Enhancing maize yield through sustainable and eco-friendly practices: the impact of municipal organic waste compost and soil amendments

Abstract

Municipal organic waste (MOW) compost is considered a sustainable and environmental friendly fertilizer management system throughout the world for hybrid maize production. It can enhance the production of maize by using MOW compost as a soil amendment. Therefore, two field trials were executed during November 2021–March 2022 and November 2022–March 2023 to study the consequences of compost treatments derived from MOW, MOW added with vermiculite, MOW added with cow manure, and combination of 150 kg/ha NPK fertilizer and MOW compost on maize yield and yield components. The MOW compost was applied at three levels (5, 10 and 15 t ha⁻¹) in the maize field. The statistical design was a split plot with three replications. Compost levels were in the main plots, and sub-plots were four treatments (MOW, vermiculite + MOW, cow manure + MOW and a combination of 150 kg/ha NPK fertilizer with MOW compost). Each plot was 6 m², with 50 cm line to line and 30 cm plant to plant distance. MOW compost with NPK fertilizer significantly affected the yield and yield-contributing characters, followed by vermiculite and cow manure-added composts. These effects were more pronounced at the rate of 15 t ha⁻¹ compost than 10 t ha⁻¹. In conclusion, MOW mixed with NPK at the rate of 15 t ha⁻¹ was found to be the best for all studied traits of maize. This qualitative and quantitative assessment will not only provide new information about the MOW conversion methods to compost in the arid land agriculture but also will open new avenues for maize production in a significant and worthwhile way.

Keywords:

• Additive
• arid land
• compost
• maize
• municipal organic waste

REVIEWING EDITOR:

• Manuel Tejada
• Universidad de Sevilla
• Spain

SUBJECTS:

• Agriculture & Environmental Sciences
• Agriculture
• Agricultural Development
• Crop Science
• Botany
• Soil Science

1. Introduction

Maize (Zea mays L.) is widely grown worldwide for both human consumption and animal feed (Erenstein et al., 2022). The average yield per hectare for maize in Saudi Arabia in 2022–2023 was 6.00 tons, with the total harvest amounting to 12,000 tons from 2000 ha (Elzaki et al., 2022). Urbanization raises life expectancy and land living status, but it also disrupts the municipal food supply system, causing malnutrition and food insecurity (Knorr et al., 2020). Maize serves as a significant supply of raw material for several industries, as well as human food, poultry feed, and cattle fodder (Choudhary et al., 2021). However, maize devours mineral fertilizers and uses more nutrients than other cereal crops during the growth season (Yadav et al., 2023). In high-yielding regions, when seed maize production exceeds 16 tons per hectare, maize can utilize 250–300 kg of nitrogen per hectare (Biswas et al., 2022). This frequently forces farmers to overuse chemical fertilizers to maximize seed yield. However, extensive use of chemical fertilizers leads to negative consequences for soil health, environmental concerns, and reduced economic returns due to high input costs (Chen et al., 2022). Incorporating organic compost with chemical fertilizer is a successful approach to sustainable agricultural production systems in many countries (Etesami et al., 2023).

The amendments had a great impact on the nutrient status of compost and reduced emissions of harmful gases while improving plant nutrition (Wu et al., 2022). Vermiculite-added composts improved early maize growth and corn yields on dry land. Compost is a cheaper alternative to base fertilizers for increasing organic matter in soil (Berti et al., 2023). Sandy soils treated with vermiculite-containing manure improved maize growth (Fang & Su, 2019). Vermiculite reduces poisonous metals in soil that plants can take up. This helps crop production without food chain and groundwater contamination (Parmar et al., 2021). Soil amended with vermiculite has been shown to improve nutrient retention by plants and reduce nutrient runoff from fields, leading to greater crop yields with lower input costs (Govindasamy et al., 2023). Additionally, cow manure is full of crop nutrients and organic matter, particularly phosphorus (P) and nitrogen (N). Cow manure-added compost saves N losses from leaching in any type of soil and saves soil nutrients losses in the runoff (Rayne & Aula, 2020). It reduces the abuse of inorganic fertilizers, which are declining soil quality, and it helps to ensure sustainable crop production (Aryal et al., 2021). The application of cow manure to agricultural soil has been observed to positively impact soil structure, facilitating the regeneration process (Fu et al., 2022). Moreover, cow dung has been recognized as a valuable source of essential nutrients required for the cultivation of various plant species, ranging from cereal crops to horticultural plants and even fruits and vegetables. The cultivation of plants can be carried out using organic methods, thereby eliminating the necessity for the application of chemical inputs (Behera & Ray, 2021).

Every year, more than 15 million tons of waste are produced in Saudi Arabia, which will double by 2033 (Abdullah et al., 2022). Recycling municipal organic waste (MOW) and decomposing it into useful organic compost is the principal crop nutrition management approach. Composting is an effective way to recycle and transform municipal organic waste (Rastogi et al., 2020). Compost is a popular eco-friendly organic fertilizer that helps to enhance the fertility of soil, sustain nutrient uptake, and boost maize production (Chew et al., 2019). Compost enhances soil fertility and water-holding capacity as it has a high amount of humus content. As a result, optimum utilization of compost will help to achieve other goals of Vision 2030: ‘improve land utilization and management in the agricultural sector’ as well as ‘ensure development and food security’. In MOW composts, the use of NPK may affect the quality of the compost and its ability to improve crop yields (Kuligowski et al., 2023) but these implications are unclear in Saudi Arabia. The additives with MOW could assist in positive changes in composting, crop production, agriculture, and municipal waste management processes. Therefore, this study examined how various additives, together with compost obtained from municipal waste, affect the growth of maize crop in dry areas of Saudi Arabia.

2. Materials and methods

2.1. Experimental site

The experiment took place at King Abdulaziz University’s Agricultural Research Farm in Hada al Sham, Jeddah City, in 2021–2022, 2022–2023. The experimental field is located at latitude 21˚47’56.68” N and longitude 39˚43’49.10” E and an elevation of 792 ft. Monthly temperature, relative humidity, and rainfall averages were recorded in the field during the experiment. Seasonal temperatures ranged from 21.28 °C to 35.64 °C and averaged 27.55 °C. Humidity ranged from 22.53 to 69.55%. The highest total rainfall was 119.20 mm and the lowest was 0.00 mm (Figure 1).

Figure 1. Average weather information for the field during the experimental period.

2.2. Experimental design

A split plot design with three replications was used. Compost levels were in the main plots, and different composts derived from municipal organic waste (MOW): control (only MOW), Vermiculite + MOW, cow manure +  MOW, and combination of NPK (20:20:20) @ 150 kg ha⁻¹ with MOW compost were in sub-plots. Each plot was 6 m² in size, 3  m in length, and 2 m in width. Line-to-line distance was 50  cm, and plant-to-plant distance was 30 cm.

2.3. Compost preparation from MOW

Municipal organic waste was collected from the Jeddah landfill center, which included food scraps, yard waste, agricultural waste like fruits and vegetables, and other compostable materials. After collection, all plastic, inorganic, and non-decomposable materials were sorted out from MOW. Following the process of categorization, we have successfully incorporated vermiculite at a concentration of 10% relative to the overall volume of the MOW.

In our research, we conducted an experiment wherein we employed a combination of municipal organic waste and cow manure at a ratio of 10:1. Incorporation of bovine excrement, commonly referred to as cow manure or dung, was implemented at a concentration of 10% relative to the overall weight of the MOW.

Subsequently, a thorough blending of all components was conducted, ensuring optimal homogeneity within the mixture. The resulting mixture was then carefully deposited into a designated composting area, specifically a hole measuring 1.5 m in length, 1.0 m in width, and 1.0 m in depth. This meticulous process was undertaken to facilitate the composting process effectively. Within a fortnightly timeframe, the composting materials undergo a regular process of being turned over and thoroughly mixed once more. Water is an essential component that is added to maintain optimal moisture levels and facilitate effective composting processes. Following a period of three months, composts derived from MOW were meticulously prepared.

2.4. Application of MOW compost and NPK (20:20:20) fertilizer

MOW composts were incorporated into the upper 30 cm of the field before one month of sowing. Three rates (5 tons/ha, 10 tons/ha, and 15 tons/ha) of compost used in this study to optimize the best rate for maize production following fertilizer recommendation guidelines (Ahmed, 2018). During each growing season, a total of 150 kg ha⁻¹ NPK (20:20:20) combined with only MOW compost treatment was applied to the respective plots of NPK + MOW. When nitrogen is provided in its entirety prior to the growth of crops, there is an increased vulnerability of nitrogen to denitrification, leaching, or volatilization. The reduction of nutrient loss, particularly nitrogen, is achieved by employing the practice of splitting. The adoption of split nitrogen applications presents a promising approach to optimizing the effective utilization of nitrogen in agricultural crop systems. In order to mitigate nitrogen loss from the soil and ensure optimal uptake by plants, a strategic approach was employed for NPK (20:20:20) application in NPK+MOW fertilizer treatment to the experimental plots. This approach involved dividing the fertilizer application into four equal splits, administered at specific intervals after sowing, namely 15, 30, 60, and 90 days. By adhering to this regimen, we aimed to maximize the efficiency of nitrogen utilization while minimizing any potential losses. A drip irrigation system was implemented within the experimental field, with irrigation occurring at a frequency of once every two days.

2.5. Determination of agronomic traits of maize

In every experimental plot, 10 plants were randomly selected from the middle lines, avoiding the plants from the border site, to record data on plant height (cm), cob length (cm), seeds per cob, seeds weight per cob (g), 100 seeds weight (g), shelling (%), seeds yield (ton/ha), stover yield (ton/ha), total biological yield (ton/ha), and protein (%).

2.6. Measurement of biological yield and seed protein content (%)

Biological yield data was determined by collecting the mature cobs from the middle two rows of each plot, allowing them to air dry in the sun for a couple of days, and then weighing them (kg/ha). After threshing, cleaning, and weighing, the cobs were turned into seed yield (ton/ha).

Total biological yield (ton/ha) = seed yield (ton/ha) + stover yield (ton/ha), and shelling % = seed weight (10 cobs) * 100/total weight (10 cobs).

Protein content (%) = total nitrogen percentage of seed multiplied by 6.25, as outlined by the Association of Official Analytical Chemists in 1990 (Mariotti et al., 2008).

2.7. Soil and compost nutrient analysis

Soil samples from (0–15 cm depth) experimental site and compost samples were analyzed (Tables 1 and 2) at the soil science lab of the department of agriculture at King Abdulaziz University, KSA. A Kjeletec Auto 1030 analyzer was used to calculate the total nitrogen (N) content of the soil using the procedures provided by Pansu & Gautheyrou (Berger et al., 2013). Total phosphorus (P) and potassium (K) in soils were determined using an extraction digestion procedure utilizing perchloric and nitric acids by Palma et al. (2015). Soil phosphorus levels were evaluated using a Spectrophotometer set to 640  nm, and soil potassium (K) concentrations and heavy metals (Cd, Cr, Co, Pb, and Ni) were determined by VARIAN (ICP-OES). In Table 2, we found that all types of heavy metal concentrations in these MOW-derived composts were detected as lower than the acceptable levels of range according to the Heavy Metals Limit, EU-Range, and US-Range.

Table 1. Analysis of the physicochemical qualities of the experimental soil (0–15 cm).

Soil properties	Values	Soil particle (%)	Values
pH	7.27	Sand	83.3
OM (%)	0.73	Silt	15
Total N (%)	0.06	Clay	1.7
Available P (mg/kg)	0.001	Soil Texture	Sandy loam (SL)
K	0.0629
Ca	0.224
Mg	0.1270

Table 2. Chemical properties of cow manure (CM) and composts derived from MOW compost with additives.

Compost (C)	pH	EC (dS/cm)	Macronutrients			Moisture	Heavy metal
			N	P	K		Cd	Cr	Co	Pb	Ni
			%	g/kg		%	mg/kg
MOW	7.35	5.51	1.98	4.51	16.32	32.14	BDL	56.6	48.4	159.4	69.6
Ver + MOW	7.16	5.81	1.73	5.41	14.70	20.85	BDL	54.8	57.8	164.8	94
CM + MOW	7.28	5.11	2.16	5.86	17.66	35.79	BDL	56.2	58.4	161.8	81.4
CM	6.9	4.44	0.89	1.35	0.83	16.60	–	–	–	–	–
Heavy metals limit, EU-Range^a							10	200	–	1000	20
Heavy metals limit, US-Range^a							39	1200	–	300	420

Note. ^a(CIWMB 2009), MOW: Municipal Organic Waste; Ver: Vermiculite; and BDL: Below Detectable Level.

2.8. Statistical analysis

An analysis of variance (ANOVA) was used to statistically examine the plant growth and yield data. The SAS 9.4 program was used for the ANOVA of group means (Ganesan et al., 2010). Least Significant Difference (LSD) was used to compare treatment means at p ≤ 0.05 (Ali et al., 2020). Three independent biological replicates were used for all observations.

3. Results

Tables 3 and 4 reveal that the different MOW-derived composts, levels and their interaction significantly (p ≤ 0.05) affected the plant height, yield, and its components in both 2022 and 2023.

Table 3. Average values of plant height, cob length, seeds number/cob, seeds weight/cob, and 100-seed weight of hybrid maize affected by MOW-derived composts, levels, and their interactions in two seasons (2022 and 2023).

		2022 Season							2023 Season
		Compost level (L)			Average (C)	LSD			Compost level (L)			Average (C)	LSD
Attributes	Compost (C)	5	10	15		C	L	C x L	5	10	15		C	L	C X L
Plant height (cm)	MOW	149.8	181.4	164.3	165.1b	4.5	3.9	7.8	162.9	183.0	183.0	176.4a	3.8	3.3	6.6
	Ver + MOW	162.7	190.1	171.8	174.9a				160.7	189.1	172.0	173.9a
	CM + MOW	163.3	178.0	181.3	174.2a				163.2	178.0	181.3	174.2a
	NPK + MOW	158.9	183.8	189.3	177.3a				161.7	170.0	174.7	168.8b
Average (L)		158.7c	183.1a	176.9b					162.1b	180.0a	177.8a
Cob length (cm)	MOW	20.6	21.4	20.1	20.7a	1.1	0.9	1.9	19.1	21.2	21	20.4a	1.1	0.9	1.9
	Ver + MOW	19.9	21.6	20.1	20.5a				19.2	21.6	20.8	20.5a
	CM + MOW	20.9	19.8	21.6	20.8a				19.1	20.9	21.3	20.4a
	NPK + MOW	20.4	21.3	21.0	20.9a				20.3	21.1	21.5	21.0a
Average(L)		20.4a	21.0a	20.7a					19.4a	21.2a	21.2a
Seed number/cob	MOW	370.7	413.3	432.1	405.3c	10	8.6	17.3	398.6	473.3	492.1	454.6b	11.2	9.7	19.5
	Ver + MOW	390.4	440.2	461.6	430.7b				393	436.6	475.3	434.9c
	CM + MOW	402.1	458.2	467	442.4b				398.1	418.2	473.6	429.9c
	NPK + MOW	421.5	479.2	499.9	466.8a				400.4	492.2	502.9	465.1a
Average (L)		396.1c	447.7b	465.1a					397.5c	455.0b	485.9a
Seeds weight/cob (g)	MOW	123.3	168.9	197.3	163.2b	5.0	4.3	8.7	132.3	168.9	195.0	165.4b	7.2	6.2	12.5
	Ver + MOW	127.4	160.7	189.5	159.2bc				128.0	158.1	189.5	158.5bc
	CM + MOW	134.3	156.5	180.6	157.1c				137.3	156.5	177.3	157.0c
	NPK + MOW	128.2	175.4	211.7	171.7a				130.7	209.8	185.7	175.4a
Average (L)		128.3c	165.4b	194.8a					132.1c	173.3b	186.9a
100 seed weight (g)	MOW	34.2	35.0	34.6	34.6b	1.4	1.2	2.5	32.5	34.6	35.0	34.0b	1.3	1.1	2.2
	Ver + MOW	31.9	37.0	36.9	35.3ab				33.1	36.9	35.7	35.2ab
	CM + MOW	34.4	37.4	36.5	36.1a				34.4	34.8	37.4	35.5a
	NPK + MOW	33.3	38.8	36.9	36.4a				33.5	36.9	38.8	36.4a
Average (L)		33.5b	37.1a	36.2a					33.4b	35.8a	36.7a

Note: According to the LSD, the mean values in the same column or row marked with the same letters are not statistically different at the 0.05 level of probability.

Table 4. Average biological yield, stover yield, seed yield, shelling (%) and protein (%) of hybrid maize affected by MOW-derived composts, levels, and their interactions in two seasons (2022 and 2023).

		2022 Season							2023 Season
		Compost level (L)			Average (C)	LSD			Compost level (L)			Average (C)	LSD
Attributes	Compost (C)	5	10	15		C	L	C x L	5	10	15		C	L	C X L
Biological yield (ton/ha)	MOW	21.1	21.7	22.9	21.9c	1.0	0.8	1.7	20.4	22.5	25.7	22.9c	1.0	0.9	1.8
	V + MOW	22.3	25.5	26.9	24.9b				22.7	26.5	27.6	25.6ab
	CM + MOW	21.0	26.0	27.2	24.7b				20.9	26.1	27.5	24.8b
	NPK + MOW	22.4	26.5	29.3	26.1a				23	27.3	28.7	26.3a
Average (L)		21.7c	24.9b	26.6a					21.8c	25.6b	27.4a
Stover yield (ton/ha)	MOW	15.4	15.4	15.7	15.5b	0.9	0.8	1.6	15.1	15.6	18.1	16.3b	0.9	0.8	1.6
	Ver + MOW	16.4	18.0	18.1	17.5a				16.3	18.2	18.9	17.8a
	CM + MOW	14.7	18.3	18.8	17.3a				14.8	18.2	18.7	17.2ab
	NPK + MOW	16.5	18.4	19.5	18.1a				16.1	18.4	19.0	17.8a
Average (L)		15.8c	17.5b	18.0a					15.6c	17.6b	18.7c
Seed yield (ton/ha)	MOW	5.7	6.3	7.2	6.4c	0.2	0.2	0.4	5.3	6.9	7.6	6.6c	0.3	0.2	0.5
	Ver + MOW	5.9	7.5	8.8	7.4b				6.3	8.4	8.8	7.8b
	CM + MOW	6.2	7.8	8.4	7.5b				6.1	7.9	8.8	7.6b
	NPK + MOW	6.9	8.1	9.8	8.3a				6.9	8.9	9.7	8.5a
Average (L)		6.2c	7.4b	8.6a					6.1c	8.0b	8.7a
Shelling (%)	MOW	79.0	81.6	82.9	81.1a	2.7	2.3	4.7	80.9	81.6	81.9	81.5a	3.1	2.7	5.4
	Ver + MOW	83.2	83.7	84.0	83.6a				82.9	83	83.0	83.0a
	CM + MOW	81.2	84.0	83.1	82.8a				82.7	82.9	83.1	82.9a
	NPK + MOW	82.7	84.9	85.1	84.2a				83.3	85.1	84.9	84.4a
Average (L)		81.5a	83.5a	83.7a					82.5a	83.2a	83.2a
Protein content (%)	MOW	4.4	6.3	10.7	7.1c	0.7	0.6	1.2	4.1	7.3	10.7	7.4c	0.5	0.5	1.0
	Ver + MOW	4.5	9.5	10.4	8.1b				4.8	9.4	10.9	8.4b
	CM + MOW	3.7	10.2	10.9	8.3b				4.8	10.5	11.2	8.8b
	NPK + MOW	4.7	11.2	12.6	9.5a				5.2	11	12.6	9.6a
Average (L)		4.3c	9.3b	11.2a					4.7c	9.6b	11.4a

Note: According to the LSD, the mean values in the same column or row marked with the same letters are not statistically different at the 0.05 level of probability.

3.1. Effects of municipal organic waste composts on maize growth and yield

Results in Table 3 showed effect of compost rates (5–15 tons/ha) on plant height, ear length, seeds per cob, seed weight per cob, and 100-seed weight. In both seasons, the minimum result for each parameter was found in case of the control treatment. Table 4 shows that 10 or 15 tons/ha of compost maximized biological productivity, stover yield, and seed yield. Significant differences in seed protein (%) were observed (p ≤ 0.05) after 10 tons/ha of compost. A composting rate of 15 tons/ha resulted in the greatest mean maize yield values, followed by 10 tons/ha, which yielded similar results to control treatments in both seasons. In both growing seasons, the control had the minimum attribute values.

Plant height, cob length, seeds/cob, 100-seeds weight, biological yield, stover yield, seed yield, and protein content (%) were strongly correlated in 2022 and 2023, as shown in Tables 5 and 6. Unless cob length (cm) was significant, plant height, seeds/cob, 100-seed weight, biological yield, stover yield, seed yield, and protein (%) were positively associated. Shelling (%) inversely associated with biological yield, stover yield, and seed yield in 2023. Protein content (%) in seed was unaffected by shelling over two seasons. Protein content negatively correlated with stover yield in both seasons and seed yield in 2023.

Table 5. Pearson’s correlation coefficients (r ∼ values) between plant height, ear length, seed number per cob, seed weight per cob, and 100 seeds weight.

	Plant height (cm)		Cob Length (cm)		Seed number/cob		Seeds weight/cob (g)		100 seed weight (g)
	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023
Plant height (cm)	1	1	0.44***	0.15 NS	0.67***	0.46**	0.65***	0.53***	0.65***	0.50***
Cob length (cm)			1	1	0.30 NS	0.11 NS	0.18 NS	0.04 NS	0.28 NS	−0.03 NS
Seed number/cob					1	1	0.86***	0.11NS	0.62***	0.65 ***
Seeds weight/cob (g)							1	1	0.59***	0.73***
100 seed Weight (g)									1	1

***means significant at 0.001% ** means significant at 0.01% and * means 0.05%.

Table 6. Pearson’s correlation coefficients (r ∼ values) biological yield, stover yield, seed yield, shelling %, and protein %.

	Biological yield (ton/ha)		Stover yield (ton/ha)		Seed yield (ton/ha)		Shelling (%)		Protein (%)
	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023
Biological yield (ton/ha)	1	1	0.73***	0.76***	0.36**	0.37**	−0.11NS	−0.13NS	0.20NS	0.11NS
Stover yield (ton/ha)			1	1	−0.36**	−0.31NS	−0.24NS	−0.12NS	−0.41***	−0.45***
Seed yield (ton/ha)					1	1	0.17NS	−0.01NS	0.86***	0.81***
Shelling (%)							1	1	0.21NS	0.14NS
Protein (%)									1	1

***means significant at 0.001% ** means significant at 0.01% and * means 0.05%.

3.2. Integral influence of MOW and NPK on maize production

Tables 3 and 4 also show data regarding the combined effects of MOW compost and NPK fertilizer for both growing seasons on plant height (cm), cob length (cm), seeds number/cob, seeds weight/cob, 100-seed weight (g), biological yield (ton/ha), stover yield (ton/ha), seed yield (ton/ha), and protein content (%). Table 3 shows that, compared to other municipal organic waste-derived composts over both seasons, the combination of organic and inorganic fertilizers significantly influenced (p ≤ 0.05) maize production and yield-contributing features. However, composts with no additives (only MOW) had the lowest overall yield-contributing attributes for both seasons. Table 4 displays the results of two growing seasons of using municipal organic waste compost coupled with NPK, and the results are significant (p ≤ 0.05). The levels of 15 tons per hectare in both seasons were associated with the highest levels of biological, stover, seed, and protein content. Values were lowest in 2022 and 2023, when MOW compost was applied without amendments.

3.3. Interaction effects of MOW composts, their levels on maize production

Table 3 shows that the interaction between composts and their rates had a substantial effect on the two seasons’ worth of maize growth features. Maximum values were achieved for plant height and cob length in 10 tons/ha treatments in both seasons, and vermiculite + MOW treatment was given maximum plant height of 190.1 cm and 189.1 cm in 2022 and 2023, and cob length was recorded at 21.6 cm in both seasons. In Figure 2, we see that the highest maize seed yield (in tons per hectare) in 2022 and 2023 was obtained in the NPK + MOW treatment, followed by the Vermiculite+MOW treatment, and that the lowest seed yield was obtained in the 5 tons/ha level of compost due to the interaction effect among the composts and levels.

Figure 2. Interaction effect of municipal organic waste-derived compost (C) and compost levels (L) on maize seed yield (ton/ha) in 2022 and 2023.

Figure 3. Interaction effect of municipal organic waste-derived compost (C) and compost levels (L) on maize biological yield (ton/ha) in 2022 and 2023.

The highest number of seeds per cob and seed weight per cob were found at 15 tons/ha compost level by the combined treatment of MOW + NPK for two seasons. The maximum 100-seed weight was obtained by a 10 tons/ha compost rate followed by 15 tons/ha and the highest weight was found in case of MOW + NPK in the both seasons. For every attribute, the lowest data were found in 5 tons/ha level of compost. According to Table 4, the maize yield and seed protein% were strongly impacted by the interaction between compost and their levels in both growing seasons. The highest biological yield, stover yield (ton/ha), seed yield (ton/ha), and protein (%) were achieved by combined treatment with MOW compost application at 15 tons/ha during the two growing seasons. However, irrespective of all compost levels in both seasons showed that the combination of MOW waste compost with NPK produced the highest yield followed by vermiculite and cow manure added MOW composts and 15 ton/ha of compost produced maximum yield and yield related attributes (Figure 1).

4. Discussion

Compost with NPK fertilizers increased yield for all treatments compared to control (p > 0.05). The seed production of corn was greatly improved by organic manures. At the 15-tons/ha level of compost, treatment MOW + NPK yielded the maximum seeds (9.8 tons/ha) compared to control (7.2 tons/ha) (p > 0.05). This supports previous research findings that NPK and organic fertilizer treatments improved crop growth and production. Researchers discovered that the combined application of NPK and organic manures had a positive impact on crop growth and production (Kandil et al., 2020). Grain yield increased as a result of enhanced growth and yield attributing variables, nutrient usage efficiency, and grain development. Combined organic and inorganic fertilizer treatments increased nutrient usage efficiency and produced comparable maize yields to inorganic N fertilizer and organic fertilizer enhanced with inorganic nitrogen (El-Gawad & Morsy, 2017). The result in this experiment was also in agreement with Kabato et al., 2022 that higher wheat yields in the treatments that used a combination of inorganic and organic fertilizers. The organic matter in composts improves many biological and physical-chemical soil properties. This may explain why maize parameters go up a lot when a lot of compost is used or when a combination of organic and chemical fertilizers is used instead of just chemical fertilizer (Nigussie et al., 2021).

Plant height, cob length, number of seeds per cob, seed weight per cob and 100-seed weight were deemed to have increased maize yield. Compost at the rate of 15 tons/ha produced maximum maize plant height (189.3 cm and 174.7 cm), number of seeds per cob (499.99 and 502.9), and seed weight per cob (211.7 g and 175.4 g) followed by 10 tons/ha as it was recorded plant height (183.8 cm and 170 cm), number of seeds per cob (449.2 and 492.2), seed weight per cob (175.4 g and 209.8) for the both years. For the two parameters number of seeds per cob and seed weight per cob were found higher in second year than first year. The control treatment (MOW) consistently yielded the lowest values for the plant characteristics in both seasons. Lower grain yield from the control implies that insufficient nutrients reduced light interception. This was seen in the form of a lower leaf area index. However, when artificial fertilizers were supplied with organic composts and these compost rate was increased from a low 5 tons/ha to a high rate of 15 tons/ha, the yield response was dramatically altered. Similar findings were reported by Kenea et al., (2021), who found that a higher yield response was obtained for maize as NPK was added to the treatment. Based on the results, it appears that 15 tons of compost per hectare (ha) supplemented with NPK fertilizers is optimal for maximizing grain yield per cob. This may be because this treatment maximizes the efficiency with which nitrogen is used, in addition to making phosphorus and potassium readily available. It appears unnecessary and expensive to apply more than 15 tons of treatment per hectare. These findings are consistent with (Gao et al., 2020) who found that fertilizer use increased the average number of grain rows per corn cob.

Incorporating compost into soil is gaining popularity as it improves soil quality and inceases agricultural yields (Wright et al., 2022). Several researchers also found the similar results that increasing compost rate increased maize yield and yield components (Kandil et al., 2020). Compost boosts soil fertility, stabilizes nitrogen uptake and corn yields, and lowers nitrogen loss (Farid et al., 2022). Improved crop yields and soil fertility status can be attained through the implementation of organic fertilizer modification techniques like compost (Hernández et al., 2016). Organic amendments increase crop productivity by boosting soil nutrients. (van Zwieten, 2018).

Another study found that compost boosted growth and production (Quy Tuong et al., 2019). Maximum yields of maize and wheat were achieved in that setting by combining organic manure with inorganic fertilizer (ZHAO & ZHOU, 2011). In contrast, compost increases production if applied to complement artificial fertilizer applications (NPK) to supply extra nutrients (J. Wang et al., 2023). Maize growth and yield were increased when NPK was combined with organic manure, as shown (El-Gawad & Morsy, 2017). Organic additions and compost help maintain soil productivity. The NPK plus compost treatment enhanced maize seed production more than the NPK treatment (Liang et al., 2021).

Maize total biological yield (29.3 and 28.7 tons/ha for 2022 and 2023), and stover dry yield (19.5 and 19.0 tons/ha for 2022 and 2023) were enhanced with MOW compost and NPK (20:20:20) fertilizers at 15 tons/ha. The NPK fertilizer and manure treatment resulted in a significantly higher (p > 0.05) biological yield in the maize crop compared to the control treatment, suggesting that the fertilizer and manure had an influence on the crop during its growth stage. All treatments except the control had more biomass (p > 0.05), confirming the findings of the literature. (Speratti et al., 2017) and demonstrating the importance of organic fertilizers on maize biomass (Table 4).

Both organic and inorganic fertilizers considerably (p ≤ 0.05) enhanced the growth parameters and yields of maize when compared to the control. Despite this, (Jjagwe et al., 2020) found no statistically significant difference (p ≤ 0.05) in maize yields between fertilizer treatments. In another study, compost treatment improved soil fertility, nitrogen uptake, plant vegetative growth, and yield (Imran et al., 2021). This study supports the recent emphasis on soil amendments in agriculture to enhance soil quality and crop output (Antonious & Antonious, 2016). Maize’s growth and yield were positively affected by organic additions, with only minor variations between types of organic amendments. Organic additions boost crop yields in arid environments and maize yield performance.

The treatment combination of vermiculite with MOW has observed several benefits during the study. Firstly, vermiculite helps to improve soil aeration and drainage, preventing waterlogging and allowing roots to access oxygen more easily. As a result, in healthier root development and improved nutrient uptake by the maize plants. Additionally, vermiculite has the ability to retain moisture in the soil, reducing water stress for the maize plants during dry periods. This can be particularly beneficial for the selective regions with limited water availability or during drought conditions. The organic compost, when combined with vermiculite, enriches the soil with essential nutrients such as nitrogen, phosphorus, and potassium, as well as micronutrients. These nutrients are released slowly over time, providing a steady supply to the maize plants throughout their growth stages. It can contribute to improved plant growth, increased yield, and better overall plant health.

Protein is another important component of maize crop besides biomass and yield. The study found that applying 15 tons/ha NPK fertilizer with manure increased protein content by 1.6 and 2.3% for compost rate of 10 and 5 tons/ha respectively. The increase in protein content following NPK and manure application is consistent with research (Cai et al., 2019). X. X. Wang et al. (2017) who suggested that high chlorophyll content may be responsible. Overall, 15 tons/ha manure and blended fertilizer (NPK) improved biomass, yield, and protein content.

5. Conclusion

The scientific consideration for arid land agriculture has dramatically increased over the past decade, but few studies have been conducted on the conversion of MOW to composting for maize production. We used the conversion of MOW approach to assess the quality of compost for crop yield, and explored the resources of soil amendments. It appears most likely that various interesting and important characteristics are available in the composts derived from MOW. These features are valuable and significant in the preparation of these composts for maize production. The findings of the two-year field trials showed that the growth, production, and quality characteristics of maize in a dry agro-ecosystem were significantly affected by the various additives added municipal organic waste composts and its combination with NPK treatments.

6. Recommendation

The utilization of municipal organic waste-derived compost for sustainable maize production presents a promising and environmentally conscious approach to address the ongoing issue of waste generation in urban regions. Moreover, the application of such composts in agricultural fields for crop production further enhances the eco-friendliness of this practice. Based on our extensive research findings, we propose the following recommendations to policymakers, agronomists, and farmers in order to promote sustainable crop production through the utilization of composts derived from municipal organic waste (MOW).

• Compost made from MOW raise safety concerns because of the potential for heavy metal transfer to plants and ultimately humans. In our study, Cd levels were determined to be BDL (below detectable level), and low Cr concentrations and an apparent lack of other heavy metals in the MOW composts reduce the danger associated with using them on croplands. So, mixing additives at the rate of 10% of total weight of MOW are recommended to produce compost but we encourage more investigations to evaluate safe and optimal MOW compost application rates.

• 15 tons/ha compost rate positively influenced plant growth and yield in all aspects and we recommended this compost rate for organic maize production but follow-up field experiments are highly recommended to evaluate the predicted rates.

• It is highly recommended to conduct multi-environment trials to assess the various com­binations of MOW compost and inorganic fertilizers. This approach will allow us to thoroughly examine the impact of different soil types and climatic conditions on the growth and yield of maize after the application of MOW compost alone or in conjunction with NPK fertilizers. In conclusion, it is highly recommended to conduct additional research in order to assess the economic viability of utilizing MOW compost either independently or in conjunction with NPK.

Acknowledgments

The authors acknowledge DR. Mohammed Reda Kabli dean of the faculty of engineering at King Abdulaziz university and Professor Qing Chen from the College of Resources and Environmental Sciences, China Agricultural University, Beijing, China, for their help in writing the project proposal and achieving the funding under Project 397. The authors also extend their appreciation to the Deputyship for Research and Innovation, Ministry of Education in Saudi Arabia, for funding this research work through project number (397).

Disclosure statement

The authors state that the research had no commercial or financial conflicts of interest.

Additional information

Funding

The authors extend their appreciation to the Deputyship for Research and Innovation, Ministry of Education in Saudi Arabia, for funding this research work through project number (397).

Notes on contributors

Shahadat Hossain

Shahadat Hossain is working as a scientific officer at the Bangladesh Agricultural Research Institute. He is currently pursuing a PhD degree with the Department of Agriculture at King Abdulaziz University, Saudi Arabia. His research interests include organic waste management for sustainable crop production.

Samir G. M. Al-Solaimani

Professor Samir G. M. Al-Solaimani works on soil chemistry and fertility in the Department of Agriculture at King AbdulAziz University. He has dedicated his career to researching irrigation, fertilization, and the utilization of treated sewage water for crop production. His current research interests are in phytoremediation and organic crop production.

Fahad Alghabari

Dr. Fahad Alghabari is a professor in the Department of Agriculture at King AbdulAziz University. He has obtained his PhD from the University of Reading, UK. The current research interest is sustainable crop production techniques for stress environments in Saudi Arabia.

Khurram Shahzad

Dr. Khurram Shahzad A lifecycle-based ecological assessment expert with a background in chemical engineering and environmental sciences. More than ten years of international experience and cross-sector exposure. Experienced in team-based and multidisciplinary projects. Passionate about sustainability and dedicated to sustainable development, circular economy, climate change issues, net zero emission technologies, processes, and services that can positively contribute to society/organization’s economic and social impacts. The google scholar citation index reveals that his published work has been cited more than 2500 times with an H-index of 21 and an i-10 index of 45.

Muhammad Imtiaz Rashid

Dr. Muhammad Imtiaz Rashid He completed his PhD from Wageningen University, The Netherlands, in soil quality and farming system ecology groups. He has >10 years’ research experience in soil, plant, and environmental interactions. His research interests include nutrient cycling in agro-ecosystems, organic waste (municipal and agricultural) management for composting, biochar, and nanobiochar production and their sustainable use in agriculture, as well as assessing the microbiology of compost. He also worked in soil-plant interactions and feedback, nano-agrochemicals in agriculture and their toxicity assessment for soil biota, soil functions and plant production, reclamation of degraded soil with use of organic fertilizers, nanomaterial use in agriculture for sustainable and smart fertilizers production.