In order to investigate the effects of different phytohormones combined with chelating agent(EDTA)on the growth and remediation efficiency of grain amaranth under cadmium stress,this experiment was conducted taking grain amaranth with large biomass as material and by pot method to study the effects of different combined treatments on the growth and cadmium accumulation amount of grain amaranth under cad-mium stress.The results showed that,compared with the single Cd2+treatment,the combined treatments of phytohormones and chelating agent alleviated the influence of Cd2+stress to the growth of grain amaranth,in-creased the biomass of each part,enhanced the absorption and enrichment of Cd2+in root and shoot,and fur-ther improved the phytoremediation efficiency.The combined treatments had higher remediation efficiency by root watering.
In order to study the physiological response law and salt tolerance of different species of cut chrysanthemum under salt stress,six cut chrysanthemum varieties were used as materials to study the effects of different concentrations of NaCl on plant growth and physiological and biochemical indexes,and their salt tol-erance was comprehensively evaluated by principal component analysis.The results showed that there were sig-nificant differences among the indexes of different cut chrysanthemum varieties under salt stress.With the in-crease of salt concentration,the chlorophyll content(SPAD)and leaf relative water content(RWC)showed downward trends,the relative conductivity(REC)and malondialdehyde(MDA)content showed upward trends,and the soluble protein(SP)content and superoxide dismutase(POD)and peroxidase(SOD)activi-ties first increased and then decreased.Based on the performance of various indicators of the cut chrysanthe-mum varieties,the salt tolerance of the six varieties was evaluated and sequenced as Seoul＞Princess Heart＞Funi＞Kevin Pink＞Stripe＞Silver Star Purple.The principal component analysis results of the indexes showed that REC,MDA content and SOD activity could summarize most of the information of the seven indexes,and could be used to evaluate the salt tolerance of cut chrysanthemum.
In order to enrich the germplasm bank of Helianthus tuberosus L.and provide a basis for breeding new special varieties and developing H.tuberosus industry in saline-alkali land,in this experiment,thirty four H.tuberosus germplasms were selected to analyze the differences of plant characters,tuber yield and quality characters,and comprehensive evaluation was carried out by principal component analysis.The results showed that there were significant differences in plant traits,tuber yield and quality traits among different germplasms,and the coefficient of variation of main stem branching number and yield were higher,reaching 60.49%and 58.55%,respectively.The coefficient of variation of tuber number,stem number and starch con-tent per plant were also larger,and their values ranged from 33.34%to 44.10%;the coefficient of variation of the other traits was below 30%.The high-yield(＞30 t/hm2)germplasms as S9,S12,S15,S16,S17,S24,S33,S34 and S35,the high-protein germplasms as S11,S13,S23 and S35,the high-soluble sugar germ-plasms as S6,S23 and S24,the high-fiber germplasms as S3,S12,S26,S30 and S34,and the high-starch germplasms as S1,S6,S25 and S33 were preliminarily screened out.The principal component analysis of the 34 H.tuberosus germplasms were conducted based on 9 agronomic traits(including plant traits and yield traits),and 3 principal components were extracted,which could reflect 74.00%of the total information.After comprehensive evaluation,six germplasms suitable for planting in saline soil of Dongying City,Shandong Province were selected,namely X2020-2,HZ,TJ,L2-1,X2020-1 and N2019-4.Among them,the main stem height and node height of HZ were the lowest,the secondary stem and main stem were thicker,and the yield was significantly higher than the other germplasmes,reaching 85.75 t/hm2.The results of this study could provide germplasm re-sources for breeding high-yield,good quality and special functional H.tuberosus varieties.
Continuous cropping seriously affects the growth of plants,resulting in decreased yield and quality of peanut.In addition,long-term continuous cropping also leads to soil acidification and loss of ex-changeable calcium in soil,resulting in hindered development of peanut pod.Supplementing exogenous calci-um could significantly improve pod and seed yields.In order to investigate the synergistic effect of arbuscular mycorrhizal fungi and exogenous calcium on the growth and development of continuous cropping peanut,Hua-yu 22 was used as the test material to study the effects of Funneliformis mosseae synergizing with exogenous cal-cium on the plant traits,dry matter accumulation,mineral element content,yield and quality of continuous cropping peanut.The results showed that the synergistic effect of F.mosseae and exogenous calcium could sig-nificantly increase the plant height and branch number of continuous cropping peanut,promote the accumula-tion of dry matter and the absorption of mineral elements,and thus improve the yield and quality of peanut.In conclusion,the combination of F.mosseae and exogenous calcium could improve the yield and quality of con-tinuous cropping peanut,which could provide practical and theoretical bases for increasing the yield of contin-uous cropping peanut.
In order to determine whether exogenous salicylic acid(SA)can alleviate alkali(Na2 CO3)stress in plants,the Petunia hybrida variety Dream was used as material,and the effects of foliar spraying SA(0.75 mmol·L-1)on seedling growth,protective enzymes activities and chlorophyll fluorescence parameters under Na2 CO3(100 mmol·L-1)stress were studied.The results showed that compared with the control(CK),the plant height,leaf number,plant fresh and dry weights,total root length,total root surface area,root vol-ume,fine root(diameter at 0～2 mm)length and surface area of P.hybrida seedlings decreased significantly after treated with Na2 CO3,while the POD and CAT activities increased significantly,and the TRo/RC and PI-abs decreased significantly.Compared to not spraying SA,foliar spraying SA under Na2 CO3 stress increased the plant height,leaf number,fresh and dry weights of aboveground part,total root length,total root surface area,fine root length and surface area,POD activity,ABS/RC,TRo/RC and PIabs of P.hybrida seedlings.In conclusion,Na2 CO3 stress significantly inhibited the growth of P.hybrida seedlings,and foliar spraying SA could alleviate the inhibitory effect to a certain extent by promoting the growth of fine roots,improving the ac-tivities of protective enzymes and photosynthetic performance of PSⅡ.
In order to improve the temperature management technology level for cold storage of radish fleshy root,'Weixian Qing'radish was used to study the trend of temperature change during storage,and the effects of different storage methods(cold storage,soil storage,warehouse storage)on radish bolting,flowering and physical and chemical indexes of leaves.The results showed that the soil and warehouse storage tempera-ture was divided into three stages,and there was an obvious temperature change process in about one month after harvest and before planting.Compared to soil and warehouse storage methods,the bolting time of cold storage was delayed by 11 days and 7 days,and the flowering time was delayed by 12 days and 7 days,respec-tively.The radish plant height of cold storage was significantly lower than that of the other two storage meth-ods;the diameter of flower stem was significantly lower than that of warehouse storage,and was also lower than that of soil storage.During bolting and flowering,the contents of soluble sugar,soluble protein and hor-mone and the enzymes activities in leaves of warehouse storage were lower compared with soil and cold storage methods.Based on the results of this experiment,if the cold storage temperature increase gradually about 1 month before the spring planting of radish,the fleshy root would be stimulated by a warming signal similar to the traditional storage method,then the flower bud differentiation process would be initiated earlier,and the process of bolting and flowering would be accelerated after planting;the energy would also be saved effectively.This conclusion could provide theoretical references for scientific and efficient use of cold storage,and increase the seed quantity of radish in the process of breeding.
The experiment was conducted under the condition of returning all the straw into the field.Wheat variety'Yannong 24'and maize variety'Zhengdan 958'were used as experimental materials.With farmers'conventional water and fertilizer management(flood irrigation+conventional fertilization)as control(CK),five treatments including conventional water and fertilizer management with decomposing agent(CKD),optimal water and fertilizer management Ⅰ(drip irrigation+slow and controlled release fertilizer,SS),optimal water and fertilizer management Ⅰ with decomposing agent(SSD),optimal water and fertilizer management Ⅱ(integrated water and fertilizer,SF)and optimal water and fertilizer management Ⅱ with de-composing agent(SFD)were set to study the effects of optimal water and fertilizer management combined with straw-decomposing agent on soil nutrients and crop yield in wheat-maize rotation system.The results were as follows.In maize season,the content of soil available nutrients under each treatment showed an irregular fluc-tuation trend,and topdressing at flare opening stage effectively alleviated the decline of soil nutrients and maintained soil fertility.In wheat season,the content of available nitrogen,phosphorus and potassium de-creased gradually with the advance of growth period.At maturity stage,SSD and SFD treatments significantly increased the content of alkali-hydrolyzed nitrogen and available phosphorus in 0～20-cm soil layer in corn sea-son by 27.9%and 35.9%,12.5%and 19.5%compared with SS and SF treatments,respectively.The maize yield of CKD treatment was the highest as 10.0 t/hm2,followed by SFD and SF treatments,which significantly increased by 16.3%,11.6%and 9.3%compared with CK,respectively.The wheat yield of SFD treatment was the highest as 8.6 t/hm2,followed by SS and SF treatments,which significantly increased by 19.4%,18.1%and 15.3%compared with CK,respectively.Correlation analysis showed that the maize yield was significantly negatively correlated with the contents of alkali-hydrolyzed nitrogen and available phosphorus in 0～20-cm soil layer at seedling stage and 20～40-cm soil layer at maturity stage,but significantly positively correlated with the content of available potassium in 20～40-cm soil layer at flare opening stage and 0～20-cm soil layer at filling stage.The wheat yield was mainly correlated with the soil available nutrients at reviving stage.In sum-mary,under the same water and fertilizer management,combined application of decomposing agent could help maintain the content of soil available nutrients,and had positive effects on the yield of wheat and maize.In maize season,the content of soil available nutrients was higher under SS and SFD treatments.In wheat season,the content of soil available nutrients was higher under SSD treatment.The yield of maize under CKD treat-ment,and that of wheat under SFD treatment were higher.
Tuta absoluta,which originated in Peru,South America,is a devastating invasive pest.This pest invaded Shandong Province in 2023 and had been found to occur sporadically in many counties.The to-mato leaf miner is highly contagious and harmful.It has great potential outbreak risk in Shandong Province,which is an important vegetable producing area in China.In order to effectively prevent the further spread of tomato leaf miner,the prevention and control strategies and opinions were put forward from the aspects of plant quarantine,monitoring and early warning,and green prevention and control(including ecological regulation,biological control,physical and chemical induction and control,and scientific drug use),so as to provide technical support for effectively preventing and controlling the spread of tomato leaf miner and ensuring the safety of vegetable industry and high-quality agricultural development in Shandong Province.
Tomato leaf miner(TLM),Tuta absoluta(Meyrick),is a worldwide quarantine pest.Be-cause it has developed resistance to chemical pesticides,biological control methods should be needed for sus-tainable control.The aim of this study was to determine the parasitism potential of three indigenous Tri-chogramma species(T.chilonis,T.ostrinia,T.dendrolimi)on their natural host eggs of TLM,and to provide scientific bases for breeding good Trichogramma species and exploring their control potential to tomato leaf miner.The parasitic egg number,emergence rate and female ratio of the three Trichogramma species on TLM eggs within 24 hours were measured in laboratory.The results showed that T.chilonis and T.ostrinia had cer-tain parasitism effect on TLM eggs,and T.dendrolimi had no parasitism.The number of parasitic eggs of T.chilonis on TLM eggs was 16.93,and the number of parasitic eggs of T.ostrinia was 10.80.The offspring emer-gence rate of parasitic progeny was sequenced as T.chilonis＞T.ostrinia,and both were more than 70%with the female ratio more than 65%.In conclusion,T.chilonis and T.ostrinia could parasite TLM eggs,and T.chilonis was more suitable for controlling TLM and had broad application prospects.
In order to clarify genetic variation of Mesona chinensis agronomic traits and select excellent germplasms,25 M.chinensis germplasm materials collected from different regions were used for the experi-ment,and 12 agronomic traits were investigated and measured.The genetic variation analysis,correlation a-nalysis,principal component analysis and cluster analysis were used for genetic diversity analysis and compre-hensive evaluation.The results showed that the agronomic traits were significantly different between different M.chinensis germplasms with the variation coefficient from 7.33%to 50.90%;among them,the variation coef-ficient of branch length was the largest,followed by yield per plant.These germplasm materials had rich genet-ic diversity.The Shannon-Wiener diversity index(H′)ranged from 1.219 to 2.111,and that of leaf length and branch length were higher.Correlation analysis results showed that the yield per plant was positively correlated with the number of branches,branch length,leaf length and leaf weight ratio,so they could be used as the main indexes for evaluating the germplasm resources of M.chinensis.Four principal components were extracted by principal component analysis,and their cumulative contribution rate reached 75.081%,which could reflect most information of the agronomic traits of M.chinensis.The germplasms V18,V16 and V22 obtained higher score after comprehensive evaluation,so they were excellent suitable for selection of M.chinensis parents.Through cluster analysis,the 25 M.chinensis germplasms could be divided into three groups;among which,the general performance of type Ⅲ germplasms(V24 and V25)was the best,while that of type Ⅱ germ-plasms(V1,V2 and V3)was the worst,and that of the other germplasms(type Ⅰ)was in between.These results would provide references for the development of M.chinensis germplasm resources and breeding of new varieties.
Tuta absoluta(Meyrick)(Lepidoptera:Gelechiidae)is an important invasive pest on the So-lanaceae plant,which was firstly reported in Peru,South Americain 1917,and has spread to China since 2017.It poses a great threat to the world's Solanaceae crop production,and can lead to drastic tomato yield losses by 80%to 100%in severe cases.In this study,the biological and ecological characteristics,geograph-ical distribution characteristics and suitable habitat,main hazard characteristics and host adaptability,and be-havioral regulation techniques of T.absoluta were reviewed aiming to provide guidance for its effective preven-tion and control.
In this experiment,50 batches of LONICERAE JAPONICAE FLOS collected from Shandong,Hebei and Henan provinces were used as materials to analyze the differences in appearance and quality,and also the correlations between the appearance characteristics(color,flower bud diameter and length)and the contents of main effective constituents(luteolin,chlorogenic acid,isochlorogenic acid A and isochlorogenic acid C).The results showed that the ΔL∗ value was significantly negatively correlated with chlorogenic acid content and significantly positively correlated with luteolin content.The Δa∗,Δb∗and the diameter of upper bud were significantly negatively correlated with isochlorogenic acid content.The diameters of middle and lower parts of flower bud were positively correlated with luteolin content,while the total length of flower bud was sig-nificantly negatively correlated with luteolin content.It indicated that it was feasible to judge the quality of LONICERAE JAPONICAE FLOS by appearance.The results of this study verified the scientificity of using the theory of"judge quality by apperance"to identify the quality of LONICERAE JAPONICAE FLOS to a certain extent,and laid a foundation for establishing a rapid evaluation system for its quality identification.
In order to find a method for extracting high-quality DNA quickly from onion seeds and satisfy the requirements for accurate identification of the purity of a large number of onion hybrids,the DNA quality of onion seeds extracted by the TransGen PlantZol kit,TIANGEN rapid plant genomic DNA extraction system,TPS method and CTAB method were compared firstly in the study,and then the optimal extraction method was selected.The seeds with different germination days and the number of seeds for extracting effective DNA were also optimized and screened.Then,SCAR molecular markers were used to identify the purity of onion hybrid seeds to further verify the extraction quality of onion seed DNA.The results showed that the TIANGEN rapid plant genomic DNA extraction system failed to obtain the total genomic DNA of dried onion seed.The bands of DNA extracted by CTAB method were neat and consistent,single and bright,no tailing and degradation,and no obvious RNA and protein pollution.The DNA extracted from one dried onion seed and the germinated seeds after 3-day germination were more complete with higher purity.Using the total genomic DNA of one dried onion seed extracted by CTAB method as the template,SCAR markers were used to identify the Ms loci genotypes of onion hybrids.The PCR amplified bands were clear and bright,and the differences between different nuclear genotypes of onion could be clearly distinguished according to the migration positions of the bands.In summa-ry,this study determined that CTAB method was the best extraction method for the total genomic DNA from dried onion seeds,and the effective DNA obtained from one dried onion seed could satisfy the requirements of hybrid molecular marker identification,and realize the early identification of hybrid purity.
After the tomato leaf miner(Phthorimaea absoluta Meyrick)invaded China,a trend of this pest occurring together with other four common pests,including Liriomyza sativae Blanchard,Bemisia tabaci Gennadius,Thrips palmi Karny and Tetranychus urticae Koch,which posed great threats to the safety produc-tion of tomato in China.In order to screen out the pesticides simultaneously controlling P.absoluta and the oth-er 4 pests,the toxicity of 16 common pesticides to P.absoluta larvae,L.sativae larvae,B.tabaci adults,T.palmi adults and T.urticae adults were determined to comprehensively analyze the simultaneous treatment of these pesticides.The results showed that the pesticides with higher toxicity(LC50＜5.0 mg a.i./L)to P.abso-luta larvae were chlorantraniliprole,abamectin,spinetoram,cyantraniliprole,clorfenapyr,emamectin benzo-ate and tetrazolamide.The pesticides with high toxicity(LC50＜18.0 mg a.i./L)to P.absoluta and L.sativae were cyantraniliprole,spinetoram,abamectin,chlorfenapyr,chlorantraniliprole,emamectin benzoate and tet-razolamide.The pesticides with high toxicity(LC50＜28.0 mg a.i./L)to P.absoluta and B.tabaci were cyan-traniliprole,thiamethoxam,abamectin and emamectin benzoate.The pesticides with high toxicity(LC50＜24.0 mg a.i./L)to P.absoluta,L.sativae and B.taboci mainly included cyantraniliprole,abamectin and emamectin benzoate,which also had high toxicity(LC50＜7.0 mg a.i./L)to T.palmi.Abamectin and emamectin benzoate showed higher toxicity to the five pests with the LC50 of 0.22～9.24 and 0.80～6.90 mg a.i./L,respectively.In toma-to production,the co-treatment pesticides should be chosen according to the species and harm degree of tomato leaf miner and other pests,and their alternate use should be noted.
The trapping efficacy of three kinds of sex pheromone traps on Tuta absoluta in greenhouse was evaluated.The results showed that the trapped moth number of the smaller blue water pan trap with diame-ter at 26 cm was 82.8%of that of the blue sticky card trap,and the difference between them was not signifi-cant.The trapped moth number of the larger red water pan trap with diameter at 30 cm was 1.486 times of that of the blue sticky card trap,and the difference between them was significant(P＜0.05).Considering cost and convenience of use,the larger red water pan trap should be recommended as the current preferred sex phero-mone trap for tomato leaf miner trapping.
Three different types of maize inbred lines(ZM027,ZM7211,and Chang7-2)were used as experimental materials to study the development dynamics of silk fresh weight,cob extension,cob diameter,cob fresh weight,and cob volume.The results showed that the changes of silk fresh weight in different types of maize inbred lines basically increased at first and then decreased.The 1st to 3rd day was a gradual increase period,and the 3rd to 9th day was a rapid increase period,with the silk fresh weight increasing sharply.The cob elongation of the three inbred lines showed gradually increasing trends on the whole,and the change am-plitude was the same from the 1st to 7th day.After that,the cob elongation of ZM7211 was significantly faster than that of ZM027 and Chang 7-2.The Logistic model was used to quantify the development dynamic of cob e-longation,and the cob elongation rates of the three inbred lines showed Chang 7-2＞ZM7211＞ZM027.The cob diameter of the three inbred lines increased first and then decreased,which could be stimulated well by power equations.The cob's fresh weight increased slowly from the 1st to 7th day,and then the change was obviously different among the three inbred lines.The cob volume of ZM7211 increased gradually,while that of ZM027 and Chang 7-2 increased first and then decreased.The positive correlations between silk fresh weight and cob length,diameter,fresh weight and cob volume were significant or extremely significant as a whole,indicating that silk and cob characters maintained synchronous development.
Metarhizium rileyi(Farlow)Kepler is an important entomopathogenic fungus that has both pathogenic and nonpathogenic forms during parasitism,but only the pathogenic form can kill the host.In order to understand the molecular mechanism of the transformation from nonpathogenic form to pathogenic form of M.rileyi,transcriptomic analysis of these two forms was performed.The results showed that a total of 89 498 Uni-genes were obtained from the two morphological fungus,and the proportion of genes related to"cellular com-ponent"in GO annotation was the highest,and also that related to"general function prediction only"in KOG annotation.However,for KEGG annotation,the genes involved in"metabolic pathways"in"metabolism"subclass and"MAPK signaling pathway"in"environmental information processing"subclass were the high-est,while in"cellular processes"subclass,the genes related to"quorum sensing"were also highly ex-pressed.These initially provided genetic evidence for quorum sensing regulation mechanism of the two morpho-logical transitions of M.rileyi.Differential expression gene(DEG)analysis showed that 3 113 genes were up-regulated and 3 671 genes were down-regulated during the morphological transformation of M.rileyi,but the difference enrichment analysis(DEGs)did not obtain effective results.In conclusion,the gene expression was significantly changed during morphological transformation of M.rileyi,and the metabolism was vigorous,quo-rum sensing mechanism was triggered and cell signal transduction pathway was activated,and finally the trans-formation from nonpathogenic form to pathogenic form was completed.This study could provide a useful refer-ence for in-depth understanding of the molecular mechanism of the M.rileyi pathogenicity.
In this study,the effects of nitrogen application on biomass accumulation and distribution in the aboveground part and nitrogen use efficiency of maize under waterlogging stress were studied in order to re-veal the mechanism of water stress at early growth stage of maize,so as to provide scientific guidance for high-yielding and high-efficiency cultivation of maize.Split-block design was used in the experiment.The nitrogen application rates including 0,120,180,240 and 300 kg/hm2 under the conditions of suitable irrigation during the whole growth period(WW)and waterlogging for 6 days at joining stage(WL)were set.The results showed that under the WL condition,the biomass,nitrogen accumulation,nitrogen harvest index,nitrate re-ductase activity,nitrogen use efficiency and nitrogen partial factor productivity(NPFP)of maize seedlings re-duced significantly under all the nitrogen application treatments compared with WW.In addition,the above parameters except NPFP showed increasing trends with the increase of N application rate,as well as root length density and root biomass.It indicated that suitable increase of nitrogen application rate(300 kg/hm2)could help improve the biomass accumulation and allocation in aboveground part and nitrogen use efficiency of maize in waterlogging field.
In order to select the best rootstock cultivars suitable for grafting muskmelon(Cucumis melo L.)variety Tianbao in Qingdao,6 rootstock cultivars were used in this experiment.The changes of survival rate,physiological indexes,economic characters and fruit quality of muskmelon grafted with different rootstock cultivars were analyzed.The results showed that grafting could significantly improve the survival rate and en-hance the photosynthesis and root vitality of continuous cropping muskmelon plants,and increase the trans-verse and longitudinal diameters,single fruit weight and yield of muskmelon fruits.The single fruit weight and yield of muskmelon grafted with Qingnong 4 were the highest,which increased by 42.9%and 88.7%compared with the self-rooted seedlings,respectively.The contents of soluble solid,soluble sugar and VC,and the solid-acid ratio and sugar-acid ratio of muskmelon after grafting reduced to varying degrees,but the organic acid content increased to varying degrees,and the soluble protein content changed in different degrees.The con-tents of soluble solid,soluble sugar and VC,and the solid acid ratio and sugar-acid ratio of the muskmelon grafted with Mugeng 719 were second only to those of self-rooted seedlings,but there were no significant differ-ences in fruit texture indexes such as hardness,adhesion,cohesiveness,elasticity,adhesiveness and chew-ability.Grafting had no significant effect on aroma components of muskmelon fruits except grafting with Sheng-zhen 1 rootstock,but might lead to the reduction of volatile substances such as ammonia.In the principal com-ponent analysis,the first principal component had the contribution rate of 96.14%,and the data distribution showed that the grafted muskmelon with Mugeng 719 was the closest with the self-rooted seedlings.Comprehen-sive analysis showed that the muskmelon grafted with Mugeng 719 had good fruit quality and the best compre-hensive performance;the muskmelon grafted with Qingnong 4 had the highest yield and the second comprehen-sive performance.The two cultivars could be used as excellent rootstock varieties for Tianbao muskmelon grafting.
In order to explore the interaction mechanism between cultivated soil nutrients and soil micro-bial communities in the Loess Hilly Region,the phospholipid fatty acid(PLFA)method was used to study the effects of five fertilization treatments,including no fertilizer(CK),organic fertilizer(M),nitrogen and phos-phorus fertilizers(NP),nitrogen,phosphorus and potassium fertilizers(NPK)and organic fertilizer com-bined with nitrogen and phosphorus fertilizers(MNP),on soil nutrients and microbial community structure and their relationships.The results showed that the effects of soil nutrients on microbial communities were dif-ferent with different fertilization treatments.The contents of soil nutrients were significantly affected by different fertilization treatments,and those under CK and chemical fertilizer treatments were lower than those under M and MNP treatments.Fertilization treatments could significantly affect the microbial community structure by providing nutrients for soil microorganisms.The soil microbial community structure under M treatment,espe-cially MNP treatment,had significant changes compared with CK,NP and NPK treatments.MNP treatment could increase the biomass of bacteria,actinomycetes and total microbial biomass,reduce the ratio of Gram-positive to Gram-negative bacteria and the ratio of fungi to bacteria,improve the microbial nutrient utilization capacity,and increase the community diversity.In conclusion,the results of this study could provide ascientif-ic bases for increasing soil fertility and developing farmland ecological management model in the Loess Hilly Region.
