Effect Of Ginseng Root Exudates On Rhizospheric Soil Microecology

In recent years,the value of ginseng receives more and more approval from the world and takes seriously,and the planting scale of ginseng industry also becomes more and more popular. But the ginseng continuous cropping barrier has been the major issue.puzzleing the academic circle.The using question again of the old ginseng soil is a big difficult problem which has not been able to solve radically in the senate industry production.The ginseng can not be able the continuous cropping.like other perennials.The massive experiments proved:if the ginseng continuous cropping,the crop rotation will present the serious plant disease,such as the fever must,the rotten root.So no matter the new forest earth or the farmland planting the senate is facing the old ginseng question with sustaining development ginseng industry.The ginseng soil amelioration and planting the ginseng forever are the great difficulty questions to be soiled at present,and also has been the direction of producers and scientific researchers in recent 50 years.So this research has studied the effect of different successive cropping on ginseng roots soil microecology,the repairing function of microecology in old ginseng roots soil with different plants and the changs of enzyme activities in different periods in ginseng roots soil.The findings indicated:1.T he microorganism numbers had had the big change in the different continuous cropping ginseng soil.Compareing with the forest earth,the bacterium quantity changed from 62.9%to 49.1%and actinomycetes quantity changed from 35.2%to 22%in the soil reduced along with the continuous cropping age increaseing,and the reduceing of actinomycetes quantity was more obvious.But actinomycetes quantity changed from 1.9%to 27.9%increased along with the continuous cropping age increasing.Along with the increasing of continuous cropping age,the value of B/F in the rhizosphere presentd the declining trend and the soil fertility had the declining trend.The soil causesd by the ginseng continuous cropping developd from the bacterium to the fungus.2.I n the different continuous cropping ginseng soil,the microorganism population also had had the big change.In forest earth,the bacterium superiority population was P.fluorescens, Enterobacter cloacae and Brevibacterium epidermidis.Compareing with the forest earth,bacterium type did not change obviously in the ginseng soil used one year.But in the ginseng soil used two years and four years,P.fluorescens was vanished,and A.lices and Micrococcus Luteus appearanced. In forest earth,the fungus superiority population was Penicillium,Aspergillus and Trichoderma.Along with the increaseing of the continuous cropping age,Trichoderma was vanished and type reduced obviously.In the he ginseng soil used two years and four years, Graphiuam and Fusarium appearanced.Compareing with the forest earth,along with the increaseing of the continuous cropping age,actinomycetes population had not changed obviously,which is mainly Streptomycete.3.Along with the increaseing of the continuous cropping age,enzyme activities in ginseng soil changed in degree.Compareing with the forest earth,enzyme activities in ginseng soil reduced in degree.Along with the increaseing of the continuous cropping age,enzyme activities of the polyphenoloxidase changed from 0.4963 mg/lg·2h to 0.2060 mg/lg·2h,the proteinase changed from 0.6970 mg/g·24h to 0.5469 mg/g·24h,and the sucrase changed from 1.2887 ml/g·24h to0.7543 ml/g·24h,had reduces year by year,and this changing tendency is consistent with the pH changeing tendency.Enzyme activities of Catalase,urease and acid phosphatase presentd the declining trend in ginseng soil along with the increaseing of the continuous cropping age,enzyme activities of Catalase changed from 0.1802 ml/g·20min to0.1050 ml/g·20min. enzyme activities of urease changed from 23.1743 mg/g·24h to4.2331 mg/g·24h,enzyme activities of acid phosphatase changed from 6.5411 mg/g·24h to2.1484 mg/g·24h.But they had the rise tendency in ginseng soil used four years,enzyme activities of Catalase was 0.1632 ml/g·20min. Enzyme activities of urease was8.7748 mg/g·24h.Enzyme activities of acid phosphatase was2.3087 mg/g·24h.4.T he microorganism numbers in the old ginseng soil received different repairing function by the repairing of three kind of plants.The bacterium and the actinomycetes proportion rised, the fungus proportion dropped.The repairing degree To the old ginseng soil was is the alfalfa, white clover,Perilla frutescens order from large to small.5.After the repairing to the old ginseng soil by three kind of plants,superiority population in the soil had changed.Compairing with the old ginseng soil,P.fluorescens appearedand Micrococcus Luteus dispeared in the soil repaired by the alfalfa.Brevibacterium epidermidis dispeared in the soil repaired by white clover,and Perilla frutescens.6.After three kind of plants repairs,6 kind of enzyme activities display the varying degree elevation.Compairing with enzyme activities in the old ginseng soil,the repairing degree of six kind of enzyme activities in order from large to small was the sucrase rised78.79%,the urease rised67.92%,the polyphenoloxidase rised44.71%,the acid phosphatase rised6.95%,the proteinase rised提高了3.07%,and the catalase rised2.76%in the old ginseng soil repaired by the alfalfa for one year;the repairing degree of six kind of enzyme activities in order from large to small was the sucrase rised76.83%,the urease rised11.14%,the polyphenoloxidase rised6.94%,the acid phosphatase rised2.96%,the proteinase 2.77%rised and the catalase rised2.76%in the old ginseng soil repaired by the Perilla frutescens for one year;the repairing degree of six kind of enzyme activities in order from large to small was the sucrase rised76.03%,the polyphenoloxidase rised29.17%,the acid phosphatase rised6.93%,the proteinase rised5.3%,the catalase rised2.33% and the urease rised1.28%in the old ginseng soil repaired by the white clover for one year.7.6 kind of enzyme activities had the different changing tendency in the different time.Compalring with enzyme activity in the comparison soil,Polyphenoloxidase activity had remarkable reduction in the leaf time;along with ginseng growth after the flowering season, enzyme activity rised0.3602mg/2h·1g had elevated until the green fruit time;but it receded to 0.3282mg/2h·1g until the red fruit time;finally,when it arrived the harvesting time,enzyme activity obtained elevated,and achieved the maximum0.4085 mg/2h·1g in the development period.After the ginseng transplanted,catalase activity reduced gradually in the soil along with the growth;when it growd to the green fruit time,the enzyme activity had the trend of escalation,it wan 0.1640 ml/g·20min;to the red fruit time,the enzyme activity had the declining trend,it was 0.1172 ml/g·20min,and enzyme activity in this time achieved the minimum value in the entire development period;in the harvesting time,catalase activity goes up.Along with ginseng growth,the sucrose enzyme activity reduced gradually;when it growed to the green fruit time,the enzyme activity achieved the minimum value 1.2584 ml/g·24h in the entire development period;when it growd to thered fruit time,the enzyme activity achieved the maximuml.3024ml/g·24h in the entire development period;in the harvesting time,enzyme activity had reduced slightly.In the entire growth process,phosphatase activity varied in the different period.The changing tendency of phosphatase activity and The changing tendency of the sucrose activity were similar. From the leaf time to the green fruit time,the enzyme activity reduces gradually,;in the green fruit time,the enzyme activity achieved the minimum value0.3161 mg/g·24h.From the green fruit time to the red fruit time,the enzyme activity had the trend of escalation.When it growed to the harvesting time,the enzyme activity also reduced slightly.After the ginseng transplants,namely from the leaf time to the green fruit time,the urease activity in soil strengthened gradually along with the ginseng growth;and to the green fruit time, the enzyme activity reached the maximum22.4644 mg/g.24h.Along with the ginseng to grow Continuely,the urease activity had the declining trend.When the ginseng was in the red fruit time, the enzyme activity reduced.In the harvesting time,the urease activity rised slightly.Along with the ginseng growth,the protein enzyme activity demonstrated the tendency which varied from the elevation to reduction.When the ginseng growed to the green fruit time,the enzyme activity presented the high point,it was 0.5919 mg/g·24h,and from the green fruit time to the harvesting time,enzyme activity declined gradually.