Impact of manure compost amendments on NH3 volatilization in rice paddy ecosystems during cultivation.

Livestock manure has been widely used in agriculture to improve soil productivity and quality. However, intensive application can significantly enhance soil nitrogen (N) availability and facilitate ammonia (NH 3) volatilization during rice cultivation. The effects of different rates of manure application on the NH 3 volatilization rate, its mechanism, and their relationships have not been comprehensively investigated. In this study, field trials were conducted to investigate NH 3 volatilization in rice paddy soils amended with different livestock manure, cattle manure (CM), and swine manure (SM), at a rate of 0 (NPK), 10, 20, and 40 Mg ha⁻¹ during cultivation. Moreover, the soil physicochemical and biological properties and rice N uptake were investigated. Ultra-fine particulate matter (PM 2.5) was measured quantitatively and qualitatively. Manure application significantly increased NH 3 emissions compared to the control. Much higher volatilization rates were observed in the SM soils than in the CM soils, even when the same amount of N was applied. This is mainly related to the higher labile NH 4 ⁺ concentration and urease activity in SM soils. With increasing application levels, NH 3 emission rates proportionally increased in the SM, but there was no significant difference in the CM. Livestock manure application significantly increased NH 3 volatilization, particularly during the initial manure application and additional fertilization stages during rice cultivation. The results showed that the application of livestock manure significantly increased NH 3 volatilization. Moreover, the biochemical properties of manure composts, including labile N and urease activity, mainly affected NH 3 dynamics in rice paddies during cultivation rather than their type. Irrespective of manure application, PM 2.5 , did not show a significant difference at the initial stage of cultivation. NH 3 volatilization was not significantly correlated with the formation of PM 2.5. It is necessary to develop effective strategies for mitigating NH 3 volatilization and maintaining soil quality without decreasing rice productivity in paddy ecosystems. [Display omitted] • Swine manure caused higher NH 3 volatilization than cattle manure even at the same N amount. • Labile NH 4 ⁺ and urease activity mainly affect NH 3 volatilization in rice paddies during cultivation. • PM 2.5 did not show any significant difference in different manure amended fields. • NH 3 volatilizations were not significantly correlated with quantitative formation of PM 2.5. Manure compost applications significantly increased NH 3 volatilization. Much higher NH 3 volatilizations were observed in the SM applied soils than in the CM, even though the same amount of N was applied into the field. [ABSTRACT FROM AUTHOR]