Study On The Allelopathic Effect Between Cassava And Peanut

Cassava/peanut intercropping is a common planting pattern,the reasonable intercropping model can improve land equivalence ratio and value equivalence ratio.The mechanisms to increase yield consist of the complementarity of living resources and biological complementarity,namely allelopathy.So the allelopathic effect of water extracts from cassaca/peanut leaf,root and soil on peanut at stage of germination,seedling and late development,and on cassava at stage of germination,seedling and root tuber expansion of cassava using a combination of indoor bioassays and potted plants in this study.It will provide theoretical basis for cultivation techniques for high-yield and high-efficiency of cassava/peanut intercropping.The main conclusions are as follows:Allelopathic effect of cassava leaf water extracts on germination of peanut seeds is not significant.There was no allelopathic effect of low concentration of cassava root eaudates and water extracts from the rhizosphere soil on germination of peanut seeds.The allelopathic inhibition is obvious if the concentration of cassava root eaudates reaches 10g/L～20g/L,while allelopathic promoting effect is obvious if the water extracts from rhizosphere soil reaches 10g/L～20g/L.There was no allelopathic effect of water extracts from peanut leaf,root and rhizosphere soil on germination of cassava stems.The allelopathy effects are not significant on growth at stage of seedling of cassava and peanut.Water extracts from cassava leaf can promote the growth of peanut during late development stage by the principal component analysis.There was no allelopathic effect of cassava soil water extracts on growth of peanut during late development stage because of the score of the different concentration are similar to that of CK.The allelopathic effect of the peanut leaf water extract on growth have the trend of"low denisty to promote,high density to suppress" during cassava tuber expansion period.Cassava leaf and rhizosphere soil water extracts significantly can inhibite acid phosphatase,number of culturable fungi,bacteria and B/F values,total soil fungi,abundance and diversity of fungal communities.The leaf water extracts of cassava has no significant effect on the dominant bacteria and fungi.Cassava rhizosphere soil water extracts can significantly inhibited Delftia,Catenaria,Cochliobolus,Rhizopus,Kluyveromyces genus.When the rhizosphere soil aqueous extracts of cassava was 10g/L,the Rhizopus genus increased significantly.When the rhizosphere soil aqueous extracts of cassava was 5g/L,the Kluyveromyces genus increased significantly.The water extract from peanut leaf has trend of first lower and then increase on Acid phosphatase during cassava tuber expansion period,fungal community abundance and diversity,Delftia,Catenaria,Cochliobolus and Gibberella genus are Significant reduction,Cultivable B/F value are significant increase.The water extracts from peanut rhizosphere soil can significantly increase the activity of catalase,total bacteria and total fungi in the rhizosphere soil of cassava,but the abundance and diversity of fungal community,Delftia,Catenaria,Cochliobolus,Rhizopus and Kluyveromyces genus are Significant reduction.The allelopathic effect of cassava leaf water extract on peanut is presented:Germinating period<seedling stage<late growth stage.The allelopathic effect of water extract from rhizosphere soil on peanut is presented:Germination period>seedling stage>late growth stage.The allelopathy effect of cassava root exudates on peanut seedlings is higher than that of peanut Germinating.The allelopathic effect of peanut leaf water extract on cassava showed that:Germination period ≈Tuber expansion period<seedling stage.The allelopathic effects of water extracts from peanut rhizosphere soil on cassava showed that:Germination period>seedling stage>Tuber expansion period.Peanut root exudates of all concentrations showed similar allelopathic inhibitory effects on cassava germination and seedling stage,except that 0.5g/L root exudates from peanut had significant allelopathic stimulative effects on cassava germination.