Ammonia Volatilization from Direct Seeded Later-rice Fields as Affected by Irrigation and Nitrogen Managements

Abstract

Ammonia volatilization (AV) from direct seeded later-rice (DSR) fields was investigated based on plot experiment with different irrigation (traditional flooding irrigation (TI) and controlled irrigation (CI)) and nitrogen (farmers' fertilization practice (FF) and controlled released urea (CU)) managements. Seasonal AV losses were 64.0, 69.5, 33.0 and 24.6 kg N ha -1 from CIFF, TIFF, TICU and CICU fields, accounting for 18.3, 19.9, 13.7 and 10.3% of nitrogen inputs not as high as expected, and falling in the range reported in transplanted rice fields with the similar nitrogen treatments. Thus, it is difficult to answer the question if DSR practice will lead to significantly higher AV loss than transplanted cultivation. Mixed basal nitrogen fertilizer into muddy and frequently rainfall in the first forty days in rice season might account for the low AV loss percentages from DSR field in current research. Both nitrogen and irrigation management significantly affected AV loss from DSR fields, with the nitrogen management as the predominant factor. Compared with the farmers' fertilization， controlled released urea led to the reduced and retarded AV process. The controlled irrigation led to higher AV peaks immediately after nitrogen application in short period, but lower AV rates in long periods after the pulse AV emission than traditional flooding irrigation. The combination of controlled irrigation and controlled released urea is help to reduce AV loss from DSR field.

Impact of Biochar Application on Ammonia Volatilization from Paddy Fields under Controlled Irrigation

“…Ammonia volatilization in paddy fields is mainly caused by ammonium ions on the soil surface. The application of nitrogen fertilizer is the main reason for ammonia volatilization in fields [31,32]. When nitrogen fertilizer, such as urea, is applied to the paddy field, NH 4 + and OH − are rapidly generated through hydrolysis, leading to an increase in the NH 4 + concentration in the surface water within a short period [33,34].…”

Rice yield in Costa Rican Central Pacific did not improve with a urease inhibitor

“…Tillage practices and nitrogen (N) management are essential factors for rice production. Urea is the most used fertilizer worldwide (Li et al, 2017), although its efficiency is usually low (Liao et al, 2015). Decreased N use efficiency (NUE) associated with the N loss via ammonia (NH 3 ) volatilization, reduces crop productivity and its subsequent deposition generates an indirect greenhouse gas effect, eutrophication of water bodies and soil acidification (de Vries, 2021;Skorupka and Nosalewicz, 2021).…”