查看更多>>摘要：·The use of human excrement as fertilizer is a characteristic of traditional Chinese agriculture.·The application of excrement from urban residents in agriculture since the Song Dynasty has ensured the cleanliness and hygiene of ancient Chinese cities.·As early as the Ming Dynasty,the Chinese people defined the principle of fertilizing fields with human excrement from the perspective of material circulation.·The concept Peri-URban ecosystems(PURE)provides inspiration for urban-rural symbiosis regarding circular economy.The use of human excrement in fertilization is a major attribute differentiating the Chinese traditional agriculture from the agriculture in other regions around the world.Despite the fact that the exact record showing that human excrement was used as fertilizer in China emerged in the Western Han Dynasty(B.C.202-A.D.8),such records did not become prevalent until the Southern Song Dynasty(A.D.1127-1279).In the Ming and Qing eras(A.D.1368-1912),human excrement was even considered"top-class fertilizer"and served as the most essential fertilizer in farmland fertilization.The importance of human excrement in the Ming and Qing was mainly reflected by farmers'purchase of human excrement from urban areas.As fertilization practices became increasingly popular during the period,men of letters built a localized theoretical system centering on human excrement.Although the use of human excrement had both positive and negative impacts on public health and the ecological environ-ment,the positive overshadowed the negative as a whole.Today,it is worth pondering on how the utilization of human excrement as an agricultural resource can be improved so that a material cycle system can be rebuilt to re-connect the urban and rural areas.
Bisma JanAli Haider ShahMudasir Ahmad BhatArif Tasleem Jan...
11-27页
查看更多>>摘要：·Nematode identification serves as an important param-eter to study their behaviour,importance and pathogenic-ity.·Application of classical morphometric based identifica-tion methods prove to be lacking due to insufficient knowledge on morphological variations among closely related taxa.Molecular approaches such as DNA and protein-based information,microarray,probing,sequence-based methods and others have been used to supplement morphology-based methods for nematode identification.·Ascarosides and certain protein-based nematode-associated molecular patterns(NAMPs),can be perceived by the host plants,and can initiate a signalling cascade.·This review primarily emphasizes on an updated account of different classical and modern tools used for the identification of nematodes.Besides we also summa-rize the mechanism of some important signalling pathways which are involved in the different plant nematode interactions.Nematodes constitute most diverse and least studied group of soil inhabiting invertebrates.They are ecologically and physiologically important,however,wide range of nematodes show harmful impact on the individuals that live within their vicinity.Plant parasitic nematodes(PPNs)are transparent,pseudocoelomate,free living or parasitic microorganisms.PPNs lack morphometric identification methods due to insufficient knowl-edge on morphological variations among closely related taxa.As such,molecular approaches such as DNA and protein-based information,microarray,probing,sequence-based methods and others have been used to supplement morphology-based methods for their identification.To invade the defense response of different plant species,parasitic nematodes have evolved different molecular strategies.Ascarosides and certain protein-based nematode-associated molecular patterns(NAMPs),can be perceived by the host plants,and can initiate a signaling cascade.To overcome the host confrontation and develop certain nematode feeding sites,some members can inject effectors into the cells of susceptible hosts to reprogram the basal resistance signaling.This review primarily emphasizes on an updated account of different classical and modem tools used for the identification of PPNs.Besides we also summarize the mechanism of some important signaling pathways which are involved in the different plant nematode interactions.
查看更多>>摘要：·No consistent variation was found in soil respiration Q10 under various O2 conditions.·Substrate C quality had a strong effect on Q10 in oxic soils.·N limitation had a large impact on Q10 in soils under O2 limitation.Current studies on the temperature sensitivity(Q10)of soil organic matter(SOM)decomposition mainly focus on aerobic conditions.However,varia-tions and determinants of Q10 in oxygen(O2)-deprived soils remain unclear.Here we incubated three grassland soils under oxic,suboxic,and anoxic conditions subjected to varying temperatures to compare variations in Q10 in relation to changing substrates.No consistent variation was found in Q10 under various O2 conditions.Further analysis of edaphic properties demon-strated that substrate carbon quality showed a strong influence on Q10 in oxic soils,whereas nitrogen limitation played a more important role in suboxic and anoxic soils.These results suggest that substrate carbon quality and nitrogen limitation may play roles of varying importance in determining the temperature sensitivity of SOM decomposition under various O2 conditions.
查看更多>>摘要：·The unique gut habitat led to a core intestinal micro-biome in diverse soil ecosystems.·The collembolan guts may help eliminate soil pathogens.·Host-selection carried more weight on community assembly of gut microbiome.Soil invertebrates are widely distributed in the ecosystem and are essential for soil ecological processes.Inverte-brate gut microbiome plays an important role in host health and has been considered as a hidden microbial repository.However,little is known about how gut microbiome in soil invertebrates respond to diverse soil ecosystems.Based on a laboratory microcosm experiment,we characterized the assembling of microbiome of soil collembolans(Folsomia candida)from six representative regions of the soil ecosystem which they inhabit.Results showed that collembolan gut microbial communities differed significantly from their surrounding soil microbial communities.A dominant core gut microbiome was identified in gut habitat.Community analyses indicated that deterministic process dominated in the community assembly of collembolan gut microbiome.The results further demonstrate a dominant contribution of host selection in shaping gut microbiome.It is also worthy to mention that pathogens,such as common agricultural phytopathogenic fungi Fusarium,were involved in core microbiome,indicating that collembolans could act as vectors of pathogens.Our results unravelled the existence of gut core microbiome of collembolans in soil ecosystems and provided new insights for under-standing the crucial role of gut microbiome of soil fauna in maintaining microbial biodiversity and stability of soil ecosystems.
查看更多>>摘要：·LDPE had no effect on the mortality,growth,and reproduction of earthworms.·LDPE did not alter the mortality,growth,and reproduction of earth-worm caused by Cd.·LDPE alleviated histopathological damage to earthworms caused by Cd.·LDPE alleviated DNA damage in earthworm coelomocytes caused by Cd.·LDPE did not affect the accumulation of Cd in earthworms.Cadmium(Cd)can accumulate in the food chain,with serious impacts on human health and safety.Microplastics(MPs)such as low-density polyethylene(LDPE)should be considered not only as a single pollutant but also as a carrier of other pollutants.In this study,we investigated the joint effects of 30％LDPE and 313 mg kg-1 Cd on mortality,growth,reproduction,microstructure,DNA damage,oxidative stress,and mRNA levels in the earthworm Eisenia fetida.We found that 313 mg kg-1 Cd inhibited growth and reproduction and damaged the microstructures of the skin and intestine.Meanwhile,LDPE had no effect on the mortality,growth,or cocoon production of earthworms.Moreover,it did not increase the mortality,growth,or inhibition of cocoon production caused by Cd and instead alleviated the DNA damage in coelomocytes caused by Cd treatment.Finally,it did not alter the accumulation of Cd in the worms.These indicators can be used for toxicity safety assessment and soil ecological risk assessment of LDPE and Cd cooccurrence in soil.
Mohammed F.S.A.GhanemShahid AfzalHumira NesarZarrin Imran...
61-75页
查看更多>>摘要：·Sewage water in agriculture threatens human health and soil ecosystems through metal pollution.·Nematodes show promise as bioindicators of soil health due to their abundance and position in soil food webs.·Metal-polluted water decreased abundance of certain nematode groups and Sigma Maturity Index.·Metal pollution positively affected nematode groups with r-selected life cycles.Sewage water has been inappropriately used in agriculture,posing possible threats to human health and the soil ecosystems by its constituent pollutants,especially heavy metals.Correct evaluation of its influences on soil biomes needs to consider the response of soil fauna.Among soil organisms,nematodes are seen as the best promising candidates for bioindicators of soil health.Here in,we collected soil samples from fresh water irrigated field from three sites(S1,S2 and S3)and sewage water irrigated distance gradient(5 m-40 m),to assess the influence of metal(Cu,Zn,Cd,Mn,Pb)polluted water on various characteristics of nematode communities.The results indicated that the heavy metals decreased the abundance of C-p3 nematodes,herbivores,and predatory nematodes as well as sigma maturity index,whereas,C-p1,C-p2,bacterivore and fungivore nematodes abundance and diversity positively responded to the metal pollution.Generally,nematode genera with r-selected life cycle were positively affected and those with K-selected life cycle were negatively affected by metal pollution.Overall nematode community has potential to be used as indicator of pollution stress in agricultural soils to check soil health and sustainability.
查看更多>>摘要：·Responses of soil DIRB to lignocellulosic fractions during a 6-week microcosm incubation were investigated.·Anaeromyxobacter,Bacillus,and Clostridium maintained their domi-nance throughout the incubation.·Distinct DIRB groups proliferated under specific lignocellulosic fraction amendments.·Limits of insufficient ferric iron on the proliferation varied by DIRB group.Dissimilatory iron reducing bacteria(DIRB)are phylogenetically and physi-ologically diverse in paddy soils,where iron reduction closely couples with the oxidation of rice straw-derived carbon in the straw returning scenarios.However,few studies have addressed the niche differentiation within DIRB groups during the degradation of lignocellulosic fractions of rice straw.This study conducted a 6-week microcosm incubation experiment to reveal the distinct responses of DIRB groups under specific lignocellulosic fraction amendments with and without ferrihydrite(Fh)addition in a flooded paddy Ultisol.Results showed that the total absolute abundance of the 19 detected DIRB groups did not vary significantly during the incubation.Anaeromyxobacter,Bacillus,and Clostridium were the dominant DIRB groups for all lignocellulosic treatments whereas Thermincola was dominant but only under xylan amendment with Fh addition.DIRB-nodes in the co-occurrence networks of bacterial community mainly belonged to Anaeromyxobacter and Bacillus.Clostridium and Thermincola,Alkaliphilus and Anaeromyxobacter,and Alicyclobacillus,Desulfobulbus,and Desulfosporosinus were specifically proliferated under xylan,cellulose,and lignin amendments,respectively.Whether the proliferation was limited by insufficient ferric iron varied by bacterial group.These findings suggested the lignocellulosic fraction-induced niche differentiation within DIRB groups,which advanced our understanding of the ecology of DIRB in paddy soils under straw returning.
查看更多>>摘要：·Nutrient constraints in low-fertility soil were modified by different species combinations.·Grass-clover assemblages benefited both species in terms of nutrient procurement.·Interplay of competition and facilitation is demonstrated.·An invasive weed removed essential nutrients from the grazing cycle.To investigate the interplay of competition and facilitation between plants in low-fertility pasture grasslands of New Zealand,we compared nutrient uptake and acquisition of key nutrients of three species from different func-tional groups.Combinations of Pilosella officinarum(mouse-eared hawk-weed,an invasive weed),Trifolium repens(white clover,a nitrogen fixer)and Dactylis glomerata(cocksfoot,a pasture grass)were planted into a soil with low-to-deficient concentrations of key nutrients.Highest yields were achieved by the grass growing alone but,when the clover and grass had grown together,there were complementary benefits in terms of procurement of a wide range of nutrients from soil despite lower root biomass.The inva-sive weed negated these benefits,and soil nutrients were exploited less efficiently when Pilosella had grown alone or in a mixture with the other species.Competition from the weed removed the benefits of grass-legume coexistence.These findings are interpreted to suggest that requirements for legumes to be the main source of nitrogen in pasture grasslands may be compromised unless competitive weeds are controlled to avoid disrupted procurement of key nutrients.It is likely these constraints to nutrient procurement would similarly impact conservation grasslands.
查看更多>>摘要：·Afforestation effectively improved soil microbial communities and significantly increased soil nitro-gen mineralization rate(Rm).·Soil microorganisms drive Rm by regulating soil N-cycling genes.·Soil nitrification genes had a major effect on soil Rm than denitrification genes after afforestation.Assessing the function of forest ecosystems requires an understanding of the mechanism of soil nitrogen mineralization.However,it remains unclear how soil N-cycling genes drive soil nitrogen mineralization during afforestation.In this study,we collected soil samples from a chrono-sequence of 14,20,30,and 45 years of Robinia pseudoacacia L.(RP14,RP20,RP30,and RP45)with a sloped farmland(FL)as a control.Through metagenomic sequencing analysis,we found significant changes in the diversity and composition of soil microbial communities involved in N-cycling along the afforestation time series,with afforestation effectively increasing the diversity(both alpha and beta diversity)of soil microbial communities.We conducted indoor culture experiments and analyzed correlations,which revealed a significant increase in both soil nitrification rate(Rn)and soil nitrogen mineralization rate(Rm)with increasing stand age.Furthermore,we found a strong correlation between soil Rm and soil microbial diversity(both alpha and beta diversity)and with the abundance of soil N-cycling genes.Partial least squares path modeling(PLS-PM)analysis showed that nitrification genes(narH,narY,nxrB,narG,narZ,nxrA,hao,pmoC-amoC)and denitrification genes(norB,nosZ,nirK)had a greater direct effect on soil Rm compared to their effect on soil microbial communities.Our results reveal the relationships between soil nitrogen mineralization rate and soil microbial communities and between the mineralization rate and functional genes involved in N-cycling,in the context of Robinia pseudoacacia L.restoration on the Loess Plateau.This study enriches the understanding of the effects of microorganisms on soil nitrogen mineralization rate during afforestation and provides a new theoretical basis for evaluating soil nitrogen mineralization mechanisms during forest succession.
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