Abstract/Summary

Ammonia (NH3) volatilization from rice cultivation contributes to poor air quality and is indicative of low nitrogen use efficiency in farming. Organic fertilizers could meet the nitrogen requirement for rice growth yet, the simultaneous effects of organic fertilizers on ammonia volatilization and yield in rice paddy fields are poorly understood and quantified. To help address this knowledge gap, experimental field plots were constructed in a conventional double-cropping rice paddy fields in the Pearl River Delta, China. Five treatments were used in addition to a no fertilizer control: fresh organic fertilizer, successively composted organic fertilizer, chemical composted organic fertilizer, chemical composted organic fertilizer with inorganic fertilizer, and chemical fertilizer. NH3 volatilization was measured using a batch-type airflow enclosure method. The results showed no significant differences in grain yield between the different organic fertilizer and conventional chemical fertilizer treatments yet, when compared with the use of chemical fertilizer, the total NH3 volatilization significantly decreased with the use of a chemical composted organic fertilizer (70% reduction) and a successively composted organic fertilizer (68% reduction). The ammonium (NH4+-N) concentration in the field surface water had a strong positive correlation with NH3 volatilization for all fertilization treatments (P < 0.01). The outcome demonstrates chemical composted organic fertilizer can maintain rice yield and reduce NH3 volatilization, and an important next step is to up-scale these field-based measurements to similar rice cultivation areas to quantify the regional and national-scale impact on air quality and nitrogen deposition to sensitive areas, and fertilizer best practice.