By Kehinde Ojeniyi, Ngonidzashe Chirinda, Krishna Devkota, and Donald Madukwe
Researchers evaluated the effects of optimizing types and amounts of fertilizer, based on national and regional fertilizer recommendations, on soil characteristics, nutrient use efficiency, and maize production in the mid-belt region of Nigeria.
Maize plays a crucial role as a staple cereal crop in Nigeria. This is fueled by the country’s growing population, expanding poultry sector, and burgeoning food processing industry. Studies indicate that the potential yields of maize in Nigeria could range from 9 to 12 t ha-1 (GYGA, 2017; Tofa et al., 2020), yet the average yield hovers between 1.3 to 2 t ha-1. This results in an annual production of approximately 11 million t (Mt) (FAOSTAT, 2023; Liverpool et al., 2017), which is inadequate if compared to an estimated annual demand of 12 to 15 Mt (The Nation, 2021). How to address this gap of 2 to 4 Mt, satisfy escalating food requirements, and enable opportunities to export to other countries remain critical research questions.
Nigerian maize farmers in the mid-belt region commonly apply blended triple-15 NPK fertilizers at 300 kg/ha plus a mid-season topdressing of urea at 100 kg/ha (IITA, 2020). However, outdated blending technology often leads to uneven distribution of fertilizers in the field, and suboptimal nutrient delivery to plants (Pichler et al., 2017). Given this situation, the use of straight fertilizer types can allow nutrients to be applied more precisely to match the recommended rate and timing needed for optimal nutrient absorption and plant uptake. This research is focused on assessing the effect of applying national and regional fertilizer recommendations, in both straight and blended forms, on soil properties, nutrient use efficiencies, and maize productivity. Many factors determine the yield gap of maize, including crop, soil, and climatic factors. In this study, we focus only on optimal fertilizer application. Other factors must also be considered to fully achieve the potential yield.
Study site description
Nigeria’s guinea savannah zone is characterized by a single rainy season from April to September and a dry season from December to March. Average annual rainfall is 1200 mm and the average temperature is 28 C (World Bank, 2021). Soil at this location was sandy loam in texture with a pH of 6.5, low available iron (Fe) concentration, and soil organic carbon (C) and total nitrogen (N) both below critical thresholds (Shehu et al., 2015).
Prior to the start of the experiment, maize was grown at site 1, and tomatoes at site 2. The land was cleared with herbicide (paraquat) at 16.7 ml L-1 of water, manually ploughed after 3 days, and planted with the Super-king F1 maize variety 4 days later with a spacing of 70 cm Å~ 30 cm (48,000 plants ha-1). Weeding was done manually at 2 and 5 weeks after seeding (WAS). Drip irrigation was provided at 1.3 L hr-1, twice daily, until the rainy season began.
Blended versus straight fertilizer forms
An unfertilized control plot (T1) and farmer’s current fertilization practice (T2) were compared with NPK Blends (T3 and T5) to evaluate the potential yield from recommended practices, as well as with split applications (T4 and T6) to assess the yield and efficiency of using straight fertilizers.
Table 1. Description of fertilizer source, rate, and timings for maize planted in the guinea savannah zone, Nigeria.

As is outlined in Table 1, farmer practice (T2) received a 15-15-15 NPK blend applied at 14 DAS, followed by a urea top-dressing at 28-30 DAS. Treatment 2 timings, methods and rates were based on a pre-experiment survey on farmer practice. National and regional recommendations were assessed with treatments T3 and T5, which received the NPK blend at 7 DAS and 30 DAS (IITA, 2020; Kamara et al. 2022). Treatments T4 and T6 tested the national and regional recommendation schemes but with straight fertilizer sources (Urea, SSP and MOP). These treatments used split doses at 7 DAS, 30 DAS, and 60 DAS to better align with the nutrient requirements of maize throughout the growing season.
Considering the dynamic nature of soil N mobility, leaching and volatilization, N applications were split into three stages: 25% basally, 50% at V10 stage or 30-32 DAS, and 25% at the VT/R1 stage at 65 DAS (Bender et al., 2013). Since phosphorus (P) is crucial in the early crop stages, while potassium (K) is relatively immobile in soil with minimal fixation, these two nutrients were respectively applied at 75% and 50% at 7 DAS, 25% and 30% at the first top dressing, and 0% and 20% at the second top dressing.
Fertilizer was surface applied in the farmer practice treatment while all other treatments used a spot application 2 to 5 cm beneath the soil.
Maize crop development: Days to tasseling and silking
Control plots took longer to reach the 50% tasseling and silking stages compared to other treatments (Fig. 1). At site 1, NR-NPK and RR-split reached 50% tasseling in 49 days, while the control took 55 days. At site 2, FP, NR-NPK, and RR-NPK reached tasseling in 54 to 55 days, RR-split took 66 days, NR-split took 61 days, and the control took 70 days.

For days to silking, at site 1, most fertilized plots reached 50% silking in 55 days, but the control took 61 days. At site 2, the control and NR-split took the longest to reach 50% silking at 73 and 69 days, respectively, FP and RR-split were faster at over 60 days, and NR-NPK and RR-NPK took less than 60 days to reach this crop stage. The delayed tasseling and silking in the control group were likely due to earlier crop establishment in fertilized plots where better nutrient availability promoted faster development.
Yield and yield attributes
Generally, grain yield increased with split applications of straight fertilizers compared to the treatments using the NPK blend (Table 2). The regional recommendation (RR-split) treatment generated the highest grain yields of 2.37 t ha-1 (site 1) and 3.08 (site 2) t ha-1, which points to the apparent advantage to adopting a more regional approach to nutrient use. Yields at both sites for FP, NR-NPK, NR-split, and RR-NPK were statistically similar.
Table 2. Maize yield as affected by straight and compound fertilizer use in mid-belt, guinea savannah region, Nigeria.

Nutrient efficiency
Mean N uptake efficiency ranged from 0.52 to 0.55 across sites and treatments, indicating plants absorbed about half of the amount of applied N (Table 3). Mean P uptake efficiency was 0.39 and 0.38, respectively.
Table 3. Nutrient uptake efficiency for maize as affected by fertilizer treatment, guinea savannah zone, Nigeria.

Mean K uptake efficiency ranged from 0.79 to 1.2 and there were no significant differences between blend and split application across the sites. Overall, P uptake efficiency was low across all treatments, consistent with Bah et al. (2006). Anas et al (2020) reported N use efficiency ranging from 30.2% to 53.2%, while Gasper et al (2017) found K uptake efficiency to be between 1.5 and 2.5 in tropical soil.

Summary
Split applications, particularly in combination with the regional recommendation, generated the highest maize grain yields of 2.37 to 3.08 t/ha. Nitrogen uptake efficiency ranged from 0.44 to 0.56 kg N uptake per kg N applied, and P uptake remained steady near 0.39 kg P uptake per kg P applied. Potassium uptake exceeded 100% in certain treatments.
While blended fertilizers aim for tailored formulations, this research emphasizes the effectiveness of split application strategies with straight fertilizers, based on regional recommendations, to boost maize production in Nigeria’s mid-belt region. Split application of the regional recommendation providing 119:38:20 kg ha-1 of N, P, and K from straight fertilizer produced higher yields and better nutrient efficiency than NPK blends, and proved to be effective for optimum maize production in the region.
Mr. Ojeniyi (e-mail: kehinde.ojeniyi@um6p.ma) is a M.Sc. Student, School of Agriculture, Fertilization, and Environmental Sciences, Mohammed VI Polytechnic University (UM6P), Benguérir, Morocco. Dr. Chirinda is Professor Sustainable Tropical Agriculture, UM6P. Dr. Devkota is Senior Scientist, International Center for Agricultural Research in Dry Areas (ICARDA). Dr. Madukwe is Head of Agronomy, OCP Africa.
Cite this article
Ojeniyi, K., Chirinda, N., Devkota, K., Madukwe, D. 2024. Optimizing Split-Fertilizer Applications for Enhanced Maize Yield and Nutrient Use Efficiency in Nigeria’s Mid-Belt, Growing Africa 3(2): 10-14. https://doi.org/10.55693/ga32.MUMG1695
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