Ferti-fortification of zinc and iron on green fodder yield and quality of fodder maize

Introduction

Agriculture and animal husbandry are closely linked in India, where livestock plays an important role in supporting rural livelihoods and crop production. Despite possessing only 2.3% of the world's land area and 4.2% of water resources, India supports about 15% of the global livestock population and 17% of the human population (Kumar et al., 2012) [10] . However, fodder crops are often cultivated on marginal lands under poor management, resulting in low-quality forage. Only about 8.4 million hectares (5.23% of the total agricultural area) are devoted to fodder cultivation, which is insufficient to meet the growing feed requirements of livestock (Mohan et al., 2017) [12] . Future projections indicate significant deficits in green and dry fodder by 2050, highlighting the need to improve fodder productivity through better resource management and crop integration (IGFRI, 2018) [4] . Maize (Zea mays L.), known as the "Queen of Cereals," is an important dual-purpose crop used for both human consumption and animal feed. Fodder maize is highly valued due to its rapid growth, high biomass production, excellent palatability and nutritive value. It contains appreciable levels of crude protein, fiber fractions, cellulose and hemicellulose, making it a preferred fodder crop for dairy animals (Rupa et al., 2021) [15] . In India, maize occupies more than 108 lakh hectares, with the majority cultivated during the kharif season (ANGRAU, 2024). Micronutrients, particularly zinc (Zn) and iron (Fe), are essential for plant growth, forage quality, and animal nutrition. Zinc is involved in numerous enzymatic activities, while iron plays a crucial role in photosynthesis, respiration, and chlorophyll synthesis. Zinc deficiency has become a widespread problem in Indian soils, affecting crop productivity and forage quality (Kumar et al., 2024) [6] . Agronomic biofortification through soil and foliar application of Zn and Fe has emerged as an effective strategy to enhance the nutritional quality of crops and fodder. Studies have shown that zinc-and iron-enriched fodder improves forage quality, increases micronutrient concentration in animal feed, enhances milk quality, and reduces disease incidence in livestock (Kumar et al., 2016; Patel and Rathod, 2024) [8,13] . Although biofortification has been widely studied in food crops, limited information is available on forage crops. Therefore, agronomic biofortification of fodder maize with zinc and iron offers a promising, cost-effective approach to improve fodder productivity, nutritional quality, and livestock health, especially in regions with micronutrient-deficient soils.

Materials and Methods

Soil and climate of experiment location

The field experiment was conducted during the kharif season of 2025 at Main Forage Research Station, Anand Agricultural University, Anand (Gujarat) India (22°35′ N and 72°55′ E with a 45.1 m above mean sea level). During experiment period, mean weekly weather parameter was recorded at Department of Agricultural Meteorology, B.A. College of Agriculture and these standard meteorological week wise data are presented in Fig. 1. The experimental soil was loamy sand in texture with good drainage and moisture retention capacity. Before sowing, composite soil sample was taken for physicochemical properties of soil (Table 1). The recommended dose of fertilizers (80-40-00 kg NPK/ha) was applied uniformly to all treatments. Recommended nitrogen and phosphorus were applied through urea and single super phosphate; half dose of nitrogen (40 kg/ha) and full dose of phosphorus (40 kg/ha) was applied as basal and remaining fifty percent nitrogen (40 kg/ha) was applied at 30 days after sowing. Soil application of 25 kg ZnSO4 and 50 kg FeSO4 applied as basal dose and foliar solution of 0.5% ZnSO4 and FeSO4 with 0.25% neutralized lime water at 15 and 30 days after sowing. For experiment purpose fodder maize (Gujarat Fodder Maize 1 Anand Tall) was used as the test crop and it was sown at 30 cm between two rows with seed rate 80 kg/ha. For uniform and better germination, after sowing immediate apply one irrigation. For healthy growth and reducing weed competition crop should be free from any type of weeds for the two-hand weeding and one interculture operation was carried out during crop growth period. Experiment field was ready through harrowing and planking after two cross cultivations. Uniform field level is required for better movement of irrigation in field and uniform germination. For growth and yield attributing character's observation selected five random plants from net plot area. At milking phase fodder maize was harvested, first selected tag plant was harvested for recording necessary biometric observations afterwards produced was added to the net plot respectively. For proximate analysis purpose, collect fresh choup 500 g green plant sample from each plot according to standard process for quality analysis (Table 2). Field experiment was conducted in Randomized Complete Block Design. According to set of observation collect all data from net plot area and converted into mean data. The mean data of experiment was analysed through ANOVA technique for statistical analysis of Randomized Complete Block Design as described by Gomez and Gomez (1984). Neutral detergent fiber (%) Forage fiber analysis US method (Goering and Van Soest 1975) [3] 2 Acid detergent fiber (%) Forage fiber analysis US method (Goering and Van Soest 1975) [3] 3

Crude protein content (%) Kjeldahl's digestion method (Jackson 1973) [5] 4

Total micronutrient Zn and Fe Atomic Absorption Spectrophotometric Method (Piper 2019) [14] 5 DTPA Zn and Fe Atomic Absorption Spectrophotometric Method (Lindsay and Norvell 1978) [11] Proximate analysis of green fodder Fodder Dry matter percentage Dry matter percentage was determined by using the following formula.

Dry matter yield (q/ha) was calculated by dry matter 5 and fresh fodder yield of maize.

Analysis of crude protein content was done through a digestion process. Nitrogen was calculated from the amount of acid that was used in titration. Then the reading was multiply with 6.25 to obtain crude protein percentage (Jackson (1973) [5] .

Fodder Crude protein yield (q/ha) The crude protein yield was estimated by multiplying crude protein% with dry matter yield by employing the formula given below and express in q/ha.

Following formula was used to calculate nutrient uptake by fodder maize

Results and Discussion

Effect of different treatment on growth attributes and growth of fodder maize was found significant (Table - 3). A perusal of the data in Table 3 indicates that the different treatments had a nonsignificant effect on the plant population at 15 DAS and the number of leaves per plant. This confirms that the plant population remained uniform across and not found treatment effects on plant population. Data reported in Table 3 revealed that periodical plant height of fodder maize as significantly influenced by different treatments.

According to mean value, plant height at 30 DAS was not significantly affected by the different treatments later on higher plant at 45 DAS (127.47 cm) and at harvest (209.73 cm) was noted in treatment T 10 (RDF + ZnSO 4 .7H 2 O @ 25 kg/ha + FeSO 4 .7H 2 O @ 50 kg/ha as a basal fb foliar application of 0.5% ZnSO 4 + 0.5% FeSO 4 ) than rest of treatments except treatment T 3 (RDF + FeSO 4 .7H 2 O @ 50 kg/ha as a soil application), T 4 (RDF + ZnSO 4 .7H 2 O @ 25 kg/ha + FeSO 4 .7H 2 O @ 50 kg/ha as a basal), T 5 (RDF + foliar application of 0.5% ZnSO 4 ),T 6 (RDF + foliar application of 0.5% FeSO 4 ) and T 8 (RDF + ZnSO 4 .7H 2 O @ 25 kg/ha as a basal fb 0.5% ZnSO 4 foliar application) at 45 DAS (Range of height from 127.47 to 90.47 cm) whereas at harvest (Range of height from 209.73 to 159.02 cm), treatment T 10 (RDF + ZnSO 4 .7H 2 O @ 25 kg/ha + FeSO 4 .7H 2 O @ 50 kg/ha as a basal fb foliar application of 0.5% ZnSO 4 + 0.5% FeSO 4 ) remain at par with treatment T 3 (RDF + FeSO 4 .7H 2 O @ 50 kg/ha as a soil application), T 4 (RDF + ZnSO 4 .7H 2 O @ 25 kg/ha + FeSO 4 .7H 2 O @ 50 kg/ha as a basal), T 5 (RDF + foliar application of 0.5% ZnSO 4 ), T 7 (RDF + foliar application of 0.5% ZnSO 4 + 0.5% FeSO 4 ), T 8 (RDF + ZnSO 4 .7H 2 O @ 25 kg/ha as a basal fb 0.5% ZnSO 4 foliar application) and T 9 (RDF + FeSO 4 .7H 2 O @ 50 kg/ha as a basal fb 0.5% FeSO 4 ). The minimum plant height (90.47 and 159.02 cm) was observed under the control treatment (T 1 ) at 45 DAS and at harvest. The improvement in plant height may be due to the combined application, which improves the availability and supply of balanced nutrients. The application of nitrogen drives rapid vegetative growth, accelerating cell division and elongation, which leads to longer internodes and increased leaf area. It also promotes robust early-stage root development, allowing the plant to absorb more water and soil nutrients. Furthermore, these nutrients are essential for energy transfer (ATP), enzyme activation, hormone function, and chlorophyll synthesis. Together, they ensure that macro-nutrients (such as N and P) are efficiently utilized, preventing stunting or nutrient lockout. Combined application of recommended dose of fertilizer along with zinc and iron micronutrition application through soil and foliar application lead to improve in economical yield. Data presented in Table 3 indicated that application of 100% (80-40-0 NPK kg/ha) + ZnSO 4 .7H 2 O @ 25 kg/ha + FeSO 4 .7H 2 O @ 50 kg/ha + 0.5% ZnSO 4 + 0.5% FeSO 4 (T 10 ) recorded the higher green fodder yield (402.90 q/ha), which remained statistically at par with T 4 (379.31 q/ha) and T 9 (345.43) which is significantly superior over the remaining treatments (Table 3). The lowest green fodder yield (300.28 q/ha) was recorded under the control treatment (T 1 ). Comparison with control treatment (T 1 ) treatment T 10 recorded 34.17% higher green fodder yield. Combined application of Zn and Fe along with foliar sprays significantly improved growth and yield of fodder maize. optimizing plant growth hormones, maximizing chlorophyll synthesis, and improving nutrient absorption through dual-delivery pathways (Kumar et al., 2017, 2018 and Adesh et al., 2021) [9,7,1] . The combined application of zinc and iron along with recommended dose of macro nutrients significantly improved fodder quality, nutrient concentration, nutrient uptake, and micronutrient status in soil (Table 456). In connection to dry matter content (25.9%) and dry matter yield (104.07 q/ha) were recorded under T 10 (soil application of ZnSO 4 and FeSO 4 along with foliar spray of ZnSO 4 and FeSO 4 ), it was 64.10% higher than control (T 1 ). Enhanced dry matter accumulation may be attributed to improved photosynthetic activity, chlorophyll synthesis, and nutrient utilization resulting from adequate Zn and Fe supply (Sewhag et al., 2022) [16] . Zinc (Zn) is critical for the synthesis of tryptophan, an amino acid that serves as a precursor to auxins (growth hormones). Zinc promotes rapid cell division and stem elongation. Iron (Fe) is an absolute requirement for the synthesis and maintenance of chlorophyll molecules. It acts as a structural component in the electron transport chain (cytochromes), ensuring maximum solar energy conversion. Phosphorus drives energy storage and transfer via adenosine triphosphate (ATP).

Along with zinc, it stimulates extensive root development, allowing the plant to absorb more water and nutrients.

Furthermore, zinc acts as a vital structural component and activator of enzymes, such as tryptophan synthetase, which are responsible for protein biosynthesis. Without adequate zinc, protein synthesis suffers significantly. Crude protein (5.38%) and crude protein yield (5.61 q/ha) of fodder maize was reported higher in treatment T 10 (80-40-0 NPK kg/ha) + ZnSO 4 .7H 2 O @ 25 kg/ha + FeSO 4 .7H 2 O @ 50 kg/ha + 0.5% ZnSO 4 + 0.5% FeSO 4 ) than rest of treatments (Table-4). In case of crude protein yield, treatment T 10 was statistically at par with treatment T 2 (RDF + ZnSO 4 .7H 2 O @ 25 kg/ha as a soil application), T 3 (RDF + FeSO 4 .7H 2 O @ 50 kg/ha as a soil application), T 4 (RDF + ZnSO 4 .7H 2 O @ 25 kg/ha + FeSO 4 .7H 2 O @ 50 kg/ha as a basal), T 7 (RDF + foliar application of 0.5% ZnSO 4 + 0.5% FeSO 4 ) , T 8 (RDF + ZnSO 4 .7H 2 O @ 25 kg/ha as a basal fb 0.5% ZnSO 4 foliar application) and T 9 (RDF + FeSO 4 .7H 2 O @ 50 kg/ha as a basal fb 0.5% FeSO 4 ). Increase in crude protein content in fodder maize may be attributed to the combined application of nutrients, which work synergistically to maximize chlorophyll production, amino acid synthesis, and nitrogen assimilation. Zinc activates the carbonic anhydrase enzyme, accelerating carbon fixation and creating the carbon skeletons required for protein synthesis. Meanwhile, iron serves as a critical structural component of nitrate reductase and nitrite reductase enzymes, which convert absorbed nitrate into ammonium. Together, zinc and iron enhance root growth and metabolic activity, thereby increasing the plant's capacity to absorb soil-applied nitrogen. Neutral detergent fiber (NDF) measures the overall plant cell wall components to predict how much forage an animal can consume, whereas acid detergent fiber (ADF) measures the highly indigestible parts to estimate the overall energy value of the feed. Response of different treatments on acid detergent fiber and neutral detergent fiber was found nonsignificant (Table-4). Micronutrient enrichment of fodder maize was markedly enhanced by Zn and Fe fertilization. Treatment T 10 (80-40-0 NPK kg/ha) + ZnSO 4 .7H 2 O @ 25 kg/ha + FeSO 4 .7H 2 O @ 50 kg/ha + 0.5% ZnSO 4 + 0.5% FeSO 4 ) recorded higher Zn content (23.04 mg/kg), Zn uptake (239.69 g/ha), Fe content (83.09 mg/kg), and Fe uptake (865.43 g/ha). The increased nutrient concentration and uptake were primarily due to greater nutrient availability and higher biomass production under integrated soil and foliar application (Patel and Rathod 2024) [13] . Application of 80-40-0 NPK kg/ha) + ZnSO 4 .7H 2 O @ 25 kg/ha + FeSO 4 .7H 2 O @ 50 kg/ha + 0.5% ZnSO 4 + 0.5% FeSO 4 (T 10 ) noted significantly higher value of S content (0.14%) and uptake (14.21 g/ha). The improvement in sulphur content likely resulted from the balanced application of all targeted nutrients. Similarly, DTPA-extractable Zn (0.55 mg/kg) and Fe (5.05 mg/kg) in soil were significantly improved under T 10 (Table 3), indicating the beneficial residual effect of micronutrient fertilization. Overall, the integrated application of ZnSO 4 and FeSO 4 through soil and foliar methods proved most effective in enhancing fodder yield, quality, biofortification, nutrient uptake, and soil micronutrient status in fodder maize. The results are in accordance with the those of findings reported by Patel and Rathod (2024) [13] .

Digestibility is an important parameter for measurement of the animal feed nutritive value. In present study there are different digestibility parameter was calculated (

Conclusion

The combined application of zinc and iron significantly improved the growth, yield, quality, nutrient content and nutrient uptake of fodder maize. Treatment T 10 [RDF + ZnSO₄.7H₂O @ 25 kg/ha + FeSO 4 .7H₂O @ 50 kg/ha + 0.5% ZnSO 4 + 0.5% FeSO 4 ] recorded the highest values for plant height, dry matter content, crude protein content, crude protein yield and Zn and Fe content and uptake, remaining statistically at par with T 4 [RDF + ZnSO₄.7H₂O @ 25 kg/ha + FeSO₄.7H₂O @ 50 kg/ha]. However, ADF, NDF, number of leaves per plant and available sulphur in soil were not significantly affected by the treatments. Overall, soil application of ZnSO₄.7H₂O @ 25 kg/ha and FeSO₄.7H₂O @ 50 kg/ha (T 4 ) proved to be the most economical and effective treatment for zinc and iron Ferti-fortification, enhancing fodder productivity, quality, nutrient enrichment and soil micronutrient status under the loamy sand conditions of Anand, Gujarat.

Acknowledgement

AcknowledgementFor scientific studies, support, technical guidance, authors are grateful to Director of Research and Dean PG Studies, for their kind support during research. We are thankful to Principal and Dean, B. A. College of Agriculture, Anand Agricultural University, Anand, for providing the necessary knowledge and facilities during course of investigation. We are heartly thankful to Research Scientist (Forage), Main Forage Research Station, Anand Agricultural University, Anand for providing facility proximate analysis.

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