Blends and Timing of Polymer Coated and Uncoated Urea: Effects on Corn and Cotton in the Deep South.

Environmentally Smart Nitrogen (ESN) is a commercially available controlled-release urea-N source (44-0-0) for crop production and may offer benefits for corn and cotton production compared to urea alone.  Pure formulations and blends of ESN and urea were applied either pre-plant or split applied during three site-years for corn and five site-years for cotton. Blend treatments were 100% urea, 50:50 urea:ESN, 25:75 urea:ESN, and 100% ESN, plus a 0 N check.  Application timing treatments were 100% at planting or 25% at planting/75% at first bloom. Treatments were arranged as a randomized complete block with four replications at Jay, FL and Citra, FL. ESN release rates for both applications were determined using litterbag methodology at both locations during 2015 and 2016. ESN release rates will be discussed in conjunction with N source and timing effects on corn and cotton yield and quality.