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| DOI：10.13522/j.cnki.ggps.2025230 |
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| Combined effects of drip irrigation and biochar application on rhizosphere ammonia-oxidizing microorganisms |
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Guo Jinxiu, Qiu Husen, Feng Miaomiao, Yu Haonan, Li Rongchao, Xu Huiqi, Liu Jieyun
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1. School of Resources and Environmental Engineering, Suzhou University, Suzhou 234100, China;
2. Key Laboratory of Water-saving Irrigation Engineering, Ministry of Agriculture and Rural Affairs,
Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China
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| Abstract: |
| 【Objective】Ammonia oxidation is a key process in soil nitrogen cycling and is influenced by various biotic and abiotic factors. This study investigated the interactive effects of biochar application and drip irrigation on ammonia-oxidizing microorganisms in the rhizosphere.【Method】The experiment was conducted under field conditions and comprised two irrigation treatments: furrow irrigation (control) and surface drip irrigation, each combined with three biochar application rates: 0, 10 and 20 t/hm2. The abundances of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) were determined using quantitative real-time PCR targeting the amoA functional gene. Soil enzymatic activities and physicochemical properties were also measured to elucidate the interactive effects of irrigation and biochar on ammonia-oxidizing microorganisms in the rhizosphere.【Result】Compared with furrow irrigation, drip irrigation significantly reduced rhizosphere NH4?-N concentration by 61.7%-69.8%, while increasing NO3--N concentration by 70%-300%. Drip irrigation reduced water use by 50% relative to furrow irrigation, while simultaneously enhancing soil ammonia oxidation, increasing AOB-amoA abundance by up to 200%, and decreasing AOA-amoA abundance by 30.2%-60.8%. Under drip irrigation, biochar application increased rhizosphere NH4?-N concentration while slightly decreasing NO3--N concentration. In contrast, under furrow irrigation, biochar application had no significant effect on AOA-amoA abundance but significantly increased AOB-amoA abundance. Compared with furrow irrigation without biochar application, drip irrigation combined with biochar application increased AOA-amoA and AOB-amoA abundances by 1.3-1.8-fold and 1.5-2.3-fold, respectively.【Conclusion】Drip irrigation combined with biochar application promoted rhizosphere nitrogen transformation, stimulated proliferation of ammonia-oxidizing microorganisms, particularly AOB, and enhanced soil ammonia oxidation. These findings highlight the potential of integrating drip irrigation with biochar amendment as an effective strategy for regulating rhizosphere nitrogen cycling and improving nitrogen bioavailability. |
| Key words: drip irrigation biochar ammonia-oxidizing microorganisms nitrification process |
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