1. Introduction
Agriculture in the Sahel faces many problems, such as soil depletion, which leads to low crop productivity and remains the most alarming threat [1] [2]. Located in the heart of the Sahel, Niger has a relatively undiversified economy that is largely dependent on agriculture. Like in other Sahelian countries, land degradation in Niger results in a decrease in soil fertility and low agricultural production, although the fact that agriculture is the main economic activity in the country, employing nearly 80% of the rural population [3]. This drop in productivity concerns several crops, including maize (Zea mays L.)
Maize is a cereal plant of the Poaceae family, producing grains and haulms widely used in sub-Saharan Africa [4]. It is an annual plant with almost no tillering [5] cultivated worldwide on more than 130 million hectares, with an estimated yield of 5.71 tonnes/ha in 2022 [6]. This yield is estimated at 2.22 tonnes/ha in Africa and 678 kg/ha in Niger [6]. In sub-Saharan Africa, maize grains are the basis for human food and also serve as raw material in several industries, and the residues are used for animal feed [7]. The maize plant plays an essential role in food security in Niger.
In Niger, corn is consumed grilled or after being transformed into flour to make dough or local couscous [8]. The deficit of agricultural products during the 2023 campaign led in 2024 to a steep rise in corn prices in sub-Saharan Africa in general and in Niger in particular [9]. According to the same authors, the kg of corn, which in previous years was between 100 FCFA and 150 FCFA, reached nearly 400 FCFA in 2024. Consequently, it is essential to create the conditions to increase the production of this commodity in sub-Saharan Africa in general and in Niger in particular. Furthermore, the use of fertilizers on improved varieties could contribute further to improving agricultural production in the context of advanced land degradation. Indeed, agricultural activity is only profitable with considerable nutrient inputs [10]. Researchers, namely Mukengere [11], Useni [12], Li [13], Nyembo [14], Koulibaly [15], Coulibaly [16], and Bakayoko [17] have shown that the contribution of organic manure (from chickens, cows), mineral fertilizers or the combination of the two fertilizers make it possible to improve the above-ground and below-ground biomass, the weight of grains per ear and the grain yield of corn.
However, beyond 1100 kg/ha of mineral fertilizers, corn grain yield decreases [18]. In addition, the timing of basal and maintenance fertilization can improve corncob weight [19]. The uncontrolled use of all these fertilizers can have negative repercussions on the environment and human health; hence, it is important to know when, in what form, and in what quantity to provide fertilizing elements [20]-[22].
Today, few studies have been conducted in the Zinder region on the development of appropriate maize cultivation techniques to boost its productivity. Thus, to promote and popularize its cultivation in rural areas, this study aims at finding the best fertilizer to improve the productivity of the “Maka” maize variety in the Zinder region in Niger Republic.
2. Materials and Methods
2.1. Description of Study Area
The study was conducted at the Experimental site of the Faculty of Sciences of André Salifou University (UAS), located 13˚48'N latitude and 8˚59'E (Zinder region in Niger Republic) in the 2022/23 rainy season. The area is characterized by low rainfall, with 350 - 450 mm of annual rainfall mean, peaking in July and August. The dominant soil type of the site is sandy-clayey. The mean annual temperature ranges between 21.6˚C to 35.51˚C.
2.2. Experimental Materials and Design
The material used is an improved variety of corn, locally called ‘‘Maka’’, obtained from the National Institute of Agronomic Research of Niger (INRAN/Zinder).
The experimental design is a complete randomized block with three repetitions and two factors: the variety in large plots and the fertilizer in small plots and at seven levels. The repetitions are 3 m apart and each elementary plot of 2.75 m2 (2.75 m*1 m) is 1 m apart from the other. Each plot is composed of 16 pockets arranged in lines of 0.75 m and the pockets are 0.2 m apart. The treatments are composed of a Control treatment (T0; without any fertilizer input), a treatment with well-composted poultry manure (T1; 7 tons/ha), a treatment with NPK mineral fertilizer (T2; 0.3 tons/ha), a treatment with poultry manure mixed with composted cow dung (T3; 7 tons/ha), a treatment with mineral fertilizer Urea (T4; 0.2 tons/ha), a treatment with NPK mixed with composted cow dung (T5; 0.15 tons/ha and 3.5 tons/ha respectively) and a treatment with composted cow dung (T6; 7 tons/ha). All these fertilizers were weighed before application using a high-precision balance to the order of a centigram.
The plots are plowed before sowing. Sowing was done by hand due to three grains per pocket, placed at a depth of about 5 cm after a 30 mm rain in June. The plants were thinned to one plant per pocket with a density of 66,666 plants/ha. 3 weeding sessions were carried out respectively on the 14th, 30th, and 45th day after sowing, and the spreading of fertilizers was carried out after sowing in three fractions, namely the 15th, 30th, and 45th days after sowing (DAS). A phytosanitary treatment with the anti-caterpillar insecticide was carried out on the 38th DAS at the time of female flowering.
2.3. Data Collection and Analysis
All of the pockets were measured, and the measurements focused on the agronomic and morphological parameters of corn. The quantitative and qualitative descriptors used are respectively, those proposed by [23] and [24]. These are germination test or emergence percentage; Male flowering; Female flowering; Maturity; Number of leaves; Leaf length; Leaf width; Stem diameter; Plant height; cob insertion height; Number of nodes; Number of cobs per plant; cob length; cob diameter; Number of rows per cob; Number of grains per row; Dry cob weight; Weight of 100 grains; Panicle length and Number of branches per panicle. A sample of three leaves and one cob per plant taken at random were measured in order to calculate their average.
Analysis of variance (ANOVA) was used with Minitab 18 trial version 8.1 software to compare means. Principal component analysis (PCA) was performed with R software version 4.1.0 [25] to assess the influence of fertilizers.
3. Results
3.1. Agronomic Characters
The grains germinated at the same time in all treatments (Table 1). 100% appearance of male and female flowers was observed at treatment level T1 with an average value of 37 days after sowing (DAS) with a difference of 7 days less than the control treatment T0 (Table 1). The time of grain maturity was early recorded with treatments T1 and T2, respectively 66 and 67 DAS, moderately recorded in T3, T4, and T5 with all 69 DAS, and late recorded in treatment T0 and T6, respectively 71 and 72 DAS (Table 1). Also, the highest dry cob yield was obtained at T1 with 7.48 t/ha, followed by T5 with 6.4 t/ha, while the control treatment T0 recorded 1.56 t/ha as the lowest dry ear yield (Table 1).
Table 1. Analysis of the effects of fertilizers on agronomic characters.
Treatment |
FloM (JAS) |
FloFe (JAS) |
Matu (JAS) |
Rnd |
Moy |
E.typ |
Moy |
E.typ |
Moy |
E.typ |
Rendement en ha |
T0 |
43.08a |
3.332 |
48.25a |
3.6 |
71.85a |
2.432 |
1.56d |
T1 |
37.35d |
1.828 |
40.68d |
1.98 |
66.68d |
1.776 |
7.48a |
T2 |
38.08cd |
2.112 |
42.37c |
2.15 |
68.25c |
1.48 |
5.62b |
T3 |
38.52c |
2.414 |
42.56c |
2.592 |
69.22b |
3.005 |
6b |
T4 |
38.54c |
2.269 |
42.16c |
2.177 |
69.14b |
2.154 |
5.45b |
T5 |
38.22cd |
1.905 |
42.25c |
1.874 |
69.29b |
2.192 |
6.39ab |
T6 |
41.16b |
3.309 |
45.29b |
3.274 |
71.62a |
2.059 |
4.25c |
P |
0.000 |
0.000 |
0.000 |
000 |
S |
*** |
*** |
*** |
*** |
Statistically equal with the Fisher method; S: Significance at the 5% threshold; NS: Not significant; ***: Very highly significant; T0: Control; T1: Composted poultry manure; T2: NPK 15-15-15; T3: Composted poultry manure + Composted cow dung; T4: Urea; T5: NPK + Composted cow dung; T6: Composted cow dung; P: Probability; E.typ: Standard deviation; FloM: Mean days of 100% male flowering; FloFe: Mean days of 100% female flowering; Matu: Mean day of 100% maturity.
3.2. Quantitative Morphological Characters
Unlike plant height (Hp), leaf length (Lfe), leaf width (lfe), and number of leaves (Nbrfe), the mean value of stem diameter gradually increased from 30th to 50th DAS and decreased at maturity (Table 2). Treatments T2, T1, and T5 gave the highest plant heights at maturity with respective mean values of 259.02 cm, 257.98 cm, and 252.46 cm, while the lowest values were obtained with treatment T0 and T6 with respectively 172.27 cm and 230.21 cm (Table 2). The highest values of the number of stem nodes, number of leaves, length, and width of the leaf are recorded at the level of treatments T1, T4, and T5, while the lowest values are recorded with the control (Table 2). Treatment T1 has the highest number of panicle branches (19.09) and the highest value of panicle length (41.44 cm; Table 2).
The height of the stem and that of insertion of the first cob, the number of ears per plant, the length and diameter of the ear, the weight of the ear, the number of rows per ear, the number of grains per row, the number of grains per ear and the weight of 100 grains are different from one treatment to another. Indeed, with the exception of the height of insertion of the first ear, the average values obtained with treatment T1 are all higher than those obtained with the other treatments. The highest averages recorded after treatment T1 of the NbrE, PE, and P100Gr were recorded with treatment T5, respectively 2.02 g, 279 g, and 22.29 g (Table 2). The greatest height (89.09 cm) of insertion of the first ear was recorded with treatment T2 (Table 2). For all the variables, the lowest values were recorded at the level of the control treatment T0 (Table 2).
Table 2. Analysis of the effects of fertilizers on quantitative morphological characters.
|
Traitement |
T0 |
T1 |
T2 |
T3 |
T4 |
T5 |
T6 |
P |
S |
NbrN |
Moy |
10.97d |
13.06a |
12.47bc |
12.12c |
12.85ab |
12.70ab |
12.14c |
0.000 |
*** |
E.typ |
1.139 |
0.976 |
1.01 |
0.981 |
0.945 |
0.849 |
1.01 |
|
|
Nbrfe |
Moy |
12e |
14.25a |
13.64bc |
13.43cd |
13.95ab |
14.08a |
13.18d |
0.000 |
*** |
E.typ |
0.851 |
1 |
1.041 |
0.987 |
1.01 |
1.048 |
0.938 |
|
|
Lfe (cm) |
Moy |
77.83d |
93.33a |
88.99b |
87.30b |
93.53a |
89.33b |
84.36c |
0.000 |
*** |
E.typ |
5.999 |
6.746 |
5.676 |
6.085 |
7.29 |
5.691 |
4.226 |
|
|
lfe (cm) |
Moy |
7.020e |
9.16a |
8.60bc |
8.23d |
8.91ab |
8.22d |
8.31cd |
0.000 |
*** |
E.typ |
0.4976 |
0.76 |
0.803 |
0.947 |
0.792 |
0.971 |
0.749 |
|
|
DT (mm) |
Moy |
21.66d |
30.76b |
30.44b |
29.99b |
32.01a |
31.04ab |
28.09c |
0.000 |
*** |
E.typ |
3.523 |
3.014 |
3.45 |
3.098 |
2.352 |
2.127 |
2.509 |
|
|
Hp (cm) |
Moy |
172.27e |
257.98a |
259.02a |
241.63c |
248.52bc |
252.46ab |
230.21d |
0.000 |
*** |
E.typ |
24.1 |
17.93 |
22.51 |
22.98 |
25.34 |
20.96 |
26.48 |
|
|
HIE (cm) |
Moy |
59.86e |
84.7ab |
89.09a |
77.58bc |
76.2c |
85.55a |
67.97d |
0.000 |
*** |
E.typ |
17.79 |
17.06 |
24.93 |
16.68 |
15.96 |
22.77 |
15.2 |
|
|
NbrBPa |
Moy |
13.47d |
19.08a |
16.29bc |
15.93bc |
16.95bc |
17.56ab |
15.18cd |
0.000 |
*** |
E.typ |
3.759 |
5.335 |
3.853 |
3.905 |
3.957 |
5.214 |
4.783 |
|
|
Lpa (cm) |
Moy |
33.06c |
41.44a |
38.53b |
39.05ab |
38.06b |
38.06b |
37.95b |
0.000 |
*** |
E.typ |
5.831 |
6.418 |
7.93 |
5.43 |
6.435 |
6.156 |
4.673 |
|
|
NbrE |
Moy |
1.041e |
2.25a |
1.77bcd |
2.02ab |
1.68cd |
1.89bc |
1.58d |
0.000 |
*** |
E.typ |
0.2019 |
0.812 |
0.6601 |
0.6681 |
0.719 |
0.722 |
0.5392 |
|
|
LE (cm) |
Moy |
14.76d |
19.99a |
18.78b |
17.75c |
19.15b |
19.21ab |
17.75c |
0.000 |
*** |
E.typ |
1.068 |
2.498 |
1.871 |
2.234 |
2.071 |
1.632 |
2.103 |
|
|
DE (mm) |
Moy |
32.49e |
49.44a |
46.08bc |
43.90d |
46.27bc |
46.68b |
44.91cd |
0.000 |
*** |
E.typ |
3.029 |
4.028 |
3.804 |
3.416 |
3.777 |
3.694 |
2.904 |
|
|
NbrR |
Moy |
13.20d |
18.33a |
16.56bc |
15.81c |
17.06b |
17.08b |
16.22bc |
0.000 |
*** |
E.typ |
1.75 |
2.355 |
2.072 |
1.841 |
2.206 |
2.916 |
2.013 |
|
|
NbrGrR |
Moy |
22.27e |
38.89a |
36.43b |
34.20c |
37.43ab |
38.72a |
32.20d |
0.000 |
*** |
E.typ |
3.375 |
3.888 |
4.037 |
4.182 |
4.021 |
3.63 |
4.968 |
|
|
P (g) |
Moy |
70.26e |
336.6a |
252.9c |
270.2bc |
245.3c |
287.8b |
191.62d |
0.000 |
*** |
E.typ |
16.02 |
87.3 |
91.4 |
90.4 |
86.9 |
91.5 |
66.3 |
|
|
P100Gr (g) |
Moy |
15.47e |
23.04a |
21.79bc |
22.29ab |
21.11c |
21.19bc |
18.75d |
0.000 |
*** |
E.typ |
2.761 |
2.627 |
2.898 |
3.13 |
2.688 |
2.742 |
3.114 |
|
|
For each character, the values with the same letters are statically equal with the Fisher method; S: Significance at the 5% threshold; ***: Very highly significant; T0: Control; T1: Composted poultry manure; T2: NPK 15-15-15; T3: Composted poultry manure + Composted cow dung; T4: Urea; T5: NPK + Composted cow dung; T6: Composted cow dung; P: Probability; E.typ: Standard deviation; Avg: Mean; NbrN: Number of nodes; Nbrfe: Number of leaves; Lfe: Leaf length; lfe: Leaf width; DT: Stem diameter; HP: Plant height; NbrBPa: Number of branches per panicle; LPa: Panicle length; NbrE: Number of spikes; LE: Spike length; DE: Spike diameter; NbrR: Number of rows; NbrGrR: Number of grains per row; PEtot: Total weight of dry ear; P100gr: Weight of 100 grains.
3.3. Effect of Fertilizers on Corn Production
The principal component analysis (PCA) shows that the first two components absorb 67.87% of the total variability of the information (Figure 1). Axis 1 alone explains more than 57.42% of the total variation observed. The PCA results show that all treatments are different from the control treatment T0 (Figure 1). Considering the first plane, the treatments are organized into 4 distinct groups: group 1 consisting of treatment T0 on the far left of axis 1, followed by group 2 consisting of treatment T6 on the left of the origin on axis 1, group 3 consisting of treatment T2, T4 and T5 on the right of the origin on axis 1 and group 4 consisting of treatment T1 on the far right of axis 1. The first four groups are distinguished from each other by axis 1 and group 5, consisting of treatment T3 is distinguished from the rest by axis 2. Furthermore, considering Figure 2, we note that groups 1 and 2 (treatment T0 and T6) are characterized by late male (FloM) and female (FloF) flowering unlike the other treatments. Group 4 is much more characterized by ear length (LE); the number of grains per row (NbrGrR); fresh ear weight (Pefrai); ear diameter (ED); stem diameter (SD); total dry ear weight (PEtot) and plant height (HP) than group 3.
![]()
Figure 1. Organization of treatment groups based on their similarity.
Figure 2. Contribution of the characteristics to the building of the first two components of the PCA.
4. Discussion
The result of the variance analysis shows that fertilizers significantly affect most of the agronomic traits studied. Comparing the mean values, all treatments gave a higher result than the control treatment (T0, without fertilizer). This result confirms that of [26], who observed differences in the durations of the vegetative and reproductive phases for four types of fertilizer. It emerges from this experiment that agronomic parameters such as male and female flowering and maturity studied at the level of composted poultry manure (T1) gave the best results for precocity. In addition, the best yield in dry corn cobs was obtained with treatment T1, with a yield greater than 7 tons per hectare. Treatment T1 and T5, respectively made it possible to obtain 4.8 and 4.2 times the yield obtained by the control. The same observation was made by [26], who shows that organic manure based on chicken droppings improves corn yield compared to the control treatment. In addition, the combination of composted cow dung with NPK made it possible to obtain 4.2 times the yield obtained with the control treatment. This result confirms that of [11], who also shows that the combination of organic and mineral fertilizers creates the best production conditions.
The results show that vegetative growth parameters such as plant height, stem collar diameter and number of leaves, leaf length and width at 35th DAS, 50th DAS, and maturity have different values between treatments and gave greater growth to treatment T1. This finding could be explained by the availability of mineral elements, including nitrogen, phosphorus, and potassium, in organic fertilizers based on poultry droppings for crop growth and development [27]. These results corroborate those of [22], who show that treatments based on poultry droppings have significant repeated and residual effects on soil chemical parameters and that repeated application of poultry droppings still induces significant differences, including the highest N, P, and K contents. Also, plots treated with mineral manures or in combination with organic fertilizer gave a yield significantly different from unfertilized plots. This is due to the fact that the major nutrients in mineral fertilizers are substances that are readily assimilated by the plant. Kiari [28] notes that in the Maradi and Dosso regions, the use of NPK in sorrel cultivation favorably increased the leaf and grain yield of the latter.
Comparison of the mean stem diameter value showed that the mean values at maturity slightly decreased compared to those at the 35th and 50th DAS. This has already been reported by [26] in their study on “The effect of four types of fertilizers on the growth and productivity of two maize genotypes”, whereby they found that the mean values of collar diameter of plants treated with any fertilizer remain statistically equivalent from 85th to 92nd DAS.
As for the vegetative parameters, the contribution of poultry manures with or without the addition of mineral fertilizers significantly influenced all the yield parameters. The number of ears per plant, the number of grain rows per ear, the weight of grains per ear, the weight of 100 grains, and the grain yield were significantly affected by the contribution of fertilizers. The highest averages in number of ears, the weight of ears, and the weight of 100 grains were obtained with the treatment in composted poultry manure T1, followed by T5, which is a combination of cow dung plus NPK. These results could be due to the fact that the phosphorus (P) contained in these manures promotes fertilization, fruiting, and grain formation. Similar results were reported by [29], according to which the contributions of composted poultry manure and NPK during the rainy and dry seasons on the cultivation of three okra varieties had positive effects on the growth and the production variables of the plants.
The principal component analysis carried out on the agronomic and morphological characteristics shows that treatment T1, followed by treatment T5 of group 3 are clearly far from the control treatment T0. This analysis also confirms that treatment T1 is clearly the best compared to the others. This result corroborates that of [26], which shows that organic manure based on chicken droppings improves corn productivity compared to the control treatment.
5. Conclusion
The results of the study have shown that the treatment with composted poultry manure (T1) increases corn production. This treatment is the best for corn production. In addition, the combination of composted cow dung mixed with composted poultry manure (T5) and the combination of composted cow dung mixed with NPK (T3) also made it possible to obtain good yields of dry corn cobs. Finally, it appears from the study that the three treatments, including composted poultry manure (T1), the combination of composted cow dung with composted poultry manure (T5), and the combination of composted cow dung mixed with NPK (T3), are recommended to farmers in order to improve corn production and reduce environmental pollution following the use of mineral fertilizers.