To determine the effect of agricultural management on the dynamics and functional diversity of soil nematode communities in a carrot field at Kibbutz Ramat Hakovesh, Israel, soil samples from 0-10 cm and 10-20 cm dept...To determine the effect of agricultural management on the dynamics and functional diversity of soil nematode communities in a carrot field at Kibbutz Ramat Hakovesh, Israel, soil samples from 0-10 cm and 10-20 cm depths were collected during the growing season of carrot. Indices were used to compare and assess the response of soil free-living nernatode communities to agricultural management. Eighteen nematode families and 20 genera were observed during the growing period, with Cephalobus, Rhabditidae, Aphelenchus, Tylenchus, and Dorylaimus being the dominant genera/families. During the planting, mid-season and post-harvest periods the total number of nematodes at both depths was significantly lower (P < 0.01) in the carrot treatment than in the control plots, while during the harvest period at both depths total nematodes and bacterivores were significantly higher in the treatment plots (P < 0.01). The values of the maturity index (MI) at both depths were found to be significantly lower in the treatment plots than in the control plots during the pre-planting period (P < 0.05). Overall, WI, MI and PPI were found to be more sensitive indicators than other ecological indices for assessing the response of nematode communities to agricultural management in a Mediterranean agroecosystem展开更多
Numerous studies have been devoted to the physical-chemical weathering processes leading to the creation of unique soil formations having their own history that induce soil-biotic diversity.However,the extent to which...Numerous studies have been devoted to the physical-chemical weathering processes leading to the creation of unique soil formations having their own history that induce soil-biotic diversity.However,the extent to which unique geomorphic formations influence soil biotic seasonal variation is not clear.Our aim was to define seasonal variations of soil biota in soils of different-aged terraces of the Makhtesh Ramon anticline erosional cirque in southern Israel.The strong effect of Makhtesh Ramon (Ramon crater) erosional fluvial terrace age initiated by climatic changes during the Late Pleistocene- Early Holocene period on seasonal variations in both soil properties and the abundance and composition of soil biota were demonstrated.However,age dependence was not constant and values for observed soil properties and microbial activity were negligible between younger and older terraces for certain seasons,while free-living nematodes along with bacterial-feeding group were strongly dependent on the geomorphic features of the ages throughout the study period.展开更多
“Evolution Canyon”is a typical Mediterranean-basin canyon with a summer dry stream at the bottom and large differences in vegetation cover and solar radiation between the north-facing slope(NFS)and the south-facing ...“Evolution Canyon”is a typical Mediterranean-basin canyon with a summer dry stream at the bottom and large differences in vegetation cover and solar radiation between the north-facing slope(NFS)and the south-facing slope(SFS).It is known to act as an abiotic mediator influencing the community structure of soil fauna.The aim of this study was to determine the spatial dispersion of soil microbial and free-living nematode communities in the open sites(between shrubs)in the upper(0-10 cm)soil layer at four altitudes on both slopes.The combination of relative soil moisture availability and temperature,known to be one of the main triggers for soil biota activity,was explained by slope orientation.The above-mentioned differences were found to significantly affect microbial biomass and CO_(2)evolution resulting in temporary stress,corresponding to higher values in metabolic quotient(qCO_(2))values.These differences may represent microbial investment in energy in order to overcome stress resulting from the microclimatic differences between the two slopes.Moreover,the degree of substrate limitation(primary production due to the differences in plant cover)of microbial activity was explained by the difference in microbial functional groups.The total abundance of soil free-living nematodes was found to be 2-fold higher on the SFS than on the NFS.Thirty-nine genera,including 12 bacteria-feeders,5 fungifeeders,12 plant-parasites,and 10 omnivore-predators,were found at the study site,with 34 genera on the NFS and 29 on the SFS.The generic diversity of the bacteriafeeding nematodes was higher on the SFS than on the NFS.This study elucidates the importance of slope orientation and its effect on the structural levels of soil microbial and nematode communities.展开更多
基金Project partly supported by the Fred and Barbara Kort Sino-Israel Postdoctoral Fellowship
文摘To determine the effect of agricultural management on the dynamics and functional diversity of soil nematode communities in a carrot field at Kibbutz Ramat Hakovesh, Israel, soil samples from 0-10 cm and 10-20 cm depths were collected during the growing season of carrot. Indices were used to compare and assess the response of soil free-living nernatode communities to agricultural management. Eighteen nematode families and 20 genera were observed during the growing period, with Cephalobus, Rhabditidae, Aphelenchus, Tylenchus, and Dorylaimus being the dominant genera/families. During the planting, mid-season and post-harvest periods the total number of nematodes at both depths was significantly lower (P < 0.01) in the carrot treatment than in the control plots, while during the harvest period at both depths total nematodes and bacterivores were significantly higher in the treatment plots (P < 0.01). The values of the maturity index (MI) at both depths were found to be significantly lower in the treatment plots than in the control plots during the pre-planting period (P < 0.05). Overall, WI, MI and PPI were found to be more sensitive indicators than other ecological indices for assessing the response of nematode communities to agricultural management in a Mediterranean agroecosystem
文摘Numerous studies have been devoted to the physical-chemical weathering processes leading to the creation of unique soil formations having their own history that induce soil-biotic diversity.However,the extent to which unique geomorphic formations influence soil biotic seasonal variation is not clear.Our aim was to define seasonal variations of soil biota in soils of different-aged terraces of the Makhtesh Ramon anticline erosional cirque in southern Israel.The strong effect of Makhtesh Ramon (Ramon crater) erosional fluvial terrace age initiated by climatic changes during the Late Pleistocene- Early Holocene period on seasonal variations in both soil properties and the abundance and composition of soil biota were demonstrated.However,age dependence was not constant and values for observed soil properties and microbial activity were negligible between younger and older terraces for certain seasons,while free-living nematodes along with bacterial-feeding group were strongly dependent on the geomorphic features of the ages throughout the study period.
文摘“Evolution Canyon”is a typical Mediterranean-basin canyon with a summer dry stream at the bottom and large differences in vegetation cover and solar radiation between the north-facing slope(NFS)and the south-facing slope(SFS).It is known to act as an abiotic mediator influencing the community structure of soil fauna.The aim of this study was to determine the spatial dispersion of soil microbial and free-living nematode communities in the open sites(between shrubs)in the upper(0-10 cm)soil layer at four altitudes on both slopes.The combination of relative soil moisture availability and temperature,known to be one of the main triggers for soil biota activity,was explained by slope orientation.The above-mentioned differences were found to significantly affect microbial biomass and CO_(2)evolution resulting in temporary stress,corresponding to higher values in metabolic quotient(qCO_(2))values.These differences may represent microbial investment in energy in order to overcome stress resulting from the microclimatic differences between the two slopes.Moreover,the degree of substrate limitation(primary production due to the differences in plant cover)of microbial activity was explained by the difference in microbial functional groups.The total abundance of soil free-living nematodes was found to be 2-fold higher on the SFS than on the NFS.Thirty-nine genera,including 12 bacteria-feeders,5 fungifeeders,12 plant-parasites,and 10 omnivore-predators,were found at the study site,with 34 genera on the NFS and 29 on the SFS.The generic diversity of the bacteriafeeding nematodes was higher on the SFS than on the NFS.This study elucidates the importance of slope orientation and its effect on the structural levels of soil microbial and nematode communities.
