摘要
以长期施加氮肥及添加氧化钙调节的酸性土壤为研究对象,运用定量PCR和DGGE技术,探讨了土壤氨氧化微生物及硝化作用对不同施肥处理及氧化钙调节的响应。长期施化学氮肥导致酸性土壤p H(KCl)值(3.35—3.47)和硝化潜势(0.02—0.14μg NO-2-N g-1土壤h-1)进一步降低,而添加Ca O后土壤酸化得以缓解(p H值4.10—4.46),土壤硝化潜势(0.22—0.34μg NO-2-N g-1土h-1)显著增加。同时,添加Ca O处理对氨氧化古菌(AOA)的群落结构无明显影响,但明显提高了各施肥处理土壤中氨氧化细菌(AOB)的群落多样性,加Ca O处理的土壤中,AOA的数量降低而AOB的数量增加。这些结果表明虽然酸性土壤中AOA在数量和活性上占主导优势,AOB在功能上冗余,但当添加Ca O后,AOA和AOB对环境变化迅速作出响应,并根据其不同的生态位需求重新分配优势地位,二者交替作用共同驱动酸性土壤硝化作用。
High levels of N fertilization and acid deposition could cause soil acidification directly and indirectly. The nitrogen cycle,especially nitrification,makes a great contribution to the acidification of agricultural soils across China,which further leads to the mobilization of potentially toxic metals such as aluminum（ Al） and manganese（ Mn） and decerases crop yields. Chemicals（ e. g.,Ca O） are amended as soil conditioners to relieve soil acidification. Ammonia oxidation,the rate-limiting step in the nitrification process,is driven by ammonia-oxidizing bacteria（ AOB） and ammoniaoxidizing archaea（ AOA）. Increasing evidence demonstrates that p H is one of the most important factors determining the niche separation of AOA and AOB,and AOA play the more important role in nitrification of acidic soils. However,abundant AOB have been detected in acidic soils but little is known about their ecological function. In this study,the effects of long-term N fertilization practices and liming on nitrification and ammonia oxidizers in acidic soils were investigated usingquantitative PCR and DGGE methods combined with soil physiochemical analysis. Compared with a previous study conducted 6 years ago at the same site,N fertilizer application without liming further decreased soil p H（ 3.35—3.47） and potential nitrification rate（ PNR）（ 0.02—0.14 μg NO2^--N g^-1soil h^-1）,while 2 years liming alleviated soil acidification（ p H 4.10—4.46） and increased PNR（ 0.22—0.34 μg NO2^--N g^-1soil h^-1） significantly. There was a significantly positive correlation between soil p H and PNR,indicating the increase in soil p H via liming had positive effects on nitrification in acidic soils. AOA amo A gene copy numbers（ 7. 40 × 10^7—4. 08 × 10^8 copies / g） were significantly higher than their counterpart AOB（ 1.67 × 10^6—2.57 × 10^7 copies / g） in soils that received different chemical N fertilizers. Ratios of AOA and AOB amo A gene abundance ranged between 10. 9 and 44. 3. After ame
出处
《生态学报》
CAS
CSCD
北大核心
2015年第19期6362-6370,共9页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目(41171217
41322007)
