[Objective] This study aimed to reveal distribution characteristics of soil nutrients in tropical farmland, thereby providing a reference for cropland management and balanced fertilization in the tropical area. [Metho...[Objective] This study aimed to reveal distribution characteristics of soil nutrients in tropical farmland, thereby providing a reference for cropland management and balanced fertilization in the tropical area. [Method] Combining field survey and laboratory analysis, distribution status of nutrients in arable land of Baisha Li Autonomous County of Hainan Province was investigated. [Result] The soil in Baisha Li Autonomous County was acidic in overall with average pH value of 5.0. it had medium organic matter level （average of 19.3 g/kg） and rich alkali-hydrolyzable nitrogen content, but was lack of available phosphorus and available potassium. The spatial distribution of available nitrogen, available phosphorus and available potassi- um in the soil was uneven. The spatial distribution of soil nutrients was mainly related to soil parent materials of the investigated area and pH value of the investigated soil. [Conclusion] According to the distribution characteristics of nutrients in the soil, awareness of land use and land maintenance should be strengthened, application amount of organic fertilizers should be increased, chemical fertilizers should be applied rationally, and fertilization structure should be optimized in the future.展开更多
[Objective] The study aimed to identify Alternaria Nees from some areas of China at molecular level by analyzing the rDNA ITS sequence. [ Method ] The DNA sequences coding for the 5.8S rDNA and the flanking internal t...[Objective] The study aimed to identify Alternaria Nees from some areas of China at molecular level by analyzing the rDNA ITS sequence. [ Method ] The DNA sequences coding for the 5.8S rDNA and the flanking internal transcribed spacers （ ITS1 and ITS2） were amplified by PCR with universal primers ITS4 and ITS5 and subsequently sequenced for 34 Alternaria isolates from different areas of China. [Result] Sequences analysis showed that 5.8S rDNA was 159 bp and no variation in tested 34 isolates. There had variables sites in ITS. The isolates that had same sequences as A. tenuissima or A. alternata all put up eurytopicity to area and host. The variables sites of the isolates showed the diver- sity of Alternaria in the hosts of Oleaceae, Rosaceae and Solanaceae. At the same time that ITS could not clearly separated the isolates was indicated. The results indicated that the phylogenetic relationship were not closely related to the geographical origin and hosts of these isolates. [ Conclusion] The sequence analysis of ITS region could provide theory basis for the identification of Alternaria Nees..展开更多
文摘[Objective] This study aimed to reveal distribution characteristics of soil nutrients in tropical farmland, thereby providing a reference for cropland management and balanced fertilization in the tropical area. [Method] Combining field survey and laboratory analysis, distribution status of nutrients in arable land of Baisha Li Autonomous County of Hainan Province was investigated. [Result] The soil in Baisha Li Autonomous County was acidic in overall with average pH value of 5.0. it had medium organic matter level （average of 19.3 g/kg） and rich alkali-hydrolyzable nitrogen content, but was lack of available phosphorus and available potassium. The spatial distribution of available nitrogen, available phosphorus and available potassi- um in the soil was uneven. The spatial distribution of soil nutrients was mainly related to soil parent materials of the investigated area and pH value of the investigated soil. [Conclusion] According to the distribution characteristics of nutrients in the soil, awareness of land use and land maintenance should be strengthened, application amount of organic fertilizers should be increased, chemical fertilizers should be applied rationally, and fertilization structure should be optimized in the future.
基金Supported by National Natural Science Foundation of China(3046003)~~
文摘[Objective] The study aimed to identify Alternaria Nees from some areas of China at molecular level by analyzing the rDNA ITS sequence. [ Method ] The DNA sequences coding for the 5.8S rDNA and the flanking internal transcribed spacers （ ITS1 and ITS2） were amplified by PCR with universal primers ITS4 and ITS5 and subsequently sequenced for 34 Alternaria isolates from different areas of China. [Result] Sequences analysis showed that 5.8S rDNA was 159 bp and no variation in tested 34 isolates. There had variables sites in ITS. The isolates that had same sequences as A. tenuissima or A. alternata all put up eurytopicity to area and host. The variables sites of the isolates showed the diver- sity of Alternaria in the hosts of Oleaceae, Rosaceae and Solanaceae. At the same time that ITS could not clearly separated the isolates was indicated. The results indicated that the phylogenetic relationship were not closely related to the geographical origin and hosts of these isolates. [ Conclusion] The sequence analysis of ITS region could provide theory basis for the identification of Alternaria Nees..
