Influence of Crop Geometry and Different Sources of Fertilizers on the Morphology and Yield Attributes of Spring Maize (Zea mays L.)

Maize (Zea mays L.) is one of the crucial crops with a high range of adaptability, versatility and high yield potential that play a key role in ensuring global food security (Shiferaw et al., 2011; Thejesh et al., 2024). With the depleting resources in the agriculture sector, utilizing resources effectively is vital. Crop geometry is one of the most effective methods because it enables plants to make better use of resources like sunlight, water and nutrients from the soil to achieve enhanced plant performance in terms of the growth, productivity as well as crop quality (Thakur et al., 2020). Ensuring an optimal crop geometry implies that each plant receives enough light and helps to ensure that light is distributed uniformly (Mohan et al., 2021). Wider planting allows for efficient resource utilization. Better sunlight interception and moisture aid in superior photosynthetic activity (Uphoff et al., 2011), good plant-water relations and ultimately superior photoassimilates translocation from source to sink (Waghmare et al., 2018; Aliveni et al., 2025).
       
Fertilizers play a crucial role in providing essential nutrients to crop plants, enhancing their growth and yield. However, different types of fertilizers can have varying effects on plant performance (Balasubramanian et al., 2023). Conventional fertilizers are most widely used. The fertilizer has less nutrient use efficiency (Alemayehu et al., 2015) and most of the applied nutrients are lost in the form of various losses such as runoff, leaching, volatilization etc. They negatively impact the soil, degrade and lead to soil acidification, nutrient imbalances and fertility (Ju et al., 2009). Nano fertilizers utilize nanoparticles to deliver nutrients to plants. These nanoparticles with a unit size of 1-100 nm are significantly smaller than conventional fertilizer particles, allowing for more efficient absorption by plant roots (Badawi et al., 2022) and plant cells (Perez-de-Luque,  2017). Nutrients are released slowly, minimizing losses and environmental impact (Rathnayaka et al., 2018) and improve plant resistance to stress and diseases. Due to the unique features like high surface-to-volume ratio and nanoscale regime, nano fertilizers are engrossing the attention (Kumar et al., 2021).
       
Customized fertilizers are formulated to meet the specific nutrient needs of a particular crop or soil type by mixing two or more fertilizers which consist of all kinds of nutrient sources (including both macro and micro with or without inert material) (Rakshit et al., 2012). Less fertilizer is used, reducing costs and environmental impact (Majumdar et al., 2018). Ferticapsule is a new technology in which the recommended dose of fertilizers is filled in the empty gelatin capsule. These prepared gelatin capsules are placed near the plant root zone similar to the band placement of fertilizers which acts as the powerhouse for nutrients by creating a microenvironment. Nutrients are more readily accessible to plant roots. So, the current research has been implemented with the objective to evaluate the influence of crop geometry and different sources of fertilizers on the morphology, yield and quality attributes of spring maize (Zea mays L.).

Experimental details
 
The research trial was carried out at research farm, of the School of Agriculture, Lovely Professional University, Punjab, India during the spring season of the year 2022 and 2023. The soil of the research site was sandy loam texture with slightly alkaline in nature (7.8 pH); low level of available nitrogen (N) (210.74 kg/ha); high level of phosphorous (23.71 kg/ha) and moderate in potassium (171.26 kg/ha). The field trial was executed in split-plot design with the three main plots viz. S₁- 40 x 40 cm², S₂- 50 x 50 cm², S₃- 60 x 20 cm² and four sub-plots viz. F₁- Normal Fertilizer, F₂- Nano fertilizer, F₃- Ferti-capsules, F₄-Customized fertilizer in three replications after the randomization of treatments. Table 1 present detail of factors and treatment combinations applied during the experiment. Initially, with the help of a cultivator, the field was thoroughly ploughed to break the large clods followed by planking to ensure proper land levelling. Each replication divided into three main plots which were further divided into four sub-plots with a net plot size of 25 m². The variety (PMH-10) was selected for the experiment at a seed rate of 25 kg/ha. Recommended dose of N: P: K (120:60:40 kg/ha) was applied uniformly in all the plots given throughout the field trial period. Four representative plants were designated for sampling throughout the experiment from the center of each plot. The selected plants were tagged with indicative labels and used for recording the various observations related to morphological attributes viz. plant height (cm) and number of leaves were recorded separately. As the crop attained harvesting maturity, the crop was harvested from 3 m² of each plot. After being completely sun-dried, the cobs were threshed to separate the grains and, the stover was bundled and further weighed. The grain and yield were converted to tonnes per hectare (t/ha) after recorded for uniform analysis. Harvest index was computed with the formula mentioned below and expressed in per cent (%).
 

  

 
The obtained data was subjected to analysis of variance (ANOVA) by using R studio statistical computing software. The obtained results of treatments were tested by Duncan’s multiple range test (DMRT) at the 5% level of significance (Gomez and Gomez, 1984).

Morphological attributes
 
Plant height (cm)
 
The effect of crop geometry was found significant at all the growth stages (Table 2). The maximum plant height of 19.4, 77.2, 157.7 and 189.0 cm was recorded under S₂ while the minimum plant height of 15.7, 66.7, 145.4 and 176.7 cm was recorded under S₁ at 25, 50, 75 and 100 DAS respectively. Similarly, the different sources of fertilizers have shown their impact on plant height. The maximum plant height of 19.6, 77.6, 158.2 and 189.1 cm was recorded under nano fertilizers and minimum plant height of 15.4, 66.5, 144.4 and 176.1 cm was recorded under F₁ at 25, 50, 75 and 100 DAS respectively. The interaction effect of both factors on plant height was found to be statistically significant at 25 DAS (Fig 1). The maximum plant height of 20.7 cm was recorded under T₆, where T₇ and T₂ shared statistical parity with T₆. However, at other growth stages the data was found to be non-significant. An increase in plant height of 32.3%, 23.7%, 13.6% and 10.7% was recorded at 25, 50, 75 and 100 DAS respectively under T₆ over the T₉.




       
The application of nano fertilizers through irrigation i.e., fertigation during the initial growth stages might have positively affected the plant height (Reddy et al., 2022). More precision of foliar application of nano fertilizers at later stages has aided in efficient absorption and nutrient use efficiency (Maheta et al., 2023). The improved and continuous nutrient availability through nano sources at diverse physiological stages could have perhaps amplified the metabolic processes (cell division, cell respiration, cell elongation) (Meena et al., 2023). They might have provided balanced crop nutrition and promoted auxin synthesis in maize, which resulted in superior plant height (Rashmi et al., 2023). There was a lesser impact of spacing at 25 DAS when compared to the other growth intervals at which the good foliage cover was recorded. The wider plant spacing might have promoted the plant height by reducing the competition among plants for essential resources like light, water nutrients and space etc. Increased light interception enhanced photosynthesis activity and growth hormone production that promoted cell elongation (Meena et al., 2022). Improved nutrient and water absorption by roots resulted in improved nutrient content and better plant-water relations. Lower ethylene accumulation due to wider spacing, perhaps permitted the plant to focus on vertical growth which helped in attaining a virtuous plant height. Similar outcomes were obtained by (Akpan et al., 2021).
 
Number of leaves
 
The different crop geometries were effective in amplifying the leaf number at all the growth stages (Table 2). The maximum number of leaves (6.6, 9.9, 14.5 and 13.8) were recorded under S₂, while the minimum (6.7, 9.9, 14.5 and 13.8) were recorded under S₁ at 25, 50, 75 and 100 DAS respectively. The different sources of fertilizers have shown their effect on augmenting the leaf count. The maximum number of leaves (6.7, 9.9, 14.5 and 13.8) were obtained under F₂ and the minimum number of leaves (4.0, 7.9, 13.2 and 12.2) were obtained under F₁ at 25, 50, 75 and 100 DAS respectively. The interaction effect of both factors was found non-significant at all the growth stages except at 25 DAS (Fig 2). The maximum number of leaves (7.5) was recorded under T₆ and T₇. While the minimum number of leaves (3.5) was recorded under T₉. However, the treatments T₂ and T₈ have shared statistical parity with T₆. An increase in the leaf count of 53.3%, 32.4%, 14.9% and 19.9% was recorded at 25, 50, 75 and 100 DAS respectively under T₆ over T₉.


       
The residues of nano fertilizers in the soil due to the application through irrigation might have enriched the rhizosphere with nutrients which improved nutrient uptake due to targeted nutrient delivery. Especially the N that is crucial for chlorophyll synthesis and assisted in the growth of more leaves as the plant has more energy and resources to allocate for superior leaf and biomass production (Rashmi et al., 2023). The nano fertilizers could have assisted plants to withstand environmental stress by enabling the effective physiological responses of a healthier plant and enhanced stress resistance that has resulted in more leaves (Reddy et al., 2022; Meena et al., 2023). Initially, the influence of spacing was less due to less foliage development and competition. At later growth stages, the wider spacing might have reduced competition that has enabled the plant to have more access to resources and good air circulation. The optimum plant growth curbed stress development and assisted the plants in prioritizing lateral growth along with vertical growth. Eventually, the effective utilization of resources might have helped in the generous foliage production by avoiding the premature die-off of leaves (Meena et al., 2022).
 
Yield attributes
 
Grain yield (t/ha)
 
The implementation of crop geometries has shown its impact on amplifying the grain yield of spring maize (Table 2). The highest grain yield of 9.7 t/ha was recorded under S₃ and lowest under S₂ (8.0 t/ha). Correspondingly, the different sources of fertilizers were effective in increasing the grain yield. The highest grain yield of 9.74 t/ha was recorded under F₂ and lowest under F₁ (7.9 t/ha). The interaction effect of both factors was found statistically non-significant (Fig 3). An increase in grain yield of 30.6% was recorded under T₁₀ when compared to T₅.


       
Nano fertilizers are engineered to be more readily absorbed by plants due to their small size, larger surface area with controlled and slow release with targeted delivery (Rashmi et al., 2023). All these characteristic features might have ensured the accessibility of nutrients like N, P and K and their translocation throughout the cropping season that promoted growth and eventually yield (Maheta et al., 2023). Use of conventional fertilizers often suffer from nutrient losses in the soil. In contrast, nano fertilizers might have maintained consistent growth, optimal grain filling and yield due to the slow release of nutrients in a controlled manner according to the requirement of the crop with targeted nutrient delivery (Parameshnaik et al., 2024). Plant population play a crucial role in obtaining superior grain yield. Closer spacing results in a higher number of plants per unit area, which might have potentially increased overall grain yield per hectare despite smaller ears, fewer and lighter kernels (Golla et al., 2020). The 50 x 50 cm (with plant population: 40,000/ha) with 51.9% and 36% lesser plant population than 60 x 20 cm (with plant population: 83,333/ha) and 40 x 40 cm (with plant population: 62,500/ha) respectively has recorded superior growth and yield contributing attributes. Due to the smaller plant population, the overall grain yield has been impacted which ultimately led to lower grain yield (Hamid et al., 2022).
 
Stover yield (t/ha)
 
The employment of different crop geometries has shown a positive impact on stover yield (Table 2). The highest stover yield of 15.8 t/ha was recorded under S₃ and lowest under S₁ (13.7 t/ha). The different sources of fertilizers have shown increment in the stover yield. The maximum stover yield of 15.83 t/ha was recorded under F₂ and minimum under F₁ (13.6 t/ha). The interaction effect of both factors was found to be statistically significant (Fig 3). An increase in the stover yield of 22.4% was recorded under T₁₀ when compared to T₅. However, the treatment T₁₁ and T₂ have shared statistical parity with T₁₀.

       
A similar trend of results as recorded for grain yield was found for stover yield. Nano fertilizers which show better efficiency in the use of nutrients due to their small particle size, led to better nutrient use efficiency, particularly N (Meena et al., 2023). This might have supported the overall growth of a plant i.e., stem elongation, leaf area etc. (Rashmi et al., 2023) that resulted in greater biomass accumulation and ultimately increased the stover yield when compared to the other fertilizer sources (Parameshnaik et al., 2024). The wider plant spacing with more access to resources for each plant, might have helped to develop thicker stalks and larger leaves as the plants could have allocated more resources towards vegetative growth (Meena et al., 2022). While in the closer spacing, the contrast conditions led to thinner stalks and smaller leaves (Gaire et al., 2020). Due to variation in the plant population in the three spacing patterns, the closer plant spacing with a higher plant population resulted in superior stover yield compared to wider plant spacing with a lesser population despite its good growth.
 
Harvest index (%)
 
The employment of different crop geometries has a non-significant influence on the harvest index (Table 2). The maximum harvest index of 37.90% was recorded under S₃ and the minimum under S₂ (36.7%). The different sources of fertilizers have shown non-significant influence on harvest index. The highest harvest index of 37.9% was recorded under F₂, while the lowest recorded under F₄ (36.8%). The interaction effect of both factors was found to be statistically non-significant (Fig 3). However, the maximum harvest index of 38.2% was recorded under T₁₁, while the minimum stover yield of 35.8% was recorded under T₅.
       
The harvest index is the key parameter that defines the reproductive efficiency of plants. The application of nano fertilizers has promoted the harvest index when compared to other fertilizer sources (Parameshnaik et al., 2024). This might be due to improved nutrient uptake, photosynthesis, reduced excessive vegetative growth as well as ensured efficient resource allocation towards grain production (Rashmi et al., 2023). The impact of wider plant spacing was evident which resulted from the reduced competition for resources, improved photosynthetic efficiency and promoted better allocation of nutrients to grain production. This might have led to maximum grain yield per unit of biomass resulted in superior harvest index (Meena et al., 2022).

The results of present experiment suggest that different crop geometries and fertilizer sources positively influenced the morphological characters and yield performance of maize. The application of nano fertilizers in combination with 50 x 50 cm and 60 x 20 cm plant spacing enhanced growth and yield attributes, respectively. The results revealed that wider spacing, when integrated with nano fertilizers, promoted efficient utilization of resources, better crop management, stress mitigation and reduced inter-plant competition. These factors collectively ensured improved nutrient translocation and plant-water relations, ultimately boosted the growth, yield and quality parameters of spring maize. Although the 50 x 50 cm spacing combined with nano fertilizers demonstrated superior productivity per plant, it is important to recognize that, from a farmer’s perspective, overall yield and economic returns remain the primary considerations. Therefore, it is concluded that the treatment 60 x 20 cm + nano fertilizers was found effective in obtaining the highest grain yield of spring maize.

The authors are grateful and express gratitude to the Department of Agronomy, School of Agriculture, Lovely Professional University, Phagwara, Punjab for providing the necessary facilities for their assistance, encouragement and support.
 
Disclaimers
 
The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.
 
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The authors declare that there are no conflicts of interest regarding the publication of this article.