Effect of NPK and foliar application of zinc on soil health of baby corn (Zea mays L.)

Introduction

Baby corn (Zea mays L.) is one of the most popular and economically viable specialty corn crops belonging to the family Poaceae (Prasad et al., 2018) [20] . It refers to the young, fresh, and unfertilized ear of the maize plant, harvested prematurely within 2-3 days of silk emergence (Thakur et al.,2019) [33] . Unlike standard grain maize, baby corn is cultivated primarily as a highvalue vegetable crop due to its sweet taste and crunchy texture (Mishra et al., 2021) [15] . It is considered a powerhouse of nutrition, being exceptionally rich in dietary fiber, Vitamin A, Vitamin C, iron, phosphorus, and calcium (Singh et al., 2021a) [30] . Because it is consumed entirely along with the cob, it provides a significantly higher amount of fibrous nutrients compared to mature grain kernels (Joshi et al., 2020) [9] . This rich nutritional profile makes it an ideal and healthy dietary component, particularly gaining immense popularity among urban and vegetarian populations globally (Sharma et al., 2022) [26] . In the global agricultural economy, India is recognized as one of the fastest-growing producers and exporters of baby corn (Des et al., 2023) [5] . The crop is widely preferred by farmers due to its short growth duration of only 60 to 75 days (Kumar et al., 2020) [10] . This short life cycle allows it to fit efficiently into intensive multi-cropping systems, enabling farmers to harvest 3 to 4 crops in a single year from the same piece of land (Rao et al., 2021) [21] . Furthermore, baby corn cultivation offers a highly lucrative dual-purpose utility to agrarian economies (Kumar et al., 2019) [13] . While the primary harvest provides tender cobs for human consumption, the remaining biomass yields highly nutritious, succulent green fodder for livestock (Singh et al., 2020) [29] . This green fodder is highly palatable and easily digestible, thereby significantly improving the milk yield and overall health of dairy animals (Verma et al., 2022) [35] . The growth, quality, and economic productivity of baby corn are heavily influenced by precise nutrient management practices (Sharma et al., 2020) [27] .

Balanced application of primary chemical fertilizers, specifically nitrogen, phosphorus, and potassium (NPK), is fundamental to boosting the photosynthetic capacity and vegetative vigor of the plant (Patel et al., 2021) [19] . Adequate nitrogen application accelerates earlyv egetative growth, whereas phosphorus plays a crucial role in root development and early cob initiation (Reddy et al., 2019) [22] . Consequently, shifting towards integrated nutrient management (INM) systems has become imperative for sustaining long-term agricultural productivity (Reddy et al., 2022) [23] . INM combines optimal doses of inorganic fertilizers with organic manures and microbial biofertilizers to maintain ecological balance (Choudhary et al., 2023) [3] .

Materials and methods

The present study entitled "Effect of NPK and Foliar application of Zinc on Soil Health of Baby Corn (Zea mays L.)" Variety G-5417 comprise of a field experiment which was carried out at the Soil Science Research Farm Prof. Rajendra Singh (Rajju Bhaiya) University Naini Prayagraj during Rabi season 2025-2026. The maximum temperature of the location reaches up to 46 0 C -48 0 C and seldom falls as 4 0 C -5 0 C. The relative humidity ranged between 20 to 94%. The average rainfall in this area is around 1100 mm annually. It comes under subtropical climate receiving the mean annual rainfall of about 1100 mm, major rainfall from July to end of September. However, occasional precipitation was also not uncommon during winter. The winter months were cold while summer months were very hot and dry. The minimum temperature during the crop season was to be 5.4 o C and the maximum was to be 41.2 o C. The minimum humidity was 48.2% and maximum was 87.6%. Experiment was laid out in randomized block design with Different levels of NPK and Foliar application of Zinc on Soil Health. Plot size was 3 x 3 m 2 for crop seed rate is 25 kg ha -1 (Zea mays L.) Var G-5417. Basal dose of fertilizer was applied in respective plots according to treatment allocation uniform furrows opened by about 5 cm. All the agronomic practices were carried out uniformly to raise the crop. They provide fertilizer NPK (120:60:40:5) Source of Urea, SSP, MOP and Zinc Sulphate. Row to row spacing 50cm and plant to plant 30 cm. The experimental site had initial soil properties including a bulk density of 1.30 g cm⁻³, particle density of 2.45 g cm⁻³, pore space 46.50%, water holding capacity 38.66%, pH (7.21), EC (0.314 dSm⁻¹), and organic carbon (0.31%). Available nitrogen (215.4 kg ha⁻¹), phosphorus (17.91 kg ha⁻¹), potassium (182.67 kg ha⁻¹) and zinc (9.11 ppm). Treatment data, including a 12-day irrigation interval and Intercultural operations at 25 and 50 days, were analyzed using ANOVA in OPSTAT to assess their significant effects on crop growth and yield parameters. The crop was harvested in March. Treatment combination for T 1 Absolute control, T 2 NPK @ 50%, T 3 NPK @ 50% + 5 Kg Zn ha -1 , T 4 NPK @ 100% , T 5 NPK @ 50% + 0.2% Zn foliar Spray, T 6 NPK @ 50% + 0.5% Zn foliar Spray , T 7 NPK @ 100% + 5 Kg Zn ha -1 , T 8 NPK @ 100% + 0.2% Zn foliar Spray, T 9 NPK @ 100% + 0.5% Zn foliar Spray. Bulk density, Particle density, Pore space and Water holding capacity analyze Measuring cylinder method given by Muthuvel et al.,1992 [16] , Soil pH analyze Digital pH meter given by M. L. Jackson, 1958 [8] . Electrical conductivity analyze Digital conductivity meter given by Wilcox, 1950 [37] , Organic carbon analyze Wet oxidation method given by Walkley and Black, 1947 [36] , Available Nitrogen analyze Modified alkaline permanganate oxidation method given by Subbiah and Asija 1956 [31] , Available Phosphorus. analyze Olsen's extraction followed by Spectrophotometric method given by Olsen et al., 1954 [17] , Available Potassium analyze Neutral normal ammonium acetate extraction fallowed by Flame photometric given by Toth and Prince, 1949 [34] . Available Zinc analyze: DTPA extraction followed by Atomic Absorption Spectrophotometry (Lindsay and Norvell in 1978).

Results and discussion

The Results and Discussion section presents the data generated during the investigation and provides a scientific explanation of the observed results by relating them to treatment effects, underlying mechanisms, and findings of previous studies.

The data presented in Table and fig. 1 revealed that bulk density was not significantly influenced by different nutrient management practices. The lowest bulk density was recorded under T₉ (100% NPK + 0.5% Zn foliar spray) with values of 1.16 and 1.20 Mg m⁻³ at 0-15 and 15-30 cm soil depths, respectively. This was followed by T 7 (NPK @ 100% + 5 Kg Zn/ha) 1.19 and 1.23 Mg m⁻³ at 0-15 and 15-30 cm. The highest bulk density was observed under T₁ (Absolute Control) with values of 1.29 and 1.32 Mg m⁻³ at 0-15 and 15-30 cm soil depths, respectively. The lower bulk density under T₉ may be attributed to improved soil aggregation, enhanced root growth and increased biological activity resulting from balanced nutrient application. The extensive root system and greater organic matter addition improved soil structure and reduced soil compaction. (Singh et al., 2021a) [28, 30] (Mallipeddi et al., 2025) [14] .

The particle density of soil was found to be non-significantly affected by different treatments. The lowest particle density was recorded under T₉ (100% NPK + 0.5% Zn foliar spray) with values of 2.42 Mg m⁻³ and 2.49 Mg m⁻³ at 0-15 cm and 15-30 cm depths, respectively. This was followed by T₈ (100% NPK + 0.2% Zn foliar spray) and T₇ (100% NPK + 5 kg Zn ha⁻¹). The highest particle density was observed under T₁ (Absolute Control) with values of 2.44 Mg m⁻³ and 2.49 Mg m⁻³, respectively. The lower particle density under T₉ may be attributed to increased organic matter accumulation and enhanced root biomass production, which improved soil structure and reduced the proportion of dense mineral particles. (Kumar et al., 2018) [11] and (Hekmat et al., 2019) [7] .

The pore space was significantly influenced by different nutrient management practices. The highest pore space was recorded under T₉ (100% NPK + 0.5% Zn foliar spray) with values of 54.78% and 52.15% at 0-15 cm and 15-30 cm soil depths, respectively. This was followed by T₈ (100% NPK + 0.2% Zn foliar spray) and T₇ (100% NPK + 5 kg Zn ha⁻¹). The lowest pore space was observed under T₁ (Absolute Control) with values of 48.50% and 46.53%, respectively. The higher pore space under T₉ may be attributed to better soil aggregation, enhanced root proliferation and increased microbial activity, which promoted the formation of stable soil pores and improved soil aeration. (Singh et al., 2021) [28,30] , (Mallipeddi et al., 2025) [14] and (Kumar et al., 2014) [12] Water Holding Capacity (%) The water holding capacity of soil was significantly affected by different treatments. The highest water holding capacity was recorded under T₉ (100% NPK + 0.5% Zn foliar spray) with values of 43.20% and 41.20% at 0-15 cm and 15-30 cm depths, respectively. This was followed by T₈ (100% NPK + 0.2% Zn foliar spray) and T₇ (100% NPK + 5 kg Zn ha⁻¹).

The lowest water holding capacity was observed under T₁ (Absolute Control) with values of 39.70% and 36.40%, respectively. The increase in water holding capacity under T₉ may be due to improved soil aggregation, greater pore space and increased organic matter content, which enhanced the moisture retention capacity of the soil. (Singh et al., 2021) [28,30] , (Mallipeddi et al., 2025) [14] and (Kumar et al., 2014) [12] Effect of NPK and foliar application of zinc on bulk density (mg m -3 ), particle density (mg m -3 ) pore space (%) and water holding capacity (%) of soil

Soil pH

The soil pH was non-significantly influenced by different nutrient management practices. The lowest pH was recorded under T₇ (100% NPK + 5 kg Zn ha⁻¹) with values of 6.29 and 6.37 at 0-15 and 15-30 cm soil depths, respectively. This was followed by T₉ (100% NPK + 0.5% Zn foliar spray) with values of 6.58 and 6.79 at 0-15 and 15-30 cm soil depths. The highest pH was observed under T₁ (Absolute Control) with values of 7.24 and 7.39, respectively. The slight reduction in pH under T₇ may be attributed to nitrification of applied nitrogen fertilizers and increased microbial activity. (Singh et al., 2021b) [28] , (Kumar et al., 2014) [12] , (Kumar et al., 2018) [11] and (Hekmat et al., 2019) [7] .

Electrical Conductivity (dSm⁻¹)

The electrical conductivity of soil was non-significantly affected by nutrient management practices. The highest EC was recorded under T₇ (100% NPK + 5 kg Zn ha⁻¹) with values of 0.41 and 0.43 dS m⁻¹ at 0-15 and 15-30 cm depths, respectively. This was followed by T 8 (100% NPK + 0.2% Zn foliar spray) with values of 0.37 and 0.39 at 0-15 and 15-30 cm soil depths. The lowest EC was observed under T₁ (Absolute Control) with values of 0.32 dS m⁻¹ and 0.28 dS m⁻¹, respectively. The increase in EC under T₇ may be attributed to the addition of soluble nutrient ions through fertilizer application, which increased the ionic concentration of the soil solution. (Singh et al., 2021) [28,30] and (Tahani et al., 2026) [32] .

The organic carbon content of soil was non-significantly influenced by different nutrient management practices. The highest organic carbon content was recorded under T₇ (100% NPK + 5 kg Zn ha⁻¹) with values of 0.43 and 0.38% at 0-15 and 15-30 cm depths, respectively. This was followed by T₉ (100% NPK + 0.5% Zn foliar spray) with values of 0.42 and 0.37 at 0-15 and 15-30 cm soil depths. The lowest organic carbon content was recorded under T₁ (Absolute Control) with values of 0.31% and 0.28%, respectively. The increase in organic carbon under T₇ may be attributed to enhanced biomass production, vigorous root growth and greater incorporation of crop residues into the soil. (Singh et al., 2021b) [30] and (Tahani et al., 2026) [32]

The available nitrogen content of soil was significantly influenced by nutrient management practices. The highest available nitrogen content was recorded under T₇ (100% NPK + 5 kg Zn ha⁻¹) with values of 286.28 and 212.30 kg ha⁻¹ at 0-15 and 15-30 cm depths, respectively. This was followed by T 9 (NPK @ 100%+0.5Zinc foliar spray) with values of 283.73 and 211.35 kg ha⁻¹. The lowest available nitrogen content was recorded under T₁ (Absolute Control) with values of 219.88 kg ha⁻¹ and 194.15 kg ha⁻¹, respectively. The higher nitrogen content under T₇ may be attributed to the combined application of NPK and zinc, which improved nutrient retention, microbial activity and nitrogen-use efficiency. (Kumar et al., 2014) [12] , (Kumar et al., 2018) [11] and (Hekmat et al., 2019) [7] .

The available phosphorus content of soil was significantly affected by different treatments. The highest available [28,30] , (Tahani et al., 2026) [32] and (Hekmat et al., 2019) [7] .

The available potassium content of soil was significantly influenced by nutrient management practices. [28,30] , (Tahani et al., 2026) [32] , (Mallipeddi et al., 2025) [14] and (Kumar et al., 2014) [12] .

The available zinc content of soil was significantly influenced by zinc application. The highest available zinc content was recorded under T₇ (100% NPK + 5 kg Zn ha⁻¹) with values of 18.06 and 15.85 ppm at 0-15 and 15-30 cm depths, followed by T₉ (100% NPK + 0.5% Zn foliar spray) with values of 17.46 and 14.50 ppm at 0-15 and 15-30 cm depths. The lowest available zinc content was recorded under T₁ (Absolute Control) with values of 9.91and 6.49 ppm, respectively. The higher zinc content under T₇ may be attributed to the direct soil application of zinc, which increased zinc availability and improved nutrient uptake efficiency in baby corn. (Mallipeddi et al., 2025) [14] , (Kumar et al., 2014) [12] , (Kumar et al., 2018) [11] and (Hekmat et al., 2019) [7] .

Acknowledgement

AcknowledgementsThe authors are grateful to the Hon'ble Vice chancellor Prof. Rajendra Singh (Rajju bhaiya) University, Department of Soil Science and Agricultural Chemistry, Prayagraj for taking their keen interest and encouragement to carry out the research work.

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