查看更多>>摘要：Paddy fields are considered a major source of methane (CH4) emissions.Aerobic irrigation methods have proven to be efficacious in mitigating CH4 emissions in paddy cultivation.The promising role of compound microbial agents in refining the rhizospheric ecosystem suggests their potential as novel agents in reducing CH4 emissions from paddy fields.To explore a new method of using compound microbial agents to reduce CH4 emissions,we conducted pot and field experiments over the period of 2022-2023.We measured CH4 flux,the redox potential (Eh) of the soil,the concentration of dissolved oxygen (DO) in the floodwater,and the gene abundance of both methanogens (mcrA) and methanotrophs (pmoA).The results showed that the application of the compound microbial agent led to a significant increase in the DO levels within the floodwater and an increase of 9.26％ to 35.01％ in the Eh of the tillage soil.Furthermore,the abundance of pmoA increased by 31.20％,while the mcrA/pmoA ratio decreased by 25.96％ at the maximum tillering stage.Applying 45-75 kg/hm2 of the compound microbial agent before transplanting resulted in a reduction of cumulative CH4 emissions from paddy fields by 17.49％ in single-cropped rice and 43.54％ to 50.27％ in double-cropped late rice during the tillering stage.Correlation analysis indicated that CH4 flux was significantly negatively correlated with pmoA gene abundance and soil Eh,and positively related to the mcrA/pmoA ratio.Additionally,soil Eh was significantly positively correlated with pmoA gene abundance,suggesting that paddy soil Eh indirectly affected CH4 flux by influencing the pmoA gene abundance.In conclusion,the pre-planting application of the compound microbial agent at a rate of 45-75 kg/hm2 can enhance the Eh in the rhizosphere and increase the abundance of the pmoA gene,thereby reducing CH4 emissions from paddy fields during the tillering stage of rice growth.
查看更多>>摘要：Boron (B) is an essential micronutrient for plant growth and yield.We investigated the optimal growth stage for B fertilizer application to improve rice production.The study was conducted using a 2 × 4 factorial design in a randomized complete block during the rainy season of 2022.We utilized two premium Thai rice varieties Khao Dawk Mali 105 (KDML105) and Pathum Thani 1 (PTT1),and four soil B fertilizer treatments:a control (no B application),B application at the tillering stage,B application at the flowering stage,and B application at both the tillering and flowering stages.The results showed that the application of B fertilizer at the flowering stage and at both the tillering and flowering stages increased grain yield of KDML105 by 25.0％ and 34.0％,respectively.In contrast,the grain yield of PTT1 showed no response to B application.The increased grain yield of KDML105 was attributed to an increased number of panicles per plant and a higher filled grain rate,which was due to the elevated B concentration in all plant parts and the total B uptake,particularly when B was applied at the flowering and tillering stages.Notably,B application increased the fertilized grain rates and reduced the proportion of unfertilized grains,a phenomenon that corresponded with the increased B concentration across all plant parts.The total B uptake ranged from 5.11 to 15.85 mg/m2 in KDML105 and from 8.37 to 24.26 mg/m2 in PTT1,with the highest total B uptake observed when B was applied at both the tillering and flowering stages for both rice varieties.
万方数据
维普