Effects of Coated Urea Amended with Biological Inhibitors on Physiological Characteristics,Yield, and Quality of Peanut

Four kinds of new developed urea, some of which were amended with biological inhibitors and coated and some of which were only coated with inorganic materials, were prepared by coating conventional granular urea (nitrogen 46.0%). Using a coated urea [resin-coated urea, 90 day, (RCU)] made in China and a conventional granular urea as check, their effects on physiological characteristics, yield, and quality of peanut were examined in a field experiment. The results indicated that four kinds of urea kept greater ammonium nitrogen (NH₄ ⁺ -N) and nitrate nitrogen (NO₃^?N) contents at flowering stage (FS) and podding stage (PS) compared to conventional urea, and coated urea + dicyandiamide + hydroquinone treatment (CU + DCD + HQ) had the greatest contents, being similar to RCU treatment. At FS and PS, the chlorophyll content, photosynthetic rate, transpiration rate, and chlorophyll fluorescence parameters were significantly increased upon CU + DCD, CU + HQ, and CU + HQ + DCD treatments. In addition, CU + HQ + DCD treatment produced 27.3% more pod yield, 6.7% more total yield, and 9.17% more protein content and decreased NO₃^?-N content by 46.56% as compared to conventional urea treatment. This product has excellent slow-release capacity, is inexpensive and environmentally friendly, and could be especially useful in agricultural application.