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本研究以重庆北碚新垦坡耕地中性土壤为对象,采用裂区设计法研究种植紫花苜蓿并配施根际有盖微生物(PGPR)对紫花苜蓿生长及土壤微生物的影响.本研究涉及的PGPR菌包括根瘤菌、联合固氮菌、硅酸盐细菌和巨大芽孢杆菌.设置种植紫花苜蓿不接种(A)、种植紫花苜蓿接种根瘤菌(A+R)、种植紫花苜蓿接种PGPR(A+PG-PR)和空地(CK)等4个处理.结果显示:各处理对紫花苜蓿农艺品质、土壤微生物数量及土壤微生物生物量氮含量的影响程度大小顺序均为A+PGPR,A+R,A,CK;而对微生物生物量碳含量的影响大小顺序是A,A+PGPR,A+R,CK.与CK相比,接种PGPR处理显著提高了紫花苜蓿瘤质量、株高、根干质量、地上部干质量和全氮含量(p<0.05);接种PGPR较CK显著增加了土壤细菌、真菌、放线菌、根瘤菌、硅酸盐细菌和固氮菌数量(p<0.05);接种PGPR的土壤微生物生物量碳、氮含量较CK处理的分别显著提高了60.12%和63.28%(p<0.05);同时,该处理还显著提高了土壤的各项基本化学肥力指标.相关性分析表明,微生物生物量氮与植物全氮以及土壤养分各指标显著相关.研究表明,种植紫花苜蓿并配施PGPR能够显著增加新垦地土壤微生物数量,促进新垦地土壤培肥.
In this study, we studied the effects of planting rhizosphere microbes (PGPR) on the growth of Medicago sativa and soil microorganisms by using split-plot design method, Bacteria include rhizobia, azotobacter, silicate bacteria, and Bacillus megaterium. The planting alfalfa was inoculated (A), the alfalfa was inoculated with Rhizobium (A + R), the alfalfa was inoculated with PGPR (A + PG- PR) and open ground (CK). The results showed that the order of the effect degree of each treatment on agronomic quality, soil microbial quantity and soil microbial biomass nitrogen content was A + PGPR, A + R, A, CK, while the effect on the microbial biomass C was A, A + PGPR, A + R and CK. Compared with CK, inoculation PGPR significantly increased alfalfa tumor mass, plant height and root dry weight, (P <0.05). PGPR significantly increased the number of soil bacteria, fungi, actinomycetes, rhizobia, silicate bacteria and azotobacter compared with CK (p <0.05). PGPR inoculated soil Microbial biomass carbon and nitrogen contents were significantly higher than CK treatment 60.12% and 63.28%, respectively (p <0.05) .At the same time, the treatment also significantly increased the basic chemical fertility indexes of soil, and the correlation analysis showed that the microbial biomass nitrogen was significantly correlated with plant total nitrogen and soil nutrients. The results showed that planting alfalfa with PGPR could significantly increase the amount of soil microbes in newly reclaimed land and promote soil fertility in newly cultivated land.