连作茶树根际土壤酸度对土壤微生物的影响

Effect on soil microbes of the rhizospheric soil acidity of tea tree continuous cropping

为了解连作茶树根部土壤酸化对微生物生物量及区系的影响,以不同种植年限黄金桂茶树根际土壤为研究对象,分析茶树根际土壤p H值对土壤微生物量、微生物数量和微生物类群的影响以及土壤微生物对土壤酸度响应的敏感性趋势.结果显示,茶树根际土壤的微生物生物量碳、微生物呼吸强度、微生物生物量氮及细菌、放线菌、氨化细菌、亚硝酸细菌、反硝化细菌、好气性自生固氮菌、好气性纤维素分解菌的数量随着茶树树龄的增加呈现下降趋势,且与茶树根际土壤p H值呈现极显著正相关(P<0.01),而真菌、嫌气性纤维素分解菌、硫化细菌的数量呈现上升趋势,且与茶树根际土壤p H值呈现极显著正相关(P<0.01).敏感性分析结果显示,不同微生物指标响应茶树根际土壤p H值变化的趋势为微生物呼吸强度(8.721 8)>细菌(8.428 7)>微生物量碳(7.955 2)>硫化细菌(7.726 8)>放线菌(5.780 0)>真菌(4.740 8)>嫌气性纤维素分解菌(4.065 0)>氨化细菌(3.760 6)>好气性自生固氮菌(2.368 3)>反硝化细菌(2.340 6)>微生物量氮(2.324 2)>亚硝酸细菌(2.219 8)>好气性纤维素分解菌(1.772 0).综上表明,茶树根际土壤酸化显著影响了土壤微生物数量变化,不同的微生物指标响应土壤酸度的敏感性存在一定差异.(图3表3参32)

To explore effect of soil acidification on the microbial biomass and the flora at the root of tea tree, the rhizospheric soils of Huangjingui with different ages were used as materials, and effects of rhizospheric pH value on the microbial biomass, the number of microbe and microbial populations were analyzed. Meanwhile, the sensitivity of soil microbe response to acidification was got. The results showed that the microbial biomass, microbial respiration, the number of bacteria, actinomycetes, ammonifier, nitrite bacteria, denitrifier, aerobic azotobacter and aerobic cellulose decomposer decreased as the age of tea tree increased, which were significantly and positively correlated with the pH value of the rhizospheric soil（P 〈 0.01）. The number of fungi, anerobic cellulose decomposer and sulphate reducer increased as the age of tea tree increased, which were significantly and negatively correlated with the pH value rhizospheric soil（P 〈 0.01）. Sensitivity analysis result showed that responses of different microbial indexes to soil pH value presented microbial respiration （8.7218） 〉 bacteria （8.4287） 〉 microbial biomass （7.9552） 〉 sulphate reducer （7.7268） 〉 actinomycetes （5.7800） 〉 fungi （4.7408） 〉 anerobic cellulose decomposer （4.0650） 〉 ammonifier （3.7606） 〉 aerobic azotobacter （2.3683） 〉denitrifier （2.3406） 〉 microbial biomass （2.3242） 〉 nitrite bacteria （2.2198） 〉 aerobic cellulose decomposer （1.7720）. In brief, the acidity of tea tree rhizospheric soil had significant effect on the number of microbe, and different indexes of the microbe had different sensitivity to rhizospheric soil acidity. To explore effect of soil acidification on the microbial biomass and the flora at the root of tea tree, the rhizospheric soils of Huangjingui with different ages were used as materials, and effects of rhizospheric pH value on the microbial biomass, the number of microbe and microbial populations were analyzed. Meanwhile, the sensitivity of soil microbe response to acidification was got. The results showed that the microbial biomass, microbial respiration, the number of bacteria, actinomycetes, ammonifier, nitrite bacteria, denitrifier, aerobic azotobacter and aerobic cellulose decomposer decreased as the age of tea tree increased, which were significantly and positively correlated with the pH value of the rhizospheric soil（P 〈 0.01）. The number of fungi, anerobic cellulose decomposer and sulphate reducer increased as the age of tea tree increased, which were significantly and negatively correlated with the pH value rhizospheric soil（P 〈 0.01）. Sensitivity analysis result showed that responses of different microbial indexes to soil pH value presented microbial respiration （8.7218） 〉 bacteria （8.4287） 〉 microbial biomass （7.9552） 〉 sulphate reducer （7.7268） 〉 actinomycetes （5.7800） 〉 fungi （4.7408） 〉 anerobic cellulose decomposer （4.0650） 〉 ammonifier （3.7606） 〉 aerobic azotobacter （2.3683） 〉denitrifier （2.3406） 〉 microbial biomass （2.3242） 〉 nitrite bacteria （2.2198） 〉 aerobic cellulose decomposer （1.7720）. In brief, the acidity of tea tree rhizospheric soil had significant effect on the number of microbe, and different indexes of the microbe had different sensitivity to rhizospheric soil acidity.