In order to expound the role of litter in controlling soil and water loss,the soil and water conservation functions of litter in Chinese pine stand have been studied,using the method of location monitor combined with ...In order to expound the role of litter in controlling soil and water loss,the soil and water conservation functions of litter in Chinese pine stand have been studied,using the method of location monitor combined with simulation experiment.The results of the studies showed that the average interception rate of the litter is 12.4%,it’s retarding effect on runoff is related to litter thickness,slope and runoff depth.The mathematical equation between them is ΔT =13.490· l 0.245 · α -0.200 · q -0.186 ,the annual soil evaporation restrained by litter of 2 cm in thickness is 138 6mm,and the litter of 1 5 cm in thickness can decrease the splash erosion by 97 5% and increase soil antiscourability by 96 7%.Compared with the bare slope,the physical and chemical properties of soil covered with litter are improved obviously.All these provide the scientific basis for the rational management of forest and the estabishment of the optimal structure of stand.展开更多
Soil and water conservation mechanism of vegetation has been explained through analysing the effects of vegetation at different layers on rainfall. The vegetation cause the result of reduction of runoff amount,runoff ...Soil and water conservation mechanism of vegetation has been explained through analysing the effects of vegetation at different layers on rainfall. The vegetation cause the result of reduction of runoff amount,runoff energy and runoff carrying sediment. and vegetation improving soil to make a great role of soil and water conservation because of vegetation increasing resistant soil erosion. The research point out soil and water conservation function of vegetation is due to using out runoff amount continually by vegetation at different layers, and the accumulation effects of vegetation at different layers lead quickly reduction of soil erosion amount as to realize bring function of vegetation soil and water conservation into full play.展开更多
目的对2004-2009年从病人标本中分离的羊种3型布鲁氏菌进行遗传多态性分析,了解菌株的遗传特征及遗传进化关系。方法采用多位点序列分型(Multiple locus sequence typing,MLST)技术,对47株布鲁氏菌菌株的7个管家基因、1个外膜蛋白基因及...目的对2004-2009年从病人标本中分离的羊种3型布鲁氏菌进行遗传多态性分析,了解菌株的遗传特征及遗传进化关系。方法采用多位点序列分型(Multiple locus sequence typing,MLST)技术,对47株布鲁氏菌菌株的7个管家基因、1个外膜蛋白基因及1个基因间区的序列进行测定,将各个基因的序列与标准菌株的等位基因型进行比对,确定其等位基因谱型及菌株序列型(STS),分析与其它ST型间的遗传关系。结果 47株布鲁氏菌中,19株omp25基因与目前已有的等位基因型不同,被定义为1个新的等位基因型,即ST28。其余28株与已知的ST8型的各等位基因型一致。结论我国流行的羊种布鲁氏菌主要是羊3型菌株,国内的菌株与国外菌株遗传背景上有差异。MLST分型可以作为研究布鲁氏菌进化关系的重要手段之一。展开更多
The intercepting dynamic processes of P.tabulaeformis forest canopy have been studied by local measuring methods for evaluating forest benefits of soil and water conservation and explaining mechanism of soil and water...The intercepting dynamic processes of P.tabulaeformis forest canopy have been studied by local measuring methods for evaluating forest benefits of soil and water conservation and explaining mechanism of soil and water conservation. The result showed that interception amount of the canopy averaged in six-years was 104.8mm and interception rate was 23.7%.The intercepting processes has a limited increasing processes with raining time.The maximum value of interception amount occurred in the middle process.Then intercepting amount changes like a wave, which can be described using the combination of linear and sine展开更多
文摘In order to expound the role of litter in controlling soil and water loss,the soil and water conservation functions of litter in Chinese pine stand have been studied,using the method of location monitor combined with simulation experiment.The results of the studies showed that the average interception rate of the litter is 12.4%,it’s retarding effect on runoff is related to litter thickness,slope and runoff depth.The mathematical equation between them is ΔT =13.490· l 0.245 · α -0.200 · q -0.186 ,the annual soil evaporation restrained by litter of 2 cm in thickness is 138 6mm,and the litter of 1 5 cm in thickness can decrease the splash erosion by 97 5% and increase soil antiscourability by 96 7%.Compared with the bare slope,the physical and chemical properties of soil covered with litter are improved obviously.All these provide the scientific basis for the rational management of forest and the estabishment of the optimal structure of stand.
文摘Soil and water conservation mechanism of vegetation has been explained through analysing the effects of vegetation at different layers on rainfall. The vegetation cause the result of reduction of runoff amount,runoff energy and runoff carrying sediment. and vegetation improving soil to make a great role of soil and water conservation because of vegetation increasing resistant soil erosion. The research point out soil and water conservation function of vegetation is due to using out runoff amount continually by vegetation at different layers, and the accumulation effects of vegetation at different layers lead quickly reduction of soil erosion amount as to realize bring function of vegetation soil and water conservation into full play.
文摘目的对2004-2009年从病人标本中分离的羊种3型布鲁氏菌进行遗传多态性分析,了解菌株的遗传特征及遗传进化关系。方法采用多位点序列分型(Multiple locus sequence typing,MLST)技术,对47株布鲁氏菌菌株的7个管家基因、1个外膜蛋白基因及1个基因间区的序列进行测定,将各个基因的序列与标准菌株的等位基因型进行比对,确定其等位基因谱型及菌株序列型(STS),分析与其它ST型间的遗传关系。结果 47株布鲁氏菌中,19株omp25基因与目前已有的等位基因型不同,被定义为1个新的等位基因型,即ST28。其余28株与已知的ST8型的各等位基因型一致。结论我国流行的羊种布鲁氏菌主要是羊3型菌株,国内的菌株与国外菌株遗传背景上有差异。MLST分型可以作为研究布鲁氏菌进化关系的重要手段之一。
文摘The intercepting dynamic processes of P.tabulaeformis forest canopy have been studied by local measuring methods for evaluating forest benefits of soil and water conservation and explaining mechanism of soil and water conservation. The result showed that interception amount of the canopy averaged in six-years was 104.8mm and interception rate was 23.7%.The intercepting processes has a limited increasing processes with raining time.The maximum value of interception amount occurred in the middle process.Then intercepting amount changes like a wave, which can be described using the combination of linear and sine
