53 rice germplasm resources warehoused during 1981-1984 were regarded as materials to monitor the viability at warehouse time and different years after warehoused. The results showed that seed germination rates of dif...53 rice germplasm resources warehoused during 1981-1984 were regarded as materials to monitor the viability at warehouse time and different years after warehoused. The results showed that seed germination rates of different rice germplasm resources assumed descending trend in storage, with annual decreasing rate between 0.12%-3.05% ; the seed germination rates of most cultivars were above 75% after stored for 26 years; forecasting analysis based on the germination rate of 75% as reference showed a huge difference of safe storage life for different rice germplasm resources, ranging from 12 to 50 years, even longer time. The results suggest that track monitoring on viability and regeneration of rice cultivars is of great importance for germplasm resources conservation.展开更多
To investigate the effects of long term tobacco-rice continuous cropping on soil nutrients and flue-cured tobacco leaf yield and quality, the soils of different con- tinuous cropping years were selected in tobacco-ric...To investigate the effects of long term tobacco-rice continuous cropping on soil nutrients and flue-cured tobacco leaf yield and quality, the soils of different con- tinuous cropping years were selected in tobacco-rice multiple system of Hengyang. Some important indexes, including pH, contents of organic matter and available nu- trients of N P K, contents of medium trace elements of soil samples, and contents of main chemical components of flue-cured tobacco samples were detected for fur- ther analyzing. The results showed that pH value of moderate continuous cropping soil（≤7 years） was more coordinated, in addition, leaf yield and quality of flue-cured tobacco were contained, and the sugar-nicotine ratio and potassium-chlorine ratio were proper. However, under long-term continuous cropping （≥10 years） condition, the soil became acidification, and yield and output value of flue-cured tobacco de- clined. It was suggested that improving soil quality by planting green manure or keeping fallow after continuous cropping 7 years in tobacco-rice system.展开更多
Land use changes affect belowground ecosystems.During the past few decades,land use in Northeast China has changed considerably,and the area of paddy fields has increased rapidly from upland.In this study,soil charact...Land use changes affect belowground ecosystems.During the past few decades,land use in Northeast China has changed considerably,and the area of paddy fields has increased rapidly from upland.In this study,soil characteristics and soil biotic community in paddy fields with different years of rice cultivation were measured to examine the effects of land use change from upland to paddy fields on soil micro-food web.The upland maize fields were selected as control and the microbial community composition was characterized using phospholipid fatty acids(PLFAs) analysis.The microbial biomass(total PLFA),bacteria biomass,and fungi biomass were higher in the 20-40-year(late-stage) than 1-10-year(early-stage) paddy fields.The abundances of total nematodes and bacterivores were lower in the early-stage than late-stage paddy fields.The abundance of herbivores was the highest in the early-stage paddy fields but that of omnivore-predators was the highest in the late-stage paddy fields.Structural equation model indicated that soil food web was developed and structured after 20 years of paddy cultivation.Our results suggested that soil micro-food web may be a good indicator for soil development and stabilization of paddy fields following land use change.展开更多
文摘53 rice germplasm resources warehoused during 1981-1984 were regarded as materials to monitor the viability at warehouse time and different years after warehoused. The results showed that seed germination rates of different rice germplasm resources assumed descending trend in storage, with annual decreasing rate between 0.12%-3.05% ; the seed germination rates of most cultivars were above 75% after stored for 26 years; forecasting analysis based on the germination rate of 75% as reference showed a huge difference of safe storage life for different rice germplasm resources, ranging from 12 to 50 years, even longer time. The results suggest that track monitoring on viability and regeneration of rice cultivars is of great importance for germplasm resources conservation.
基金Supported by Improvement Mechanism and Application of Soil Quality by Succession Planting and Reclamation in Tobacco Field(14-16ZDAa01)
文摘To investigate the effects of long term tobacco-rice continuous cropping on soil nutrients and flue-cured tobacco leaf yield and quality, the soils of different con- tinuous cropping years were selected in tobacco-rice multiple system of Hengyang. Some important indexes, including pH, contents of organic matter and available nu- trients of N P K, contents of medium trace elements of soil samples, and contents of main chemical components of flue-cured tobacco samples were detected for fur- ther analyzing. The results showed that pH value of moderate continuous cropping soil（≤7 years） was more coordinated, in addition, leaf yield and quality of flue-cured tobacco were contained, and the sugar-nicotine ratio and potassium-chlorine ratio were proper. However, under long-term continuous cropping （≥10 years） condition, the soil became acidification, and yield and output value of flue-cured tobacco de- clined. It was suggested that improving soil quality by planting green manure or keeping fallow after continuous cropping 7 years in tobacco-rice system.
基金supported by the National Key Research & Development(R&D) Plan of China(No. 2016YFD0300204)the National Basic Research Program(973 Program) of China(No.2011CB100504)
文摘Land use changes affect belowground ecosystems.During the past few decades,land use in Northeast China has changed considerably,and the area of paddy fields has increased rapidly from upland.In this study,soil characteristics and soil biotic community in paddy fields with different years of rice cultivation were measured to examine the effects of land use change from upland to paddy fields on soil micro-food web.The upland maize fields were selected as control and the microbial community composition was characterized using phospholipid fatty acids(PLFAs) analysis.The microbial biomass(total PLFA),bacteria biomass,and fungi biomass were higher in the 20-40-year(late-stage) than 1-10-year(early-stage) paddy fields.The abundances of total nematodes and bacterivores were lower in the early-stage than late-stage paddy fields.The abundance of herbivores was the highest in the early-stage paddy fields but that of omnivore-predators was the highest in the late-stage paddy fields.Structural equation model indicated that soil food web was developed and structured after 20 years of paddy cultivation.Our results suggested that soil micro-food web may be a good indicator for soil development and stabilization of paddy fields following land use change.
