Cropping history affects nodulation and symbiotic efficiency of distinct hairy vetch (Vicia villosa Roth.) genotypes with resident soil rhizobia

Compatible rhizobia strains are essential for nodulation and biological nitrogen fixation (BNF) of hairy vetch (Vicia villosa Roth, HV). We evaluated how past HV cultivation affected nodulation and BNF across host genotypes. Five groups of similar HV genotypes were inoculated with soil dilutions from six paired fields, three with 10-year HV cultivation history (HV+) and three with no history (HV?), and used to determine efficiency of rhizobia nodulation and BNF. Nodulation was equated to nodule number and mass, BNF to plant N and Rhizobium leguminosarum biovar viceae (Rlv) soil cell counts using qPCR to generate an amplicon of targeted Rlv nodD genes. Both HV cultivation history and genotype affected BNF parameters. Plants inoculated with HV+ soil dilutions averaged 60 and 70 % greater nodule number and mass, respectively. Such plants also had greater biomass and tissue N than those inoculated with HV? soil. Plant biomass and tissue N were strongly correlated to nodule mass (r ²?=?0.80 and 0.50, respectively), while correlations to nodule number were low (r ²?=?0.50 and 0.31, respectively). Although hairy vetch rhizobia occur naturally in soils, past cultivation of HV was shown in this study to enhance nodulation gene-carrying Rlv population size and/or efficiency of rhizobia capable of nodulation and N fixation.     

Genetic diversity and symbiotic efficiency of population of rhizobia of <Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> L. in Brazil

The genetic diversity and symbiotic efficiency among indigenous rhizobia isolates obtained from native field with or without organic fertilization and superficial mineral fertilization were investigated. Eighty-six indigenous rhizobia were isolated from these fields using four common bean varieties as trap-host. The common bean varieties Mexico 309 and Rio Tibagi selected the most efficient rhizobia strains because they showed the best yields and N contents results. The genetic characterization of 36 rhizobia isolates was evaluated by using electrophoretic profiles of amplification products using primers ERIC1-R and ERIC-2. Our results demonstrated that besides the large diversity in the indigenous rhizobial community, the genotype of the trap-host probably influences the selection of the most efficient strains.     

Genetic diversity and relationship between Bradyrhizobium strains isolated from blackgram and cowpea

The genetic diversity of bradyrhizobial strains associated with blackgram and cowpea grown in two different agricultural soils (non-saline and saline) along the coastline of Tamil Nadu has been analysed. Phenotypically indistinguishable isolates were analysed for DNA polymorphism using random amplification of polymorphic DNA (RAPD) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of 16S rDNA and nifD. Although these bacteria belong to a group with a broad host range, RAPD analysis showed a considerable level of genetic diversity among the strains isolated from different host plants. Soil pH and salinity seem to have an effect on the selection of natural populations as revealed by PCR-RFLP of 16S rDNA. A combination of PCR-RFLP genotyping with nodulation studies indicates that monocropping of blackgram and the salinity of the soil have made ineffective rhizobia the dominant genotype, thereby creating an ecological burden on their other compatible hosts. A group of strains and a type strain sharing three different 16S PCR-RFLP types were shown to have the same set of symbiotic genes as inferred from the PCR-RFLP pattern of nifD. Another group of cowpea rhizobia that were found to be effective nitrogen fixers and sharing distinct 16S profiles were found to have a different set of symbiotic genes.     

Size, symbiotic effectiveness and genetic diversity of field pea rhizobia (Rhizobium leguminosarum bv. viciae) populations in South Australian soils

Field pea (Pisum sativum L.) is widely grown in South Australia (SA), often without inoculation with commercial rhizobia. To establish if symbiotic factors are limiting the growth of field pea we examined the size, symbiotic effectiveness and diversity of populations of field pea rhizobia (Rhizobium leguminosarum bv. viciae) that have become naturalised in South Australian soils and nodulate many pea crops. Most probable number plant infection tests on 33 soils showed that R. l. bv. viciae populations ranged from undetectable (six soils) to 32×10³ rhizobia g⁻¹ of dry soil. Twenty-four of the 33 soils contained more than 100 rhizobia g⁻¹ soil. Three of the six soils in which no R. l. bv. viciae were detected had not grown a host legume (field pea, faba bean, vetch or lentil). For soils that had grown a host legume, there was no correlation between the size of R. l. bv. viciae populations and either the time since a host legume had been grown or any measured soil factor (pH, inorganic N and organic C). In glasshouse experiments, inoculation of the field pea cultivar Parafield with the commercial Rhizobium strain SU303 resulted in a highly effective symbiosis. The SU303 treatment produced as much shoot dry weight as the mineral N treatment and more than 2.9 times the shoot dry weight of the uninoculated treatment. Twenty-two of the 33 naturalised populations of rhizobia (applied to pea plants as soil suspensions) produced prompt and abundant nodulation. These symbioses were generally effective at N₂ fixation, with shoot dry weight ranging from 98% (soil 21) down to 61% (soil 30) of the SU303 treatment, the least effective population of rhizobia still producing nearly double the growth of the uninoculated treatment. Low shoot dry weights resulting from most of the remaining soil treatments were associated with delayed or erratic nodulation caused by low numbers of rhizobia. Random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) fingerprinting of 70 rhizobial isolates recovered from five of the 33 soils (14 isolates from each soil) showed that naturalised populations were composed of multiple (5-9) strain types. There was little evidence of strain dominance, with a single strain type occupying more than 30% of trap host nodules in only two of the five populations. Cluster analysis of RAPD PCR banding patterns showed that strain types in naturalised populations were not closely related to the current commercial inoculant strain for field pea (SU303, ≥75% dissimilarity), six previous field pea inoculant strains (≥55% dissimilarity) or a former commercial inoculant strain for faba bean (WSM1274, ≥66% dissimilarity). Two of the most closely related strain types (≤15% dissimilarity) were found at widely separate locations in SA and may have potential as commercial inoculant strains. Given the size and diversity of the naturalised pea rhizobia populations in SA soils and their relative effectiveness, it is unlikely that inoculation with a commercial strain of rhizobia will improve N₂ fixation in field pea crops, unless the number of rhizobia in the soil is very low or absent (e.g. where a legume host has not been previously grown and for three soils from western Eyre Peninsula). The general effectiveness of the pea rhizobia populations also indicates that reduced N₂ fixation is unlikely to be the major cause of the declining field pea yields observed in recent times.     

枣园生草处理对土壤养分和细菌群落的影响

为了明确枣园种植长柔毛野豌豆(Vicia villosa Roth.)对土壤养分和细菌群落的影响,本试验以5年生金丝4号(Zizyphus jujuba Mill.)为试材,研究了枣园不同生草处理(清耕、自然生草、长柔毛野豌豆)对土壤基本理化指标和土壤细菌群落的影响.结果表明,与清耕(对照)相比,枣园生草提高了 土壤含...     

Hairy Vetch Incorporated as Green Manure Inhibits Sulfathiazole Uptake by Lettuce in Soil

Veterinary antibiotics like sulfonamides are frequently detected in arable lands and they can potentially contaminate food crops. It is thus of great importance to identify strategies to reduce food crops’ uptake of antibiotics. For the first time, using a pot culture experiment, sulfathiazole (STZ) uptake by lettuce (Lactuca sativa L.) grown in antibiotic-contaminated soils (10 and 100 mg STZ kg^?1 soil) and treated with (in)organic amendments, namely chemical fertilizer (NPK), compost, and hairy vetch, was investigated. Subsequent enhanced plant growth was witnessed when using hairy vetch treatment. The amount of antibiotic uptake was significantly reduced to 5 and 33% with hairy vetch application compared to compost or NPK application at 10 and 100 mg kg^?1 STZ, respectively. The total amounts of accumulated STZ in plant parts increased as the levels of STZ contaminated in soils were increased. STZ was much more abundant in the roots than the leaves. Within 30 days, the extractable STZ in the treated soils—especially with hairy vetch—diminished considerably to concentrations that are frequently detected in arable soils. We conclude that utilization of green manure (cover crop—hairy vetch) is a viable strategy for safer crop production in antibiotic-contaminated soils.     

Effects of resident rhizobial communities and soil type on the effective nodulation of pulse legumes

Communities of resident rhizobia capable of effective nodulation of pulse crops were found to vary considerably over a range of soil environments. These populations from soils at 50 sites in Southern Australia were evaluated for nitrogen fixing effectiveness in association with Pisum sativum, Vicia faba, Lens culinaris, Vicia sativa, Cicer arietinum and Lupinus angustifolius. The values for nitrogen fixing effectiveness could be related to soil pH as determined by soil type and location. It was found that 33% of paddocks had sufficient resident populations of Rhizobium leguminosarum bv viciae for effective nodulation of faba bean, 54% for lentils, 55% for field pea and 66% for the effective nodulation of the vetch host plant. Mesorhizobium cicer populations were very low with only 7% of paddocks surveyed having sufficient resident populations for effective nodulation. Low resident rhizobial populations (<10 rhizobia g⁻¹ soil) of R. leguminosarum bv viciae and M. cicer were found in acid soil conditions. In contrast, Bradyrhizobium populations increased as soil pH decreased. Inoculation increased faba bean yields from 0.34 to 4.4 t ha⁻¹ and from 0.47 to 2.37 t ha⁻¹ for chickpeas on acid soils. On alkaline soils, where resident populations were large there was no consistent response to inoculation. Observations at experimental field sites confirmed the findings from the survey data, stressing the importance of rhizobial inoculation, especially on the acid soils in south-eastern Australia.     

Diversity of Paenibacillus polymyxa populations in the rhizosphereof wheat (Triticum durum) in Algerian soils

The diversity of Paenibacillus polymyxa populations associated with the rhizosphere of durum wheat was investigated in Algerian soils sampled in regions where wheat had been cultivated for 5 and 26 years (Hamiz, H5 and Z26), 70 years (Algiers, D70), and more than 2 000 years (Tiaret, T2000 and K2000). A total of 111 strains were isolated by immunotrapping and identified as P. polymyxa using an API50CHB kit and restriction analysis of the amplified 16S rDNA gene. The phenotypic characteristics of the P. polymyxa populations were compared and the strains found not to cluster according to their origin. The longer the history of wheat cultivation, the lower the phenotypic diversity and the higher the frequency of nitrogen-fixing strains. Population genetic diversity, evaluated by ERIC-PCR, showed the same trends as phenotypic diversity. The distribution of ERIC genotypes among the different populations studied were compared using Pearson’s Chi-squared test. The strains isolated in D70, Z26, and H5 derived from soil populations sharing the same genetic structure, but those isolated in T2000 and K2000 each stemmed from a population with a specific genetic structure. These data suggest that the genetic structure of P. polymyxa populations has been affected by long-term wheat cultivation.     

Competitive ability of selected Cyclopia Vent. rhizobia under glasshouse and field conditions

This study tested the competitive ability of three locally isolated Cyclopia rhizobia and strain PPRICI3, the strain currently recommended for the cultivation of Cyclopia, a tea-producing legume. Under sterile glasshouse conditions, the three locally isolated strains were equally competitive with strain PPRICI3. In field soils, the inoculant strains were largely outcompeted by native rhizobia present in the soil, although nodule occupancy was higher in nodules growing close to the root crown (the original inoculation area). In glasshouse experiments using field soil, the test strains again performed poorly, gaining less than 6% nodule occupancy in the one soil type. The presence of Cyclopia-compatible rhizobia in field soils, together with the poor competitive ability of inoculant strains, resulted in inoculation having no effect on Cyclopia yield, nodule number or nodule mass. The native rhizobial population did not only effectively nodulate uninoculated control plants, they also out-competed introduced strains for nodule occupancy in inoculated plants. Nonetheless, the Cyclopia produced high crop yields, possibly due to an adequate supply of soil N.     

Genetic diversity of rhizobia associated with alfalfa in Serbian soils

We have evaluated the genetic diversity and phylogeny of alfalfa rhizobia, originating from different types of soils in Serbia and their ability to establish an effective symbiosis with alfalfa (Medicago sativa L.). A collection of 65 strains isolated from root nodules of alfalfa were characterized by rep-PCR analysis, partial and complete 16S rDNA gene and recA gene sequencing, as well as atpD gene sequencing and DNA–DNA hybridizations. The results of the sequence analyses revealed that Sinorhizobium meliloti is the dominant species in alfalfa nodules. Only one strain was identified as Sinorhizobium medicae, two strains as Rhizobium tibeticum and one strain as Rhizobium sp. Despite the fact that the majority of strains were identified as S. meliloti, a high genetic diversity at strain level was detected. Almost all isolates shared the ability to nodulate and fix nitrogen with M. sativa, except 11 of them, which were incapable of fixing nitrogen with this species. About 50% of the isolates showed values of symbiotic effectiveness (SE) above 50%, while 10% of the strains were highly effective with SE values above 70%. Some of the strains which were highly effective in nitrogen fixation at the same time could intensively solubilize phosphates, offering a possibility for multipurpose inoculum development. This was the first genetic study of rhizobia isolated from this region and also the first report of natural presence of R. tibeticum in root nodules of M. sativa.     

Diversity and phylogeny of rhizobial strains isolated from Lotus uliginosus grown in Uruguayan soils

Lotus uliginosus is generally nodulated by rhizobia of the genus Bradyrhizobium when used for improvement of Uruguayan pastures. The genetic diversity and phylogenetic relationships of 111 isolates from nodules of L. uliginosus collected from four fields with or without prior inoculation history were analyzed in this study. Genetic diversity estimated by ERIC-PCR revealed 75 different genomic fingerprints, and showed a relatively greater value compared with other methods and varied by soil type. 16S ribosomal RNA gene RFLP analysis revealed three different ribogroups, A, B and C, with 71 isolates in ribogroup A, three isolates in ribogroup B and only one in ribogroup C. Phylogenetic analyses based on 16S RNA gene sequences, ITS, as well as atpD, recA and glnII gene sequences indicated that ribogroup A strains were affiliated with B. japonicum bv. genistearum strains. The three isolates in ribogroup B did not clearly associate with any Bradyrhizobium species described previously and could represent a novel species within this genus. Unlike B. japonicum strains these isolates were able to nodulate and fix nitrogen with other Lotus species as well as with Spartium, a leguminous shrub. The unique isolate in ribogroup C clustered with Mesorhizobium and appeared genetically and phenotypically related to broad host-range Mesorhizobium sp. NZP2037. Our data suggest that Uruguayan soils contain native or naturalized bradyrhizobia that are able to nodulate L. uliginosus as efficiently as the commercial strain NZP2309 but could have adaptive advantages making them more suitable for inoculant purposes.     

Preheating Method for the Determination of Total Phosphorus Content in Andosols

Abstract

The identification of rhizobial strains is a major problem in studies for the evaluation of the symbiotic effectiveness of specific strains in soils containing native rhizobia. Bradyrhizobium japonicum which includes most strains of soybean-nodulating bacteria is known to display a wide range of genetic diversity (Miyashita 1987). It is, therefore, necessary to develop a reliable taxonomic system based on the genetic traits, which would enable to differentiate and identify of the strains.     

Soybean [<Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merrill] rhizobial diversity in Brazilian oxisols under various soil,cropping, and inoculation managements

In this study, soybean nodules were collected from 12 sites in the State of Mato Grosso, in the Brazilian Cerrados, where both exotic soybean [Glycine max (L.) Merrill] and bradyrhizobial strains have been introduced from 1 to 18 years before. All soils were originally devoid of rhizobia capable of effectively nodulating soybean and varied in terms of chemical and physical properties, inoculation procedures, and cropping systems. Rhizobial genetic diversity was assessed on 240 isolates by rep-PCR fingerprinting with BOX primer, and indices of diversity (abundance-based coverage estimator and traditional and modified Shannon indices) were applied to the profiles obtained. The genetic diversity was much greater than expected, as after the introduction of a maximum of four strains, up to 13 profiles were identified, some sharing many similar bands with the inoculant strains, but others quite distinct from the putative parental genotypes. The increase in the number of rep-PCR profiles could be attributed to genetic variability due to the stressful tropical environmental conditions, but also might indicate that indigenous rhizobia become capable of nodulating the host legume. After the third year of cropping with the host legume, inoculation did not affect rhizobial diversity. A high content of clay decreased diversity in comparison with that seen in a sandy soil, probably due to reduced aeration. Diversity was higher under the no-tillage system when compared to the conventional tillage management, highlighting the importance of maintaining crop residues in tropical soils. Understanding the ecology of exotic rhizobia after being introduced into new cropping areas represents a first step towards the establishment of better strategies of inoculation, which in turn may result in sustainability and higher plant yields.     

Diversity of native rhizobia isolated in south Brazil and their growth promotion effect on white clover (Trifolium repens) and rice (Oryza sativa) plants

In this study, rhizobia strains isolated from white clover (Trifolium repens) root nodules were evaluated in an effort to identify an efficient nitrogen-fixing rhizobia strain that can also improve the growth of rice plants (Oryza sativa). White clover plants were collected from seven sites in south Brazil, and 78 native rhizobia isolates were obtained. The genetic diversity analysis of those isolates was carried out by BOX-polymerase chain reaction. Overall, the native rhizobia isolated showed a high genetic diversity, but when the bacterial isolates from the same site were compared, the diversity was lower. One native rhizobia, POA3 (isolated from the Porto Alegre locality), was able to promote the growth of both plants and is therefore a good candidate for new inoculant formulation. Finally, we can conclude that the community of native rhizobia symbiont of white clover plants in southern Brazil is highly diverse and the growth promotion effect of rhizobia inoculation on rice plants was more pronounced in a poor nutrient substrate condition than in a rich nutrient substrate condition.     

Switchgrass Compositional Variations Arising from Spatial Distribution and Legume Intercropping

Due to genetic diversity within and among switchgrass (Panicum virgatum), there may be genotype x environment and management-induced differences among secondary cell walls. Consequently, two separate experiments were conducted to determine feedstock variance using near-infrared spectrometry (NIRS). One experiment tested legume-intercrops [red clover (RC; Trifolium pratense), crimson clover (CC; Trifolium incarnatum), hairy vetch (HV; Vicia villosa), and partridge pea (PP; Chamaechrista fasciculata)], nitrogen (N) fertilization (0, 67, and 135 kg-N ha^?1), and location impacts on characteristics. The second one determined on-farm bale variance within and across locations. Clustering NIRS data indicated that chemical signatures differed among locations and N-levels, but less so among intercrops. Results suggest that homogeneity may vary within a region responsible for supplying biomass to a biorefinery. Thus, conversion efficiencies and enzymatic requirements for ethanol production may be affected. Consequently, legumes may displace inorganic-N with minimal compositional changes, whereas location and N-level influence feedstock quality and recalcitrance level to a greater extent.     

New insights into the origins and evolution of rhizobia that nodulate common bean (Phaseolus vulgaris) in Brazil

It is generally accepted that there are two major centers of genetic diversification of common beans (Phaseolus vulgaris L.): the Mesoamerican (Mexico, Colombia, Ecuador and north of Peru, probably the primary center), and the Andean (southern Peru to north of Argentina) centers. Wild common bean is not found in Brazil, but it has been grown in the country throughout recorded history. Common bean establishes symbiotic associations with a wide range of rhizobial strains and Rhizobium etli is the dominant microsymbiont at both centers of genetic diversification. In contrast, R. tropici, originally recovered from common bean in Colombia, has been found to be the dominant species nodulating field-grown common-bean plants in Brazil. However, a recent study using soil dilutions as inocula has shown surprisingly high counts of R. etli in two Brazilian ecosystems. In the present study, RFLP-PCR analyses of nodABC and nifH genes of 43 of those Brazilian R. etli strains revealed unexpected homogeneity in their banding patterns. The Brazilian R. etli strains were closely similar in 16S rRNA sequences and in nodABC and nifH RFLP-PCR profiles to the Mexican strain CFN 42^T, and were quite distinct from R. etli and R. leguminosarum strains of European origin, supporting the hypothesis that Brazilian common bean and their rhizobia are of Mesoamerican origin, and could have arrived in Brazil in pre-colonial times. R. tropici may have been introduced to Brazilian soils later, or it may be a symbiont of other indigenous legume species and, due to its tolerance to acidic soils and high temperature conditions became the predominant microsymbiont of common bean.     

Effect of strains of Rhizobium trifolii on the establishment of oversown white clover (Trifolium repens)

Strains of Rhizobium trifolii incorporated into commercial peat inoculants were compared for their effect on the establishment and growth of oversown white clover (Trifolium repens) on soils devoid of infective rhizobia.There were marked differences in numbers of seedlings establishing and clover dry matter production per hectare with the various strains. However, when adjusted to a constant number of established seedlings, dry matter production from all strains, apart from one strain at one site, were similar indicating that the strains did not appear to influence the growth of individual clover plants.The marked differences in establishment of clover inoculated with the various strains could not be accounted for by differences in the number of rhizobia in the peat inoculant.Selecting strains of rhizobia for ability to increase establishment is considered important where clover is oversown onto soils devoid of rhizobia.     

Nitrogen Inputs with Different Substrate Quality Modified pH,Eh, and N Dynamics of a Paddy Soil Incubated under Waterlogged Conditions

Synthetic fertilizer, livestock manure, and green manure are the typical nitrogen (N) sources in agriculture. This study was conducted to investigate the effects of different N sources on soil chemical environment and N dynamics. Changes in pH, redox potential (Eh), and concentration and δ¹⁵N of dissolved N [ammonium (NH₄⁺), nitrate (NO₃^?), organic N, and total N] of soils treated with urea (U), pig manure compost (PMC), and hairy vetch (HV) were investigated in an incubation experiment under waterlogged conditions. The patterns of pH, Eh, and N concentration reflected both a greater mineralization potential of N derived from U than that from HV and PMC and easier decomposability of HV than PMC. The δ¹⁵N further suggested that nitrification was more active for U than for HV- and PMC-treated soils and that N loss via NH₃ volatilization and denitrification would be greater for HV than U and PMC treatments.     

Effects of hairy vetch foliage application on nodulation and nitrogen fixation in soybean cultivated in three soil types

We investigated the effects of applying hairy vetch foliage on nodulation and atmospheric nitrogen (N₂) fixation in soybean cultivated in three soil types in pot experiments. Soybean plants were grown in Gley Lowland soil (GLS), Non-allophanic Andosol (NAS), and Sand-dune Regosol (SDR) with hairy vetch foliage application in a greenhouse for 45 days. In GLS, the nodule number was not influenced by the application, however, nodule dry weight and N₂ fixation activity tended to increase. In NAS and SDR, nodule formation was depressed by foliage application. Soybean plant growth was promoted in GLS and SDR but not in NAS. These promotive effects of hairy vetch foliage application on soybean plant growth in GLS were considered to be mainly caused by the increase in N₂ fixation activity of the nodules, whereas it was considered to be mainly caused by the increase in nitrogen uptake activity of the roots in SDR. The varying effects of hairy vetch foliage application on soybean nodulation may be due to soil chemical properties such as pH and cation exchange capacity, which are related to soil texture. Therefore, we conclude that it is important to use hairy vetch for soybean cultivation based on the different effects of hairy vetch on soybean plant growth in different soil types.     

天津地区不同冬绿肥培肥土壤的效果

  【目的】  研究天津地区长期冬绿肥–春玉米轮作体系对土壤性质的影响,探讨该模式对土壤综合肥力的贡献。  【方法】  田间定位试验于2012—2019年在天津进行,供试作物为春玉米,冬绿肥处理包括冬绿肥二月兰(Orychophragmus violaceus L.)、毛叶苕子(Vicia villosa Roth L.)、黑麦(Secale cereale L.)、黑麦草(Lolium L.)、毛叶苕子二月兰混播、毛叶苕子黑麦混播及冬闲对照,共7个处理。测定土壤理化性质及酶活性,并通过主成分分析方法分析种植不同冬绿肥及其组合对土壤综合肥力的贡献。  【结果】  冬绿肥–春玉米轮作均显著增加了土壤有机质、全氮、全磷、有效磷、速效钾、微生物量碳、微生物量氮含量,同时增加了土壤饱和持水量,降低了土壤EC值。与冬闲–春玉米处理相比,冬绿肥–春玉米轮作土壤细菌数量、真菌数量、放线菌数量分别提高26.67%～75.89%、61.9%～97.9%和51.4%～92.1%,土壤脲酶活性显著增加6.59%～20.47%。毛叶苕子黑麦混播、毛叶苕子、黑麦处理显著提高土壤磷酸酶活性,黑麦、黑麦草处理显著提高土壤蔗糖酶活性,毛叶苕子二月兰混播、毛叶苕子处理显著提高土壤过氧化氢酶活性,毛叶苕子、黑麦草、二月兰和黑麦处理显著提高土壤多酚氧化酶活性。主成分分析结果表明冬绿肥种植显著提高土壤综合肥力,特别是冬绿肥混播种植,提升效果从高到低排序为毛叶苕子二月兰混播>毛叶苕子黑麦混播>毛叶苕子>二月兰>黑麦草>黑麦。  【结论】  华北春玉米种植区,长期冬绿肥种植显著改善了土壤理化性质和生物学性质,提高了土壤综合肥力水平,冬绿肥混播处理对土壤综合肥力贡献高于冬绿肥单播处理。