Corn (Zea mays L.) is one of the most cultivated crops in the United States, covering about 86.5 million acres, representing about 17% of the total land area (514.93 million acres) devoted to corn worldwide (Our World in Data, 2023). In 2024, corn was cultivated on 70,000 acres in Arizona, with 50,000 acres devoted to silage corn, producing approximately 1,350,000 tons (Food and Agriculture Organization of the United Nations, 2025). Silage corn in Arizona requires a substantial amount of water, especially during the reproductive growth stages (Payero et al., 2006). Depending on weather, irrigation methods, and crop management practices, silage corn may require 16 to 30 acre-inches of water per season (Andales and Schneekloth, 2017) and is typically harvested at the dent, R5 reproductive stage, when whole-plant moisture reaches about 60-70%. Harvesting at this stage maintains silage quality and digestibility while minimizing yield losses (Lauer, 2016; Roth and Heinrichs, 2001).
In consideration of water scarcity and the necessity for water conservation, the implementation of deficit irrigation strategies in arid and semi-arid regions, aligned with crop growth stages and their respective sensitivity to water stress, can enhance on-farm management practices by reducing irrigation water consumption, diminishing evaporation losses, minimizing energy consumption, and increasing economic returns from investments in irrigation water supplies (Elsadek et al., 2023, 2025; Elshikha et al., 2024). Furthermore, improving soil quality through accurate estimation of the salt leaching fraction and soil amendments may enhance soil structure and increase water retention capacity, thereby contributing to higher crop yields (Elshikha et al., 2025).
In this context, this publication provides information on irrigation water management, silage corn yield, water productivity, and quality under different irrigation methods, rates (80% and 100% of calculated crop evapotranspiration, ETc), and soil conditions: A soil amendment (a), Liquid Natural Clay (LNC), provided by the Desert Control Company (accessed on 20 November 2025), that was evaluated for its effects on soil moisture retention and yield and compared to an unamended control. The findings will guide growers to make informed decisions to enhance silage corn yield, water productivity, and quality in Arizona, USA.
Irrigation methods and total water applied
The experiment was conducted at the Maricopa Agricultural Center, Arizona, from March to June 2025 in a 15-acre field with three irrigation systems: flood (F), subsurface drip (D), and center pivot (CP). The study was arranged as a split-plot randomized complete block design (RCBD) with three replications. Each irrigation system was evaluated at two irrigation levels, 80% and 100% of crop evapotranspiration (ETc), under amended (with LNC) and non-amended soil conditions. Each plot was 640 ft by 21 ft. Within replicated plots under the F and D systems, designated sampling areas of approximately 32 ft2 were randomly selected for manual harvest. Under the CP system, the field was divided into six equal sections, with a radius of 320 ft, and irrigation treatments (CP100 and CP80) were alternately assigned to these sections. Within each section, 32-ft2 subplots were randomly designated for manual harvest.
Silage corn from the designated subplots was harvested by hand on June 24 at the dent stage (R5), as described by Lauer (2016). Harvest timing was determined when kernel denting was evident, and whole plant moisture was approximately 70%. Yield was then adjusted to 65% moisture content, in accordance with Lauer and Undersander (2004) and Lee (2022). The total water applied (TWA, in), including irrigation and precipitation for F, D, and CP under different irrigation rates (80% and 100% of ETc), is shown in Figure 1 and summarized in Table 1. The TWA ranged from 18.6 in (D80%) to 29.9 in (F100), which is within the usual range of TWA for flood-irrigated silage corn in Maricopa, Arizona (Subramani and Loper, 2012).
Figure 1. Total water applied for silage corn cultivated under different irrigation methods: (a) flood (F), (b) subsurface drip (D), and (c) center pivot (CP), at the University of Arizona, Maricopa Agriculture Center in 2025.
Table1. Summary of the total water applied (TWA, in), silage corn yield at 65% moisture level (Y, t/ac), and Water productivity (WP, t/ ac-in) during the 2025 growing season at the University of Arizona, Maricopa Agriculture Center
| System | Flood (F) | Subsurface drip (D) | Center pivot (CP) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Treatment | F 100% | Fa 100% | F 80% | Fa 80% | D 100% | Da 100% | D 80% | Da 80% | CP 100% | CPa 100% | CP 80% | CPa 80% |
| TWA, in | 29.9 | 23.8 | 24.1 | 18.6 | 26.2 | 21.1 | ||||||
| Y, t/ac | 26.6 (-1.6) | 23.9 (-0.6) | 21.6 (-2.3) | 23.5 (-2.2) | 28.9 (-2.1) | 29.6 (-2.3) | 24.6 (-5.4) | 23.8 (-5.6) | 27.6 (-2) | 32.3 (-2.5) | 25.4 (-1.4) | 24.1 (-2.4) |
| % change in TWA compared to F100 | - | -20.4 | -19.4 | -37.8 | -12.4 | -29.4 | ||||||
| % change in Y compared to F100 | - | -10.2 | -18.8 | -11.7 | 8.6 | 11.3 | -7.5 | -10.5 | 3.8 | 21.4 | -4.5 | -9.4 |
| WP, t/ ac-in | 0.89 | 0.8 | 0.91 | 0.99 | 1.2 | 1.23 | 1.32 | 1.28 | 1.05 | 1.23 | 1.2 | 1.14 |
Yield, water productivity, and quality
The fresh biomass yield (Y, t/ac) was collected from different treatments and replicates, then averages were considered for comparison. The water productivity (WP, t/ac-in) was estimated following Molden et al. (2010):
WP = Y/TWA
Our results demonstrated that D and CP performed better than F in terms of Y (t/ac) even under the 80% irrigation rate, whereas the highest silage corn yield was 32.3 t/ac under the CP100a% treatment (Table 1). This may be due to higher evaporation losses from the soil surface and the lower irrigation efficiency of flood irrigation compared with other irrigation methods. However, the lowest silage corn yield was 21.6 t/ac under the F80% treatment. It was observed that the LNC soil amendment (a) increased the silage corn yield under 100% treatments for center pivot (32.3 t/ac for CPa100% vs 27.6 t/ac for CP100%) and subsurface drip (29.6 t/ac for Da100% vs 28.9 t/ac for D100% ), but not under flood (26.6 t/ac for F100% vs 23.9 t/ac for Fa100%), nor 80% treatments except for flood (23.5 t/ac for Fa80% vs 21.6 t/ac for F80%) [Table 1]. The cause of inconsistency of Y variation under the amended soil is unclear and requires more investigation to understand the possible interference of both biotic and abiotic growth parameters, including soil water holding capacity, soil salinity, root development, and nutrient distribution.
On the other hand, the highest WP was recorded under the D80% treatment (1.32 t/ac-in), while the lowest WP was 0.80 t/ac-in under the F100a% treatment (Table 1). Adoption of the deficit irrigation strategy led to an increase in water productivity, especially under the subsurface drip, largely due to reduced irrigation losses and improved crop yield (Figure 1 and Table 1).
Our findings agreed with previously cited studies, which highlight the benefits of deficit irrigation in arid regions (e.g., Elsadek et al., 2023; Elshikha al., 2025; Elshikha et al., 2024; Elshikha et al., 2023; and Ragab, 2014). Additionally, our findings aligned with Elsadek (2023), Elshikha et al. (2025), Gouertoumbo et al. (2022), and Hamad et al. (2023), who reported that while ensuring adequate irrigation, deficit irrigation would improve water use efficiency and water productivity.
Silage corn quality was analyzed using a Near-Infrared Spectroscopy (NIRS) laboratory method (accessed on 20 November 2025). Nutritional parameters, including Neutral-Detergent Fiber (NDF), Acid-Detergent Fiber (ADF), Crude Protein (CP), Total Digestible Nutrients (TDN), and Starch, are compared in Figure 2. With the biomass moisture around 70% at harvest, the nutritional parameters in our case showed a typical range of values for a desired silage corn. Laboratory analysis indicated that deficit irrigation did not compromise silage corn quality under any of the three tested irrigation systems. Among the treatments, D80% achieved the highest water productivity, followed by Da80%, Da100%, CPa100%, D100%, CP80%, CPa80%, CP100%, Fa80%, F80%, F100%, and Fa100% (in descending order).
Figure 2. Nutritional parameters, including Neutral-Detergent Fiber (NDF), Acid-Detergent Fiber (ADF), Crude Protein (CP), Total Digestible Nutrients (TDN), and Starch of silage corn under different irrigation methods: flood (F), subsurface drip (D), and center pivot (CP), with different irrigation rates (100% and 80% ETc replacement) and amended (a) and non-amended soils.
Conclusions and recommendations
This study evaluated the effects of three irrigation methods (flood, subsurface drip, and center pivot), two irrigation application rates (100% and 80% of ETc), and soil amendments on silage corn production under arid and semi-arid conditions. Findings from a single growing season at one location indicated that silage corn can be produced under reduced irrigation levels without observed changes in measured nutritional quality parameters, while maintaining yields and water productivity within acceptable ranges. Among the evaluated treatments, subsurface drip irrigation at 80% ETc (D80) resulted in the largest observed reduction in applied water relative to F100 and the highest measured silage corn water productivity. Additionally, inconsistent variation was observed in the amended soil treatments, highlighting the need for further investigation. Longer-term monitoring is required to better characterize the effects of soil amendments on soil properties and to document crop response over time.
These findings are preliminary and specific to the conditions of this study and should not be considered management recommendations. Confirmation through multi-season, multi-location studies with comprehensive statistical analysis is necessary before drawing any broader conclusions.
Acknowledgement
This work was supported by the University of Arizona Cooperative Extension Water Irrigation Efficiency Program, which is funded by the Arizona State Legislature
References
Andales, A., and Schneekloth, J., 2017. Seasonal Water Needs and Opportunities for Limited Irrigation for Colorado Crops. Colorado State University Extension publications. [WWW Document]. URL https://extension.colostate.edu/resource/seasonal-water-needs-and-opportunitiesfor-limited-irrigation-for-colorado-crops/ (accessed 11.20.25).
Elsadek, E.A., Attalah, S., Waller, P., Norton, R., Hunsaker, D.J., Williams, C., Thorp, K.R., Orr, E., Elshikha, D.E.M., 2025. Simulating Water Use and Yield for Full and Deficit Flood-Irrigated Cotton in Arizona, USA. Agronomy 15, 2023. https://doi.org/10.3390/agronomy15092023.
Elsadek, E.A., 2023. Study on the In-Field Water Balance and the Projected Impacts of Climate Change on Rice Yields in the Nile River Delta. Hohai University, China.
Elsadek, E., Zhang, K., Mousa, A., Ezaz, G.T., Tola, T.L., Shaghaleh, H., Hamad, A.A.A., Alhaj Hamoud, Y., 2023. Study on the In-Field Water Balance of Direct- Seeded Rice with Various Irrigation Regimes under Arid Climatic Conditions in Egypt Using the AquaCrop Model. Agronomy 13, 609. https://doi.org/10.3390/agronomy13020609.
Elshikha, D.E., Attalah, S., Waller, P., Hunsaker, D., Thorp, K., Williams, C., Sanyal, D., Singh, B., Sanchez, C., Norton, R., Alshraah, S., Barnes, E., Orr, E., Elsadek, E.A., 2025. Enhancing Cantaloupe and Broccoli Water Productivity Under Arid Climate Conditions in Arizona, in: 2025 Toronto, Ontario, Canada, July 13-16, 2025, ASABE Paper No. 2500006. American Society of Agricultural and Biological Engineers, St. Joseph, MI, p. 1. https://doi.org/10.13031/aim.202500006.
Elshikha, D.E., Attalah, S., Elsadek, E.A., Waller, P., Thorp, K., Sanyal, D., Bautista, E., Norton, R., Hunsaker, D., Williams, C., Wall, G., Barnes, E., Orr, E., 2024. The Impact of Gravity Drip and Flood Irrigation on Development, Water Productivity, and Fiber Yield of Cotton in Semi- Arid Conditions of Arizona, in: 2024 Anaheim, California, July 28-31, 2024. American Society of Agricultural and Biological Engineers, St. Joseph, MI, pp. 1–16. https://doi.org/10.13031/aim.202400004.
Elshikha, D.E.M., Wang, G., Waller, P.M., Hunsaker, D.J., Dierig, D., Thorp, K.R., Thompson, A., Katterman, M.E., Herritt, M.T., Bautista, E., Ray, D.T., Wall, G.W., 2023. Guayule growth and yield responses to deficit irrigation strategies in the U.S. desert. Agric. Water Manag. 277, 108093. https://doi.org/10.1016/j.agwat.2022.108093.
Food and Agriculture Organization of the United Nations, 2025. Crops and livestock products https://www.fao.org/faostat/en/#data/QCL (accessed 11.29.25).
Gouertoumbo, F.W., Alhaj Hamoud, Y., Guo, X., Shaghaleh, H., Ali Adam Hamad, A., Elsadek, E., 2022. Wheat Straw Burial Enhances the Root Physiology, Productivity, and Water Utilization Efficiency of Rice under Alternative Wetting and Drying Irrigation. Sustainability 14, 16394. https://doi.org/10.3390/su142416394.
Hamad, A.A.A., Ni, L., Shaghaleh, H., Elsadek, E., Hamoud, Y.A., 2023. Effect of Carbon Content in Wheat Straw Biochar on N2O and CO2 Emissions and Pakchoi Productivity Under Different Soil Moisture Conditions. Sustainability 15, 5100. https://doi.org/10.3390/su15065100.
Lauer, J., 2016. Timing corn silage harvest. Integrated Pest and Crop Management. University of Wisconsin-Madison. [WWW Document]. URL https://ipcm.wisc.edu/blog/2016/08/timing-corn-silage-harvest/ (accessed 11.20.25).
Lauer, J. and Undersander, D., 2004. Pricing corn silage for sale. In Proceedings and Joint Meeting of the Professional Nutrient Applicators of Wisconsin, Wisconsin Custom Operators, and Wisconsin Forage Council. Eau Claire, WI (pp. 87-91).
Lee, Seungki; 2022. Corn Silage Price Calculation. Ohio State University Cooperative Extension, College of Food, Agriculture, and Environmental Sciences, Ohio State University, USA. [WWW Document]. URL https://dairy.osu.edu/sites/dairy/files/imce/Corn%20Silage%20Price%20Calculation%20-%20revised2.pdf (accessed 11.20.25).
Molden, D., Oweis, T., Steduto, P., Bindraban, P., Hanjra, M.A., Kijne, J., 2010. Improving Agricultural Water Productivity: Between Optimism and Caution. Agric. Water Manag. 97, 528–535. https://doi.org/10.1016/j.agwat.2009.03.023.
Our World in Data, 2023. Land Area per Crop Type, United States, 2023. [WWW Document]. URL https://ourworldindata.org/grapher/land-area-per-croptype?tab=discrete-bar&time=latest&country=~USA (accessed 11.20.25).
Payero, J. O., Melvin, S. R., Irmak, S., and Tarkalson, D., 2006. Yield Response of Corn to Deficit Irrigation in a Semiarid Climate. Agric. Water Manag. 84(1-2), 101-112. https://doi.org/10.1016/j.agwat.2006.01.009.
Ragab, R., 2014. A Note on Water Use Efficiency and Water Productivity [WWW Document]. Water4Crops. URL http://www.water4crops.org/water-use-efficiencywater-productivityterminology/ (accessed 5.25.22).
Roth, G.W., and Heinrichs, J. (2001). Corn Silage Production and Management. Penn State Extension. [WWW Document]. URL https://extension.psu.edu/corn-silageproduction-and-management (accessed 11.20.25).
Subramani, Jay, and Shawna Loper (2012). Silage Corn Variety Trial in Central Arizona. University of Arizona Cooperative Extension, College of Agriculture, Life, and Environmental Sciences, University of Arizona, USA. [WWW Document]. URL https://repository.arizona.edu/bitstream/handle/10150/211155/az1559f-2011.pdf?sequence=1&isAllowed=y (accessed 11.20.25).