Furrow Irrigation Spacing Impacts on Corn Production in Sharkey Clay Soils

Investigators: Trey Freeland, Drew Gholson, Gurpreet Kaur, Gurbir Singh

Date: 2021

Project Summary

Introduction

The Sharkey clay soil series, comprised mainly of 2:1 clay, is the dominant soil mapped in the Mississippi Delta, consisting of about one million acres (Pettry and Switzer, 1996). More than 40% of the land is classified under clay soils in the Mississippi Delta. Clayey soils are prone to frequent flooding and waterlogging. Kaur et al. (2020) reported that corn loses between 5-30% of yield with each day of waterlogging. Every-row and one-row-skip irrigation spacing practiced by Mississippi growers often results in saturated conditions which can lead to lower corn yield. Therefore, the objective of this research was to evaluate if altering irrigation spacings on Sharkey clay soils can reduce the waterlogging damage to corn and subsequently provide a benefit in corn yield.

Materials and Methods

An on-station field experiment was conducted at the National Center for Alluvial Aquifer Research (NCAAR), Stoneville, MS (33°25′26″N, 90°54′54″W), in 2021. All treatments were established in a randomized complete block design with four replications. Irrigation spacings included in this study were every row irrigation (ER; 40-inch spacing), 1 row skip irrigation (1R; 80-inch spacing), 4 row skip irrigation (4R; 160-inch spacing), and 8 row skip irrigation (8R; 320-inch spacing) (Figure 1). For 4R and 8R, yield data was collected from rows along the irrigated furrows (4R-I and 8R-I) and from rows furthest away from the irrigated furrows (4R-NI and 8R-NI). Corn hybrid DKC66-75 was planted at a seeding rate of 42,000 seeds/ac on 4/7/2021 at 40-inch row spacing. Urea ammonium nitrate (UAN-32) was split-applied at a seasonal nitrogen rate of 244 lb/ac. Weeds were managed using a pre-emergence spray of 96 oz/ac Lexar + 48 oz/ac paraquat + 0.25% v/v Scanner. 3 pt/ac Halex GT + 48 oz/ac Roundup PowerMAX 3 + 0.25% v/v Scanner was used for post-emergence weed management. Volumetric water content (VWC) was taken using a FieldScout TDR 350 Soil Moisture Meter (Aurora, IL) at a depth of 0-8” (Figure 2). Data was taken from every furrow before irrigation (event 1), after first irrigation (event 2), and after the second irrigation (event 3). Corn was harvested on 8/28/2021 using a Kincaid 8XP plot combine equipped with a harvest master H2 grain gauge.

Results and Discussion

There were no significant differences between the 4R-NI and ER treatments for corn grain yield (Figure 3). The 8R-NI had a significantly lower yield (9.21%) than all other treatments except 4R-I and 1R (Figure 3). Treatment 4R-NI yielded 10.14% higher than 8R-NI. However, the 4 row skip spacing held the highest VWC in both events 1 and 3 when compared to all other spacings (Figure 4). This shows that 4 row skip irrigation had sufficient subsurface lateral movement and that water moved efficiently through the plot for crop water demands without over-saturating the soil.

Conclusion

Results from the first year of study on the Sharkey clay soil indicate that 4 row skip irrigation would be ideal for growers when accounting for the risks associated with over-saturation or soil waterlogging losses in corn grain yield with every row or skip row irrigation. This research will be continued for more years to further assess the effectiveness of 4 row skip irrigation on Sharkey clay soils without adverse impact on yields.

References

Kaur, G., Singh, G., Motavalli, P. P., Nelson, K. A., Orlowski, J. M., & Golden, B. R. (2020). Impacts and management strategies for crop production in waterlogged or flooded soils: A review. Agronomy Journal, 112(3), 1475-1501.

Pettry, D. E., & Switzer, R. R. (1996). Sharkey Soils in Mississippi (MAFES Bulletin 1057). Mississippi State University.

Project Photos

• Crop Type:
• Corn

• Topic:
• Irrigation Scheduling
• Irrigation