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| Effects of moisture content on N2O emissions in different fertilized soils under tobacco-rice rotation |
| Received:October 20, 2022 |
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| KeyWord:N2O emission;culture experiment;long-term fertilization;microbial functional genes;flood-upland rotation |
| Author Name | Affiliation | E-mail | | ZHAO Weidong | College of Tropical Crops, Hainan University, Haikou 570228, China
Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences/Fujian Provincial Key Laboratory of Plant Nutrition and Fertilizer, Fuzhou 350013, China | | | GUO Baoling | Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences/Fujian Provincial Key Laboratory of Plant Nutrition and Fertilizer, Fuzhou 350013, China | | | ZHENG Xiangzhou | Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences/Fujian Provincial Key Laboratory of Plant Nutrition and Fertilizer, Fuzhou 350013, China | z85103@qq.com | | TANG Shuirong | College of Tropical Crops, Hainan University, Haikou 570228, China | tangshuirong@163.com | | MENG Lei | College of Tropical Crops, Hainan University, Haikou 570228, China | | | ZHANG Yushu | Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences/Fujian Provincial Key Laboratory of Plant Nutrition and Fertilizer, Fuzhou 350013, China | |
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| Abstract: |
| Nitrous oxide（N2O）emissions from soil with different fertilization treatments under flood-upland rotation are important for N 2O emissions regulation. In this study, soil samples from a long-term fertilization positioning experiment（tobacco-rice rotation） in a subtropical region were collected for N2O emission study. The eight treatments in the incubation experiment were as follows：60% water holding capacity（WHC）+ no fertilization（UCK）, 60%WHC + recommended fertilization（UNPK）, 60%WHC + high nitrogen fertilization （UNhPK）, 60%WHC+recommended fertilization combined with straw（UNPKS）, flooding+no fertilization（FCK）, flooding+recommended fertilization（FNPK）, flooding + high nitrogen fertilization（FNhPK）and flooding+recommended fertilization combined with straw（FNPKS）. Soil N2O emissions and the abundance of related functional genes under different moisture content fertilization were investigated. The results were as follows：Compared with CK treatment, soil pH was significantly decreased by fertilization; soil organic matter（SOM）and total nitrogen（TN）contents were significantly increased by NPKS. Compared with NPK treatment, C/N ratio was significantly decreased by NhPK and NPKS. The N2O emissions of fertilization treatment under 60%WHC and flooding conditions were 0.56–1.44 mg·kg-1 and 14.89–20.70 mg · kg-1, respectively. Compared with the 60%WHC conditions, soil N2O emission were significantly promoted under flooding conditions. Soil N2O emissions under UNPKS treatment were lower than those under UNPK treatment. The amount of N2O emission was negatively correlated with the soil NH+4-N content and positively correlated with NO-3-N content. Compared with the UCK treatment, the copy number of AOA genes was significantly improved under UNPK and UNhPK, and the copy number of AOB genes was significantly increased under UNPK. The copy numbers of nirK, nirS and nosZ genes were significantly reduced under UNhPK, and the copy number of nirS genes was significantly reduced under UNPKS. Compared with FCK treatment, the gene copy numbers of AOA and AOB were significantly increased by FNPK, FNhPK and FNPKS, accompanied by a decrease in the nirS gene copy number. The copy numbers of AOA and AOB genes and the ratio of（nirK+nirS）/nosZ in fertilization treatments under flooding were 1.80–2.49, 1.19–2.19 times and 1.25–1.42 times greater than that under 60% WHC. The ratio of（nirK+nirS）/nosZ under UNPKS treatment was 21% lower than that under UNPK treatment. Compared with UNPK treatment, soil denitrification intensity and N2O emissions were reduced under UNPKS treatment. The results of this study indicated that flooding increased soil N2O emission, but reduced the effects of fertilization on N2O emission. Chemical fertilizers combined with straw application could significantly reduce N2O emission under low moisture conditions. |
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