Combined Effects of Straw Returning and Chemical N Fertilization on Greenhouse Gas Emissions and Yield from Paddy Fields in Northwest Hubei Province, China

Abstract

The effects of crop straw returning or chemical N fertilization on greenhouse gas emissions and crop yield have been extensively studied, but their interaction effects remain unclear. So, this study aimed to investigate greenhouse gas emissions and yield from paddy fields as affected by straw returning, chemical N application, and their interactions in the 2017 and 2018 rice-growing seasons in northwest Hubei Province, China. The static chamber-gas chromatography method was used to determine CH 4 and N 2 O fluxes. Straw returning had no significant effect on N 2 O emissions, but significantly increased CH 4 emissions due to increased mcrA abundance and global warming potential (GWP). Chemical N fertilization significantly decreased CH 4 emissions by 7.2-18.8% and GWP by 13.5-17.9%, but increased N 2 O emissions by 72.5-311.1% due to increased abundance of AOA-amoA, AOB-amoA, nirK, and nirS. Both straw returning and chemical N fertilization significantly increased rice yield. Straw returning significantly increased greenhouse gas intensity (GHGI), while N fertilization obviously decreased the GHGI. Moreover, significant interaction effects of straw returning and chemical N fertilization on CH 4 emissions, GHGI, and grain yield were observed. The combination of 250 kg N ha −1 of chemical N application and no straw resulted in the lowest GWP, second lowest GHGI and relatively high grain yield among all treatments. In conclusion, 250 kg N ha −1 of chemical N application without straw returning may be an ecological and economic practice for rice production in this study. Nevertheless, ecologicalfriendly methods of straw returning for sustainable agriculture should be further explored in future studies. Keywords CH 4 flux. Global warming potential. Greenhouse gas intensity. N 2 O flux. Straw management * Cougui Cao

Depth Distribution of Bulk and Aggregate-Associated Manganese Oxides Mediated by Soil Chemical Properties in a Long-Term Fertilized Paddy Soil

“…The long-term fertilizer inputs therefore translated into alteration of soil pH which impacted on the Mn pools. Observation from our study is also tied to the report by Hu et al (2019) suggesting that crop straw is an important organic fertilizer source that elevates carbon and nitrogen in the soil and this translates into the enhancement of soil physicochemical properties.…”

“…Straw inclusion as an organic fertilizer source can elevate organic carbon to distribute microelements in the soil which improves soil fertility (Hu et al 2019). Fertilizer treatment 30F recorded significantly (P ≤ 0.05) higher pools of Mn oxides compared to other treatments in both bulk soil and aggregate sizes.…”

Straw Incorporation Coupled with Deep Placement of Nitrogen Fertilizer Improved Grain Yield and Nitrogen Use Efficiency in Direct-Seeded Rice

“…On the other hand, no significant improvements in rice yield were noted in straw return treatments; however, substantial improvements in soil physical and biological properties, i.e., saturated water content, soil aggregates, soil urease, and invertase activities, were noted in the top (0-15 cm) soil layer as compared with straw removal treatment (Zhao et al 2019). Straw incorporation has a great potential to reduce the use of chemical fertilizer and the N 2 O emissions and hence can alleviate the environment pollution (Yin et al 2018;Liu et al 2019b); however, it may promote the CH 4 emissions from rice lands (Hu et al 2020).…”

Straw mulching and nitrogen application altered ammonia oxidizers communities and improved soil quality in the alkaline purple soil of southwest China

“…In addition, the implications of straw returning and chemical N fertilization for soil microbial community have been extensively studied. Hu et al ( 2019 ) showed that straw returning, N fertilization, and their interactions significantly increased the abundance of AOA and AOB in paddy soil, and AOA was more abundant than AOB. Similarly, further research revealed that fertilizer combined with straw could increase AOB number, and AOA was more abundant than AOB in clay loam (Wessén et al 2010 ).…”