Submitted to: Archives of Agriculture and Environmental Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/28/2018
Publication Date: 6/12/2018
Citation: Bruns, H.A. 2018. Grain sorghum (Sorghum bicolor L. Moench) fails to consistently respond to N-fertilizer when grown on a Tunica clay soil in the lower Mississippi River Valley, USA. Archives of Agriculture and Environmental Science. 3(2): 157-162.

Interpretive Summary: Grain sorghum acreage is increasing in the Mississippi Delta but information on nitrogen fertilization of the crop when grown on clay soils is not readily available and what little there is, is outdated. An experiment looking into this problem was conducted by a Scientist with the USDA-ARS Crop Production Systems Research Unit at Stoneville, MS. Rates of 0, 100, and 200 lbs of added nitrogen fertilizer were applied to six different grain sorghum hybrids. No consistent differences in yield or the yield components of heads per acre, seed per head, or seed weight were observed. Yields in the experiment were below most nearby variety trials, indicating heavy clay soils may not be well suited for grain sorghum production.

Technical Abstract: Nitrogen fertilization of grain sorghum (Sorghum bicolor L. Moench) on clay soils in the Mississippi Delta and similar environments have not been extensively researched. Six hybrids grown with 0.0, 100.0, and 200.0 lbs A-1 added N-fertilizer on a Tunica clay soil (clayey over loamy, montmorillonitic, non-acid, thermic, Vertic Halaquept) in 2014 and 2015 were evaluated for yield and yield components. The 2014 seeding did not require irrigation while three irrigations were applied in 2015. No yield differences occurred between N-treatments in 2014 but added N did increase yields in 2015. No consistent differences in yield or yield components occurred between hybrids. Yields were sub-standard to regional variety trial data probably due in part to the water and nutrient availability inherent to the clay soil. Rates of N-fertilizer at 100.0 lbs N A-1 probably will benefit grain sorghum yields from clay soils most years but higher levels most likely are not necessary.