As primary and secondary forests are being replaced by plantations across the globe,the soil macrofauna community structure is also affected,but little is known about the impact of mixed culture plantations compared w...As primary and secondary forests are being replaced by plantations across the globe,the soil macrofauna community structure is also affected,but little is known about the impact of mixed culture plantations compared with monocultures on the soil macrofauna.To determine the impact of forest conversion on soil macrofauna,we surveyed the soil macrofauna in two broad-leaved and three coniferous monoculture stands and four coniferous-broadleaved mixed stands,and in adjacent reserved secondary stands as a reference.Soil macro fauna community composition was significant affected by forest type,season and their interaction(P<0.05).The abundance,taxa richness and diversity of soil macro fauna changed to different degrees depending on the plantation type.Broadleaved monoculture stands and secondary stands had similar macrofauna abundance and taxa richness,but values were lower in coniferous stands than in secondary stands.The Shannon index for macrofauna in coniferous stands was also the lowest,but the Pielou index did not differ between forest types.The negative effects of the conifer monoculture on soil macro fauna were not present in the mixed stands with broad-leaved trees.Forest conversion impacted soil properties;soil moisture,NO_(3)^(-),and pH were significant drivers of soil macrofauna community structure.The impact of forest conversion on soil macrofauna was closely dependent on tree species composition and diversity.The macro fauna community structure in the broadleaved and the mixed stands were relatively similar to that in the natural forest,and thus recommended for forest conversion in the study area.展开更多
Insects attack vegetable crop, leading to an overuse of pesticides. Organic amendments are recommended to increase soil fertility. The impact of two insecticides, on soil macrofauna under rainfed cultivation of tomato...Insects attack vegetable crop, leading to an overuse of pesticides. Organic amendments are recommended to increase soil fertility. The impact of two insecticides, on soil macrofauna under rainfed cultivation of tomato (Lycopersicon esculentum L.) with or without organic amendments was evaluated. The insecticides were Lambda Super (lambda-cyhalothrin) and Dursban (chlorpyrifos ethyl) and organic amendments were compost, pig manure and cattle manure. An experimental device in split-plot with three replicate was installed. Pesticides were applied periodically each week during the experiment. The results have showed that with organic amendments, Lambda super increased the earthworm population compared to the control. Indeed, we found 42 individuals/m2 with compost;1 individuals/m2 with pig manure and 27 individuals/m2 with cattle manure but the control was 0 individuals/m2 in the presence of Lambda super without organic amendment. Similarly, Dursban increased the population of earthworms in the presence of organic amendment with 11, 37 and 91 individuals/m2 respectively for compost, pig manure and cattle manure. Lambda super with compost has led to a total elimination of termites. In the presence of Dursban, a decrease in the number of termites was observed when adding cattle manure (11 individuals/ m2) compared to the control containing only Dursban (21 individuals/m2). Better distribution of macrofauna was obtained with treatment with Dursban and compost (E = 0.99 for earthworms and E = 0.96 for termites). All organic amendments used in our study stimulated earthworm population, but more in the presence of Lambda super or Dursban.展开更多
The alpine wetlands in the Qinghai-Tibetan Plateau have degraded in recent decades.However,the response of the soil food web to the degradation is still unclear.Four habitats including a wet meadow(WM),a grassland mea...The alpine wetlands in the Qinghai-Tibetan Plateau have degraded in recent decades.However,the response of the soil food web to the degradation is still unclear.Four habitats including a wet meadow(WM),a grassland meadow(GM),a moderately degraded meadow(MDM)and a severely degraded meadow(SDM)(sandy meadows)were selected along the degrees of degradation.The soil macrofaunal biomass and the environmental factors of vegetation and soil were investigated.The soil macrofaunal community biomass increased significantly from WMto MDM and decreasedto a very small amount in SDM,with most taxa disappearing.The biomass of the trophic groups of detritivores,herbivores and predators exhibited similar responses to soil macrofaunal communities.The relative biomass of detritivores increased from WM to MDM,but herbivores responded in an opposite manner,resulting in the dominant trophic group and trophic structure varying progressively from WM to GM to MDM.Soil properties but not vegetation determined the changes in trophic groups and trophic structure.The results implied that the higher trophic levels(carnivores or omnivores)responded more sensitively than the lower trophic levels(herbivores)to alpine wetland degradation.Our results also suggested that soil macrofauna have a habitat-specific characteristic trophic structure and can be used as indicators of soil health conditions.展开更多
Restoration of cropland(termed 'Farm') after abandonment including shrubs(termed 'Shrub'),trees(termed 'Tree') and natural grassland(termed 'Grass') has become a routine process aimed t...Restoration of cropland(termed 'Farm') after abandonment including shrubs(termed 'Shrub'),trees(termed 'Tree') and natural grassland(termed 'Grass') has become a routine process aimed to improve land productivity and control desertification. During this restoration process, soil macro-faunal diversity, and trophic structure were investigated at four types of sites(Farm, Shrub, Tree, and Grass)during growing season in the semi-arid agro-pasture zone of northern China. Results indicated that the Staphylinidae family was found to dominate at the Grass, Shrub, and Tree sites, whiles larval Pyralidae individuals were found at the Grass site only. The density of the omnivores(i.e., Formicidae family) was significantly(P<0.05) greater at the Grass site than at the Tree and Farm sites. The total density and richness of predator and phytophages were found to be markedly(P<0.05) greater at the Grass site than at the Farm site. Meanwhile, we found the taxon richness of predators was significantly(P<0.05) higher at the Shrub site than at the Farm and Tree sites. Compared with the Farm and afforested Shrub/Tree sites,the Grass site had greater density, taxon richness, and Shannon index(P<0.05). In conclusion, natural restoration of abandoned croplands toward grassland was an effective strategy relative to artificial afforestation for improvement of soil biological diversity. Moreover, planting shrub is a preferable measure in abandoned croplands for land development in the semi-arid agro-pasture zone of northern China.展开更多
Conservation agriculture (CA) is one option for dealing with such a challenge, but its main difficulty in West Africa is in maintaining permanent soil cover, particularly with crop residues, due to their preferential ...Conservation agriculture (CA) is one option for dealing with such a challenge, but its main difficulty in West Africa is in maintaining permanent soil cover, particularly with crop residues, due to their preferential use for livestock fodder. The aim of our study was to determine the effect of crop residue mulching on the efficiency of cropping systems based on the principles of conservation agriculture. The experimental design was based on on-station experiments, intended to assess the specific effect of different levels of crop residue mulching on the biological and chemical soil fertility parameters, while in on-farm experiments we mainly assessed the ability of farmers to actually collect crop residues for soil cover and the associated effects on weeds and yields. The on-station experimental design was in fully randomized factorial blocks comprising five treatments and three replicates. The treatments compared the conventional system, tillage and cropping without mulching, and CA systems with 1 ton, 2 tons, and 4 tons of straw per hectare in plots of 10 m<sup>2</sup>. The effects of CA on the macrofauna, respiratory activity, and soil chemical parameters were evaluated in the 2014 and 2015 growing seasons. For the on-farm experiments, the conventional and CA practices of 15 farmers were compared to conventional practices in 2013 and 2014 in plots of 626 m<sup>2</sup>. The on-station results showed that the presence of crop residue mulching induced an increase in the density of termites. A significant release of carbon dioxide (CO<sub>2</sub>) in the CA treatments compared to the conventional treatment was also observed. For the chemical parameters (pH, N, P and K) were significantly and positively affected by mulch in the top 5 centimeters of soil. The on-farm experiments confirmed the difficulty of farmers in collecting enough biomass, with negative effects on grass cover leading to generally lower yields than conventional treatments. Other practices also affected the results, such as the maize sowing date, the gap between sowing and weeding, the gap between sowing and urea supply, the number of years of CA practices in the plot and, the gap between maize sowing and cowpea sowing. For the farmers having the human resources to collect enough crop residues for soil cover and follow the steps of the crop management sequences, it was possible to maintain yields compared to the conventional practice.展开更多
基金supported by the Fundamental Research Funds for the Central Universities (572017PZ03,2572020DR04 and 2572019CP16)。
文摘As primary and secondary forests are being replaced by plantations across the globe,the soil macrofauna community structure is also affected,but little is known about the impact of mixed culture plantations compared with monocultures on the soil macrofauna.To determine the impact of forest conversion on soil macrofauna,we surveyed the soil macrofauna in two broad-leaved and three coniferous monoculture stands and four coniferous-broadleaved mixed stands,and in adjacent reserved secondary stands as a reference.Soil macro fauna community composition was significant affected by forest type,season and their interaction(P<0.05).The abundance,taxa richness and diversity of soil macro fauna changed to different degrees depending on the plantation type.Broadleaved monoculture stands and secondary stands had similar macrofauna abundance and taxa richness,but values were lower in coniferous stands than in secondary stands.The Shannon index for macrofauna in coniferous stands was also the lowest,but the Pielou index did not differ between forest types.The negative effects of the conifer monoculture on soil macro fauna were not present in the mixed stands with broad-leaved trees.Forest conversion impacted soil properties;soil moisture,NO_(3)^(-),and pH were significant drivers of soil macrofauna community structure.The impact of forest conversion on soil macrofauna was closely dependent on tree species composition and diversity.The macro fauna community structure in the broadleaved and the mixed stands were relatively similar to that in the natural forest,and thus recommended for forest conversion in the study area.
文摘Insects attack vegetable crop, leading to an overuse of pesticides. Organic amendments are recommended to increase soil fertility. The impact of two insecticides, on soil macrofauna under rainfed cultivation of tomato (Lycopersicon esculentum L.) with or without organic amendments was evaluated. The insecticides were Lambda Super (lambda-cyhalothrin) and Dursban (chlorpyrifos ethyl) and organic amendments were compost, pig manure and cattle manure. An experimental device in split-plot with three replicate was installed. Pesticides were applied periodically each week during the experiment. The results have showed that with organic amendments, Lambda super increased the earthworm population compared to the control. Indeed, we found 42 individuals/m2 with compost;1 individuals/m2 with pig manure and 27 individuals/m2 with cattle manure but the control was 0 individuals/m2 in the presence of Lambda super without organic amendment. Similarly, Dursban increased the population of earthworms in the presence of organic amendment with 11, 37 and 91 individuals/m2 respectively for compost, pig manure and cattle manure. Lambda super with compost has led to a total elimination of termites. In the presence of Dursban, a decrease in the number of termites was observed when adding cattle manure (11 individuals/ m2) compared to the control containing only Dursban (21 individuals/m2). Better distribution of macrofauna was obtained with treatment with Dursban and compost (E = 0.99 for earthworms and E = 0.96 for termites). All organic amendments used in our study stimulated earthworm population, but more in the presence of Lambda super or Dursban.
基金This work was supported by the National Natural Science Foundation of China(41971064,U20A2008 and 40801092)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0302).
文摘The alpine wetlands in the Qinghai-Tibetan Plateau have degraded in recent decades.However,the response of the soil food web to the degradation is still unclear.Four habitats including a wet meadow(WM),a grassland meadow(GM),a moderately degraded meadow(MDM)and a severely degraded meadow(SDM)(sandy meadows)were selected along the degrees of degradation.The soil macrofaunal biomass and the environmental factors of vegetation and soil were investigated.The soil macrofaunal community biomass increased significantly from WMto MDM and decreasedto a very small amount in SDM,with most taxa disappearing.The biomass of the trophic groups of detritivores,herbivores and predators exhibited similar responses to soil macrofaunal communities.The relative biomass of detritivores increased from WM to MDM,but herbivores responded in an opposite manner,resulting in the dominant trophic group and trophic structure varying progressively from WM to GM to MDM.Soil properties but not vegetation determined the changes in trophic groups and trophic structure.The results implied that the higher trophic levels(carnivores or omnivores)responded more sensitively than the lower trophic levels(herbivores)to alpine wetland degradation.Our results also suggested that soil macrofauna have a habitat-specific characteristic trophic structure and can be used as indicators of soil health conditions.
基金supported by the National Natural Science Foundation of China (41661054 41867005)+4 种基金Project for Top Young Talent Candidates of Ningxia (RQ0010)Science Research Foundation of Ningxia Higher Education (NGY2018007)Ningxia Natural Science Foundation (2018AAC02004)Specialized Foundation for Fundamental Condition Construction in Ningxia Science and Technology (2018DPC05021)the Project of First-Class University of Western China for Key Laboratory of Ningxia University (NXYLXK2017B06, GZXM2017001)
文摘Restoration of cropland(termed 'Farm') after abandonment including shrubs(termed 'Shrub'),trees(termed 'Tree') and natural grassland(termed 'Grass') has become a routine process aimed to improve land productivity and control desertification. During this restoration process, soil macro-faunal diversity, and trophic structure were investigated at four types of sites(Farm, Shrub, Tree, and Grass)during growing season in the semi-arid agro-pasture zone of northern China. Results indicated that the Staphylinidae family was found to dominate at the Grass, Shrub, and Tree sites, whiles larval Pyralidae individuals were found at the Grass site only. The density of the omnivores(i.e., Formicidae family) was significantly(P<0.05) greater at the Grass site than at the Tree and Farm sites. The total density and richness of predator and phytophages were found to be markedly(P<0.05) greater at the Grass site than at the Farm site. Meanwhile, we found the taxon richness of predators was significantly(P<0.05) higher at the Shrub site than at the Farm and Tree sites. Compared with the Farm and afforested Shrub/Tree sites,the Grass site had greater density, taxon richness, and Shannon index(P<0.05). In conclusion, natural restoration of abandoned croplands toward grassland was an effective strategy relative to artificial afforestation for improvement of soil biological diversity. Moreover, planting shrub is a preferable measure in abandoned croplands for land development in the semi-arid agro-pasture zone of northern China.
文摘Conservation agriculture (CA) is one option for dealing with such a challenge, but its main difficulty in West Africa is in maintaining permanent soil cover, particularly with crop residues, due to their preferential use for livestock fodder. The aim of our study was to determine the effect of crop residue mulching on the efficiency of cropping systems based on the principles of conservation agriculture. The experimental design was based on on-station experiments, intended to assess the specific effect of different levels of crop residue mulching on the biological and chemical soil fertility parameters, while in on-farm experiments we mainly assessed the ability of farmers to actually collect crop residues for soil cover and the associated effects on weeds and yields. The on-station experimental design was in fully randomized factorial blocks comprising five treatments and three replicates. The treatments compared the conventional system, tillage and cropping without mulching, and CA systems with 1 ton, 2 tons, and 4 tons of straw per hectare in plots of 10 m<sup>2</sup>. The effects of CA on the macrofauna, respiratory activity, and soil chemical parameters were evaluated in the 2014 and 2015 growing seasons. For the on-farm experiments, the conventional and CA practices of 15 farmers were compared to conventional practices in 2013 and 2014 in plots of 626 m<sup>2</sup>. The on-station results showed that the presence of crop residue mulching induced an increase in the density of termites. A significant release of carbon dioxide (CO<sub>2</sub>) in the CA treatments compared to the conventional treatment was also observed. For the chemical parameters (pH, N, P and K) were significantly and positively affected by mulch in the top 5 centimeters of soil. The on-farm experiments confirmed the difficulty of farmers in collecting enough biomass, with negative effects on grass cover leading to generally lower yields than conventional treatments. Other practices also affected the results, such as the maize sowing date, the gap between sowing and weeding, the gap between sowing and urea supply, the number of years of CA practices in the plot and, the gap between maize sowing and cowpea sowing. For the farmers having the human resources to collect enough crop residues for soil cover and follow the steps of the crop management sequences, it was possible to maintain yields compared to the conventional practice.