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ISSN : 2287-5824(Print)
ISSN : 2287-5832(Online)
Journal of The Korean Society of Grassland and Forage Science Vol.46 No.3 pp.249-254
DOI : https://doi.org/10.5333/KGFS.2026.46.3.249

Biomass Production, Fermentation Characteristics, and Nutritional Composition of Baled Whole-Crop Corn Silage during Long-Term Storage

Ilavenil Soundharrajan1, Ouk Kyu Han2, Jae Hyuk Kim3, Seong Hak Yang4, Jae Hoon Woo4, Seung Min Jeong4, Ha Neul Ko4, Jin Woo Jeong4, Jeong Sung Jung4*, Ki Choon Choi1*
1DasomeBio Inc., Jangseong 57248, Republic of Korea
2Department of Crop Science, Korea National College of Agriculture and Fisheries, Jeonju 54874, Republic of Korea
3Department of Agriculture, Korea National Open University, Seoul 03087, Republic of Korea
4Forages Production Systems Division, National Institute of Animal Science, Cheonan 31000, Republic of Korea
†

These authors contributed equally to this work.


*Corresponding author: Jeong Sung Jung, Forages Production Systems Division, National Institute of Animal Science, Cheonan 31000, Republic of Korea. Tel: +82-41-580-6748, Fax: +82-41-580-6779, E-mail: jjs3873@korea.kr
Ki Choon Choi, DasomeBio Inc., Jangseong 57248, Republic of Korea. Tel: +82-31-510-2242, E-mail: kichoonchoi@naver.com
September 17, 2026 September 28, 2026 September 28, 2026

Abstract


This study evaluated the whole-crop corn cultivation in different years and the effects of prolonged storage on the fermentation characteristics and nutritional composition of mechanically baled corn silage. Whole-crop corn was cultivated during the 2023 and 2024 growing seasons, harvested, mechanically baled, and stored under field conditions for up to 12 months. Seasonal differences significantly affected biomass partitioning between forage and grain components. Dry matter forage production was greater in 2023 than in 2024 (12,094 ± 1,039 vs. 9,167 ± 267 kg ha−1; p<0.05), whereas grain production was greater in 2024 than in 2023 (8,212 ± 299 vs. 6,585 ± 1,149 kg ha−1; p < 0.05). However, total dry matter yield did not differ significantly between years (18,679 ± 1,982 vs. 17,379 ± 434 kg ha−1). Fermentation characteristics revealed that during 12 months of storage, silage pH remained consistently low (pH 3.62–3.78), with the lowest value observed after 9 months (p<0.05). Lactic acid concentration increased during storage and reached a maximum at 9 months (12.74 ± 1.94 % DM), but an extended period significantly reduced (p<0.05). Butyric acid (BA) was detected only at 3 months of storage, but thereafter BA was not detected. Crude protein and total digestible nutrient concentrations remained stable throughout storage periods, whereas neutral detergent fiber and acid detergent fiber concentrations declined significantly (p<0.05) during the later storage periods. Overall, prolonged storage of up to 12 months appears feasible for maintaining the preservation and nutritional characteristics of baled whole-crop corn silage under the conditions evaluated.


Whole-crop corn , Cultivation , Silage , Fermentation characteristics , Nutritional composition

초록

    Ⅰ. INTRODUCTION

    Corn (Zea mays L.) is one of the most essential cereal crops and is widely cultivated for food, feed, and industrial uses. Global cereal production reached approximately 3.1 billion tonnes in 2024, reflecting consistent growth in agricultural productivity and the importance of cereals in global food and feeding systems (FAO, 2025). In contrast, South Korea has limited domestic corn production and highly relies on imports of feed sources to meet its demand. Republic of Korea is estimated to depend on imports for approximately 99 % of its corn consumption. Corn imports are projected to reach approximately 11.5 million tonnes in the 2025–2026 marketing year (USDA-FAS, 2025a). Corn is also the principal ingredient in the Korean compound-feed industry, accounting for approximately 65% of compound-feed production, highlighting its importance to the livestock sector(USDA-FAS, 2025b). Therefore, improving the production, preservation, and utilization of domestically produced whole-crop corn could contribute to a more stable local forage supply and reduce dependence on imported feed resources.

    Ensiling is widely used to preserve whole crop corn and maintain its nutritional value for livestock production. During ensiling, lactic acid bacteria (LAB) ferment water-soluble carbohydrates into organic acids, particularly lactic acid, resulting in rapid acidification of silages and inhibiting undesirable microbial growths (Akhtar et al., 2025). Effective fermentation is essential for minimizing dry matter and nutrient losses and maintaining silage quality. Conversely, unfavorable ensiling conditions can promote clostridial activity and butyric acid production, leading to undesirable fermentation with energy and nutrient losses (Wróbel et al., 2023). Baled silage represents an alternative to conventional bunker or tower silos and provides practical advantages in harvesting, handling, transportation, and storage. However, its fermentation characteristics may differ from those of conventionally stored chopped silage because bale density, moisture distribution, and oxygen exclusion can vary within and among bales (Borreani et al., 2018)

    Despite extensive research on whole-crop corn maturity and conventional ensiling, limited information is available on the long-term fermentation and nutritional changes of mechanically baled whole-crop corn under field storage conditions. Therefore, this study evaluated differences in forage, grain, and total dry matter productivity of whole-crop corn between two growing seasons and changes in pH, fermentation metabolites, and major nutritional components of mechanically baled corn silage during 12 months of storage.

    Ⅱ. MATERIALS AND METHODS

    1. Research area

    The experiment was conducted in Cheonan, Chungcheongnam-do Province, Republic of Korea, at 36.931739° N latitude and 127.106166° E longitude. It has a distinct seasonal climate with relatively high-temperatures from late spring to early autumn and cold winters. The average temperature in August, the hottest month is approximately 29.9°C, whereas February is the coldest month, with an average temperature of –5.8 °C. The main rainy period occurs from June to September.

    2. Corn Cultivations

    Dacheongok cultivar was cultivated in an experimental field covering 3ha in 2023 and 2024. The corn was sown in early May and harvested in mid-August in respective years. Corn was mechanically sown at a row spacing of 70cm and a within-row spacing of 25 cm. The experiment was conducted over a total area of 3 ha. Basal fertilization was applied at rates of 100 kg ha−1 nitrogen (N), 150 kg ha−1 phosphorus (P), and 150 kg ha−1 potassium (K). An additional 100 kg ha−1 of nitrogen was top-dressed when the corn reached 50 cm in height (Ilavenil et al., 2025).

    3. Silage Production by bale silage method

    Whole crop corn was harvested at the yellow ripening stage. The forage was mechanically baled to produce a total of 12 silage bales and wrapped with polyethylene film to establish anaerobic conditions. The wrapped bales were stored under field conditions for 12 months. Three bales were randomly selected for sampling at each 3-month interval (3, 6, 9, and 12 months). Approximately 500 g of silage was collected from the center and multiple locations within each bale using a clean sampling probe to obtain representative samples. The collected samples were immediately placed in sealed plastic bags and stored at −20°C until analysis.

    4. Nutrient composition and Organic acid profiles

    For fermentation analysis, 10 g of each silage sample was mixed with 90 mL of distilled water and shaken for 1 h using an orbital shaker. The pH was subsequently measured using a glass-electrode pH meter (Thomas Scientific, NJ, USA). Organic acids, including lactic, acetic, and butyric acids, were analyzed using high-performance liquid chromatography (HPLC) and gas chromatography (Jung et al., 2024). The collected silage samples were dried in a forced-air oven at 60°C until a constant weight was achieved and calculated dry matter content of samples. The dried samples were then ground through a 1-mm sieve using a laboratory mill and stored in airtight containers until analysis. Crude protein (CP) concentration (AOAC, 1990b), Neutral detergent fiber (NDF), and acid detergent fiber (ADF) concentrations were determined (Van Soest et al., 1991). The TDN was calculated from TDN = 88.9 − ( ADF % × 0.79 ) (Seo et al., 2010; Holland et al., 1990).

    5. Statistical Analysis

    Significant differences among treatments were evaluated using SPSS version 16.0 through analysis of variance (one-way ANOVA), t-test, and multivariate analysis, as appropriate. Post hoc comparisons were performed using Duncan’s multiple range test and the least significant difference (LSD) test. Descriptive statistical analysis was also conducted, and differences were considered statistically significant at p<0.05.

    Ⅲ. RESULTS AND DISCUSSION

    1. Whole Crop Corn Production

    Corn productivity significantly differed between the 2023 and 2024 growing seasons, particularly in the partitioning of biomass forage and grain quantity (Table 1). Forage yields were significantly higher in 2023 than in 2024 (12,094 ±1,039 vs 9,167 ± 267 kg ha−1) whereas grain quantity was significantly higher in 2024 than in 2023 (8,212 ± 299 vs 6,585 ±1,149 kg ha−1; p<0.05). However, total dry matter yield (forage and corn) did not differ significantly between experimental years. An average total dry matter (TDM) was 18,679 ± 1,982 vs 17,379 ± 434 kg ha−1 in 2023 and 2024, respectively. The overall mean forage, grain, and TDM yields were 10,631 ± 2,069, 7,399 ±1,150 and 18,029 ± 919 kg ha−1, respectively. The higher forage yield in 2023 and the higher grain quantity in 2024 indicate differences in biomass partitioning between vegetative and reproductive components. Environmental conditions, plant population and maturity at harvest can substantially affect whole plant corn yield and the relative contribution of grain and structural components(Peña et al., 2023). Advancing corn maturity generally increase DM and grain yield while altering the proportions of structural carbohydrates and starch in the whole plant (Tolera et al., 1998). Thus, the higher grain yield observed in 2024 may reflect more favorable conditions for reproductive development and assimilate partitioning. Since, TDM yield was statistically similar between years, the main seasonal effects in this study appears to be changed in biomass production rather than a substantial change in overall crop productivity.

    2. Silage production and its fermentative metabolites at different storage periods.

    The fermentative metabolites in experimental silage at every three months are presented in Table 2. Storage duration markedly affected the fermentation characteristics of baled silage. The silage pH remained low throughout the 12-month storage period, ranging from 3.62 to 3.78. The lowest pH occurred at 9 months (3.62), which was significantly lower than that at 3 months (3.78), while the 6- and 12-month values were intermediate. Maintenances of a lower pH indicate effective acidification and preservation of ensiled silage(Hawu et al., 2022; Weiß et al., 2022). Lactic acid concentration was increased from 5.61% DM at 3 months to 7.25% at 6 months and reached a maximum of 12.74% DM at 9 months before declining to 7.78% DM at 12 months. The significantly higher lactic acid concentration and lower at 9 months indicates higher accumulation and persistence of lactic acid during storge. However, extended storage period to 12 months sharply reduced lactic acid content of corn silage, it may be due to degradation of lactic acid into other acids by yeast and other microbes and reduced capability of LAB in fermented silage (Storm et al., 2010; Xin et al., 2022). Butyric acid is generally absent from well-fermented silages, and its presence indicates undesirable clostridial activity. Such fermentation can result in substantial dry matter losses and reduced energy recovery, thereby compromising overall silage quality (Kung et al., 2018; Pahlow et al., 2003; Zong et al., 2025). Butyric acid was detected at 3 months but not detected at 6, 9, and 12 months in ensiled silage. The detection of butyric acid at 3 months may indicate limited clostridial activity during the early stage of storage. As fermentation progressed, the lower pH and accumulation of lactic acid likely created conditions that inhibited clostridial growth and further butyric acid production. Therefore, butyric acid was not detected at 6, 9, or 12 months, suggesting that undesirable clostridial fermentation was suppressed during prolonged storage. Propionic acid concentrations remained relatively low (0.06–0.64% DM), although the highest concentration was at 9 months. Overall, the organic acid profile indicates that the baled corn silage maintained an acidic and relatively stable fermentation environment throughout storage. The results are consistent with recent evidence showing that storage conditions can continue to influence fermentation characteristics after the initial ensiling phase.

    3. Changes in nutrients composition of experimental silages at different storage periods

    Storage durations had a smaller effect on the nutrient content such as CP, NDF and acid detergent fiber ADF (Table 3). Crude protein concentration did not differ significantly among storage periods and ranged from 7.95 to 8.37% DM. The relatively stable CP concentration indicates that the total crude protein content remained relatively unchanged during storage. However, CP concentration alone cannot be used to assess the extent of proteolysis. Protein degradation is better evaluated using nitrogen fractions such as ammonia-N and soluble nitrogen. Previous studies have reported that prolonged ensiling can increase ammonia-N and soluble CP in whole-plant corn silage, even when the total CP concentration remains relatively stable (Ferraretto et al., 2015). NDF and ADF are widely used as indicators of silage structural composition and are closely associated with intake and digestibility. In the present study, NDF concentrations were significantly higher at 3 and 6 months (60.11 ± 1.71 and 61.76 ± 0.05 %; p<0.05) than at 9 and 12 months (57.67 ± 2.34 and 56.98 ± 0.75%). Similarly, ADF concentrations were decreased from 36.47 ± 0.14% to 35.89 ± 1.23, 34.51 ± 1.43% and 34.75 ± 0.5% at 6,9, and 12 months, respectively. The decline in NDF and ADF during later storage indicates modification of the structural carbohydrate fraction during storage periods (Sarıçiçek et al., 2016). Recent studies have claimed that forage maturity at harvest can influence fiber composition and digestibility. As corn maturity advances, increased grain proportion can reduce NDF and ADF concentrations in the whole plant, while changes in structural components and lignin may affect NDF digestibility (Souza et al., 2021). These effects may also vary among cultivars and harvesting stages (Souza et al., 2021) while storage duration can further influence fiber characteristics during ensiling (Ferraretto et al., 2015) . Total digestible nutrients remained statistically unchanged throughout storage, ranging from 60.09 to 61.63% DM. Thus, despite the significant changes in NDF and ADF, estimated TDN concentration remained relatively stable. This suggests that the observed changes in fiber fractions were not sufficient to substantially alter the overall estimated energy value of the silage.

    Ⅳ. CONCLUSION

    In conclusion, whole-crop corn production showed significant seasonal differences in biomass partitioning, with greater forage yield in 2023 and higher grain yield in 2024, while total dry matter yield remained statistically similar between years. The baled corn silage maintained a stable and sufficiently low pH throughout 12 months of storage, indicating effective preservation. Lactic acid production was greatest at 9 months, coinciding with the lowest pH, whereas butyric acid was absent after 3 months, suggesting limited undesirable fermentation. Storage duration had no significant effect on crude protein (CP) and total digestible nutrients (TDN) concentrations, whereas NDF and ADF concentrations decreased during prolonged storage. Overall, the results indicate that whole-crop corn can be effectively preserved as bale silage for extended storage while maintaining relatively stable nutritional value and favorable fermentation characteristics.

    Ⅴ. ACKNOWLEDGEMENT

    This work was performed with the support of the Cooperative Research Program for Agriculture Science and Technology Development (Project title: Efficient succession production of Domestic Maize and Triticale silage and feeding to Hanwoo cow and heifer for growth, reproduction and beef production; Project No. PJ017203), Rural Development Administration, Republic of Korea.

    Figure

    Table

    Comparative corn productivity for the years 2023 and 2024
    Data are presented as mean ± standard deviation (SD). Data are presented as mean ± SD. Different letters (a,b) within a column indicate significant differences among ensiling durations (p<0.05)
    Organic acids (%DM) Profiles of baled corn silage at different storage periods
    Data are presented as mean ± SD. Different letters within a column indicate significant differences among ensiling durations (p<0.05)
    Nutrient Profiles (%DM) of baled corn silage at different storage periods
    The data are presented as the mean ± STD. CP: Crude protein; NDF: Neutral detergent fiber; ADF: acid detergent fiber; TDN: total digestible nutrients. Different letters within a column indicate significant differences among ensiling durations (p<0.05)

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