Effect of spacing and silicon on growth and yield of maize (Zea mays L.)

Introduction

Maize is the world's most widely cultivated food crop providing ample food calories and protein for more than one thousand million human beings in the world. It is known as the "Queen of Cereals" because it has the highest genetic yield potential among the cereals. The term corn refers as "to sustain life" that provides nutrients for human and animals worldwide. It is cultivated throughout the year in all the seasons and grown around the globe. Because of its 72% starch, 10% protein, 8.5% fiber, 4.8% oil, 3.0% sugar, and 1.7% ash content, maize has a high nutritional value. It yields more than other cereals such as wheat, rice, and so on. Maize starch that has been hydrolyzed and enzyme-treated to produce syrups, especially high-fructose corn syrup, a sweetener, can be fermented and distilled to produce grain alcohol. Maize is one of the important food grains, which ranks fifth in area and production after rice and wheat and is grown in almost all parts of the country but it is staple food of hilly and sub mountain area of north India. Globally, maize covers an area of 200.53 million hectares with the production of 1,275.94 million tons with the productivity of 6.36 tons/ha (USDA, 2024) [25] . In India, Maize is grown over an area of about 10.04 million hectares with a production of 33.62 million tons and productivity of 3.3 t/ha. Total area coverage under maize in Uttar Pradesh is 2.61 million hectares with a production of 6.09 million tons and the productivity 2.3 t/ha (GOI, 2022) [7] . Agronomists are currently studying plant populations to find ways to increase yield per unit area. Adjustment of proper plant spacing in the maize field is important to ensure maximum utilization of solar energy by the crop and reduce evaporation of soil moisture. Planting is undesirable because it encourages inter-plant competition for resources such as nutrients, sunlight, soil moisture etc. thus, appropriate plant spacing have to be ensured with a view to maximizing maize yield. Similar result was also reported by (Hasan et al., 2018) [87] . Silicon enhances disease resistance in plants, imparts turgidity to the cell walls and has a purgative role in mitigating the metal toxicities (Bhat et al., 2019) [2] . Transpiration from leaves of some plants is considerably reduced by the application of Si (Wang et al., 2021) [26] . Several studies revealed that Si application significantly increased the water-use efficiency (WUE) of maize (Zea mays L.) plants. However, information on concentration of silicate fertilizers and their effect on growth and yield of maize is very limited. Keeping in view of the above fact, the experiment was conducted to find out "Effect of Spacing and Silicon on growth and yield of Maize". Also, proper spacing is crucial for maize production as it significantly impacts plant growth, yield, and overall crop health. Spacing is generally depends upon the expected growth of a particular crop in a given set of agro-climate, which determines the plant density. The space allowed to individual plant is one of the determining factors controlling their development and yield. Close spacing leads to overcrowding and more plant competition for growth factors, whereas wider spacing reduce the plant population enhance the vegetative growth and provide favorable condition to weed growth thereby decreasing the total yield (Johannes et al., 2021) [13] . The cumulative yield per unit area is higher under high plant population but the yield per plant is low. The optimum plant spacing provides better conditions for plant growth which results in timely commencement of reproductive phase and formation of sink (Nangial et al., 2020) [19] . The establishment of an optimum plant population per unit area of land is the contributory factor, which determines the yield of maize. Keeping in view of the above fact, the experiment was conducted to find out "Effect of Spacing and Silicon on growth and yield of Maize".

Materials and Methods

The experiment was conducted during Kharif season 2023 at Crop Research Farm, Department of Agronomy, (SHUATS), Naini, Prayagraj 211007, UP. The soil of the experimental field was sandy loam in texture, with soil (pH 6.9), low level of organic carbon (0.62%), available N (225 Kg/ha), P (38.2 kg/ha), K (240.7 kg/ha) and silicon (1.0% ml/l).The treatment consists of three levels of Spacing along with the combination of three levels of Silicon. The experiment was laid out in RBD with 10 treatments each replicated thrice. The treatment combinations are T1 Spacing (50 × 50) cm 2 + Silicon 0.5%, T2 Spacing (50 × 50) cm 2 + Silicon 1.0%, T3 Spacing (50 × 50) cm 2 + Silicon 1.5%, T4 Spacing (60 × 25) cm 2 + Silicon 0.5%, T5 Spacing (60 × 25) cm 2 + Silicon 1.0%, T6 Spacing (60 × 25) cm 2 + Silicon 1.5%, T7 Spacing (45 × 45) cm 2 + Silicon 0.5%, T8 Spacing (45 × 45) cm 2 + Silicon 0.5%, T9 Spacing (45 × 45) cm 2 + Silicon 1.5%, T10 Spacing (60 × 25) cm 2 . Data recorded on different aspects of crop, viz., plant height, dry weight, crop growth rate, relative growth rate and number of cobs/plants, number of grains/row, number of row/cob, test weight (g), seed yield (t/ha), stover yield (t/ha), harvest index (%) were subjected to statistically analyzed by analysis of variance method as described by Gomez and Gomez, (1976). The cost of cultivation for each treatment was worked out taking in prevailing market price of inputs. Similarly, gross returns were calculated based on prevailing market price of the produce. The net returns INR/ha was calculated by deducting the cost of cultivation from the gross return's INR/ha basis. The B:C ratio was calculated by Net Return INR/ha dividing by Cost of cultivation.

Results and Discussion

A. Growth Parameter Plant Height (cm): At 80 DAS, significant and higher plant height (191.00 cm) was observed in the treatment 5 [Spacing (60 × 25) cm 2 + Silicon at 1.0%]. However, treatment 3 [Spacing (50 × 50) cm 2 + Silicon 1.5%], treatment 4 [Spacing (60 × 25) cm 2 + Silicon 0.5%], treatment 6 [Spacing (60 × 25) cm 2 + Silicon 1.5%], treatment 7 [Spacing (45 × 45) cm 2 + Silicon 0.5%], treatment 8 [Spacing (45 × 45) cm 2 + Silicon 1.0%] and treatment 9 [Spacing (45 × 45) cm 2 + Silicon 1.5%] were found to be statistically at par with treatment 5 [Spacing (60 × 25) cm 2 + Silicon at 1.0%]. Significant and higher plant height was observed with [Spacing (60 × 25) cm2] may be due to plant resulted increased plant height as the plant density increased, where this might be attribute to significant effect of row spacing on plant height, similar result was also reported by Azam et al. (2017) [1] . Further, significant and higher plant height was observed with application silicon at 1.0% may be due to silicon increases plant resistance to lodging, enhancing photosynthesis, increases plant tolerance to strong sunlight or shading, decreases oxidative damage in stressful plants, similar result was also reported by Hassan et al. (2019) [9] .

Plant Dry Weight (g): At 80 DAS, significantly higher plant dry weight (165.00 g) was observed in treatment 5 [60 × 25 cm² spacing + 1.0% Silicon]. However, treatment 4 [Spacing (60 × 25) cm 2 + Silicon 0.5%] was found to be statistically at par with the treatment 5 [60 × 25 cm² spacing + 1.0% Silicon]. Significant and higher plant dry weight was observed with Spacing (60 × 25) cm 2 may be due to increases in the plant population between the row spacing which resulted may have higher plant dry weight increased the vegetative growth of the plant, Similar result was also reported by Singh et al. (2022) [21] . Further, significant and higher plant dry weight was observed with application of silicon at 1.0% may be due to the different levels of silicon, the combination of soil and foliar application recorded increase highest dry matter yield compared to individual application of soil and foliar, application of silicon was found to be lesser effect compared to soil application similar result was also reported by Jawahar et al. (2020) [11] .

Crop Growth Rate (g/m 2 /day): During 40-60 DAS intervals, treatment 5 [60 × 25) cm 2 + Silicon 1.0%] recorded highest crop growth rate (32.33 g/m 2 /day). However, treatment 4 [Spacing (60 × 25) cm 2 + Silicon 0.5%], treatment 6 [Spacing (60 × 25) cm 2 + Silicon 1.5%] was found to be statistically at par with the treatment 5 [Spacing (60 × 25) cm 2 + Silicon 1.0%]. Significant and higher crop growth rate was observed with Spacing (60 × 25) cm 2 may be due to the increase in crop growth rate is attributed to the plants accumulating more dry matter and increasing the row spacing between the plants. It began to fall after DAS because, while dry matter accumulation increased after the vegetative stage, the rate of accumulation was not as high as it was during the vegetative development stage, similar result was also reported by Jawahar et al. (2020) [11] . Further, significant and higher crop growth rate was observed with application of silicon at 1.0% may be due to, the plant growth rate (CGR) increased significantly with each increase in uptake depends on the concentration of silicon in the soil solution, pH and soil moisture content, two possible mechanisms (active and passive) were proposed for the uptake of silicon by plants, similar result was also reported by Purbajanti et al. (2022) [22] .

Relative Growth Rate (g/g/day): At 40-60 DAS intervals, higher relative growth rate was recorded (0.1017 g/g/day) in treatment 4 [Spacing (60 × 25) cm 2 + Silicon0.5%]. through there was no significant difference among all the treatments.

B. Yield Parameter Number of cobs/plants:

Treatment 5 [Spacing (60 × 25) cm 2 + Silicon 1.0%] recorded significant and maximum number of cobs/plant (1.82). However, treatment 4 [Spacing (60 × 25) cm 2 + Silicon 0.5%], treatment 6 [Spacing (60 × 25) cm 2 + Silicon 1.5%] was found to be statistically at par with treatment 5 [Spacing (60 × 25) cm 2 + Silicon 1.0%]. Significant and maximum number of cobs/plants was observed with spacing (60×25 cm) may be due to the cob length increased with each increment in spacing. Similar result was also reported by Gaire et al. (2020) [6] . Further, significant and maximum number of cobs/plants was observed with application silicon at 1.0% may be due to silicon accumulation in plant parts which reduce its lodging and enhanced resistance against biotic and abiotic stress, ultimately resulted maximum number of cobs/plants. Similar result was also reported by Prajapat et al. (2021) [20] . Significant and maximum number of grain/rows was observed with spacing (60 × 25) cm 2 might be due to the adequate plant spacing i.e. number of plants/unit area or plant density is also one of the main factors which ultimately lead to increase in cob yield or grain yield/unit area. Similar result was also reported by Manan et al. (2016) [18] . Further, significant and maximum number of grain/rows was observed with application silicon at 1.0% may be due to enhanced photosynthetic activity, density of grain by improving the translocation and accumulation of carbohydrates and increase in number of filled grains which influenced the biomass of grains resulted maximum number of grain/rows. Similar result was also reported by Prajapat et al. (2021) [20] .

Number of grains

Number of rows/cobs: Treatment 5 [Spacing (60 × 25) cm2

+ Silicon 1.0%] recorded significant and maximum number of rows/cob (12.93). However, treatment 1 [Spacing (50 × 50) cm 2 + Silicon 0.5%], treatment 2 [Spacing (50 × 50) cm 2 + Silicon 1.0%], treatment 3 [Spacing (50 × 50) cm 2 + Silicon 1.5%], treatment 4 [Spacing (60 × 25) cm2 + Silicon 0.5%]. treatment 6 [Spacing (60 × 25) cm 2 + Silicon 1.5%] and treatment 7 [Spacing (45 × 45) cm 2 + Silicon 0.5%] were found to be statistically at par with the treatment 5 [Spacing (60 × 25) cm2 + Silicon 1.0%]. Significant and maximum of rows/cob was observed with Spacing (60 × 25) cm 2 might be due to, the plant spacing beside the absorption of water and nutrient, the sunlight absorption may have affected the growth and yield of plant, good appropriate planting space improves soil fertility, soil tillage, fertilization, resulted increased the number of row/cobs. Similar result was also reported by Dwipa et al. (2020) [4] . Further, significant and maximum number of rows/cobs was observed with application silicon at 1.0% may be due to silicon resulted in carbohydrates synthesis from photosynthetic activity for longer period might have resulted in efficient translocation of food material into the sink (grain) thereby increased number of row/cobs. Similar result was also reported by Kumar et al. (2023) [17] .

Test weight (g): Significant and higher test weight (22.50 g) was observed treatment 5 [Spacing (60 × 25) cm 2 + Silicon 1.0%]. However, treatment 1 [Spacing (50 × 50) cm 2 + Silicon 0.5%], treatment2 [Spacing (50 × 50) cm 2 + Silicon 1.0%], treatment 3 [Spacing (50 × 50) cm 2 + Silicon 1.5%], treatment 4 [Spacing (60 × 25) cm2 + Silicon 0.5%], treatment 6 [Spacing (60 × 25) cm 2 + Silicon 1.5%], treatment 7 [Spacing (45 × 45) cm 2 + Silicon 0.5%] and treatment 8 [Spacing (45 × 45) cm 2 + Silicon 1.0%] were found to be statistically at par with the observed treatment 5 [Spacing (60 × 25 cm 2 + Silicon 1.0%]. Significant and higher test weight was observed with spacing (60 × 25) cm 2 may be due to the reason behind the higher hundred grain weight in row spacing could be as a result of high light capture and less competition for water outcome in greater accretion of photosynthesis. Similar result was also reported by Koirala et al. (2020) [15] . Further, significant and higher test weight was observed with application silicon at 1.0% might be due to, the increased hundred grain weight was registered under adequate irrigation condition, supplied at regular intervals, this might be due to increased plant growth characters up to significant level by increased availability of water and nutrients to plants under stress free moisture availability, Similar result was also reported by Kumar et al. (2018) [14] .

Seed yield (t/ha): Significantly higher seed yield (5.62 t/ha) was recorded in the treatment 5 [Spacing (60 × 25cm 2 + Silicon 1.0%]. However, treatment 4 [Spacing (60 × 25) cm2 + Silicon 0.5%], treatment 6 [Spacing (60 × 25) cm 2 + Silicon 1.5%] was found to be statistically at par with the observed treatment 5 [Spacing (60 × 25) cm 2 + Silicon 1.0%]. Significant and higher seed yield was observed with spacing (60 × 25) cm 2 may be due to the wider distances between plant placement which allow for less competitive growth and development of more plants thus increasing seed yield, similar result was also reported by Chim et al. (2014) [3] . Further, significant and higher seed yield was observed with application silicon at 1.0% may be because of silicon during seedling growth, silicon mediated the photosynthetic rate, root activity and nitrate reductase activity which results in improvement in the maize yield, similar result was also reported by Kalyani et al. (2023) [17] .

Stover yield (t/ha): Significant and higher stover yield (9.60 t/ha) was observed in treatment 5 [Spacing (60 × 25) cm 2 + Silicon 1.0%]. However, treatment 4 [Spacing (60 × 25) cm 2 + Silicon 0.5%] was found to be statistically at par with the observed treatment 5 [Spacing (60 × 25) cm 2 + Silicon 1.0%]. Significant and higher stover yield was observed with spacing (60 × 25) cm 2 may be due to the plant receive more sunlight by the canopy of plant and sufficient nutrient from the soil which results higher growth of plant and maximum stover yield. Similar results are obtained by Sally et al. (2019) [23] . Further, significant and higher stover yield was observed with application silicon 1.0% may be due to the silicon application which resulted in more utilization of solar radiation, moisture and nutrients since silicon provides more erectness to plant for efficient utilization of solar radiation resulting in better stover yield, Similar results are obtained by Kumar et al. (2023) [17] .

Harvest Index (%): Significant and higher harvest index (36.78%) was observed in the treatment 5 [Spacing (60 × 25) cm 2 + Silicon 1.0%]. However, treatment 4 [Spacing (60 × 25) cm 2 + Silicon 0.5%], treatment 6 [Spacing (60 × 25) cm 2 + Silicon 1.5%] and treatment 8 [Spacing (45 × 45) cm 2 + Silicon 1.0%] was found to be statistically at par with the observed treatment 5 [Spacing (60 × 25) cm 2 + Silicon 1.0%]. Significant and higher harvest index was observed with spacing (60 × 25) cm 2 may be due to the row spacing which tended to determine smaller variation of the harvest index according to plant density and maize yield. Similar results are obtained by Ion et al. (2015). Further, significant and higher harvest index was observed with application silicon at 1.0% might be due to, owing to deposition of Si at cellular parts such as cell wall, cell lumen and inter cellular space, and its deposition below and above cuticle layer that's why enhanced cell division and cell elongation than tissue parts more elongated and erect, cause erectness of leaves and stem which enhanced towards plant height and also increase in chlorophyll content. Similar results are obtained by Prajapat et al. (2022) [21] .

C. Economics

Gross return, net return and benefit cost ratio were influenced due to different treatments. [15] . Further, significant and maximum economic was observed with application silicon at 1.0% may be due to the silica which significantly enhance the growth, net return, B C ratio and post-harvest available P of soil. Among foliar application, spray of 1.0% active silica improved the growth and net return by Prajapat et al. (2022) [21] .

Conclusion

It is concluded that spacing (60 × 25) cm 2 along with silicon 1.0% (treatment 5) has recorded highest grain yield and benefit cost ratio in maize.

Acknowledgement

AcknowledgementThe authors are thankful to Department of Agronomy, Naini Agricultural Institute, Prayagraj, Sam Higginbottom University of Agriculture Technology and Sciences, (U.P) India for providing necessary facilities to undertake the studies.

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