Effect of Urea-Calcium Sulfate Cocrystal Nitrogen Fertilizer on Sorghum Productivity and Soil N2O Emissions

Abstract

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 N2O emissions remain underexplored. A greenhouse study was designed to evaluate sorghum (Sorghum bicolor (L.) Moench) yield, N uptake, and N2O emissions under six N treatments: C0 (without fertilizer), UR100 (urea), UC100 (CaSO4⋅4urea cocrystal) at 150 kg N ha−1, and CaSO4⋅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 N2O 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 N2O 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 N2O emissions and significantly increase the N use efficiency in sorghum.