| 原状土与装填土热特性的比较 |
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| 引用本文： | 邸佳颖,刘晓娜,任图生.原状土与装填土热特性的比较[J].农业工程学报,2012,28(21):74-79. |
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| 作者姓名： | 邸佳颖 刘晓娜 任图生 |
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| 作者单位： | 1. 中国农业大学资源与环境学院,北京 100193
2. 太原科技大学环境与安全学院,太原 030000 |
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| 基金项目： | 国家自然基金项目"基于农田水分平衡和土壤感热平衡分解农田蒸散的理论与方法"（41071155）;科技部973课题"作物高产高效的土壤条件与定向调控"（2009CB118607）。 |
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| 摘 要： | 土壤热特性是研究土壤—植物—大气系统中能量传输的必要参数。目前的研究集中在室内装填土柱上热特性与含水率、质地、温度和体积质量(容重)等因素的关系,田间条件下土壤结构对热特性影响的报道很少。该研究通过比较2种质地土壤田间原状土和室内装填土热特性的差异,初步探讨了不同含水率范围内结构形成对土壤热特性的影响。采集田间原状土,在室内利用热脉冲技术测定其热容量、热导率和热扩散率;然后将样品磨碎、过2mm土筛,填装后得到相同体积质量和含水率的装填土壤样品,并测定其热特性。结果表明,装填土和原状土的热容量基本一致;在中等含水率区域(砂壤土:0.07～0.24m3/m3;壤土:0.15～0.31m3/m3),重新装填后砂壤土和壤土的热导率分别降低了9.7%和9.8%。另外,结构形成增加了土壤热扩散率,在中等含水率区域尤其明显;在接近饱和区域,原状土与装填土的热扩散率趋于一致。因此,土壤结构形成对土壤热容量没有显著影响,但提高了中等含水率区域土壤的热导率和热扩散率。
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| 关 键 词： | 土壤 水分 质地 原状土 装填土 热特性 含水率 |
| 收稿时间： | 2012/6/29 0:00:00 |
| 修稿时间： | 2012/10/15 0:00:00 |
Comparative study on thermal properties of intact andrepacked soil samples |
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| Di Jiaying,Liu Xiaona and Ren Tusheng.Comparative study on thermal properties of intact andrepacked soil samples[J].Transactions of the Chinese Society of Agricultural Engineering,2012,28(21):74-79. |
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| Authors: | Di Jiaying Liu Xiaona and Ren Tusheng |
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| Institution: | 1(1. College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; 2. College of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030000, China) |
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| Abstract: | Soil thermal properties are essential for studying energy transport in the Soil-Plant- Atmosphere-Continuum. Many laboratory studies have been conducted to investigate the influences of water content, texture, temperature and bulk density on soil thermal properties using repacked soil columns. There are few reports about soil structure effects on thermal properties of intact soil samples. The objective of this study is to examine the influences of soil structure on thermal properties at different water content ranges by comparing thermal properties of intact and repacked soil samples for sandy loam soil and loam soil. Intact soil samples were collected from field and volumetric heat capacity, thermal conductivity, and thermal diffusivity were measured with the heat pulse technique. Subsequently the intact samples were air-dried, crushed, sieved through a 2 mm screen, and repacked into the same cores with identical water content and bulk density. Thermal properties of the repacked samples were then measured following the same procedure. Finally soil water content and bulk density were determined using the gravimetric method. Similar heat capacity values were obtained for repacked and intact soils. For the repacked samples, thermal conductivity of the sandy loam and loam was 9.7% and 9.8%, lower than that of their intact counterparts at intermediate water contents (0.07-0.24 m3/m3 for sandy loam, 0.15-0.31 m3/m3 for loam). Soil thermal diffusivity was increased by the formation of soil structure at intermediate water contents. At the water content near saturation, the intact and repacked samples had similar thermal diffusivity values. In summary, soil structure formation does not significantly affect heat capacity, but increases thermal conductivity and thermal diffusivity, especially at intermediate water contents. |
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| Keywords: | soils moisture textures intact soils repacked soils thermal properties soil water content |
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