Influence Of Biochar Amendments To Soils On Life History Of Nilaparvata Lugens And Abundnaces Of Dominant Arthropod Groups In Paddy Field

Biochar amendments to soils have attracted more and more attention recently because of the potential in greenhouse gas mitigation,soil improvement and increased crop productivity.Biochar amendments can affect the morphological structure and physiological and biochemical properties of plant,and may indirectly affect phytophagous insects of interest.Nilaparvata lugens is one of the important insect pests which had a huge damage to the rice productivity.Currently,some studies had reported about influence of biochar amendments to nitrogen-rich soils on N.lugens.However little attention has been focused on the influence of biochar amendments to fertile soil on life history of N.lugens.This study emphasized two investigations,one is influence of biochar amendments to fertile soil on the life history of N.lugens,another is influence of biochar amendments on abundances of dominant arthropod groups in paddy field.1.Influence of biochar amendments to fertilized soil on N.lugens life historyFour treatment levels were set up,including 0,10,50,and 200 g/kg,to observe N.lugens developmental and reproductive performnaces.The results showed that biochar amendments had no significant effect on nymphal development time,which was 12-13 days,and on nymph-to-adult survival,which was from 75%to 85%.Biochar amendments did not influence proportion of brachypterous adults at emergence,which was from 77%to 78%.But biochar amendments had a significant effect on female fecundity,which distinctly decreased at 200 g/kg as opposed to 50 g/kg.The results of this study suggest that biochar amendment can decrease N.lugens lifetime fecundity.2.Influence of biochar applications on abundances of dominant arthropod groups in paddy field.This study performed a randomized block design in paddy field,testing 6 biochar varieties and N fertilization on abundances of main arthropod groups.The biochar varieties involved were "Straw Returning"(SR),"Wheat Biochar"(WBC),"Maize Biochar 1"(MBCl.Sanli(?)),"Maise Biochar 2"(MBC2.Liuhe(?)),"Rice Biochar"(RBC),and "Municipal Waste Biochar"(MWBC).The N fertilizer was either applied or not.The survey was made across the rice growing season for abundances of arthropod groups including N.lugens,Sogatella furcifera,Cnaphalocrocis medinalis and Spider.The survey showed that biochar amendments and N fertilizer had a significant interaction in affecting the abundance of N.lugens.With N fertilizer application,the biochar RBC and SR amendments decreased abundances of N.lugens by 59.6%and 57.9%,respectively,compared with the control(no biochar amendment);the WBC and MWBC amendments decreased N.lugens abundance by 74.0%and 74.0%,respectively,compared with MBC2 amendment.Without N fertilizer application,the WBC amendment decreased N.lugens abundance by 61.8%and 61.8%compared with the MBC1 and MBC2 amendments,respectively.Biochar amendments and N fertilizer application each alone had a significant impact on spider abundance.The SR and MWBC amendments decreased spider abundance significantly,compared with the MBC2 amendment,respectively.Biochar amendments and N fertilizer application had no significant effects on abundances of S.furcifera.The results indicate that biochar amendments to paddy field may influence the structure of arthropod community,and the interactions between biochar amendments are significant.