Valorisation of Biowaste and Aquatic Invasive Plants Through Compost Production for Agricultural Use

doi:10.21203/rs.3.rs-1957994/v1

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Research Article

Valorisation of Biowaste and Aquatic Invasive Plants Through Compost Production for Agricultural Use

https://doi.org/10.21203/rs.3.rs-1957994/v1

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published 27 Mar, 2023

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This study evaluates the quality and performance of compost produced from household biowaste (CBIO), aquatic invasive plants (CAIP) and a mixture of the invasive plants and biowaste (CBAIP) in comparison with mineral fertilizer (NPK) application. The composts were produced using Aerobin 400 Composter with aquatic invasive plant collected from the Owabi dam and solid biowaste from households within the Owabi catchment in the Ashanti Region of Ghana as feedstock. A field experiment in a 35 m x 19 m plot of maize was conducted with 9 treatments of the different compost produced and mineral fertilizers in a randomized complete block design (RCBD) with 4 replications. The results show that the compost types produced have acceptable quality with regards to nutrients (NPK), organic matter (OM), organic carbon (OC), bulk density, porosity, and heavy metal contents (Cu, Zn, Cd, Pb, As, Ni) among other properties. Grain yields following treatment with CAIP (2.06 ± 0.692 tons/ha), CBAIP (2.15± 0.668 tons/ha) and CBIO (2.052 ± 0.915 tons/ha) were similar to grain yields from NPK application (2.55 ± 0.611 tons/ha) but significantly higher than the control (1.34 ± 0.500 tons/ha) at 5%. The results show that the different compost types produced have beneficial impacts on grain yields comparable to NPK application. It is, therefore, concluded that aquatic invasive plants and biowaste are suitable feedstock for the production of high-quality compost that significantly improves grain yields.

Bioresources

Invasive plants

Biowaste

Compost

waste management

The potential of household biowaste and aquatic invasive plants as bioresources is not well-understood and therefore valorisation practices are scarce especially in developing countries. As a result of this biowaste and waste from harvested aquatic invasive plants are disposed of by landfilling and another unsustainable and environmental unfriendly manner. This study demonstrated the suitability of biowaste and seven different aquatic invasive plant species as feedstock for compost production for agricultural use. The novelty of this study is that it offers a shift in paradigm from viewing household biowaste and biomass of aquatic invasive plants as an environmental menace to bioresources for agrarian livelihood development through composting.

One of the oldest and yet widely adopted means of handling organic waste materials globally is composting. Composting is a controlled, aerobic biotechnological process that results in the decomposition of polymeric compounds in organic matter into simpler substances by the activities of microorganisms [1]. The main product of this process called “compost” is a dark, humus and stable organic matter with an earthy scent that adds nutrients and improves the chemical, physical, and biological characteristics of soils [2]. Generally, the preparation of compost is done as means of nutrient recovery for agricultural use or in some cases as a strategy for safe and more environmentally friendly means of waste disposal [3]. There are also other purposes of compost production including as means of bioremediation [4], diseases and weeds control method [5], pollution prevention [6], land reclamation and erosion control [7] among many others. The purpose of compost preparation determines the feedstock use and the quality of the compost produced.

Many different organic materials can serve as feedstock for composting, but the commonly used ones include agricultural waste such as crop residues, animal wastes, food garbage, some municipal wastes, and suitable industrial wastes [2], [8], [9]. There are essential properties of these materials that favour their usage as feedstock for composting including structural composition (cellulose, hemicellulose, and lignin content), elemental composition especially carbon to nitrogen ratio (C/N ratio), and electrical conductivity among other properties [2]. High lignin content in the feedstock impedes degradation of the feedstock and therefore hinders the efficiency of the composting process and the quality of compost produced [10]. A desirable C/N ratio of 15-30:1 of the feedstock is also important to ensure effective decomposition [11]. The selection of feedstock for composting therefore requires an understanding of their quality and suitability for composting.

Besides the quality and characteristics of the materials, environmental factors such as aeration, pH, temperature and moisture level of the medium are also important to the success of composting [12]. Producing quality compost, therefore, depends on not only selecting feedstock of desirable properties but also controlling the composting system to achieve optimal conditions. The preponderance of literature have shown that most compost are prepared with a combination of green waste (nitrogen-rich) and brown (carbon-rich) waste [6]. Common examples of brown waste used in composting include fallen leaves, straw, woodchips, limbs, logs, pine needles, sawdust, and wood ash whereas the greens generally include fresh food waste, grass clippings, garden trimmings, and fresh leave [13], [14]. Animal manure such as poultry droppings, cow dung, swine and horse manure are also common feedstocks used for compost preparation [15], [16].

The preparation of compost using waste serve an important purpose of environmental protection from pollution, supports agrarian livelihood and can also serve as a source of income for producers [17]. The extent to which these benefits are realised depends on the feedstock and the efficiency of composting. In developing countries where municipal services such as waste collection and recycling are scarce, compost preparation with household biowaste takes the burden of handling waste from households and reduces the risk of environmental pollution [6]. Studies have also shown that the preponderance of household solid biowaste in these areas consist of food/kitchen waste, fruit/vegetable and crop residues which are often high in nutrient and promising feedstock for the production of high-quality compost for agricultural use [6], [18], [19]. By composting these materials, therefore, substantial environmental and economic benefits can be envisioned.

Another group of promising feedstocks for quality compost production that has however not been well explored is lignocellulosic waste from harvested nuisance invasive plants [20]. In many developing countries around the tropics, invasive plants are common in aquatic environments where they course injurious ecological and economic consequences [21]. The most common means of handling these plants often involve harvesting and discarding/dumping which is neither a sustainable nor profitable means of managing them. Economic and ecological benefits can be driven by utilising these invasive plants for the preparation of compost. Invasive plants are generally carbon-rich lignocellulosic materials and as such their potential utilisation as feedstock for compost production is high. Evidence from studies such as that of [22], [23] and [24] have shown that invasive plants such as Hydrilla verticillate, Eichhornia crassipes and Pistia stratiotes can be converted to compost of acceptable quality standard for agricultural use.

Despite the proven potential of both household biowaste and invasive plants as feedstock for compost production, they remain underutilised and poorly disposed posing a huge threat to environmental sustainability [25], [26]. In many developing countries, unsafe disposal of organic waste (biowaste) often leads to water pollution through eutrophication which then leads to the growth of invasive plants and therefore creation of other problems in these areas [27]. In Ghana, for instance, the growth and threatening takeover of major water bodies such as the Owabi dam by invasive plants have been linked to indiscriminate disposal of organic waste. In this context, promoting compost production with household biowaste and invasive plants has the potential to address the environmental problem of pollution, and contribute to farming livelihood and income generation. To ensure these practices, however, require demonstrable evidence of success in the converting of available biowaste and invasive plants to quality compost that supports crop production. This research in response to this problem involves the preparation of quality compost from biowaste and aquatic invasive plants in the Owabi Catchment in Ghana for agricultural use.

2.1 Collection of Feedstock

The feedstock for the compost preparation included mixed of aquatic invasive plants consisting of Ceratophyllum demersum (hornwort), Nymphaea odorata (water lily), Polygonum lanigerum, Arthropteris orientalis (ferns), Typha domingensis (Cattail), Pistia stratiotes (water lettuce) and Cyperus papyrus (nutgrass) as well mixed household solid biowaste that included food/kitchen waste, fruit/vegetable, crop-residue, yard waste. The invasive plants were harvested from the Owabi dam (06°43'N 01°40'W) in the Ashanti Region of Ghana, while the household solid biowaste were gathered from households within communities in the Owabi catchment area. The harvesting of the invasive plants was done manually with the aid of simple hand tool including rake and cutlass and carried in canoe with the assistance of Water Laborers at dams. The biowaste on the other hand were gathered fresh from households in communities within the Owabi catchment.

2.2 Preparation and Characterization of Feedstock

The feedstock of consisting both invasive plants and biowaste after harvesting were transported in fresh form to the site of compost preparation at the Department of Environmental Science at the Kwame Nkrumah University of Science and Technology (KNUST), Kumasi. To improve the composting process, the feedstocks were shredded to reduce the particle size for effective decomposition. Prior to composting, samples of each class of feedstock were taken for laboratory analysis. The invasive plant samples were prepared by shredding and evenly mixing each of the six (6) different invasive plant species. This was necessary to ensure that the samples analyse have an even composition of the different invasive plants that made up the feedstocks. Likewise, the biowaste were also evenly and thoroughly mixed before samples were taken for analysis. All nine (9) samples of the mixed invasive plants and nine (9) samples of the mixed biowaste were taken for laboratory analysis.

The analyses were performed at the Soil Science Laboratory at the KNUST. The parameters analysed included the structural compositions (lignin, cellulose, and hemicellulose content), pH, carbon, nitrogen and potassium content as well as moisture content. The Van Soest Method for neutral detergent fibre (NDF) and acid detergent fibre (ADF) procedure was used to establish the concentration of lignin, cellulose, and hemicellulose in percentage weight in volume (% W/V) basis. The pH of the samples were measured using a pH probe (PHYME Cobros 3 basic unit USB, Germany) while the C and N were determined using an elemental analyser (Model LECO CHN628 and 628S, St. Joseph, MI, USA) following the ASTM D-5291 standard method.

The feedstock characteristics obtained from the laboratory analysis are presented in Table 1. The C/N ratio of both the invasive plants, biowaste and their mixture as feedstock were within the desirable range of 1:15-30 [11] although biowaste feedstock has a lower ratio as compared to the invasive plants. The lignin content was higher in the invasive plants than that of the biowaste. The ratio of cellulose to hemicellulose was comparable between the invasive plants and biowaste feedstock with the latter however having a higher content of both cellulose and hemicellulose. The pH of the invasive plants' feedstock is 5.5-8 and that of the biowaste was 6-8.6 indicating both classes of feedstock have desirable pH levels suitable for composting.

Table 1

Initial Characterization of Feedstock

Parameter	Invasive plants (n=9)	Mixed of AIPs and Biowaste (n=9)	Mixed household Biowaste (n=9)
Carbon (%W/V)	6.4±0.441	10.23±0.624	14.5±0.535
Nitrogen(%W/V)	0.5±0.076	0.7±0.133	0.6±0.126
C/N ratio(%)	1:10-15	1:15-25	1:20-31
Phosphorus(%)W/V	0.22±0.025	0.21±0.011	0.15±0.0302
pH	5.5-8	6-8.5	6-8.6
Moisture(%W/V)	80.1±2.1	74±2.67	50.5±3.6
Cellulose(%W/V)	3.0±1.00	5.4±1.123	9.3±1.523
Hemicellulose(% W/V)	2.3±1.528	3.23±1.114	7.7±0.577
Lignin (ADL) (%W/V)	2.3±0.577	1.4±0.133	0.5±0.029

2.3 Description of Composting System

The compost was prepared in three Aerobin 400 Composters each with a capacity of 400 L mounted at the Department of Environmental Science of the Kwame Nkrumah University of Science and Technology, Kumasi. The Aerobin as shown in Plate 1 is designed for all-year-round aerobic hot composting. Hot composting is preferred in this study because it kills pathogens, inoculates weeds and their seeds and creates good quality compost in a short period [23]. Aerobic composting also dramatically reduces greenhouse gas emissions and bad smells from methane and rather produces Carbon dioxide. When assembled, the Aerobin 400 measures 740mm x 740mm and stands 1200mm high. Each Aerobin weighs about 26 kg when empty and up to 400kg when loaded. The vessel has a moisture recirculation system that helps maintain the correct moisture level of biomass during the composting process. It also has an aeration lung that provides ventilation to the centre of the composting material and thus no digging or turning of the compost is required. In addition to the above, the vessel (Aerobin 200) also has a leachate reservoir at the base of the Aerobin for collecting rich compost tea which can be used as liquid fertilizer when diluted approximately 20 parts water to 1-part leachate. The vessel also has an insulated wall and lid that provide optimum conditions for rapid composting all year round, even in freezing conditions.

2.4 Compost Preparation Process

To maximize the potential moisture of the material, the compost preparation was done within 48 of collection of the compost feedstock. Three (3) of the Aerobin 400 Composter were used to prepare three (3) classes of co-compost, one with only the invasive plants (CAIP), one with only the mixed household solid biowaste (CBIO) and the other mixture of invasive plants and biowaste (CBAIP). The feedstocks were weight before loading into the three (3) different Aerobins. For the Aerobin with only invasive plants (CAIP), the total weight of the feedstock that filled the vessel was 45.4 kg, that with biowaste (CBIO) contained 98.4 kg whereas that of the mixed invasive plants and biowaste (CBAIP) was 56.6 kg. The composters were tightly closed after filling with the feedstock and watering. A 5-litre plastic container was attached to each of the leachate reservoirs to collect the leachates. Plate 3.4.2 show the composting process ongoing at in the three (3) Aerobin 400 Composter vessels. The composting process was repeated to obtain enough compost for the field experiment.

The composting process was monitored for temperature, pH, and maturity on each composter vessel over the entire duration of the compost preparation. A fast response compost thermometer (ReoTemp Instrument Corporation, San Diego, CA) was used to measure the temperature within each composting vessel at 10 inches, 20 inches and 30 inches with averages recorded per each measurement daily. The pH were also measured and recorded with a hand-held Kelway soil pH sensor (Kel Instruments Co., Inc., Wyckoff, NJ) throughout the composting period. The moisture content was measured using ‘‘feel’’ test which involve taking a handful of compost and squeezing it to see if it feels like a moist sponge. The first round of composting lasted for 98 days from July 1, 2019, while the second round lasted for 91 days. The temperature profile of the compost production are presented in Figure 1. The temperature in the Aerobin with biowaste feedstock reach over 55 ^oC in the first two weeks, that with a mixture invasive plants and biowaste reached 46 ^oC, while the feedstock with invasive plants alone reach about 35 ^oC in the first two weeks. The temperature in each pile were higher than the ambient temperature until week 14 when the temperature levels were equal, an indication that no or very little decomposition taking place at this time.

2.5 Compost Sampling and Analytical methods

Compost samples for analysis were taken after the compost were matured and cured. The compost was considered matured when further degradation was taking place as indicated by the fact that the temperature of the medium was equal to the ambient temperature. The sampling was done utilizing the grab sampling technique after the vessels were empty and the compost evenly mixed. All six samples of each compost type were taken for analysis. The samples were analysed for pH, Soluble salt (EC), nutrient content (NPK), organic matter, moisture content, stability, bulk density, porosity, and presence of heavy metals. An electronic pH meter (PHYME cobros 3 basic unit USB, Germany) was used to measure pH while moisture was measured using the gravimetric method. Organic matter was measured using the loss-on-ignition organic matter method while conductivity was measured with the Jennway Conductivity meter (Jenway model 4010, UK). The atomic absorption spectrometer (AAS) (Varian Spectra 55B) method was used to measure the concentration of heavy metals which included copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), Arsenic (As) and Nickel (Ni).

2.6 Compost trial Experiment

A field experiment involving the compost produce was done at a demonstration farm located within the Owabi catchment. Randomized Complete Block Design (RCBD) experimental design was used. The crop used was maize since this was found to be the most commonly grown staple crop in the study area. The experimental plot size was 665 m² (35 m x 19 m) with a treatment plot size of 12 m²(3m x 4 m), 4 replications and nine (9) treatments. The treatment included compost from biowaste (CBIO), compost from invasive plants (CAIP), compost from invasive plants and biowaste (CBAIP), and mineral fertilizer (NPK). The recommended application rate of compost of 4, 000 kg/ha was used as a treatment for CBIO, CAIP and CBAIP as well as half-recommended rate (2 tons/ha) as treatment and labelled as 1/2CBIO, 1/2CAIP and 1/2CBAIP respectively as treatment. The standard rate of 100 kg/ha of NPK as well as half the recommended rate was also used as treatment.

The planting took place in September 2019 with the treatments applied two weeks after germination. Plant height was measured daily for the first four (4) weeks and thereafter measurements were taken weekly. The number of leaves was also taken throughout this period. No-tillage was done before the planting of the maize. The agronomic practices undertaken included weed control with Sunphosate and pest control with a suitable pesticide. Harvesting was done in December 2019 with measurements that included economic yield measurement and biological yield (biomass). The second planting took place in March 2020 at a different plot within the same vicinity, with similar agronomic practices and measurements taken and harvesting done in June 2020. The third planting which was intended to find the residual effects were done in the first experimental plots with no treatment applied.

2.7 Field Experiment measurement

The measurement taken from the experimental fields includes germination rate, plant heights, number of leaves, grains yields and above-ground biomass. The grain yields was measured after the plants were harvested from each plot's area of 4 cm x 3 cm. The grain yields was measured as the ratio of the weight of dried grain obtained per unit area extrapolated to hectares. Likewise, the above-ground biomass (biomass) was given as the weight of total harvest per unit area extrapolated to hectares.

2.8 Statistical Analysis

Data for analysis included data on the compost quality parameters/properties as well as data from the field experiment. The analysis of the data was performed using R-studio version 4.1.1. The analysis involves use of both descriptive and inferential statistics. The descriptive statistical analysis involved frequency count and measures of central tendencies (mean, median and mode). The inferential statistical analysis that were performed included a comparison of mean test that included mainly One -Way and Two-way Analysis of variance together with Tukey HSD tests. The one-way ANOVA was employed to compare the average (mean) level of the compost properties across the different compost types. The two-way ANOVA was employed to determine the effect of different fertiliser types, rate of application and interaction effects on crop (grain) yield and above-ground biomass.

3.1 Properties and Quality of Compost Produced

In this study, the characterisation was limited to the nutritional composition (NPK), organic matter (OM) and organic carbon (OC) content, conductivity, moisture content, pH, bulk density, and porosity as well as heavy metals content. These properties have been described in many studies including that of Segatelli et al. (2020), Heyman et al. (2019) and Sullivan et al. (2018) as core properties of compost that ensure the availability of nutrients and improve soil properties favourable for plant growth. The outcome of this study on the nutritional content of the different compost produced are presented in Figure 2. The results generally confirm Geng et al. (2019) assertion that compost has low nutrient content when compared to mineral fertiliser per unit weight. All three (3) types of compost have N composition of 1.8-2.2% db, P of 0.17-0.89% db and K of 0.54 to 0.83% db for the different compost types. The results however show that except for K, the remaining nutrients are proportionally comparable to that of standard compost requirements of about 2 % N, 0.5-1% P and about 2% K [31].

The results show with a 1.8% dry basis (db) composition, CBIO has lower nitrogen (N) content than CBAIP and CAIP. Generally, plant-based feedstock such as the CAIP tends to produce compost of lower P content [32]. The results confirm this assertion as the CBAIP have a high P of 0.89% relatively compared to 0.17% of the CAIP. The amount of potassium in the composts also varies significantly across the different compost types with the highest in CBIO (0.84%) and the least in CAIP (0.54% db). As Sayara & Sánchez (2021) have noted, the quality of compost with regard to nutrient values is dependent on the feedstock used. The lowest K (0.54%) was obtained from compost with invasive plants only as feedstock (CAIP) while the highest (0.83%) was obtained from compost from household waste where potassium-rich materials such as banana peels were included.

The results showing other physicochemical properties of the composts produced such as organic carbon (OC) content, organic matter (OM), moisture content (MC) in a wet basis and porosity (PO) are presented in Figure 3. Organic matter content shows the content of organic carbon, water and other ingredients necessary to improve soil structure, nutrient availability, and water holding capacity among others [33]. The results show an OM content range of 29.7-55.1% for all the compost types while OC content ranges from 16.6% to 23.5%. According to [34] the acceptable OM content of compost is about 30 to 70% db. The OM range of the compost types are comparable to standard compost. It is however noted that OM of CAIP was the lowest (29.7% db) while that of CBAIP and CBIO were more than 50 % db, an indication that the OM content was driven by the biowaste feedstock constituent.

Organic carbon is often directly related to the OM as OM consist of over 50% OC [33]. Thus, the OC content were similar low in CAIP (16.6%) but high in CBAIP (22.2%) and CBIO (23.5%) for similar reasons. While high OM is an important indicator of the ability of the soil to hold water, supply nutrients and improve aeration and other properties, a very high OM is often the result of inefficiency in the composting process. As [1] has noted, usually very high OM (>65%) in compost is an indication that the feedstocks are not thoroughly decomposed which may lead to OM lost after application as further degradation take place. The observed OM ranges of 29.7% to 55% fall within the optimal range that indicate good quality compost.

Other important properties of compost analysed further show the quality of the compost produced to be good. For instance, MC was found to have a range from 41.67 to 49.3 % wb while the porosity ranges from porosity of 66.4% to 76.5%. Usually, compost with high moisture content (>60%) are clumsy and its application on the field become difficult while those with low MC (<40%) are dusty and may cause respiratory problems. The results of this study show the compost produced were neither too high in moisture nor low. Low porosity (<30%) of compost can lead to the creation of anaerobic conditions while very high porosity (>80%) can lead to excess cooling [35].

Other important properties and characteristics of the composts produced including conductivity (EC) in dS m^-1 bulk density and pH are presented in Figure 4 to Figure 5. The results show that EC ranges from 3.5 dS m^-1 to 5.75 dS m^-1 with the highest recorded in CBAIP while the least was record by the CBIO. Also, CBIO recorded a significantly different pH from that CAIP and CBAIP. High EC (>7 dS m^-1 ) can potentially be injuries for plants while low EC ((>7 dS m^-1 ) could also deny plants of sufficient nutrients in the form of soluble solid (Sullivan et al., 2018). The EC of the composts ranging from 3.8-5.75 dS m^-1 can be said to be ideal for plant growth.

The bulk density of the composts also ranges from 264.1 kgm^-3 to 516.9 kgm^-3 with the highest recorded by CBAIP and the lowest by CBIO (Figure 5). Clearly, the results show significantly higher EC and pH in CBAIP and high pH and bulk density in CAIP while the CBIO compost type recorded the least bulk density. The bulk density of the composts which was lowest (285.2 kg m^-3 ) in CBIO, and the highest of 516.9 kg m^-3 in CAIP were generally within the acceptable range that supports soil structure, aeration and solute movement [36]. This is further evident by the porosity of 66.4% to 76.5%. It is important to note that the highest bulk density and lowest porosity were recorded in the CAIP which was largely due to the uniformity in the materials for this compost type (invasive plants) as compared to CBAIP and CBIO with heterogenous sizes and types of materials as feedstock.

Usually, plant-based feedstock compost have a pH that is moderately acidic to moderately alkaline [37] but the CAIP was found to be slightly more alkaline (pH of 8.2-9.9) as presented in Table 2. Most compost ends up with a pH that is slightly alkaline due to the mineralisation of nitrogenous compounds in the feedstock to form ammonia and ammonium, especially at the mesophilic stage leading to an increase in pH [38]. This is observed in the case of CAIP with a pH of 8.2-9.9. Low pH on the other occurs usually due to the formation of fatty acids especially the saturated type which do not often get decomposed through the composting process [39]. Most compost without the problem of saturated fatty acid formation has a pH of 7.2 to 8.3 [40] as seen in the case of CBAIP. This type of compost may be unsuitable for acid-loving plants but generally acceptable for most crops.

Table 2

pH Levels In Different Compost Variations Produced

Compost types	pH range
CAIP	8.2-9.9
CBAIP	7.2-8.3
CBIO	6.2-8.1

Among the important properties and characteristics of the compost produced include the amount of heavy metals present. Compost with high heavy metal content may be unsuitable for plant growth due to their effect on soil properties but more importantly because of the possibility of contamination and bioaccumulation along the food chain [41]. The relevant heavy metals content analysed in this study included arsenic (As), zinc (Zn), copper (Cu), cadmium (Cd), lead (Pb) and nickel (Ni). The results showing the concentration of these invasive plants in the different compost types are presented in Figure 6. From the results, it is noted that the range of As content in the composts were 0.486 -0.833 mg kg^-1while that of Cd were 0.727-2.467 mg kg^-1. The heavy metal in the highest concentration in the compost were Cu and Zn with a respective range of concentrations of 116.3-273.7 mg kg^-1 and 114.6 -243.9 mg kg-¹.

While it is impractical to expect compost to have no heavy metal, many general standards exist giving thresholds within which many heavy metals are less problematic. Irfan et al. (2021) also opined that immobilisation of some heavy metals may occur during composting, however with a decrease in mass and volume of the compost feedstock, the concentration of the heavy metals may turn to be higher in the final product. Globally acceptable threshold for Pb is 100-200 mg kg^-1, Cd is 1.5-10 mg kg^-1, Cu is 100-150 mg kg^-1, Ni is 50-120 mg kg^-1, Zn is 400-1300 mg kg^-1and As is 10 mg kg^-1[43]. The results show that the different compost types have heavy metal concentrations within acceptable threshold except for Cu content in CBIO which was 273 mg kg^-1. High Cu in compost (soil) may inhibit enzyme activities and cause toxicity to plants, animals and even humans due to bioaccumulation with food chains [44]. Evidence from some studies however suggests that the moderately high Cu content in compost does not impede soil enzyme activity [45]. A recent study by [46] also concluded that high Zn and Cu did not adversely affect crop performance in terms of seed germination, growth and yields. It is therefore expected that the relatively high Cu in CBIO has no detrimental effects on crop performance.

3.2 Effect of Compost Fertilizer Treatment On Yield Of Maize

For agricultural purpose composts, the most convincing and demonstrable evidence of quality is determined by the extent to which the application of the compost contributes to enhancing crop performance. The mechanism through which the application of compost improves crop output is usually in relation to their contributions to improving soil health and fertility [47]. Against this backdrop, the effect of the different compost and NPK fertilizer treatment on output parameters of maize namely yields (tons/ha) and biomass (tons/ha) are analysed. The results in Figure 7 show the response of yields of maize to treatment with the different composts and NPK mineral fertilizer treatment. The results in Figure 9 also show the response to a different rate of treatment or fertilizer application (full= recommended rate; half=half the recommended rate and none =control) while Figure 10 show the interaction effect of fertilizer type treatment and rate of application.

From the results, it is noted that the average yields from treatment with each compost type (CAIP=2.06 tons/ha, CBAIP=2.15 tons/ha, CBIO=2.05 tons/ha) and NPK were significantly higher than the yield of 1.34 tons/ha without treatment (control). No difference is observed with regard to average yields of maize from the different fertilizer treatments. The result of this study thus supports the assertion that the application of compost produced from biowaste and aquatic invasive plants improves the average grain yields of maize. Compost from different feedstocks with different properties are expected to have different effects on crop output with the highest quality compost expected to have the highest crop output [48]. This study however found no difference with regard to average grain yields from CAIP, CBAIP and CBIO applications indicating that the compost types have comparable effects on crop yields. The study also found no difference between grain yield from composts application and mineral fertilizers (NPK). This show that the composts produced are of comparable effect to the application of NPK mineral fertilizer.

An important consideration in compost and fertilizer application is the rate of application. A lower application rate reduces the cost of inputs but can potentially compromise output. An optimal rate of application minimises the input costs at the same time maximises yields [49]. For this reason, the effect of applying each compost type at the recommended rate (full) of 4 tonnes ha^-1 and mineral fertilizers of 100 kg ha^-1 and half recommended rate (2 tons ha^-1 for compost and 50 kg ha^-1 for NPK) were compared. The results as shown in Figure 8 demonstrated that recommended (full) rate applications resulted in higher yields (2.65±0.59 tons ha^-1) than that of half recommended rate (1.75 tons ha^-1) and control (1.34 tons ha^-1) at 5%. No difference exists between the control and half-recommended fertilizer rate application. This show that there is no benefit in applying the half recommended rate of either compost or the NPK. The interaction effect of fertilizer types of application and rate of application as presented in Figure 9 is not significant.

With above-ground biomass as the output, a significant difference was found between CBIO and NPK applications compared with CAIP, CBAIP and the control. Above-ground biomass from CAIP and CBAIP application were not different from that of the control but the average biomass from the use of recommended application rate (5.79 x 10³ tons ha^-1) was higher than the application of half recommended rate and control. This result means that CAIP and CBAIP applications offer no biomass benefits over the control. This also means that if the intended output from the maize production is above-ground biomass, then CBIO and NPK should be applied for higher yields. The difference in biomass is attributable to the significant difference in some properties of the composts produced. For instance, organic matter (OM) and organic carbon (OC) in the CBIO were significantly higher than that of CAIP and CBAIP which perhaps accounted for the difference in performance with regard to above-ground biomass. The effect of the application of either fertilizer as well as the rate of application resulted in no difference in harvest index and an indication of no imbalance in biomass to grain yield ratio across the different fertilizer treatment

The results also show significant differences in the comparison of total above-ground biomass of the crops following in response to the different treatments (CAIP, CBAIP, CBIO and NPK). As seen in Figure 10, biomass from NPK application of 5.7 tons ha^-1 and that from CBIO application of 4.8 tons ha^-1 were higher than the average biomass from other fertiliser applications and the control. The results show biomass from CAIP and CBAIP application were not different from that of the control. Likewise, in Figure 11, it is noted that the average biomass from the use of recommended application rate (5.92 tons ha^-1) was higher than the application of half recommended rate and control. No difference exists between biomass yield from the half-recommended fertiliser application rate and control. The interaction effect of fertiliser types and application rate on biomass yields is not significant (Figure 12).

The production of compost from organic waste materials can address the problem of waste management and at the same time contribute to agrarian livelihood improvement. Demonstrably evidence of the ability to produce compost with high quality from available feedstocks and improvement in agricultural productivity is required to promote such practices, especially in developing countries. The evidence from this study shows that various aquatic invasive plants, as well as household biowaste as feedstock, resulted in compost with high quality and acceptable levels of nutrients (NPK), OM, OC, MC, bulk density, porosity, and heavy metal (Cu, Zn, Cd, Pb, As, Ni) among other properties. Properties of the compost such as bulk density and porosity were also determined. The application of compost made from invasive plants (CAIP), a mixture of invasive plants and biowaste (CBAIP) and compost from biowaste only (CBIO) resulted in maize grain yield levels higher than control and comparable to NPK application. Biomass yields from NPK and CBIO were however higher than that of CAIP and CBAIP. We conclude that aquatic invasive plants and biowaste are suitable feedstock with the potential for the production of high-quality compost that significantly improves grain yields.

Funding

This study was funded by Kwame Nkrumah University of Science and Technology (KNUST) and the Ministry of Foreign Affairs of Denmark (DANIDA), DFC Project Building Stronger Universities Programme Phase III (BSU III KNUST)

Competing Interest

There is no financial or non-financial interest to disclose

Author Contributions

All authors contributed to the study conception and design.. The first draft of the manuscript was written by Albert Banunle and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Data Availability

The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.

Acknowledgments

The authors thank the Kwame Nkrumah University of Science and Technology (KNUST) and the Ministry of Foreign Affairs of Denmark (DANIDA), DFC Project Building Stronger Universities Programme Phase III (BSU III KNUST) for providing funds for this research.

D. M. Sullivan, A. I. Bary, R. O. Miller, and L. J. Brewer, Interpreting compost analyses. Corvallis, OR, USA: Oregon State University Extension Service, 2018.
T. Sayara and A. Sánchez, “Gaseous Emissions from the Composting Process: Controlling Parameters and Strategies of Mitigation,” Processes, vol. 9, no. 10, p. 1844, Oct. 2021, doi: 10.3390/pr9101844.
M. D. Vaverková, D. Adamcová, J. Winkler, E. Koda, L. Petrželová, and A. Maxianová, “Alternative method of composting on a reclaimed municipal waste landfill in accordance with the circular economy: Benefits and risks,” Science of The Total Environment, vol. 723, p. 137971, Jun. 2020, doi: 10.1016/j.scitotenv.2020.137971.
C. Lin, N. K. Cheruiyot, X.-T. Bui, and H. H. Ngo, “Composting and its application in bioremediation of organic contaminants,” Bioengineered, vol. 13, no. 1, pp. 1073–1089, Jan. 2022, doi: 10.1080/21655979.2021.2017624.
A. O. Akanmu et al., “Plant Disease Management: Leveraging on the Plant-Microbe-Soil Interface in the Biorational Use of Organic Amendments,” Frontiers in Plant Science, vol. 12, Jul. 2021, doi: 10.3389/fpls.2021.700507.
M. Ayilara, O. Olanrewaju, O. Babalola, and O. Odeyemi, “Waste Management through Composting: Challenges and Potentials,” Sustainability, vol. 12, no. 11, p. 4456, May 2020, doi: 10.3390/su12114456.
A. Pérez-Gimeno, J. Navarro-Pedreño, M. B. Almendro-Candel, I. Gómez, and A. A. Zorpas, “The use of wastes (organic and inorganic) in land restoration in relation to their characteristics and cost,” Waste Management & Research: The Journal for a Sustainable Circular Economy, vol. 37, no. 5, pp. 502–507, May 2019, doi: 10.1177/0734242X19828171.
M. I. Said, “Livestock waste and its role in the composting process: A review,” IOP Conference Series: Earth and Environmental Science, vol. 492, no. 1, p. 012087, Apr. 2020, doi: 10.1088/1755-1315/492/1/012087.
A. A. Kadir, S. N. Jamaludin, and N. W. Azhari, “An Overview of Composting Based on Variable Feedstock Material,” MATEC Web of Conferences, vol. 47, p. 05016, Apr. 2016, doi: 10.1051/matecconf/20164705016.
J. Barthod, C. Rumpel, and M.-F. Dignac, “Composting with additives to improve organic amendments. A review,” Agronomy for Sustainable Development, vol. 38, no. 2, p. 17, Apr. 2018, doi: 10.1007/s13593-018-0491-9.
M. A. Macias-Corral, J. A. Cueto-Wong, J. Morán-Martínez, and L. Reynoso-Cuevas, “Effect of different initial C/N ratio of cow manure and straw on microbial quality of compost,” International Journal of Recycling of Organic Waste in Agriculture, vol. 8, no. S1, pp. 357–365, Dec. 2019, doi: 10.1007/s40093-019-00308-5.
H. Peña, H. Mendoza, F. Diánez, and M. Santos, “Parameter Selection for the Evaluation of Compost Quality,” Agronomy, vol. 10, no. 10, p. 1567, Oct. 2020, doi: 10.3390/agronomy10101567.
J. Miller, B. Beasley, C. Drury, F. Larney, and X. Hao, “Influence of long-term application of composted or stockpiled feedlot manure with straw or wood chips on soil cation exchange capacity,” Compost Science & Utilization, vol. 24, no. 1, pp. 54–60, Jan. 2016, doi: 10.1080/1065657X.2015.1055009.
M. A. E. Hassan and K. A. M. Abo-Elyousr, “Impact of compost application on Fusarium wilt disease incidence and microelements contents of basil plants,” Archives Of Phytopathology And Plant Protection, vol. 46, no. 16, pp. 1904–1918, Oct. 2013, doi: 10.1080/03235408.2013.780696.
A. Mutungwazi, G. N. Ijoma, H. J. O. Ogola, and T. S. Matambo, “Physico-Chemical and Metagenomic Profile Analyses of Animal Manures Routinely Used as Inocula in Anaerobic Digestion for Biogas Production,” Microorganisms, vol. 10, no. 4, p. 671, Mar. 2022, doi: 10.3390/microorganisms10040671.
M. Usman, “Cow dung, goat and poultry manure and their effects on the average yields and growth parameters of tomato crop,” J Biol Agric Healthc, vol. 5, no. 5, pp. 7–10, 2015.
Z. Majbar et al., “Farmers’ Perceptions and Willingness of Compost Production and Use to Contribute to Environmental Sustainability,” Sustainability, vol. 13, no. 23, p. 13335, Dec. 2021, doi: 10.3390/su132313335.
C. Ghinea and A. Leahu, “Monitoring of Fruit and Vegetable Waste Composting Process: Relationship between Microorganisms and Physico-Chemical Parameters,” Processes, vol. 8, no. 3, p. 302, Mar. 2020, doi: 10.3390/pr8030302.
A. M. MUSA, C. F. ISHAK, D. S. KARAM, and N. Md JAAFAR, “Effects of Fruit and Vegetable Wastes and Biodegradable Municipal Wastes Co-Mixed Composts on Nitrogen Dynamics in an Oxisol,” Agronomy, vol. 10, no. 10, p. 1609, Oct. 2020, doi: 10.3390/agronomy10101609.
J. A. Sembera, T. M. Waliczek, and E. J. Meier, “Composting As an Alternative Management Strategy for Wild Taro Waste,” Horttechnology, vol. 29, no. 2, pp. 205–209, Apr. 2019, doi: 10.21273/HORTTECH04194-18.
A. E. Mayfield et al., “Impacts of Invasive Species in Terrestrial and Aquatic Systems in the United States,” in Invasive Species in Forests and Rangelands of the United States, Cham: Springer International Publishing, 2021, pp. 5–39. doi: 10.1007/978-3-030-45367-1_2.
E. Albano Pérez et al., “Seed germination and risks of using the invasive plant Eichhornia crassipes (Mart.) Solms-Laub. (water hyacinth) for composting, ovine feeding and biogas production,” Acta Botanica Gallica, vol. 162, no. 3, pp. 203–214, Jul. 2015, doi: 10.1080/12538078.2015.1056227.
E. J. Meier, T. M. Waliczek, and M. L. Abbott, “Composting Invasive Plants in the Rio Grande River,” Invasive Plant Science and Management, vol. 7, no. 3, pp. 473–482, Sep. 2014, doi: 10.1614/IPSM-D-13-00089.1.
J. E. Montoya, T. M. Waliczek, and M. L. Abbott, “Large Scale Composting as a Means of Managing Water Hyacinth ( Eichhornia crassipes ),” no. February 2016, 2013, doi: 10.1614/IPSM-D-12-00013.1.
Q. N. Nguyen, A. Cloutier, A. Achim, and T. Stevanovic, “Effect of process parameters and raw material characteristics on physical and mechanical properties of wood pellets made from sugar maple particles,” Biomass and Bioenergy, vol. 80, pp. 338–349, Sep. 2015, doi: 10.1016/j.biombioe.2015.06.010.
H. I. Abdel-Shafy and M. S. M. Mansour, “Solid waste issue: Sources, composition, disposal, recycling, and valorization,” Egyptian Journal of Petroleum, vol. 27, no. 4, pp. 1275–1290, Dec. 2018, doi: 10.1016/j.ejpe.2018.07.003.
A. Azeem, J. Sun, Q. Javed, K. Jabran, and D. Du, “The Effect of Submergence and Eutrophication on the Trait’s Performance of Wedelia Trilobata over Its Congener Native Wedelia Chinensis,” Water (Basel), vol. 12, no. 4, p. 934, Mar. 2020, doi: 10.3390/w12040934.
A. Segatelli, A. Pimenta, G. Peixoto, M. Silva, and T. D. Bosco, “Quality of Organic Compost for Vegetable Planting,” in The 5th Ibero-American Congress on Entrepreneurship, Energy, Environment and Technology - CIEEMAT 2019, Jan. 2020, p. 14. doi: 10.3390/proceedings2019038014.
H. Heyman, N. Bassuk, J. Bonhotal, and T. Walter, “Compost Quality Recommendations for Remediating Urban Soils,” International Journal of Environmental Research and Public Health, vol. 16, no. 17, p. 3191, Sep. 2019, doi: 10.3390/ijerph16173191.
Y. Geng, G. Cao, L. Wang, and S. Wang, “Effects of equal chemical fertilizer substitutions with organic manure on yield, dry matter, and nitrogen uptake of spring maize and soil nitrogen distribution,” PLOS ONE, vol. 14, no. 7, p. e0219512, Jul. 2019, doi: 10.1371/journal.pone.0219512.
N. Paul, U. Giri, and G. Roy, “Composting,” in Organic Fertilizers - History, Production and Applications, IntechOpen, 2019. doi: 10.5772/intechopen.88753.
J. S. Robinson, K. Baumann, Y. Hu, P. Hagemann, L. Kebelmann, and P. Leinweber, “Phosphorus transformations in plant-based and bio-waste materials induced by pyrolysis,” Ambio, vol. 47, no. S1, pp. 73–82, Jan. 2018, doi: 10.1007/s13280-017-0990-y.
J. H. Bhadha, J. M. Capasso, R. Khatiwada, S. Swanson, and C. LaBorde, “Raising Soil Organic Matter Content to Improve Water Holding Capacity,” EDIS, vol. 2017, no. 5, Oct. 2017, doi: 10.32473/edis-ss661-2017.
V. Mironov, A. Vanteeva, and A. Merkel, “Microbiological Activity during Co-Composting of Food and Agricultural Waste for Soil Amendment,” Agronomy, vol. 11, no. 5, p. 928, May 2021, doi: 10.3390/agronomy11050928.
T. T. K. Ho et al., “Compost to improve sustainable soil cultivation and crop productivity,” Case Studies in Chemical and Environmental Engineering, vol. 6, p. 100211, Dec. 2022, doi: 10.1016/j.cscee.2022.100211.
R. Chang, Q. Guo, Q. Chen, M. P. Bernal, Q. Wang, and Y. Li, “Effect of initial material bulk density and easily-degraded organic matter content on temperature changes during composting of cucumber stalk,” Journal of Environmental Sciences, vol. 80, pp. 306–315, Jun. 2019, doi: 10.1016/j.jes.2017.10.004.
D. M. Crohn, Assessing Compost Quality for Agriculture. University of California, Agriculture and Natural Resources, 2016. doi: 10.3733/ucanr.8514.
E. R. Oviedo-Ocaña, I. Dominguez, D. Komilis, and A. Sánchez, “Co-composting of Green Waste Mixed with Unprocessed and Processed Food Waste: Influence on the Composting Process and Product Quality,” Waste and Biomass Valorization, vol. 10, no. 1, pp. 63–74, Jan. 2019, doi: 10.1007/s12649-017-0047-2.
J. Bekier et al., “Changes in selected hydrophobic components during composting of municipal solid wastes,” Journal of Soils and Sediments, vol. 14, no. 2, pp. 305–311, Feb. 2014, doi: 10.1007/s11368-013-0696-0.
M. Schwarz and J. Bonhotal, Characteristics of a sampling of New York State composts. New York: Cornell University, 2017.
J. Briffa, E. Sinagra, and R. Blundell, “Heavy metal pollution in the environment and their toxicological effects on humans,” Heliyon, vol. 6, no. 9, p. e04691, Sep. 2020, doi: 10.1016/j.heliyon.2020.e04691.
M. Irfan et al., “Heavy metals immobilization and improvement in maize (Zea mays L.) growth amended with biochar and compost,” Scientific Reports, vol. 11, no. 1, p. 18416, Dec. 2021, doi: 10.1038/s41598-021-97525-8.
D. , L. Hoornweg and and L. O. Thomas, “Composting and its Applicability in Developing Countries; Published for Urban Development Division,” Washington DC, 2000.
M. Ibrahim, Y. Chee Kong, and N. Mohd Zain, “Effect of Cadmium and Copper Exposure on Growth, Secondary Metabolites and Antioxidant Activity in the Medicinal Plant Sambung Nyawa (Gynura procumbens (Lour.) Merr),” Molecules, vol. 22, no. 10, p. 1623, Oct. 2017, doi: 10.3390/molecules22101623.
P. R. Warman and M. D. Munroe, “The effects of high metal concentrations in soil-compost mixtures on soil enzymes,” Journal of Environmental Science and Health, Part B, vol. 45, no. 7, pp. 633–638, Sep. 2010, doi: 10.1080/03601234.2010.502421.
R. Clemente, J. A. Sáez-Tovar, and M. P. Bernal, “Extractability, Distribution Among Different Particle Size Fractions, and Phytotoxicity of Cu and Zn in Composts Made With the Separated Solid Fraction of Pig Slurry,” Frontiers in Sustainable Food Systems, vol. 4, Jan. 2020, doi: 10.3389/fsufs.2020.00002.
J. A. Antonangelo, X. Sun, and H. Zhang, “The roles of co-composted biochar (COMBI) in improving soil quality, crop productivity, and toxic metal amelioration,” Journal of Environmental Management, vol. 277, p. 111443, Jan. 2021, doi: 10.1016/j.jenvman.2020.111443.
D. Trupiano et al., “The Effects of Biochar and Its Combination with Compost on Lettuce ( Lactuca sativa L.) Growth, Soil Properties, and Soil Microbial Activity and Abundance,” International Journal of Agronomy, vol. 2017, pp. 1–12, 2017, doi: 10.1155/2017/3158207.
M. Narayanasamy, D. Dhanasekaran, and N. Thajuddin, “Frankia,” in Beneficial Microbes in Agro-Ecology, Elsevier, 2020, pp. 185–211. doi: 10.1016/B978-0-12-823414-3.00011-3.

Plates 1 and 2 are available in the Supplementary Files section.

plate1.png
Plate 1: The Aerobin 400 Composter Source: https://www.exaco.com/aerobin-composter.php
plate2.png
Plate 2: Composting Of Invasive Plants And Biowaste Underway

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Valorisation of Biowaste and Aquatic Invasive Plants Through Compost Production for Agricultural Use

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