文章编号：1008-0384（2018）11-1181-09
Abstract： Two biological agents， EM and TRI， were applied in soil on a continuous cropping field of Panax notoginseng to study the remediating effect on the soil and the mechanism associated with the application. Treatments with the agents were found significantly increased the seedling emergence rate and survival rate as well as the root yield. All nutrients in the soil treated with EM were increased， while the available potassium in the soil treated with TRI significantly improved. The HPLC analysis showed no accumulation of phenolic acids in the rhizosphere soil by these treatments indicating that allelochemicals were not directly， but might indirectly， involved in the detrimental effect on P. notoginseng caused by continuous cropping. The DGGE and qRTPCR test results showed that both EM and TRI， especially TRI， could increase the population of beneficial， while depressed the harmful， bacteria in the soil. Thereby， the rhizosphere soil was effectively repaired by alleviating the deficiency brought about by the continuous cropping practice， and consequently， the growth and yield of P. notoginseng was significantly recovered or improved.
Key words： Panax notoginseng; harmful effect of continuous cropping;microbial agents;biological agents rhizosphere soil; soil remediation
三七Panax notoginseng又名田七，享有“金不换”、“南国神草”之美誉，是一种具有活血化瘀、消肿止疼等疗效的传统中藥材[1-2]。由于三七对环境要求较高，故其生长的适宜地区狭窄，主要集中于云南省文山、砚山、建水等地及广西壮族自治区的部分县市[3]。此外，三七与太子参、地黄等多种药用植物一样，存在严重的连作障碍问题，即正常的田间经营管理下，长期在同一区域种植的同类中药材会出现抵抗力下降、产量品质恶劣，易受病虫害侵袭等现象，主要表现为烂根、萎蔫、产量低、药效差。三七种植一茬后的田地需要轮作玉米、旱稻等作物至少10年，有些学者认为轮作间隔甚至需要长达30年[4]，这就严重制约了三七产业和区域经济的可持续发展。
关于连作障碍形成的原因主要集中于以下三方面：土壤理化性质恶劣，根系分泌物的化感自毒作用，病原微生物及土传病害增加[5-6]。刘莉等[7]研究中提到相同作物在生长过程中对土壤养分的吸收情况是有规律的，一种作物长期连作，会按一定比例吸收和释放某些元素及营养物质，这会导致土壤中某些元素或物质的亏缺而另一些元素或物质的增加，进而影响连作植物的健康生长，使萎蔫率增加，产量和质量下降。有报道指出，植物在生长发育过程中会向土壤中释放大量代谢物质，同一种植物在同一地块连续种植，其根部分泌物不断积累，达到一定浓度后，会对植物的生长产生抑制作用[8]。同时，连作还使土壤中的某些病原微生物连年繁殖并积累，造成土传病害[9]。微生物菌剂是一种含有活菌的生物制剂，具有增加土壤肥力，提高植株抵抗力等多种功能。大量研究表明，微生物菌剂通过向土壤中引入有益微生物，改善土壤环境，调节微生物区系失衡，在缓解连作障碍问题上有着良好的发展前景[10-13]。本研究从连作障碍形成的原因入手，探讨两种微生物菌剂（EM和TRI）的添加对连作三七土壤理化性质和根际微生物群落的影响，以期缓解连作障碍，为三七产业的可持续发展及其他同样存在连作障碍问题的作物的研究提供理论依据。
推荐访问： 连作 两种 土壤 修复 效果
