Effect of hydroquinone, dicyandiamide and encapsulated calcium carbide on urea N uptake by spring wheat, soil mineral N content and N2O emission

Abstract

Abstract. At present about half of the N fertilizer used in China is as urea. However, recovery of urea N in crops is often limited to 30–40%. Application of urea in combination with hydroquinone plus dicyandiamide (U‐HQ‐DCD) gave an improved urea‐N recovery and grain yield by spring wheat in a pot experiment. The apparent total urea‐N recovery was 69% and 73% of this recovered N was found in the grain. The grain yield was 32% higher than in the treatment where urea was applied without inhibitors. The application of hydroquinone and dicyandiamide also resulted in a smaller soil nitrate content, which might restrict post‐harvest leaching of N. Another beneficial effect of these inhibitors was that the N2O emission from the soil—plant system was reduced by 35% compared to the treatment where only urea was applied. The use of urea in combination with hydroquinone plus encapsulated calcium carbide gave smaller beneficial effects.