypothesis (h2) where the season would become catastrophic after a good start, which would lead farmers not to apply compost after having made a contribution initial compost.

<figure><img src="image_5.png" /><figcaption>**Figure 4:** Experimental setup</figcaption></figure>

However, we can consider that this situation is generally framed by the T₁ and T₃ modalities. Fertilization treatments were assigned to main

plots. The two sorghum varieties were assigned to elementary plots. Bunds were built around the main plots to prevent compost runoff between plots.

<figure><img src="image_6.png" /><figcaption>**Figure 5:** Plan of an elementary plot</figcaption></figure>

Each elementary plot consisted of 2 lines of 7.75 m spaced 1 m apart; the inter-pocket space was 0.25 m. Five (5) to six (6) grains per pocket were sown and separated from two plants per pocket upon emergence, giving a density of 64,500 plants per hectare. The plants were transplanted onto the ridges, at a rate of 30±01 plants/ridge, or 60±02 plants per elementary plot. The spacings were 0.25

m between plants and 0.25 m between rows, with 1 plant per hole, i.e. a density of 36,000±0018 plants per hectare.

## 2.4.3. Sowing and furnishing plots

Two methods were used when using Biochar-compost. The first method consisted of spreading compost on the cultivated plots and the second
method consisted of wrapping the seeds to be sown in biochar-compost and sowing it after spreading compost on the plots to be cultivated. In both cases, biochar-compost was applied at different stages of development of each variety. The tests were conducted in rainy conditions on both sites. Before the installation of each test, a cross plowing of 30 cm depth was done. Cultivation operations (weeding, hilling and phytosanitary treatments) were carried out regularly and as necessary to maintain optimal cultivation conditions.

**2.5. Data collection of growth parameters**

Vegetative biomass (leaves + stems) was collected before late fertilization (at tillering, B₁) and after late fertilization (full flowering, B₂). On each elementary plot, 4 pockets were chosen randomly on the 2 central lines to be sampled. The dry biomass was evaluated after drying

**2.5.1. Weekly plant growth**

Growth was measured every 06 days during the dry season and the rainy season according to the Tom'Pousse method (Lambert et al., 2003): the plant per experimental unit was chosen according to the representativeness of the eight plants in the culture tank and all measures were taken on this plan (Jamal, et al., 2023). The parameters measured are weekly stem growth, length of a fully stretched mature leaf, flowering height, number of leaves and stem diameter. The weekly growth of the stem is obtained by measuring the distance between the apex and the mark left the previous week corresponding to the growth point and is taken using a measuring tape (Lambert et al., 2003; Jamal, et al., 2023). The diameter of the stem was taken at the growth point of the previous week using a vernier and represented the vigor of the plant. The mature leaf generally corresponded to the fifth leaf from the apex or the leaf immediately below the last cluster having at least one set fruit. Its length was taken using a tape measure from the tip of the leaf to the petiole. Flowering height was the distance measured between the last flowering cluster and the apex. All these measurements were useful in monitoring the progress of the plants and analyzing the growing conditions (Lambert et al., 2003).

**2.5.1. Fruit yield**

Fruit yield was assessed weekly (or according to crop stage) during fruit harvest. During the most productive summer months, two harvests per week were required. Thus, at each harvest, a classification of the fruits was carried out in order to evaluate the

external quality of the fruits (Lambert et al., 2003; Jamal, et al., 2023). For each class, the number and total weight of fruits were measured for each experimental unit. The fruit classes were as follows: fruit in good condition, fruit with apical rot, fruit with presence of macrocracks or microcracks, misshapen fruit, small fruit, green fruit and other (uneven color, calcium oxalate spots, fruit soft or stylar scar). A fruit in good condition was considered a salable fruit on the market unlike fruits with physiological abnormalities or diseases. One of the main physiological disorders encountered was apical rot which generally occurs during a calcium deficiency manifesting itself in the form of a spot initially white and becoming blackish at the apical end of the fruit. Like growth measurements, yield information is a good indicator of crop health (Lambert et al., 2003).

**2.5.1. Destructive growth**

Destructive growth measurements were also taken at the end of each change in growing conditions, i.e. twice in July 2024 and September 2024, on one plant per experimental unit. Parameters measured included total plant leaf area, number of leaves and fruits, fresh and dry mass of leaves, fruits and stem, and stem length. These measurements provided, in support of weekly growth and fruit yield measurements, an index of plant vigor and crop health. The leaf area was measured using a planimeter, the first step of which consisted of calibrating the device using calibration disks (Lambert et al., 2003). All the leaves of the plant were cut and carefully passed through a planimeter. The next step was to count the bunches and fruits. When the stem was completely devoid of its leaves and fruit, its length was measured using a measuring tape. All the fresh biomass was then divided (leaves, fruits, stem) into brown paper bags and then weighed. Subsequently, this fresh biomass contained in the bags was dried at 65°C for approximately 15 days and the dry mass was then weighed. On the other hand, each time the plants were stripped of leaves for maintenance purposes, the biomass of cut leaves was weighed fresh and dry as well as the biomass of fruits harvested at each harvest. This biomass in leaves and fruits was compiled and cumulated with the biomass of destructive growth measurements in order to obtain their total biomass converted into units per plant for the two reference periods, i.e. for cultivation weeks 1 to 11 (May to July 2024) and for cultivation weeks 12 to 24 (August to October 2024) (Lambert et al., 2003; Jamal, et al., 2023).
## 2.6. Data analysis

Means were compared using the least significant difference (LSD) test and presented values followed by letters in a column as not significantly different (P ≤ 0.05). Statistical differences between treatments were determined by analysis of variance (ANOVA) for completely randomized block designs (CRBD) and by Tukey's honestly significant difference test (P < 0.05) using of Excel and SPSS20.0.

# 3. Results and Discussion

## 3.1. Biomass sampling

The samples are taken by manual harvesting on five sites with homogeneous multi-specific vegetation located within the territory of the waters of Lake Chad: in the town of Makary (12°33'45.98 north latitude and 14°26'51.3 east longitude, 1845 km²); in the town of Logone Birni (11°46'41.3 north latitude and 15°6'13.61 east longitude.), in the town of Fotokol (12°22'39.74 north latitude and 14°13'30.22 east longitude. 3285 Km²), in the town of Darack (10°37'53.61" north latitude and 14°39'31.62" east longitude, 658.60 km²), in the town of Hilé Alifa (12° 42' 0" North latitude, 14° 19' 0" east longitude) and in the town of Blangoua (12°44'57" North Latitude and 14°34'49" East Longitude, 2116 Km²) (INS, 2005). The watercourses from Lake Chad cross these towns and villages which cover an area of approximately 110 km² out of a little more than 37,500 km² of the Cameroonian part of Lake Chad and the depth does not exceed 4 meters (LCBC, 2010). Annual

variations in humidity and temperature lead to the subdivision of the climate into: Cool and dry season (mid-October to February), a hot and dry season from March to June; a hot and humid season called the “rainy season” which lasts from mid-June to mid-September with maximum values in August.

The weakly ferralitic red soils of Lake Chad in the Logone and Chari area are characterized by thorny vegetation dominated by: *Eichhornia crassipes*, *Acacia seyal*, *Lannea humilis*, *Balanites aegyptiaca*, *Acacia senegal* and *Acacia sieberiana*. The grassy carpet is poorly developed. In the rainy season, these low permeability soils retain precipitation and the water stagnates in small pools.

The collection of raw materials is an operation which consists of mowing Eichhornia crassipes plants, waste from other invasive plants or any other from the place of their proliferation to a place of final elimination. It begins with the identification of raw materials in proliferation sites.

### 3.1.1. Living biomass and CO₂ stock

In the study sites, the average diameter of the trunks and stems of the species studied varies. The average diameter of the main trunks of *Prosopis juliflora* is 23.404±5.253 cm. The basal area covered by *Prosopis juliflora* is 3.978±1.391 m²/Ha with a coverage of 955.8±1.391m²/Ha and a biomass volume of 7.956±0.512 m³.

<figure><img src="image_7.png" /><figcaption>**Photo 1:** a) Living biomass of *Prosopis juliflora*; b) Dry dead biomass of *Prosopis juliflora*</figcaption></figure>

The average diameter of the main stems of *Eichhornia crassipes* is 5.914±0.893 cm with a

covered basal area of 2.872±0.449 m²/Ha and a biomass volume of 1.436±0.603 m³ (Table 2).

<table><caption>**Table 2:** Determination of aboveground biomass (BA)</caption><thead><tr><th>Species</th><th>Average diameter of the main trunks (and stems) of the species (cm)</th><th>Basal area covered by species (m²/Ha)</th><th>Density (Ind. No./Km²)</th><th>Volume of species biomass (m³)</th></tr></thead><tbody><tr><td><em>Prosopis juliflora</em></td><td>23.404±5.253<sup>a,g</sup></td><td>3.978±1.391<sup>d</sup></td><td>16.507±1.768<sup>a</sup></td><td>7.956±0.512<sup>e,f</sup></td></tr><tr><td><em>Eichhornia crassipes</em></td><td>5.914±0.893<sup>e</sup></td><td>2.872±0.449<sup>c</sup></td><td>151.573±21.171<sup>b</sup></td><td>1.436±0.603<sup>d</sup></td></tr></tbody></table>
The total average biomass of *Prosopis juliflora* and *Eichhornia crassipes* studied is variable. However, the total average biomass of *Prosopis juliflora* is

16.80±1.54 T/Ha, lower than the total average biomass of *Eichhornia crassipes* which is 197.77±0.79 T/Ha.

<figure><img src="image_8.png" /><figcaption>**Photo 2:** a) Live biomass of *Eichhornia crassipes*; b) Dry dead biomass of *Eichhornia crassipes*</figcaption></figure>

The average carbon stock by *Prosopis juliflora* is 7.896±0.183 T/Ha with an average Carbon Equivalent of 15.06±0.35 T/Ha while the average

carbon stock by *Eichhornia crassipes* is 92.952±1.547 T/Ha with an average Carbon Equivalent of 22.36±0.13 T/Ha (Table 3).

<table><caption>**Table 3:** Total living biomass and Carbon stock of each species</caption><thead><tr><th>Species</th><th>Aboveground biomass of species (BA,T/Ha)</th><th>Belowground biomass of species (BS,T/Ha)</th><th>Total biomass of species (BT,T/Ha)</th><th>Carbon stock of species (SC, T/Ha)</th><th>Carbon equivalent (EqC, T/Ha)</th></tr></thead><tbody><tr><td><em>Prosopis juliflora</em></td><td>2.65±0.71<sup>a</sup></td><td>14.15±0.83<sup>a</sup></td><td>16.80±1.54<sup>a</sup></td><td>7.896±0.183<sup>f</sup></td><td>15.06±0.35<sup>d</sup></td></tr><tr><td><em>Eichhornia crassipes</em></td><td>67.15±0.03<sup>c</sup></td><td>130.62±0.76<sup>b</sup></td><td>197.77±0.79<sup>a</sup></td><td>92.952±1.547<sup>a</sup></td><td>22.36±0.13<sup>e</sup></td></tr></tbody></table>

### 4.1.2. Preparation of dry dead biomass and bioenergy stock

The average weight of the trunk of the dry dead biomass of *Prosopis juliflora* is 17.02±3.00 kg/m² while its average weight is 58.27±4.56 kg/m². The

average PCI of the dry dead biomass of *Prosopis juliflora* is 17.92±0.02MJ/kg with its average dry stock is 75.29±6.18 kg/m² and the average stock of its bioenergy is 1.35±0.101 GJ/m². These values are distributed in the table below:

<table><caption>**Table 4:** Dry dead biomass and bioenergy stock</caption><thead><tr><th>Species</th><th>Trunk weight (kg/m²)</th><th>Plant weight (kg/m²)</th><th>PCI (MJ/kg)</th><th>Biomass stock (kg/m²)</th><th>Bioenergy stock (GJ /m²)</th></tr></thead><tbody><tr><td><em>Eichhornia crassipes</em></td><td>14.13±2.76<sup>a</sup></td><td>54.472±4.872<sup>b</sup></td><td>18.52±0.02<sup>a</sup></td><td>68.602±5.456<sup>c</sup></td><td>1.27±0.10<sup>a</sup></td></tr><tr><td><em>Prosopis juliflora</em></td><td>17.022±2.738<sup>b</sup></td><td>58.268±3.745<sup>a</sup></td><td>17.928±0.54<sup>b</sup></td><td>75.29±5.32<sup>a</sup></td><td>1.35±0.09<sup>c</sup></td></tr></tbody></table>

The average weight of the stems of the dry dead biomass of *Eichhornia crassipes* is 14.13±3.50 kg/m² while its average weight is 54.47±4.06 kg/m². The average PCI of the dry dead biomass of *Eichhornia crassipes* is 18.52±0.02MJ/kg with its average dry stock is 72.22±6.19 kg/m² and the average stock of its bioenergy is 1.31±0.103 GJ/m².

### 4.1.3. Preparation of Biochar and germination test

#### a- Community experimental system

Four composters (1 m wide, 2 m long and 0.3 m high) were dug. In each composter, a total of 5kg of raw material was introduced:

<table><caption>**Table 5:** Experimental content of each Compost_Biochar</caption><thead><tr><th>Raw material</th><th></th><th>Compost_Biochar 0 (100-0)%</th><th>Compost_Biochar 1 (64.28-35.71)%</th><th>Compost_Biochar 2 (47.36-52.63)%</th><th>Compost_Biochar 3 (50-50)%</th></tr></thead><tbody><tr><td rowspan="5">Compost based on</td><td>Fresh <em>Eichhornia crassipes</em> (kg)</td><td>2.5</td><td>5</td><td>5</td><td>10</td></tr><tr><td>Dry <em>Pennisetum villosum</em> (kg)</td><td>1</td><td>2</td><td>2</td><td>3</td></tr><tr><td>Fresh <em>Urtica dioica</em> (kg)</td><td>0.5</td><td>0.5</td><td>0.5</td><td>0.5</td></tr><tr><td>Beef dung (kg)</td><td>0.5</td><td>0.5</td><td>0.5</td><td>0.5</td></tr><tr><td>Urine (L)</td><td>1</td><td>1</td><td>1</td><td>1</td></tr><tr><td>Biochar based on dry <em>Prosopis juliflora</em></td><td></td><td>0</td><td>5</td><td>10</td><td>15</td></tr></tbody></table>

Each composter was treated with *Urtica dioica*, then covered with various other layers of raw

material so as to alternate fresh material with dry material. The composter was placed in the shade
in a secure location away from rodents and other animals and to prevent moisture loss.

The humidity content of the compost was maintained and adjusted to around 80% daily. Using a thermometer, temperature readings were taken daily to monitor the progress of the

maturation of the compost. After maturation, a sample of the compost was taken from each composter, then air-dried at room temperature in the shade and stored in a plastic bag for later analysis.

<figure><img src="image_9.png" /><figcaption>**Photo 3:** a) Collection of *Eichhornia crassipes* biomass; b) Sorting of dry dead biomass of *Eichhornia crassipes* c) Compost based on *Eichhornia crassipes* d) Biochar based on dry *Prosopis juliflora*, e) Compost_Biochar based on *Prosopis juliflora* _Eichhornia crassipes* left to dry.</figcaption></figure>

The tests were carried out on the plots developed in bocage and stone bunds of the NGO SAHEL NATURE CONSULTING FOR

COMMUNITIES. The surface texture of these soils was clay-sandy type (clay = 38.3%; silt = 24.4% and sand = 37.3%).

<table><caption>**Table 6:** Physico-chemical characteristics of the soil before setting up the test.</caption><thead><tr><th>Characteristics</th><th>Soil</th><th>Biochar</th><th>Compost_Biochar 0 (100-0)%</th><th>Compost_Biochar 1 (64.28-35.71)%</th><th>Compost_Biochar 2 (47.36-52.63)%</th><th>Compost_Biochar 3 (50-50)%</th></tr></thead><tbody><tr><td>Total clay (%)</td><td>38.3</td><td>-</td><td>-</td><td>-</td><td>-</td><td>-</td></tr><tr><td>Total silt (%)</td><td>24.4</td><td>-</td><td>-</td><td>-</td><td>-</td><td>-</td></tr><tr><td>Total sand (%)</td><td>37.3</td><td>-</td><td>-</td><td>-</td><td>-</td><td>-</td></tr><tr><td>Organic carbon (g/kg)</td><td>6</td><td>74.5</td><td>38</td><td>89.8</td><td>93.2</td><td>91.1</td></tr><tr><td>Total nitrogen (g/kg)</td><td>0.7</td><td>1.5</td><td>1.8</td><td>3.5</td><td>3.9</td><td>3.4</td></tr><tr><td>C/N</td><td>9</td><td>-</td><td>21.1</td><td>25.6</td><td>23.9</td><td>26.8</td></tr><tr><td>Assimilable phosphorus (mg/kg)</td><td>12</td><td>32</td><td>34</td><td>36</td><td>41</td><td>35</td></tr><tr><td>Available potassium (mg/kg)</td><td>177</td><td>141</td><td>138</td><td>144</td><td>148</td><td>146</td></tr><tr><td>Ca (mg/kg)</td><td>714</td><td>140</td><td>174</td><td>185</td><td>115</td><td>117</td></tr><tr><td>Mg (mg/kg)</td><td>171</td><td>20</td><td>87.6</td><td>80.2</td><td>43.1</td><td>41.3</td></tr><tr><td>pH-water</td><td>6.7</td><td>9.8</td><td>8.8</td><td>9.9</td><td>8.7</td><td>7.8</td></tr><tr><td>pH_KCl</td><td>5.1</td><td>-</td><td>5.7</td><td>-</td><td>-</td><td>-</td></tr><tr><td>CEC (mEq/100 g of soil)</td><td>3.9</td><td>-</td><td>5.2</td><td>-</td><td>-</td><td>-</td></tr><tr><td>WHC</td><td>-</td><td>336.7</td><td>375.4</td><td>365.4</td><td>367.1</td><td>353.6</td></tr><tr><td>Apparent density</td><td>-</td><td>70</td><td>74</td><td>73</td><td>71</td><td>70.7</td></tr><tr><td>Specific surface area (m²/g)</td><td>-</td><td>1.7</td><td>1.9</td><td>2.1</td><td>2.6</td><td>2.4</td></tr></tbody></table>

It is a soil with moderate acidity (pH-water = 6.7 and pH-KCl = 5.1) and poorly provided with essential nutrients from plants and insects, with an average cation exchange capacity equal to 3,9 mEq/100 g (table 6). The total nitrogen content is <1 g/kg of soil; the contents of Ca²⁺ and Mg²⁺ cations on the exchange complex are respectively 714 and 171 mg/kg of soil. The initial organic carbon content was 6 g/kg of soil

#### 4.1.4. Effect of Compost_Biochar based on *Prosopis juliflora* _Eichhornia crassipes* after 8 days of seed germination on the test culture.

A significant difference was noted in the percentage of crop germination between the treatments at 15 ton/ha (Table 8). The germination of *Zea mays* and *Solanum lycopersicum* L. was significantly stimulated by different doses of Compost_Biochar based on *Prosopis juliflora* _Eichhornia crassipes* (P=0:01) and (P=0:02), respectively.

<table><caption>**Table 7:** Percentage of germination after 8 days during treatment with Compost_Biochar based on *Prosopis juliflora* _Eichhornia crassipes* (CB)</caption><thead><tr><th colspan="7">Sandy clay soil T<sub>01</sub> (95%-05%) without Compost and without Biochar based on <i>Prosopis juliflora</i> _Eichhornia crassipes</th></tr><tr><th>Control treatments T<sub>01</sub> (sand/clay) %</th><th>95/05</th><th>90/10</th><th>85/15</th><th>80/20</th><th>75/25</th><th>70/30</th><th>65/35</th></tr></thead></table>
<table><tbody><tr><td>TGP (%) of Zea mays</td><td>36.3±0.47<sup>a</sup></td><td>39.4±0.43<sup>b</sup></td><td>43.4±0.39<sup>a</sup></td><td>44.3±0.94<sup>c</sup></td><td>46.5±0.79<sup>a</sup></td><td>47.8±0.65<sup>a</sup></td><td>49.3±0.79<sup>d</sup></td></tr><tr><td>TGP (%) of Solanum lycopersicum L</td><td>33.6±0.75<sup>c</sup></td><td>34.5±0.69<sup>b</sup></td><td>34.9±0.15<sup>a</sup></td><td>35.3±0.66<sup>b</sup></td><td>36.7±0.85<sup>a</sup></td><td>37.5±0.69<sup>c</sup></td><td>39.7±0.55<sup>b</sup></td></tr><tr><td colspan="8">100% biochar based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T01 (95%-05%)</td></tr><tr><td>Control treatments T02 (Biochar/Soil) %</td><td>05/95</td><td>10/90</td><td>15/85</td><td>20/80</td><td>25/75</td><td>30/70</td><td>35/65</td></tr><tr><td>TG (%) of Zea mays</td><td>43.6±0.47<sup>a</sup></td><td>45.9±0.48<sup>c</sup></td><td>47.6±0.94<sup>a</sup></td><td>49.2±0.45<sup>c</sup></td><td>49.8±0.87<sup>a</sup></td><td>52.3±0.49<sup>a</sup></td><td>53.9±0.64<sup>c</sup></td></tr><tr><td>TG (%) of Solanum lycopersicum L</td><td>45.3±0.66<sup>c</sup></td><td>46.5±0.79<sup>b</sup></td><td>51.1±0.81<sup>d</sup></td><td>55.6±0.76<sup>b</sup></td><td>56.2±0.76<sup>a</sup></td><td>57.5±0.97<sup>c</sup></td><td>59.7±0.54<sup>c</sup></td></tr><tr><td colspan="8">100% compost based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T01 (95%-05%)</td></tr><tr><td>Control treatments T03 (Compost/Soil) %</td><td>05/95</td><td>10/90</td><td>15/85</td><td>20/80</td><td>25/75</td><td>30/70</td><td>35/65</td></tr><tr><td>TGP (%) of Zea mays</td><td>63.4±0.64<sup>a</sup></td><td>64.9±0.36<sup>c</sup></td><td>67.3±0.59<sup>a</sup></td><td>69.3±0.86<sup>c</sup></td><td>71.3±0.33<sup>a</sup></td><td>72.8±0.57<sup>a</sup></td><td>74.2±0.44<sup>c</sup></td></tr><tr><td>TGP (%) of Solanum lycopersicum L</td><td>64.2±0.78<sup>c</sup></td><td>66.3±0.88<sup>b</sup></td><td>69.5±0.55<sup>d</sup></td><td>70.5±0.81<sup>b</sup></td><td>71.2±0.68<sup>a</sup></td><td>73.1±0.58<sup>c</sup></td><td>75.9±0.20<sup>c</sup></td></tr></tbody></table>

The highest germination percentage (97.9±0.96%) was recorded with 35 t/ha of Compost_Biochar 2 (47.36-52.63)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T02 (95%-05%) for Zea mays and Solanum lycopersicum L. cultures, respectively. While the lowest germination

percentage (33.6±0.75%) for *Solanum lycopersicum L.* was on sandy clay soil T01 (95% sand/05% clay) without Compost and without Biochar based on *Prosopis juliflora_Eichhornia crassipes*, and which was one of the control groups.

<table><caption>**Table 8:** Percentage of germination after 8 days during treatment with Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* (CB)</caption><caption>Compost_Biochar 1 (64.28-35.71)% based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T01 (95%-05%)</caption><thead><tr><th>T<sub>1</sub> treatments (ton/ha)</th><th>5</th><th>10</th><th>15</th><th>20</th><th>25</th><th>30</th><th>35</th></tr></thead><tbody><tr><th scope="row">TGP (%) of Zea mays</th><td>86.3±0.55<sup>a</sup></td><td>88.6±0.74<sup>c</sup></td><td>91.1±0.13<sup>a</sup></td><td>93.5±0.43<sup>c</sup></td><td>93.7±0.87<sup>a</sup></td><td>94.1±0.88<sup>a</sup></td><td>94.9±0.22<sup>c</sup></td></tr><tr><th scope="row">TGP (%) of Solanum lycopersicum L</th><td>94.1±0.18<sup>c</sup></td><td>94.6±0.83<sup>b</sup></td><td>94.8±0.55<sup>d</sup></td><td>95.5±0.61<sup>b</sup></td><td>96.2±0.78<sup>a</sup></td><td>96.7±0.62<sup>c</sup></td><td>97.9±0.96<sup>c</sup></td></tr></tbody></table><table><caption>Compost_Biochar 2 (47.36-52.63)% based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T02 (95%-05%)</caption><thead><tr><th>T<sub>2</sub> treatments (ton/ha)</th><th>5</th><th>10</th><th>15</th><th>20</th><th>25</th><th>30</th><th>35</th></tr></thead><tbody><tr><th scope="row">TGP (%) of Zea mays</th><td>81.5±0.43<sup>b</sup></td><td>81.9±0.33<sup>c</sup></td><td>83.2±0.31<sup>a</sup></td><td>83.8±0.02<sup>d</sup></td><td>85.2±0.52<sup>a</sup></td><td>86.9±0.31<sup>a</sup></td><td>87.3±0.37<sup>c</sup></td></tr><tr><th scope="row">TGP (%) of Solanum lycopersicum L</th><td>72.3±0.18<sup>c</sup></td><td>72.6±0.44<sup>b</sup></td><td>72.8±0.69<sup>d</sup></td><td>74.5±0.39<sup>b,c</sup></td><td>76.4±0.47<sup>a</sup></td><td>76.4±0.89<sup>c</sup></td><td>79.1±0.21<sup>c</sup></td></tr></tbody></table><table><caption>Compost_Biochar 3 (50-50)% based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T03 (95%-05%)</caption><thead><tr><th>T<sub>3</sub> treatments (ton/ha)</th><th>5</th><th>10</th><th>15</th><th>20</th><th>25</th><th>30</th><th>35</th></tr></thead><tbody><tr><th scope="row">TG (%) of Zea mays</th><td>83.5±0.44<sup>b</sup></td><td>84.1±0.12<sup>c</sup></td><td>86.1±0.22<sup>a</sup></td><td>86.2±0.83<sup>d</sup></td><td>89.1±0.18<sup>a</sup></td><td>90.5±0.64<sup>a</sup></td><td>91.1±0.61<sup>c</sup></td></tr><tr><th scope="row">TG (%) of Solanum lycopersicum L</th><td>83.2±0.42<sup>c</sup></td><td>84.7±0.44<sup>b</sup></td><td>84.8±0.67<sup>d</sup></td><td>85.1±0.54<sup>b,c</sup></td><td>86.3±0.11<sup>a</sup></td><td>86.5±0.13<sup>c</sup></td><td>88.5±0.87<sup>c</sup></td></tr></tbody></table>

Obviously, the capacity of Compost_Biochar 1 (64.28-35.71)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T01 (95%-05%) to retain humidity in the success of germination would have played a role preponderant as described by Kammann et al. (2011). This result would have been amplified by the combined effects of Compost_Biochar 1 (64.28_35.71)% based on *Prosopis juliflora_Eichhornia crassipes* which would have amplified the germination capacity of the sandy clay soil T01 (95%-05%) and which perhaps

corroborates the findings of Rillig et al., 2010, Ali et al., 2023, and Free et al., 2010, who reported that increasing biochar content proportionally increased germination. In other words, seeds sown in T01 sandy_clayey soils (95%-05%) amended with Compost_Biochar 1,2 and 3 germinate more quickly than in T01 sandy_clayey soils (95%-05%) without Compost and without Biochar based on *Prosopis juliflora_Eichhornia crassipes* and better than Biochar/Soil and Compost/soils.

<table><caption>**Table 9:** Physical parameters of seed germination after 8 days of treatment with Compost_Biochar (CB) based on *Prosopis juliflora_Eichhornia crassipes*</caption><thead><tr><th>Type of soil</th><th>pH</th><th>Humidity (%)</th><th>Soil permeability/soil (mm.h<sup>-1</sup>)</th><th>Soil reflectance (mg/m<sup>-3</sup>)</th><th>Maximum ground temperature (°C)</th><th>Soil conductivity (µS/cm)</th></tr></thead><tbody><tr><td>Sandy_clayey soil (95%-05%)</td><td>7.9±0.1<sup>a</sup></td><td>31±0.6<sup>b</sup></td><td>19.7±5.3<sup>a, b</sup></td><td>567.7±35.3<sup>a, b</sup></td><td>15.3±0.4<sup>c</sup></td><td>237.92±42.01<sup>a</sup></td></tr><tr><td>Compost/ Soil</td><td>8.2±0.6<sup>b, c</sup></td><td>39±0.8<sup>c</sup></td><td>17.3±2.8<sup>a, c</sup></td><td>571.3±28.2<sup>a, c</sup></td><td>13.5±0.1<sup>b</sup></td><td>254.82±53.06<sup>a, c</sup></td></tr><tr><td>Biochar/ Soil</td><td>9.8±0.3<sup>b</sup></td><td>94±0.3<sup>b, c</sup></td><td>12.4±1.3<sup>a, c</sup></td><td>582.4±31.5<sup>a, c</sup></td><td>14.7±0.8<sup>c</sup></td><td>279.38±22.53<sup>b</sup></td></tr><tr><td>Compost_Biochar 1(64.28_35.71)%</td><td>9.2±0.1<sup>a, c</sup></td><td>98±0.1<sup>c, d</sup></td><td>17.8±5.1<sup>b, d</sup></td><td>587.8±45.1<sup>b, d</sup></td><td>15.3±0.6<sup>c</sup></td><td>279.82±50.91<sup>a, c</sup></td></tr><tr><td>Compost_Biochar 2 (47.36-52.63)%</td><td>8.7±0.4<sup>d</sup></td><td>95±0.2<sup>a, d</sup></td><td>15.5±1.2<sup>c, d</sup></td><td>591.5±21.8<sup>c, d</sup></td><td>16.8±0.8<sup>c</sup></td><td>288.07±20.74<sup>d</sup></td></tr><tr><td>Compost_Biochar 3 (50-50)%</td><td>7.8±0.5<sup>c</sup></td><td>96±0.7<sup>a</sup></td><td>15.3±2.7<sup>a, b</sup></td><td>589.7±42.6<sup>a, b</sup></td><td>15.7±0.4<sup>c</sup></td><td>287.98±40.65<sup>c</sup></td></tr></tbody></table>

The change in reflectance of the Compost_Biochar substrate surface results in a substantial increase in

soil temperature (Licht and Al-Kaisi, 2005; Ali et al., 2023).
<figure><img src="image_10.png" /><figcaption>**Graph 1:** Reflectance of the surface of the Compost_Biochar substrate</figcaption></figure>

An increase in soil temperature, due to the application of biochars, would have had positive impacts on seed germination, crop establishment and early growth (Genesio et al., 2012; Ali et al., 2023).

Ecologically, Compost_Biochar 2 (47.36-52.63)% has the highest number of Lumbricina (16.43±01.92) with the number of other animal species averaging 09.15±00.22 while the lowest number Lumbricina (01.97±00.53) was observed on sandy-clayey soil (95%-05%).

<table><caption>**Table 10:** Ecological parameters of seed germination after 8 days of treatment with Compost_Biochar (CB) based on *Prosopis juliflora_Eichhornia crassipes*</caption><thead><tr><th>Soil type</th><th>Number of Lumbricina</th><th>Number of other plant species</th><th>Number of other animal species</th><th>Frequency of each species</th><th>Diversity index</th><th>Biomass abundance index</th></tr></thead><tbody><tr><td>Sandy_clayey soil (95%-05%)</td><td>01.97±00.53<sup>a, b</sup></td><td>03.77±00.53<sup>a, b</sup></td><td>01.92±00.04<sup>a</sup></td><td>01.93±00.66<sup>b</sup></td><td>03.44±00.79<sup>a, b</sup></td><td>02.37±00.73<sup>a, b</sup></td></tr><tr><td>Compost/ Soil</td><td>07.33±01.28<sup>a, c</sup></td><td>03.23±00.82<sup>a, c</sup></td><td>02.58±00.56<sup>a, c</sup></td><td>02.39±00.38<sup>c</sup></td><td>05.99±00.54<sup>a, c</sup></td><td>02.53±00.32<sup>a, c</sup></td></tr><tr><td>Biochar/ Soil</td><td>08.22±01.13<sup>a, c</sup></td><td>05.82±00.31<sup>a, c</sup></td><td>03.29±00.23<sup>b</sup></td><td>04.94±00.53<sup>b, c</sup></td><td>06.59±00.53<sup>a, c</sup></td><td>04.55±00.43<sup>a, c</sup></td></tr><tr><td>Compost_Biochar 1(64.28_35.71)%</td><td>14.78±00.51<sup>b, d</sup></td><td>08.87±00.45<sup>b, d</sup></td><td>03.82±00.91<sup>a, c</sup></td><td>05.98±00.41<sup>c, d</sup></td><td>09.89±00.88<sup>b, d</sup></td><td>06.07±00.85<sup>b, d</sup></td></tr><tr><td>Compost_Biochar 2 (47.36-52.63)%</td><td>16.43±01.92<sup>c, d</sup></td><td>09.15±00.22<sup>c, d</sup></td><td>03.87±00.74<sup>d</sup></td><td>06.95±00.52<sup>a, d</sup></td><td>11.15±00.78<sup>c, d</sup></td><td>06.95±00.32<sup>c, d</sup></td></tr><tr><td>Compost_Biochar 3 (50-50)%</td><td>15.73±02.27<sup>a, b</sup></td><td>08.97±00.43<sup>a, b</sup></td><td>03.78±00.64<sup>c</sup></td><td>05.56±00.27<sup>a</sup></td><td>09.97±00.11<sup>a, b</sup></td><td>05.55±00.65<sup>a, b</sup></td></tr></tbody></table>

The highest number of other plant species is 03.87±00.74 with a frequency of each species highest of 06.95±00.52%. The highest diversity index is 11.15±00.78 and a biomass abundance index of 06.95±00.32 in Compost_Biochar 2 (47.36-52.63)%.

Biochar improves soil fertility by increasing soil pH, organic carbon, phosphorus and potassium which stimulate seed germination (Asai et al., 2009; Ali et al., 2023). Furthermore, Steiner et al. (2008), Wardle et al. (2008) and Ali et al., 2023 observed that the application of biochar alters the mineralization of organic matter, which is linked to the release of nutrients such as nitrogen, the reduction of which by 60% by leaching, requires l addition of 20% fertilizer to minimize loss of seeds before germination and a possibility of 10% seed savings achievable through the application of biochar (Lehmann et al., 2003.). As biochar increases, seed and nutrient saving efficiency or absorption/leaching ratio will be higher (Steiner et al., 2008 and Ali et al., 2023). In short, in our case,

the germination of seeds could be explained by the fertilization of seedlings and the beginnings of crops tested with Compost_Biochar.

### 4.1.5. Effect of Compost_Biochar based on Prosopis juliflora_Eichhornia crassipes on the biomass of the shoots of the crops tested after 04 weeks of plant growth on the test crop.

Cultivated under the same conditions, the fresh and dry weights of the young shoots of *Zea mays* and *Solanum lycopersicum* L which were recorded, showed significant differences between the treatments of the control group and the test group with Compost_Biochar (CB) at basis of *Prosopis juliflora_Eichhornia crassipes* on the test culture (Table 2). The results also showed that the application of a single dose of Compost_Biochar (15 t/ha) based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil (95%-05%), increased the weight of young shoots of *Zea mays* by 35.04±2.89%, and *Solanum lycopersicum* L 19.24±1.81% compared to the weight of the control groups.

<table><caption>**Table 11:** Weight gain of plants after 04 weeks of growth and treatment with Compost_Biochar (CB) based on *Prosopis juliflora_Eichhornia crassipes* on the test culture.</caption><thead><tr><th colspan="3">Sandy clay soil T<sub>01</sub> (95%-05%) without Compost and without Biochar based on <i>Prosopis juliflora_Eichhornia crassipes</i></th></tr><tr><th>Control treatments T<sub>01</sub> (sand/clay) %</th><th>Fresh weight (g)</th><th>Dry weight (g)</th></tr></thead><tbody><tr><td><i>Zea mays</i></td><td>68.71±02.66</td><td>13.22±07.45</td></tr><tr><td><i>Solanum lycopersicum</i> L</td><td>18.04±06.72</td><td>03.48±00.76</td></tr><tr><td colspan="3">100% biochar based on <i>Prosopis juliflora_Eichhornia crassipes</i> on sandy clay soil T<sub>01</sub> (95%-05%)</td></tr><tr><th>Control treatments T<sub>02</sub> (Biochar/Soil) %</th><th>Fresh weight (g)</th><th>Dry weight (g)</th></tr><tr><td><i>Zea mays</i></td><td>184.75±06.26</td><td>64.73±03.75</td></tr><tr><td><i>Solanum lycopersicum</i> L</td><td>78.01±06.72</td><td>15.09±01.12</td></tr><tr><td colspan="3">100% compost based on <i>Prosopis juliflora_Eichhornia crassipes</i> on sandy clay soil T<sub>01</sub> (95%-05%)</td></tr></tbody></table>
<table><thead><tr><th>Control treatments T<sub>03</sub> (Compost/Soil) %</th><th>Fresh weight (g)</th><th>Dry weight (g)</th></tr></thead><tbody><tr><td><em>Zea mays</em></td><td>192.87±02.66</td><td>67.58±01.23</td></tr><tr><td><em>Solanum lycopersicum L</em> (after 20 days)</td><td>80.41±02.39</td><td>15.47±01.38</td></tr><tr><td><em>Solanum lycopersicum L</em> (after 28 days)</td><td>197.9±10.96<sup>c</sup></td><td>37.23±05.18<sup>c</sup></td></tr></tbody></table>

Although an insignificant increase was observed with single dose treatments of Compost (100%) based on *Prosopis juliflora_Eichhornia crassipes*, and half, there was a slight decrease (3.47±0.77%) with Biochar (100%) in double dose.

During the cultivation of *Zea mays* and *Solanum lycopersicum L*, Compost_Biochar 2 (47.36-52.63)% based on *Prosopis juliflora_Eichhornia crassipes*, in

single and double doses, contributed to increasing the weight of the shoots by approximately 64.58±02.22% and 56.41±05.30%, respectively of *Zea mays* and *Solanum lycopersicum L*. Although an insignificant increase was observed with single and half dose treatments, there was had a slight decrease (3%) between all treatments with Compost_Biochar 1 and 3 at double dose.

<table><caption>**Table 12:** Weight gain of plants after 04 weeks of growth and treatment with Compost_Biochar (CB) based on *Prosopis juliflora_Eichhornia crassipes* on the test culture.</caption><thead><tr><th colspan="4">Compost_Biochar 1 (64.28-35.71)% based on <em>Prosopis juliflora_Eichhornia crassipes</em> on sandy clay soil T<sub>01</sub> (95%-05%)</th></tr><tr><th>T<sub>1</sub> treatments (15 ton/ha)</th><th>Density (plants/m<sup>2</sup>)</th><th>Fresh weight (g)</th><th>Dry weight (g)</th></tr></thead><tbody><tr><td><em>Zea mays</em></td><td>7.11±20.21<sup>a</sup></td><td>196.11±20.21<sup>a</sup></td><td>67.75±05.09<sup>c</sup></td></tr><tr><td><em>Solanum lycopersicum L</em></td><td>3.18±10.76<sup>d</sup></td><td>84.18±10.76<sup>d</sup></td><td>36.54±05.62<sup>d</sup></td></tr></tbody><thead><tr><th colspan="4">Compost_Biochar 2 (47.36-52.63)% based on <em>Prosopis juliflora_Eichhornia crassipes</em> on sandy clay soil T<sub>02</sub> (95%-05%)</th></tr><tr><th>T<sub>2</sub> treatments (15 ton/ha)</th><th>Density (plants/m<sup>2</sup>)</th><th>Fresh weight (g)</th><th>Dry weight (g)</th></tr></thead><tbody><tr><td><em>Zea mays</em></td><td>7.11±20.21<sup>a</sup></td><td>197.14±10.61<sup>e</sup></td><td>69.81±10.18<sup>b</sup></td></tr><tr><td><em>Solanum lycopersicum L</em></td><td>3.18±10.76<sup>d</sup></td><td>89.15±08.87<sup>e</sup></td><td>38.86±10.11<sup>a</sup></td></tr></tbody><thead><tr><th colspan="4">Compost_Biochar 3 (50-50)% based on <em>Prosopis juliflora_Eichhornia crassipes</em> on sandy clay soil T<sub>03</sub> (95%-05%)</th></tr><tr><th>T<sub>3</sub> treatments (15 ton/ha)</th><th>Density (plants/m<sup>2</sup>)</th><th>Fresh weight (g)</th><th>Dry weight (g)</th></tr></thead><tbody><tr><td><em>Zea mays</em></td><td>7.11±20.21<sup>a</sup></td><td>194.9±10.22<sup>a</sup></td><td>68.51±07.43<sup>b</sup></td></tr><tr><td><em>Solanum lycopersicum L</em></td><td>3.18±10.76<sup>d</sup></td><td>79.91±10.96<sup>c</sup></td><td>37.23±05.18<sup>c</sup></td></tr></tbody></table>

Compost_Biochar 2 (47.36-52.63)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T02 (95%-05%) contributed effectively to the growth of young shoots.

Biochar can also improve the water retention capacity of the soil (Laird et al., 2010.), thereby facilitating seedling biomass gain (Kammann et al., 2011.). Plant growth responses can be altered by biochar-induced changes in soil nutritional conditions, particularly P and K cycling (Taghizadeh-Toosi et al., 2012.). Plant resistance was greater with biochar additions to the soil (31.32±02.01%-32.31±00.21%) (Elad et al., 2010; Elmer and Pignatello, 2011; Ali et al., 2023). Similar studies confirmed that better seed germination (30% improvement), better shoot height (24%) and better biomass production (13%) among seven native woody plants on soils subjected to charcoal from kilns have been reported compared to unamended soils (Chidumayo, 1994.).

Similar to our results, it was reported that the use of biochar resulted in an approximately 20-30% increase in durum wheat biomass compared to the

use of mineral fertilizer alone (Alburquerque et al., 2013; Ali et al., 2023) and maize biomass yield increased by 44% on charcoal site soils compared to adjacent field soils (Oguntunde et al., 2004; Ali et al., 2023). Additionally, not all soils respond the same to biochar, and it may take time to observe significant changes in soil and crop attributes after biochar addition (Nair, 2015).

## 5. Effect of Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* after 08 weeks of plant growth on the test culture.

### 5.1. Effect of Compost_Biochar on root growth parameter.

The greatest root length of *Zea mays* (39.71±01.16 cm) was recorded at 15 t/ha of Compost_Biochar 2 (47.36-52.63) % based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T02 (95%-05%) followed by the lowest root length (07.65±00.59 cm) recorded during the control of the treatment at 15 t/ha of Compost_Biochar 1 (64.28-35.71) % based on *Prosopis juliflora_Eichhornia crassipes* on T01 sandy clay soil (95%-05%).
<table><caption>**Table 13:** Effect of treatment with Compost_Biochar (CB) based on *Prosopis juliflora_Eichhornia crassipes* on root growth parameters.</caption><thead><tr><th colspan="3">Compost_Biochar 1 (64.28-35.71) % based on <i>Prosopis juliflora_Eichhornia crassipes</i> on sandy clay soil T01 (95%-05%)</th></tr></thead><tbody><tr><th scope="row">T<sub>1</sub> treatments (15 ton/ha)</th><td>Highest root length (cm)</td><td>Lowest root length (cm)</td></tr><tr><td><i>Zea mays</i></td><td>38.26±01.29<sup>a</sup></td><td>07.65±00.59<sup>c</sup></td></tr><tr><td><i>Solanum lycopersicum</i> L</td><td>18.84 ±07.16<sup>d</sup></td><td>01.36±00.54<sup>d</sup></td></tr></tbody><thead><tr><th colspan="3">Compost_Biochar 2 (47.36-52.63) % based on <i>Prosopis juliflora_Eichhornia crassipes</i> on sandy clay soil T02 (95%-05%)</th></tr></thead><tbody><tr><th scope="row">T<sub>2</sub> treatments (15 ton/ha)</th><td>Fresh weight (g)</td><td>Dry weight (g)</td></tr><tr><td><i>Zea mays</i></td><td>39.71±01.16<sup>c</sup></td><td>09.18±01.81<sup>b</sup></td></tr><tr><td><i>Solanum lycopersicum</i> L</td><td>19.85±07.87<sup>c</sup></td><td>01.83±11.86<sup>a</sup></td></tr></tbody><thead><tr><th colspan="3">Compost_Biochar 3 (50-50) % based on <i>Prosopis juliflora_Eichhornia crassipes</i> on sandy clay soil T03 (95%-05%)</th></tr></thead><tbody><tr><th scope="row">T<sub>3</sub> treatments (15 ton/ha)</th><td>Fresh weight (g)</td><td>Dry weight (g)</td></tr><tr><td><i>Zea mays</i></td><td>39.49±01.22<sup>a</sup></td><td>08.65 ±01.43<sup>b</sup></td></tr><tr><td><i>Solanum lycopersicum</i> L</td><td>17.99±01.96<sup>c</sup></td><td>01.37 ±00.38<sup>c</sup></td></tr></tbody></table>

Furthermore, the greatest root length of *Solanum lycopersicum* L (19.85±07.87 cm) was recorded at 15 t/ha of Compost_Biochar 2 (47.36-52.63)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T02 (95%-05%) followed by the lowest root length (17.99±01.96 cm) recorded during treatment control at 15 t/ha Compost_Biochar 1 (64.28-35.71)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T01 (95%-05%), and was (Table 3). These results showed that there is a significant difference between different treatments and plant root length (P ≤ 0:04) and contrasts with the results obtained by Ali et al. (2023) which indicates that the greatest maize root length was recorded in 5 t/ha BC + NPS (39.8 cm) followed by 10 t/ha BC (37.2 cm), and the root length the lowest was recorded during treatment monitoring. According to Ali et al. (2023), this can be attributed to the ability of biochar to improve soil properties, consistent with this study, not only a significant increase in root biomass (47%), but also in the number of root tips (64 %) increased in a layer of char from a forest fire with buried larch twigs, birch twigs and dwarf bamboo shoots. in a dystric Cambisol (Makoto et al., 2010; Ali et al. 2023). Others observed that the number of asparagus storage roots also increased with the addition of coconut biochar to tropical soil (Matsubara et al., 2002; Ali et al., 2023). This could be due to the enhanced symbiotic associations of mycorrhizal fungi (Makoto et al., 2010; Ali et al., 2023) and terrestrial plants. Demonstrations of positive response in plant growth and nutrient availability due to increased mycorrhizal colonization

following Biochar additions to soils have been reported (Makoto et al., 2010).

## 5.2. Effect of Compost_Biochar on the height growth of crops.

The results recorded between weeks 2 and 8 after sowing allowed us to deduce the average maximum height of *Zea mays* (143.26±20.19 cm), which was recorded with 15 t/ha of Compost_Biochar 1 (64.28-35.71)% based on *Prosopis juliflora_Eichhornia crassipes* on T02 sandy clay soil (95%-05%) followed by the average minimum height of *Zea mays* (103.65 ±06.43 cm), which was recorded during the treatment with 15 t/ha of Compost_Biochar 3 (50-50)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T01 (95%-05%). Between weeks 2 and 8 after sowing, the growth percentage was 34.62±05.73% in height and 13.64±02.88% in stem volume of *Zea mays*. Furthermore, the maximum height of *Solanum lycopersicum* L (83.95±07.87 cm) was recorded at 15 t/ha of Compost_Biochar 2 (47.36-52.63)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T02 (95%-05%) followed by the minimum height of *Solanum lycopersicum* L (21.06±04.05 cm) recorded during the treatment at 15 t/ha of Compost_Biochar 1 (64.28-35.71)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T01 (95%-05%), and was (Table 3). These results recorded between weeks 1 and 8 after sowing allowed us to deduce the growth percentage was 38.77±02.93% in height and 10.37±01.43% in volume of the stem of *Solanum lycopersicum* L.

<caption>**Table 14:** Effect of treatment with Compost_Biochar (CB) based on Prosopis juliflora_Eichhornia crassipes on plant growth parameters.</caption>

Compost_Biochar 1 (64.28-35.71)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T01 (95%-05%)
<table><thead><tr><th>T<sub>1</sub> treatments (15 ton/ha)</th><th>Maximum height (cm)</th><th>Minimum height (cm)</th><th>Maximum volume (cm<sup>3</sup>)</th><th>Minimum volume (cm<sup>3</sup>)</th></tr></thead><tbody><tr><td>Zea mays</td><td>143.26±20.19<sup>a</sup></td><td>107.56±09.05<sup>c</sup></td><td>07.84±00.77<sup>a</sup></td><td>07.16±00.93<sup>c</sup></td></tr><tr><td>Solanum lycopersicum L</td><td>81.84±16.07<sup>d</sup></td><td>21.06±04.05<sup>d</sup></td><td>02.65±00.83<sup>d</sup></td><td>01.94±00.82<sup>d</sup></td></tr></tbody></table><p>Compost_Biochar 2 (47.36-52.63)% based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T02 (95%-05%)</p><table><thead><tr><th>T<sub>2</sub> treatments (15 ton/ha)</th><th>Maximum height (cm)</th><th>Minimum height (cm)</th><th>Maximum volume (cm<sup>3</sup>)</th><th>Minimum volume (cm<sup>3</sup>)</th></tr></thead><tbody><tr><td>Zea mays</td><td>139.71±60.11<sup>c</sup></td><td>109.98±11.08<sup>b</sup></td><td>07.22±00.32<sup>a</sup></td><td>07.07±00.79<sup>c</sup></td></tr><tr><td>Solanum lycopersicum L</td><td>83.95±07.87<sup>e</sup></td><td>23.01±01.68<sup>a</sup></td><td>03.84±00.16<sup>d</sup></td><td>01.02±00.45<sup>d</sup></td></tr></tbody></table><p>Compost_Biochar 3 (50-50)% based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T03 (95%-05%)</p><table><thead><tr><th>T<sub>3</sub> treatments (15 ton/ha)</th><th>Maximum height (cm)</th><th>Minimum height (cm)</th><th>Maximum volume (cm<sup>3</sup>)</th><th>Minimum volume (cm<sup>3</sup>)</th></tr></thead><tbody><tr><td>Zea mays</td><td>140.99±10.22<sup>a</sup></td><td>103.65±06.43<sup>b</sup></td><td>08.26±00.12<sup>a</sup></td><td>07.56±00.95<sup>c</sup></td></tr><tr><td>Solanum lycopersicum L</td><td>80.79±06.19<sup>c</sup></td><td>22.37±04.08<sup>c</sup></td><td>04.84±00.17<sup>d</sup></td><td>04.06±00.45<sup>d</sup></td></tr></tbody></table>

The maximum volume gain is 08.26±00.12 cm³ for Zea mays and 04.84±00.17 cm³ for Solanum lycopersicum L recorded with 15 t/ha of Compost_Biochar 3 (50-50)% based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T02 (95%-05%), followed by the average minimum volume of Zea mays (07.07±00.79 cm³) and Solanum lycopersicum L (01.02±00.45 cm³), which was recorded during treatment with 15 t/ha of Compost_Biochar 2 (47.36-52.63)% based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T01 (95%-05%). It is noted that growth in volume and height depends on several factors which are more or less controlled by the substrate supply of Compost_Biochar. Our results contrast with those obtained by Ali et al. (2023), which showed that the highest shoot growth was recorded with the treatment with NPS fertilizers (16.36, 27, 34.28, 45.18, 62.1, 81.2 and 102, 13 cm) between weeks 2 and 8 after planting, respectively, and the lowest was recorded in the control treatment after planting. Results also showed a significant difference in wheat plant height growth between treatments by measuring height every week after planting. The highest shoot growth was recorded in the 10 t/ha biochar treatment, while the lowest shoot growth was recorded in the control treatment. Hoshi, (2001)

reported an increase of 20% in volume and 40% in height of tea trees after the addition of biochar. Idem, Zhang et al. (2013) also reported that net photosynthetic rates of rice in biochar treatments were higher than in control treatments.

### 5.3. Effect of Compost_Biochar on the number of leaves.

The results recorded between weeks 2 and 8 after sowing allowed us to deduce the average maximum number of leaves/Zea mays plant (21.87±02.26 leaves/Zea mays plant), which was recorded with 15 t/ha of Compost_Biochar 1 (64.28-35.71)% based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T02 (95%-05%) followed by the average minimum leaf number/Zea mays plant (14.04±01.23 leaves/plant of Zea mays), which was recorded during the treatment with 15 t/ha of Compost_Biochar 3 (50-50)% based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T01 (95%-05%). Between weeks 2 and 8 after sowing, the maximum weight of 100 dry leaves of Zea mays was 245.82±12.44 gr while that of Solanum lycopersicum L is 21.19±02.27 gr obtained with 15 t/ha Compost_Biochar 2 (47.36 - 52.63)% based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T02 (95%-05%).

<table><caption>**Table 15:** Effect of treatment with Compost_Biochar (CB) based on Prosopis juliflora_Eichhornia crassipes on the leaves during plant growth</caption><caption>Compost_Biochar 1 (64.28-35.71) % based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T01 (95%-05%)</caption><thead><tr><th>Control treatments T<sub>01</sub><br>(sand/clay) %</th><th>Maximum number of<br>leaves/plant</th><th>Minimum number of<br>leaves/plant</th><th>Weight of 100 dry leaves<br>(g)</th><th>CO<sub>2</sub> sequestered by leaves/m<sup>2</sup><br>(kg CO<sub>2</sub>/m<sup>2</sup>/h)</th></tr></thead><tbody><tr><td>Zea mays</td><td>21.87±02.26</td><td>17.98±03.45</td><td>218.65±22.26</td><td>14.04±03.45</td></tr><tr><td>Solanum lycopersicum L</td><td>18.04±06.72</td><td>03.48±00.76</td><td>19.79±01.69<sup>c</sup></td><td>07.23±00.18<sup>c</sup></td></tr></tbody></table><table><caption>Compost_Biochar 2 (47.36-52.63) % based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T02 (95%-05%)</caption><thead><tr><th>Control treatments T<sub>02</sub><br>(Biochar/Soil) %</th><th>Maximum number of<br>leaves/plant</th><th>Minimum number of<br>leaves/plant</th><th>Weight of 100 dry leaves<br>(g)</th><th>CO<sub>2</sub> sequestered by leaves/m<sup>2</sup><br>(kg CO<sub>2</sub>/m<sup>2</sup>/h)</th></tr></thead><tbody><tr><td>Zea mays</td><td>18.75±06.26</td><td>14.73±03.75</td><td>245.82±12.44</td><td>17.55±04.46</td></tr><tr><td>Solanum lycopersicum L</td><td>19.01±06.72</td><td>18.09±01.12</td><td>21.19±02.27<sup>a</sup></td><td>08.37±00.85<sup>c</sup></td></tr></tbody></table><table><caption>Compost_Biochar 3 (50-50) % based on Prosopis juliflora_Eichhornia crassipes on sandy clay soil T03 (95%-05%)</caption></table>
<table><thead><tr><th>Control treatments T<sub>03</sub> (Compost/Soil) %</th><th>Maximum number of leaves/plant</th><th>Minimum number of leaves/plant</th><th>Weight of 100 dry leaves (g)</th><th>CO<sub>2</sub> sequestered by leaves/m<sup>2</sup> (kg CO<sub>2</sub>/m<sup>2</sup>/h)</th></tr></thead><tbody><tr><td><em>Zea mays</em></td><td>19.87±02.66</td><td>14.04±01.23</td><td>225.68±09.92</td><td>15.21±05.88</td></tr><tr><td><em>Solanum lycopersicum</em> L</td><td>18.94±02.03</td><td>15,47±01,38</td><td>20.11±01.93<sup>a</sup></td><td>08.54±00.67<sup>c</sup></td></tr></tbody></table>

Furthermore, the CO₂ sequestered at the maximum by the leaves of *Zea mays* /m² is 17.55±04.46 kg CO₂/m²/h on substrate with Compost_Biochar 2 (47.36-52.63) %, while the CO₂ sequestered at the minimum by these *Zea mays* leaves /m² is 14.04±03.45 kg CO₂/m²/h on Compost_Biochar 1 (64.28-35.71) % substrate. The CO₂ sequestered at the maximum by the leaves of *Solanum lycopersicum* L/m² is 08.54±00.67 kg CO₂/m²/h on Compost_Biochar 3 (50-50) % substrate, while the CO₂ sequestered at the minimum by these leaves of *Solanum lycopersicum* L/m² is 07.23±00.18 kg CO₂/m²/h on Compost_Biochar 1 (64.28-35.71) % substrate based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T₀₁ (95%-05%).

Our results contrast with those obtained by Ali et al. (2023), which shows that the highest number of plant leaves was recorded in the treatment 10 t/ha + NPS fertilizer followed by 10 t/ha 8 weeks after planting and the lowest number of leaves was recorded in the control treatment. The application of biochar as a corn seed treatment significantly (P ≤ 0:05) affected the leaf number of corn plants (Ali et al., 2023). Corn plants treated with 10 t/ha of BC and NPS fertilizer showed moderately better performance (14.05 leaves/plant) than any other treatment. The average number of leaves of

untreated corn plants (controls) was 12.7 leaves/plant (Ali et al., 2023).

### 5.4. Effect of Compost_Biochar on plant productivity.

The results recorded between weeks 2 and 8 after sowing allowed us to deduce the average maximum number of ears developed per m²/week of *Zea mays* (19.87±02.66 ears developed per m²/week), which was recorded with 15 t/ha of Compost_Biochar 3 (50-50)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T₀₂ (95%-05%) followed by a maximum of 80.41±02.39 fruits of *Solanum lycopersicum* L developed per m²/week recorded during treatment with 15 t/ha of Compost_Biochar 3 (50-50)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T₀₁ (95%-05%).

At the time of harvest, a maximum of 67.58±01.23 total ears/m² of *Zea mays* was recorded while that of *Solanum lycopersicum* L was 85.47±01.38 total fruits/m² obtained with 15 t/ha Compost_Biochar 2 (47.36-52.63)% based on *Prosopis juliflora_Eichhornia crassipes* on T₀₂ sandy clay soil (95%-05%). The maximum weight of 100 ears of *Zea mays* is 38.65±02.33 gr while the maximum weight of 100 fruits of *Solanum lycopersicum* L is 156.07±02.48 gr

<table><caption>**Table 16:** Effect of treatment with Compost_Biochar (CB) based on *Prosopis juliflora_Eichhornia crassipes* on the number of ears (or fruits) developed during plant growth</caption><thead><tr><th colspan="5">Compost_Biochar 1 (64.28-35.71)% based on <em>Prosopis juliflora_Eichhornia crassipes</em> on sandy clay soil T01 (95%-05%)</th></tr><tr><th>Control treatments T<sub>01</sub> (sand/clay) %</th><th>Number of ears (or fruit) developed per m<sup>2</sup>/week</th><th>Number of total ears (or fruit) /m<sup>2</sup></th><th>Weight of 100 ears (or fruits) (g)</th><th>CO<sub>2</sub> sequestered per plant/m<sup>2</sup> (kg CO<sub>2</sub>/m<sup>2</sup>/h)</th></tr></thead><tbody><tr><td><em>Zea mays</em></td><td>16,07±02,06</td><td>32.31±00,45</td><td>31,93±03,45</td><td>982.76×10<sup>-3</sup>±04.96×10<sup>-3</sup></td></tr><tr><td><em>Solanum lycopersicum</em> L</td><td>58,41±06,72</td><td>83,04±00,24</td><td>156,07±02,48</td><td>51.67×10<sup>-3</sup>±02.48×10<sup>-3</sup></td></tr></tbody></table><table><thead><tr><th colspan="5">Compost_Biochar 3 (50-50)% based on <em>Prosopis juliflora_Eichhornia crassipes</em> on sandy clay soil T03 (95%-05%)</th></tr><tr><th>Control treatments T<sub>02</sub> (Biochar/Soil) %</th><th>Number of ears (or fruit) developed per m<sup>2</sup>/week</th><th>Number of total ears (or fruit) /m<sup>2</sup></th><th>Weight of 100 ears (or fruits) (g)</th><th>CO<sub>2</sub> sequestered per plant/m<sup>2</sup> (kg CO<sub>2</sub>/m<sup>2</sup>/h)</th></tr></thead><tbody><tr><td><em>Zea mays</em></td><td>17,75±06,26</td><td>64,73±03,75</td><td>38,65±02,33</td><td>992.87×10<sup>-3</sup>±02.49×10<sup>-3</sup></td></tr><tr><td><em>Solanum lycopersicum</em> L</td><td>78,01±06,72</td><td>85,09±01,12</td><td>154,63±03,55</td><td>56.17×10<sup>-3</sup>±00.25×10<sup>-3</sup></td></tr></tbody></table><table><thead><tr><th colspan="5">Compost_Biochar 3 (50-50)% à base du <em>Prosopis juliflora_Eichhornia crassipes</em> sur Sol sableux argileux T<sub>03</sub> (95%-05%)</th></tr><tr><th>Control treatments T<sub>03</sub> (Compost/Soil) %</th><th>Number of ears (or fruit) developed per m<sup>2</sup>/week</th><th>Number of total ears (or fruit) /m<sup>2</sup></th><th>Weight of 100 ears (or fruits) (g)</th><th>CO<sub>2</sub> sequestered per plant/m<sup>2</sup> (kg CO<sub>2</sub>/m<sup>2</sup>/h)</th></tr></thead><tbody><tr><td><em>Zea mays</em></td><td>19,87±02,66</td><td>67,58±01,23</td><td>35.44±02,76</td><td>994.09×10<sup>-3</sup>±02.55×10<sup>-3</sup></td></tr><tr><td><em>Solanum lycopersicum</em> L</td><td>80,41±02,39</td><td>85,47±01,38</td><td>155.49±02,35</td><td>52.39×10<sup>-3</sup>±00.44×10<sup>-3</sup></td></tr></tbody></table>

However, *Zea mays* sequestered a maximum of (994.09±02.55) × 10⁻³ kg CO₂/m²/h with an

amendment to the substrate with Compost_Biochar 3 (50-50) % based on *Prosopis*
juliflora_Eichhornia crassipes, while *Solanum lycopersicum* L a sequestered to the maximum (56.17±00.25) × 10⁻³ kg CO₂/m²/h with an amendment to the substrate of Compost_Biochar 2 (47.36 -52.63) % based on *Prosopis juliflora_Eichhornia crassipes*.

## 5.5. Effect of Compost_Biochar on supplied water consumption and plant productivity.

The highest seed number yield in *Zea mays* is 912.87±60.26 seeds/plant which was recorded

with 15 t/ha of Compost_Biochar 3 (50-50)% based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T₀₂ (95%-05%) followed by a maximum of 15.76±03.88 fruits of *Solanum lycopersicum* L developed and recorded during treatment with 15 t/ha of Compost_Biochar 2 (47.36-52.63)% based of *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T₀₁ (95%-05%).

<table><caption>**Table 17:** Effect of treatment with Compost_Biochar (CB) based on *Prosopis juliflora_Eichhornia crassipes* on seed number yield, plant productivity and water consumption provided during plant growth</caption><thead><tr><th colspan="6">Compost_Biochar 1 (64.28-35.71)% based on <i>Prosopis juliflora_Eichhornia crassipes</i> on sandy clay soil T<sub>01</sub> (95%-05%)</th></tr><tr><th>Control treatments T<sub>01</sub><br>(sand/clay) %</th><th>Yield in number of<br>seeds (or fruits)/plant</th><th>Average size of<br>seeds/fruits<br>harvested (mm)</th><th>Production (kg/m<sup>2</sup><br>harvested / week)</th><th>Consumption of<br>water supplied (liters<br>/ plant / day)</th><th>% leaching of the<br>substrate</th></tr></thead><tbody><tr><td><i>Zea mays</i></td><td>868.71±02.66</td><td>01.32±00.04</td><td>04.35±00.09</td><td>02.01±00.02</td><td>01.33±00.58<sup>c</sup></td></tr><tr><td><i>Solanum lycopersicum</i> L</td><td>14.08±06.72</td><td>0.05±00.06</td><td>02.15±00.03</td><td>02.01±00.04</td><td>02.53±00.67<sup>c</sup></td></tr></tbody></table><table><thead><tr><th colspan="6">Compost_Biochar 2 (47.36-52.63)% based on <i>Prosopis juliflora_Eichhornia crassipes</i> on sandy clay soil T<sub>02</sub> (95%-05%)</th></tr><tr><th>Control treatments T<sub>02</sub><br>(Biochar/Soil) %</th><th>Yield in number of<br>seeds (or fruits)/plant</th><th>Average size of<br>seeds/fruits<br>harvested (mm)</th><th>Production (kg/m<sup>2</sup><br>harvested / week)</th><th>Consumption of<br>water supplied (liters<br>/ plant / day)</th><th>% leaching of the<br>substrate</th></tr></thead><tbody><tr><td><i>Zea mays</i></td><td>881.36±62.54</td><td>01.55±00.55</td><td>04.67±00.02</td><td>02.01±00.03</td><td>01.65±00.03<sup>c</sup></td></tr><tr><td><i>Solanum lycopersicum</i> L</td><td>15.76±03.88</td><td>00.07±00.06</td><td>02.89±00.56</td><td>02.01±00.07</td><td>02.98±00.97<sup>c</sup></td></tr></tbody></table><table><thead><tr><th colspan="6">Compost_Biochar 3 (50-50)% based on <i>Prosopis juliflora_Eichhornia crassipes</i> on sandy clay soil T<sub>03</sub> (95%-05%)</th></tr><tr><th>Control treatments T<sub>03</sub><br>(Compost/Soil) %</th><th>Yield in number of<br>seeds (or fruits)/plant</th><th>Average size of<br>seeds/fruits<br>harvested (mm)</th><th>Production (kg/m<sup>2</sup><br>harvested / week)</th><th>Consumption of<br>water supplied (liters<br>/ plant / day)</th><th>% leaching of the<br>substrate</th></tr></thead><tbody><tr><td><i>Zea mays</i></td><td>912.87±60.26</td><td>01.67±01.58</td><td>04.98±00.23</td><td>02.02±00.09</td><td>01.21±00.08</td></tr><tr><td><i>Solanum lycopersicum</i> L</td><td>14.41±02.39</td><td>00.06±00.08</td><td>02.47±00.38</td><td>02.11±00.03<sup>a</sup></td><td>02.54±00.67<sup>c</sup></td></tr></tbody></table>

The seeds of *Zea mays* have maximum average sizes of 01.67±01.58 mm with Compost_Biochar 3 (50-50)% while the seeds of *Solanum lycopersicum* L have maximum average sizes of 00.07±00.06 mm with Compost_Biochar 2 (47.36-52.63)%.

The maximum water consumption of 02.02±00.09 liters/Zea mays/day on Compost_Biochar 3 (50-50)% substrate, made it possible to obtain a maximum production of 04.98±00.23 kg/m² of seeds harvested/week and maximum leaching (of substrate based on Compost_Biochar 2 (47.36-52.63)% of 01.65±00.03% while the maximum water consumption of 02.11±00.03 liters/Solanum lycopersicum L/day on substrate of Compost_Biochar 3 (50-50)%, made it possible to obtain a maximum production of 02.89±00.56 kg/m² of *Solanum lycopersicum* L seeds harvested/week and maximum leaching (of substrate based on Compost_Biochar 2 (47.36-52.63)% of 02.98±00.97%).

## 6. Conclusions

Application of Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* on Sandy clay soil T₀₃ (95%-05%) in the field experiment showed significant effects on seed germination and growth parameters of *Solanum lycopersicum* L and of *Zea mays* compared to control sites on sandy clay soil, on Compost substrate and on Biochar substrate. The results showed a significant increase in seed germination percentage as we applied more of 15 t/ha of Compost_Biochar 2 (47.36-52.63)% based on *Prosopis juliflora_Eichhornia crassipes* to agricultural land abandoned due to its degradation due to aridity and silting. The study also showed an increase in crop biomass or yield performance using Biochar (100%) based on *Prosopis juliflora_Eichhornia crassipes* alone and/or in combination with Compost based on *Prosopis juliflora_Eichhornia crassipes* on sandy soil. clayey T03 (95%-05%). The application of this Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T03 (95%-05%) also increases the growth of shoots and roots of crops, then improves crop yield by
improving the physicochemical properties and biological soils, which is probably the reason why Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* on sandy clay soil T03 (95%-05%) could contribute to plant productivity. In view of the percentage of leaching obtained due to runoff water, we conclude that, even in conditions of high precipitation (floods or irregular rainfall), leached soils of highlands for example could be sustainably improved by an amendment to Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes*. The application of Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* alone could improve the dry matter yield (crop biomass) equivalent to that resulting from the application of Biochar based on *Prosopis juliflora_Eichhornia crassipes*.

Based on the results of the study, it can be recommended that the application of Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* on a sandy clay soil T03 (95%-05%) with a view to restoring degraded agricultural soil and improve seed germination potential, crop growth performance and dry matter yield without chemical fertilizer. In addition, experiments have shown that it is now possible to manage the biodegradation of Sahelian arid zones by using invasive plants in agro-farming environments such as Compost, Biochar or Compost_Biochar for agricultural production in the highlands. This discovery makes it possible to valorize plant resources which were until now neglected and considered harmful.

This also implies that an optimal quantity of Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* on a sandy clay soil T03 (95%-05%) must be used within the framework of regional and national projects for the sustainable restoration of degraded agricultural soils and improve their potential. In particular, when other chemical amendments become expensive and cause ecological damage, it could be substituted in parallel with Compost_Biochar based on *Prosopis juliflora_Eichhornia crassipes* on a sandy clay soil T03 (95%-05%) in order to restore the long-term soil fertility and improve soil biodiversity. However, other experiences with the application of Compost_Biochar based on improved *Prosopis juliflora_Eichhornia crassipes* could lead to organic soil amendments, capable of destroying agricultural pests and certain plant diseases. Certain physical

and chemical analyzes of the soil should be carried out before it can be extended on a large scale.

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