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Chinese Agricultural Science Bulletin ›› 2024, Vol. 40 ›› Issue (11): 49-54.doi: 10.11924/j.issn.1000-6850.casb2023-0424

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Effects of C/N Ratio of Exogenous Organic Fertilizer on Red Soil Microenvironment and Quality of Flue-cured Tobacco

ZHANG Xiaowei1(), YANG Zongyun2, NI Ming3, ZHAO Xinmei3, WANG Chi3, YANG Shuming3(), XU Xingyang2   

  1. 1 Yunnan Tobacco Quality Inspection & Supervision Station, Kunming 650106
    2 Kunming Branch of Yunnan Tobacco Company, Kunming 650051
    3 Agricultural Resources & Environment Institute, Yunnan Academy of Agricultural Sciences, Kunming 650205
  • Received:2023-06-02 Revised:2023-10-09 Online:2024-04-15 Published:2024-04-11

Abstract:

C/N ratio is one of the important fertility indexes to reflect organic fertilizer efficiency. The study explored the effects of C/N ratio on rhizosphere soil microenvironment, yield and quality of flue-cured tobacco, and provided a scientific basis for soil fertilization and its sustainable management. Using flue-cured tobacco variety ‘Yunyan 87’ as material, a two-year (2021 to 2022) field experiment was conducted on the acidic upland red soil in Xundian County, Yunnan Province, and the effects of applying different C/N ratios (10:1, 15:1, 20:1 and 25:1) of organic manure on fertility, water-stable aggregate, microbial structure, yield and quality were studied under equal NPK conditions. The results showed that compared with treatment T1 (CK), treatments of T2, T3 and T5 significantly improved soil pH by 0.09-0.13 units. The treatments of T2, T3, T4 and T5 significantly increased the contents of soil organic matter, available N, P and organic carbon by 9.91%-17.40%, 9.11%-16.45%, 7.16%-43.68% and 11.61%-39.54%, respectively. Meanwhile, T2 and T3 significantly increased available K by 8.12% and 14.63%. T2, T3, T4 and T5 significantly enhanced the contents of SOC, C/N by 11.61%-39.54% and 4.48%-29.72%, respectively over the treatments of applying chemical fertilizer. Compared with CK, the contents of large-size aggregates (>5, 2-5 and 1-2 mm ) in T2, T3, T4 and T5 were significantly increased by 20.75%-75.91%, 10.06%-54.50% and 16.98%-66.13%, and the contents of micro-aggregates (0.053-0.25 and <0.053 mm) were decreased by 10.61%-54.52%. Accordingly, treatments of T2, T3, T4 and T5 significantly increased soil fungi, bacteria, actinomycetes, microbial biomass C, N community to some extent, compared with that of CK. T2 and T3 could promote the growth of tobacco plants, and their leaf area increased significantly by 7.36% and 14.92% compared with CK. Moreover, the yield and output value of T2 and T3 were significant increased by 11.99%, 16.93% and 5.92%, 15.46%, respectively. T3 could significantly increase total sugar, reducing sugar and potassium, and reduce the contents of total nitrogen and nicotine, and chemical composition of tobacco leaves was more harmonious. Application of organic fertilizer with C/N ratio (10:1, 15:1) was not only favorable to improve soil pH, fertility, aggregate structure and stability in upland red soil, but also increase soil microbial quantity and community structure abundance, promoting tobacco growth, output value and quality of tobacco leaves.

Key words: flue-cured tobacco, C/N ratio, organic manure, structure of aggregate, quality