丛枝菌根真菌和根瘤菌对连作花生养分吸收及土壤微生物特性的影响

Effects of arbuscular mycorrhizal fungi and rhizobia on nutrient uptake and soil microbial characteristics of continuous cropping peanut

探讨接种丛枝菌根(AM)真菌和根瘤菌对连作花生作用效果及可能机制,有益于缓解花生连作障碍,促进花生养分高效和持续高产。在花生典型种植区,选择有代表性的酸性砂姜黑土,设置不接种(CK)、接种AM真菌(AM)、接种根瘤菌(Rb)、双接种(AM+Rb)4个处理,采用微区试验,研究AM真菌与根瘤菌对花生生长、根系形态、养分吸收及土壤微生物特性的影响。结果表明:接种处理增加了花生第一侧枝长和分枝数,显著提高了花生根和地上部生物量、荚果重和根瘤数,其中AM+Rb处理提高效果最显著。同时AM+Rb处理的花生根系总根长、总表面积、总体积分别显著提高30.1%、20.2%和59.7%,土壤微生物总量、细菌/真菌、放线菌/真菌明显提高,不同部位氮、磷、钾、钙、镁积累量显著增加,效果优于单接种。比较AM真菌和根瘤菌2种接种方式,Rb处理的花生不同部位氮积累量较高,而AM处理的根系形态状况较好,且花生不同部位磷、钾、钙、镁吸收量较高。可见,在酸性砂姜黑土区,接种AM真菌和根瘤菌尤其是双接种有益于改善根系形态状况和根际微生物环境,增强花生养分吸收能力,从而促进花生的生长及产量的提高。

The aim was to investigate the effects of arbuscular mycorrhizal(AM)fungi and rhizobia on the growth of peanut and underlying mechanism,which was beneficial to alleviate continuous cropping obstacle and promote nutrient efficiency and sustainable high yield of peanut.Four treatments(CK,AM,Rb and AM+Rb)were conducted to study the effects of AM fungi and rhizobia on growth,root morphology,nutrient absorption and soil biological characteristics of peanut by the micro-zone experiment.The results showed that the inoculation treatment increased the first branch length,number of branches,and significantly increased the root biomass,aboveground biomass,pod weight and root nodule numbers of peanut,with the AM+Rb treatment showing the strongest effect.Compared to the control,the total length,total surface area and total volume of roots were significantly increased by 30.1%,20.2%and 59.7%,respectively,under the AM+Rb treatment.The total amount of soil microorganisms,the ratio of bacteria and fungi,the ratio of actinomycetes and fungi,the accumulation of nitrogen,phosphorus,potassium,calcium and magnesium in different parts of peanut were significantly enhanced,and its effect was better than that of single AM fungi or rhizobia.Compared with two inoculation methods of AM fungi and rhizobia,the nitrogen accumulation in different parts of peanut under the Rb treatment was higher,while the root morphology was better and the accumulation of phosphorus,potassium,calcium and magnesium in different parts of peanut was higher under the AM treatment.In conclusion,inoculation with AM fungi and rhizobia,especially double inoculation,is more beneficial to improve the root morphology and microbial environment in rhizosphere,and enhance the nutrient uptake capacity of peanuts,so as to promote the growth and yield of peanut.