Land reclamation is a process of ecosystem reconstruction, for which it is very important to keep co-adaptation between plants and the below ground habitat. In order to keep the co-adaptation among plant species, thic...Land reclamation is a process of ecosystem reconstruction, for which it is very important to keep co-adaptation between plants and the below ground habitat. In order to keep the co-adaptation among plant species, thickness of covering soil and medium of covering soil to establish a self-regulating ecosystem, the thickness of covering soil of land reclamation for plants in different living forms by synusia structure of plant below-ground habitat and medium of covering soil by ecological factors of plant below-ground habitat were studied. Synusia structure of plant below-ground habitat was recognized through investigation on structure and root of plant community, and ecological factors were determined through soil profile investigation. The thickness and medium of covering soil of land reclamation for the tree, the shrub and the herb were proposed.展开更多
[Objective] The research aimed to explore the most suitable gravel cover- ing thickness for selenium sand melon in arid region of central Ningxia. [Method] The natural gravel, which was from Nanshantai Region in Zhong...[Objective] The research aimed to explore the most suitable gravel cover- ing thickness for selenium sand melon in arid region of central Ningxia. [Method] The natural gravel, which was from Nanshantai Region in Zhongwei City, Ningxia, was acted as test materials to study the effects of different thicknesses of gravel covering on daily evaporation using evaporator overall weighing method. [Result] The daily evaporation capacity order of the gravel covering thickness was as follows： CK〉HI（5 cm）〉 H2（8 cm）〉 H3（10 cm）〉 H4（15 cm）. Meanwhile, with the increase of test days, the difference of cumulative evaporation capacity between H3 （10 cm） and H4 （15 cm） decreased gradually. Soil evaporation capacity reduced at the pow- er function with the increase of gravel covering thickness, and the decision coeffi- cient of the fitted curve reached to 0.925 5. [Conclusion] With the increase of gravel covering thickness, evaporation capacity of soil reduced gradually, and the soil water content increased gradually. Gravel covering could effectively reduce the evapora- tion. The thicker of covering, the more obvious inhibition effect on evaporation. The thickness of covering should increase moderately to prevent moisture loss from e- vaporation. Gravel inhibition effect on the evaporation wasn＇t obvious when the gravel covering thickness reached more than 10 cm. 10 cm gravel covering was the most appropriate thickness for local natural condition. The soil evaporation capacity along with the change of gravel covering could be simulated with power function e- quation Y=at^b.展开更多
The influence of the most important parameters on the service life of reinforced asphalt overlay with geogrid materials in bending mode was examined by employing the Taguchi method and analysis of variance techniques....The influence of the most important parameters on the service life of reinforced asphalt overlay with geogrid materials in bending mode was examined by employing the Taguchi method and analysis of variance techniques. The objectives of this experiment was to investigate the effects of grid stiffness, tensile strength, coating type, amount of tack coat, overlay thickness, crack width and stiffnesses of asphalt overlay and existing asphalt concrete on propagation of the reflection cracking. Results indicate that the stiffnesses of cracked layer and overlay are the main significant factors that can directly improve the service life of an overlay against the reflection cracking. Generally, glass grid is more effective in reinforced overlay than polyester grid. Effect of crack width of the existing layer is significant when its magnitude increases from 6 to 9 mm.展开更多
To study the mechanism by which the thickness of covering soil effects crop growth in an ecological restoration project of bare rock and gravel land,the physiological characteristics of summer maize were observed duri...To study the mechanism by which the thickness of covering soil effects crop growth in an ecological restoration project of bare rock and gravel land,the physiological characteristics of summer maize were observed during 2010^（–2）015. This experiment was set up on exposed rock land,which had been covered by soil with six different thicknesses： 30（C30）,40（C40）,50（C50）,60（C60）,80（C80） and 100 cm（C100）. During the experiment,soil physical properties and the physiological traits and yields of crops were recorded. The results indicated several effects. 1） With the same thickness level,soil bulk density of the covering soil increased in successive planting years. There was a logarithmic relationship between soil bulk density and covering thickness. There was also a strong algorithmic relationship between covering thickness and sedimentation coefficient（R^2=0.91）. 2） The thickness of covering soil had a significant influence on both the height of summer maize,and soil and plant analyzer development（SPAD） values. In each treatment,the growth rates of the crops during the jointing and booting stages were higher than that in the booting to grain filling stage. After two years of land-use,the mean height of the crop in the C50 treatment was 8.16%,3.32%,3.31%,9.86% and 7.55% higher than that for the C30,C40,C60,C80 and C100 treatments,respectively. The differences between treatments were significant（p 0.05）. SPAD values were highest at the heading stage. The highest value for the C50 treatment was 298.41 after two years of land-use. 3） Soil thickness significantly affected yields and the water use efficiency（WUE） of summer maize. The highest average crop yield and WUE value during the experimental period for the C50 treatment were 4614.12 kg hm^（–2） and 13.57 kg hm^（–2） mm,respectively. For the C50 treatment the multi-year average water use efficiency was significantly higher than that of the other treatments in 2010-2015. In conclusion,a soil thickness of 50 cm covering the bare exposed rock was adequate as a tillage layer for the crop,and all crop growth indexes in this treatment were better than for other soil thicknesses. The results provide a scientific basis for the land remediation and ecological restoration of bare rock and gravel land. At the same time,for Africa,where one-third of the land is desert,arable land resources are relatively scarce and agricultural ecology is fragile,can serve as a significant reference to improve the ecological environment,develop arable land resources and increase agricultural income.展开更多
文摘Land reclamation is a process of ecosystem reconstruction, for which it is very important to keep co-adaptation between plants and the below ground habitat. In order to keep the co-adaptation among plant species, thickness of covering soil and medium of covering soil to establish a self-regulating ecosystem, the thickness of covering soil of land reclamation for plants in different living forms by synusia structure of plant below-ground habitat and medium of covering soil by ecological factors of plant below-ground habitat were studied. Synusia structure of plant below-ground habitat was recognized through investigation on structure and root of plant community, and ecological factors were determined through soil profile investigation. The thickness and medium of covering soil of land reclamation for the tree, the shrub and the herb were proposed.
基金Supported by Natural Science Research Foundation Item of Ningxia University,China(ZR1208)Science and Technology Research Item of Ningxia Colleges and Universities,China(NGY2014065)~~
文摘[Objective] The research aimed to explore the most suitable gravel cover- ing thickness for selenium sand melon in arid region of central Ningxia. [Method] The natural gravel, which was from Nanshantai Region in Zhongwei City, Ningxia, was acted as test materials to study the effects of different thicknesses of gravel covering on daily evaporation using evaporator overall weighing method. [Result] The daily evaporation capacity order of the gravel covering thickness was as follows： CK〉HI（5 cm）〉 H2（8 cm）〉 H3（10 cm）〉 H4（15 cm）. Meanwhile, with the increase of test days, the difference of cumulative evaporation capacity between H3 （10 cm） and H4 （15 cm） decreased gradually. Soil evaporation capacity reduced at the pow- er function with the increase of gravel covering thickness, and the decision coeffi- cient of the fitted curve reached to 0.925 5. [Conclusion] With the increase of gravel covering thickness, evaporation capacity of soil reduced gradually, and the soil water content increased gradually. Gravel covering could effectively reduce the evapora- tion. The thicker of covering, the more obvious inhibition effect on evaporation. The thickness of covering should increase moderately to prevent moisture loss from e- vaporation. Gravel inhibition effect on the evaporation wasn＇t obvious when the gravel covering thickness reached more than 10 cm. 10 cm gravel covering was the most appropriate thickness for local natural condition. The soil evaporation capacity along with the change of gravel covering could be simulated with power function e- quation Y=at^b.
文摘The influence of the most important parameters on the service life of reinforced asphalt overlay with geogrid materials in bending mode was examined by employing the Taguchi method and analysis of variance techniques. The objectives of this experiment was to investigate the effects of grid stiffness, tensile strength, coating type, amount of tack coat, overlay thickness, crack width and stiffnesses of asphalt overlay and existing asphalt concrete on propagation of the reflection cracking. Results indicate that the stiffnesses of cracked layer and overlay are the main significant factors that can directly improve the service life of an overlay against the reflection cracking. Generally, glass grid is more effective in reinforced overlay than polyester grid. Effect of crack width of the existing layer is significant when its magnitude increases from 6 to 9 mm.
基金National Natural Science Foundation of China(41561144011)
文摘To study the mechanism by which the thickness of covering soil effects crop growth in an ecological restoration project of bare rock and gravel land,the physiological characteristics of summer maize were observed during 2010^（–2）015. This experiment was set up on exposed rock land,which had been covered by soil with six different thicknesses： 30（C30）,40（C40）,50（C50）,60（C60）,80（C80） and 100 cm（C100）. During the experiment,soil physical properties and the physiological traits and yields of crops were recorded. The results indicated several effects. 1） With the same thickness level,soil bulk density of the covering soil increased in successive planting years. There was a logarithmic relationship between soil bulk density and covering thickness. There was also a strong algorithmic relationship between covering thickness and sedimentation coefficient（R^2=0.91）. 2） The thickness of covering soil had a significant influence on both the height of summer maize,and soil and plant analyzer development（SPAD） values. In each treatment,the growth rates of the crops during the jointing and booting stages were higher than that in the booting to grain filling stage. After two years of land-use,the mean height of the crop in the C50 treatment was 8.16%,3.32%,3.31%,9.86% and 7.55% higher than that for the C30,C40,C60,C80 and C100 treatments,respectively. The differences between treatments were significant（p 0.05）. SPAD values were highest at the heading stage. The highest value for the C50 treatment was 298.41 after two years of land-use. 3） Soil thickness significantly affected yields and the water use efficiency（WUE） of summer maize. The highest average crop yield and WUE value during the experimental period for the C50 treatment were 4614.12 kg hm^（–2） and 13.57 kg hm^（–2） mm,respectively. For the C50 treatment the multi-year average water use efficiency was significantly higher than that of the other treatments in 2010-2015. In conclusion,a soil thickness of 50 cm covering the bare exposed rock was adequate as a tillage layer for the crop,and all crop growth indexes in this treatment were better than for other soil thicknesses. The results provide a scientific basis for the land remediation and ecological restoration of bare rock and gravel land. At the same time,for Africa,where one-third of the land is desert,arable land resources are relatively scarce and agricultural ecology is fragile,can serve as a significant reference to improve the ecological environment,develop arable land resources and increase agricultural income.
