Effect of Urea-Calcium Sulfate Cocrystal Nitrogen Fertilizer on Sorghum Productivity and Soil N 2 O Emissions

Urea cocrystal materials have recently emerged as high nitrogen (N) content fertilizers with low solubility capable of minimizing N loss and improving their use efficiency. However, their effects on crop productivity and N 2 O emissions remain underexplored. A greenhouse study was designed to evaluate sorghum ( Sorghum bicolor (L.) Moench) yield, N uptake, and N 2 O emissions under six N treatments: C0 (without fertilizer), UR100 (urea), UC100 (CaSO 4 ⋅4urea cocrystal) at 150 kg N ha −1 , and CaSO 4 ⋅4urea cocrystal at 40%, 70%, and 130% of 150 kg N ha −1 (UC40, UC70, and UC130, respectively). The results demonstrated that UR100, UC100, and UC130 had 51.4%, 87.5%, and 91.5% greater grain yields than the control. The soil nitrate and sulfur concentration, N uptake, and use efficiency were the greatest in UC130, while UR100 had significantly greater N 2 O loss within the first week of N application than the control and all the urea cocrystal treatments. UC130 minimized the rapid N loss in the environment as N 2 O emissions shortly after fertilizer application. Results of this study suggest the positive role of urea cocrystal in providing a balanced N supply and increasing crop yield in a more environmentally friendly way than urea alone. It could be good alternative fertilizer to minimize N loss as N 2 O emissions and significantly increase the N use efficiency in sorghum.