摘要
通过野外调查和室内分析,研究了水旱轮作条件下,不同免耕年限土壤微生物数量和生物量的变化特点及其影响因素。结果发现:(1)旱作和水作后,免耕土壤细菌数量显著低于常规耕作。随着免耕年限延长,旱作后土壤细菌数量呈先降低再增加的趋势,免耕5～6 a时最低;而水作后,不同免耕年限间无显著差异。(2)旱作后,免耕土壤真菌和放线菌数量显著高于常规耕作,而水作后,真菌和放线菌数量较常规耕作显著降低。随着免耕年限的延长,旱作后土壤真菌数量呈先降低再增加的趋势,免耕7～8 a时最低;土壤放线菌数量在免耕5～6 a后趋于稳定。水作后,土壤真菌和放线菌数量呈显著负相关。(3)旱作和水作后,免耕土壤微生物量碳和氮显著高于常规耕作,两者呈极显著正相关,变化趋势一致。随着免耕年限延长,旱作后,土壤微生物量碳、氮呈逐渐降低的趋势;水作后,土壤微生物量碳、氮呈先增加再降低的趋势。
Changes of microorganism number and microbial biomass in soils were investigated with different years of notillage under the paddy-upland rotation. Results indicated that： （1） After upland cropping and paddy cropping, the number of microorganisms in no-tillage soil was significantly lower than that in conventional tillage soil. With the increase of no-tillage years, bacteria number decreased, and then appeared an increasing trend after upland cropping. The lowest number of bacteria appeared at 5-6 years of no-tillage after upland cropping treatment. No significant differences were found in soil with different no-tillage year treatment after paddy cropping. （2） After upland cropping, the number of fungi and aetinomycetes in no-tillage soil were significantly higher than that in conventional tillage soil, but were lower after paddy cropping treatment. With the increase of no-tillage years, number of fungi had a trend of decreasing and then increasing, with the lowest number in soil under 7-8 year of no-tillage treatment. The amount of actinomycete kept stable after 5-6 year o f no-tillage treatment. After paddy cropping, number of fungi had a significant negative relationship with the number of actinomycetes in the soil. （3） After upland and paddy cropping, microbial biomass C and N in no-tillage soil were significantly higher than that in conventional tillage soil, the microbial biomass C and N had positive coorelations; with the increase of no-tillage years, microbial biomass C and N decreased after upland cropping, but it showed increasing and then decreasing trend after paddy cropping.
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2009年第1期145-150,共6页
Journal of Plant Nutrition and Fertilizers
基金
四川省教育厅重点项目(2006A008
2004A003)
四川省教育厅青年基金项目(2006B009)
四川省青年基金(06ZQ026-020)
四川农业大学校科技青年创新基金(2005)资助。
关键词
水旱轮作
免耕
微生物数量
微生物童
paddy-upland rotation
no-tillage
number of microorganism
microbial biomass
