Estimation of Ammonia Volatilization from a Paddy Field after Application of Controlled-Release Urea Based on the Modified Jayaweera–Mikkelsen Model Combined with the Sherlock–Goh Model

Abstract

ABSTRACTThe continuous airflow enclosures with an acid trap method was widely used to investigate ammonia (NH3) volatilization in field; however, it could be time-consuming for the estimation of NH3 volatilization in field with the application of controlled-release urea (CRU) because NH3 volatilization with CRU application could occur during the entire crop growth period. An NH3 volatilization estimation method based on the modified Jayaweera–Mikkelsen (J-M) model combined with the Sherlock–Goh model was used to simulate NH3 volatilization in a paddy field after 255 kg N ha−1 as CRU (polymer-coated urea with the concentration of 43% nitrogen, 100% for basal) and urea (70% for basal, 30% for topdressing) during the rice growth period including flooded and non-flooded periods in Wuxi, China. Results indicated that NH3 volatilization can be modeled with the proposed measure because no significant difference (P< 0.001) was observed between the simulated values and the observed values; the correlation coefficient (r2) was 0.615 for CRU and 0.840 for urea during the flooded period, and 0.991 for CRU and 0.946 for urea during the non-flooded period. Compared with urea, NH3 volatilization was minimized by 43.2% with the application of CRU based on simulated value within the rice growth period, which was 40.40 kg N ha−1 for CRU and 78.62 kg N ha−1 for urea during the flooded period, and 5.52 kg N ha−1 for CRU and 2.33 kg N ha−1 for urea during the non-flooded period. Therefore, CRU could be a promising nitrogen fertilizer to prevent NH3 losses in the rice paddies at the investigated area.