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[Objective] The present paper aimed to investigate the appropriate amount and tillage effect of straw-rotted organic fertilizer + vertical rotary tillage in tobacco production in Hunan's tobacco-rice rotation, with the aim of improving the soil environment of tobacco planting in Hunan and providing scientific basis for improving the quality and increasing the yield of tobacco. [ Method] The experiment used 7 treatments in randomized group design, Tl: no straw-rotted organic fertilizer + conventional tillage; T2: straw-rotted organic fertilizer 1150 kg/hm² + conventional tillage; T3: straw-rotted organic fertilizer 2300 kg/hm² + conventional tillage; T4: straw-rotted organic fertilizer 4600 kglhm2 + conventional tillage; TS: application of straw-rotted organic fertilizer 1150 kg/hm² + vertical rotary tillage ; T6: application of straw-rotted organic fertilizer 2300 kg!hm2 + vertical rotary tillage; T7: application of straw-rotted organic fertilizer 4600 kg/hm² + vertical rotary tillage. The effects of different treatments on soil nutrients, agronomic traits of tobacco plants, physical traits, appearance quality, chemical composition and economic traits of tobacco leaves after baking were studied by ANOV A and comprehensive evaluation. [ Result] The application of straw-rotted organic fertilizer + vertical rotary tillage significantly increased soil organic matter and fast-acting nutrient content, and the highest soil fertility level was achieved when the straw-rotted organic fertilizer was applied at 4600 kg/hm² . At the same level of organic fertilizer application, the treatment of organic fertilizer + vertical rotary tillage had higher soil nutrients, agronomic properties of tobacco plants, physical properties of post-baking tobacco leaves, appearance quality, chemical composition and economic properties than the treatment of organic fertilizer alone. Among them, the 17 treatment had the highest appearance quality and chemical compatibility scores, with an average increase of 19. 86%, 3. 70% and 11. 53%, 2. 78% compared with Tl and T4. The tobacco yield and production value of 17 treatment increased by 12. 85%, 8. 10% and 26. 84%, 10. 46% compared with Tl and T4. The rate of top quality tobacco increased by 13. 80 and 6. 71 percentage points compared with Tl and T4. [Conclusion ] The application of 4600 kg/hm² straw-rotted organic fertilizer + vertical rotary tillage was the best, and most beneficial to the production of high-quality tobacco in the tobacco-rice rotation area of Hunan. [ABSTRACT FROM AUTHOR]

Warming climate has been a global concern. Methane is an important greenhouse gas. Double rice cropping system in Hunan province contributes a large proportion of the national rice production. In this study, we studied the effect of agricultural managements of rice on methane emissions from double cropping paddy fields in Hunan Province, China based on Meta-analysis method. Only studies designed as side-by-side paired field experiments were included in this study. Field management practices, treatments, and controls were described in detail in each study, and the location of the experiment was provided. If seasonal accumulative CH4 emission fluxes were not directly provided, these values were calculated by multiplying time and mean CH4 emissions by the measurement period. A total of 53 published peer-reviewed papers published before 2018were obtained by reference retrieval. From them, 840 groups of data were drawn. The management measures included crop rotation, symbiosis ecosystem, tillage, nitrogen fertilizer input, organic manure and residue retention. The control and treatment groups were fallow versus winter crops, paddy-rice system versus rice-duck and rice-fish systems, conventional versus no tillage, no fertilizer-N input versus fertilizer-N input, no manure input versus fertilizer-N and manure input, and fertilizer-N input versus residue retention. Natural log of response ratio was used as the effect size in the random effect meta-analysis. Results showed that CH4 emissions from both early and late rice accounted for 97.9% of annual CH4 emissions, and more CH4 emissions from late rice was observed than that for early rice. In the double rice cropping system, adding winter crops could significantly increase CH4 emissions from double rice season by 43.88% (P < 0.05) compared to winter fallow. Moreover, the increase in methane emissions from early rice was significantly higher than that from late rice. Symbiosis ecosystem of rice (i.e., with ducks or fishes) and adopting no-till significantly decreased CH4 emissions by 37.02% and 26.84% (P < 0.05), respectively. The decrease in the emission from early rice field was much higher than that from late rice field. As for yield-scaled emission, application of N fertilizer decreased yield-scaled CH4 emissions by 40.01% (P < 0.05) mainly due to the yields increased by 73.87% (P < 0.05). Additionally, organic fertilizer application and residue retention increased 68.11% and 71.80% (P < 0.05) of yield-scaled CH4 emissions without impacting the rice yield. The results suggested adopting symbiosis ecosystem rice production or no-till along with optimized N input is conducive to balancing rice yield and CH4 emissions from fields with double rice cropping system in Hunan province. [ABSTRACT FROM AUTHOR]