| Effects of tillage methods on soil aggregation and aggregate\|associated carbon and nitrogen fractions in dryland wheat fields |
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| DOI：10.7606/j.issn.1000-7601.2023.02.21 |
| Key Words: tillage methods dryland wheat soil aggregate soil carbon and nitrogen fractions |
| Author Name | Affiliation | | WU Linjia | College of Resources and Environment, Shanxi Agricultural University, Taigu, Shanxi 030801, China
Key Laboratory of Soil Environment and Nutrient Resources of Shanxi Province, Taiyuan, Shanxi 030001, China | | QI Chen | College of Resources and Environment, Shanxi Agricultural University, Taigu, Shanxi 030801, China | | YAN Qiuyan | Institute of Wheat Research, Shanxi Agricultural University, Linfen, Shanxi 041000, China
Key Laboratory of Soil Environment and Nutrient Resources of Shanxi Province, Taiyuan, Shanxi 030001, China | | YAN Shuangdui | College of Resources and Environment, Shanxi Agricultural University, Taigu, Shanxi 030801, China | | DONG Fei | Institute of Wheat Research, Shanxi Agricultural University, Linfen, Shanxi 041000, China | | ZHANG Minmin | College of Resources and Environment, Shanxi Agricultural University, Taigu, Shanxi 030801, China |
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| Abstract: |
| The study aimed to investigate the soil aggregate stability, distribution characteristics of soil organic carbon (SOC) and its components, and total nitrogen (TN) and its fractions in water\|stable aggregates of dryland wheat field under different tillage methods and further understand the mechanism of soil carbon and nitrogen sequestration under different tillage methods. Topsoil samples (0~20 cm) for 3 consecutive years (2017-2020) were collected under three tillage methods (no tillage, subsoiling and deep tillage) after harvest in the third experimental season. A wet sieve method was used to analyze fractions of particle size, and distribution of carbon components (SOC, HFOC, LFOC, EOC, DOC, POC) and nitrogen components (TN, NO-3-N, NH+4-N, SON). The relationship between carbon\|nitrogen components was examined. The results showed that, (1) >2 mm aggregates under no tillage and subsoiling treatments were 8.8% and 22.1% higher than that under deep tillage treatment. No tillage was conducive to increasing <0.053 mm silt and clay, and 46.4% higher than subsoiling and 27.7% higher than deep tillage. R0.25, MWD and GMD under subsoiling treatment increased by 2.8%, 6.3% and 9.0% compared with deep tillage treatment. (2) The contents of SOC, LFOC, EOC, DOC and POC of soil aggregates in no tillage and subsoiling treatments were higher than those in deep tillage treatment. The content of HFOC in subsoiling treatment was higher than that in deep tillage, and the content of HFOC in no tillage was higher than that in deep tillage only in <0.053 mm. (3) The contents of TN, NO-3-N and NH+4-N in >2 mm, 0.25~2 mm and 0.053~0.25 mm aggregates under no tillage treatment were higher than deep tillage, and the contents of <0.053 aggregates were lower than deep tillage. Compared with deep tillage treatment, subsoiling treatment increased TN contents of soil aggregates and NO-3-N contents of >2 mm and 0.25~2 mm aggregates, while NH+4-N content was lower than that under deep tillage. The content of SON in no tillage and subsoiling was higher than that in deep tillage. The C/N ratio of aggregates under different particle sizes showed the fallow of subsoiling>no tillage>deep tillage. (4) The stocks of soil carbon under no\|tillage and subsoiling in 0~20 cm soil layer were 85.4% and 86.3% higher than that under deep tillage, soil nitrogen stocks were 48.1% and 32.5% higher than that under deep tillage, while the straw carbon return was higher under deep tillage. (5) Based on the structural equation model analysis, DOC and POC were the main factors affecting SOC change through synergistic EOC change. SON was the dominant factor affecting TN. In dryland wheat field of Loess Plateau, subsoiling improved soil aggregate structure, and increased soil organic carbon and total nitrogen contents. |
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