保护性耕作对大豆生长发育及土壤微生物多样性影响

Effect of Conservation Tillage Systems on Soybean Growth and Soil Microbial Diversity

明确保护性耕作对作物生长发育和土壤微生物群落的影响对于土壤管理具有重要意义。在中国科学院海伦长期定位区设置了免耕(NR)、少耕(RT)和旋松(ROT)3个耕作处理,研究了保护性耕作下大豆生长发育和产量情况,同时采用荧光定量PCR(Real-time PCR)和变性梯度凝胶电泳(DGGE)方法分析了土壤微生物多样性变化。研究结果显示:在苗期免耕和少耕对大豆生长具有一定的抑制作用,同时加重根腐病病害,但在成熟期免耕和少耕大豆生长优势明显,产量显著增加,其中少耕最高,比旋松增产3.9%,达到2 507.3 kg.hm-2。3种耕作方式对土壤细菌数量影响不大,真菌数量是免耕>少耕>旋松(P<0.05),其中免耕菌落数(CFU)和基因组DNA质量分别比旋松增加31.9%和13.3%,旋松和少耕的细菌/真菌比值要明显高于免耕。DGGE电泳分析表明,免耕和少耕对土壤细菌多样性增加不明显,但可以显著提高真菌多样性。主成分分析得出少耕和旋松细菌群落具有较高的相似性,而真菌群落结构3种耕作方式差异明显。

The effect of conservation tillage on crop growth and soil microbial community play an important role in soil manage- ment. A long-term tillage experiment was conducted at Hailun Agro-Ecological Experiment Station of the Chinese Academy of Sciences. Tillage systems included no-tillage （NT）, reduced tillage （RT）and rotary tillage （ROT）. The study was to determine soybean growth and yield under conservation tillage, and analyze soil microbial diversity with Real-time QPCR and denaturing gradient gel electrophoresis（DGGE）. NT and RT inhibited soybean growth and increased the disease severity of root rot at seedling stage. Soybean growth and yield was significantly increased under NT and RT compared with ROT at maturing stage. The highest yield of 2 507.3 kg＇ha-1 was obtained under RT,which was increased by 3.9% compared with ROT. The three tillage systems had no significant effect on the amount of bacteria,and the amount of fungi was NT 〉 RT 〉 ROT（ P 〈 0. 05 ）. The colony forming units（CFU） and the genomic DNA quality of soil fungi were increased by 31.9% and 13.3% under NT compared with ROT, respectively. The ratio of bacteria and fungi was increased significantly under RT and ROT. DGGE finger- print showed that the soil bacterial diversity had no significant difference under three tillage systems,however, NT and RT in- creased soil fungal diversity. Principal component analysis （PCA）of DGGE banding patterns indicated that the bacterial com- munity structure had a higher similarity under RT and ROT, and significant differences were observed on the fungal community structure under three tillage systems.