Hydrus软件的红壤中铁离子运移模拟
毕业论文关键词：铁离子淋溶；Hydrus；高密度电阻成像；红壤 Simulation of Iron Leaching Process in Red Soil with Hydrus Abstract：Red soil is wide spread in South China, it is characteristic for the intensive leaching process and low fertility. Considering the need of stable supply of fertility on agriculture, it is essential to evaluate a long-term soil nutrients condition precisely. In this study, Hydrus-1D was adopted to simulate Fe leaching process in red soil column (1m) on a span of 10 years from 2005 to 2014 in Guilin. The impacts of precipitation, temperature and soil texture (Kaolinite, Montmorillonite and red soil) are discussed respectively. Especially, saturated hydraulic conductivity (Ks) is measured by ERT to modify hydraulic model in Hydrus-1D. The results show that soil texture has the most significant influence on Fe leaching process, followed by precipitation and temperature. Moreover, for single soil texture, Fe concentration changes quickly during the first three years and then falls down gradually to zero until the tenth year. The maximum value and rate of change depend mainly on precipitation and temperature: the rate of concentration change decreases as temperature goes down; the more precipitation, the higher rate of concentration change with lower maximum value. This study tells the relationship between Fe leaching process and soil texture as well as meterological conditions, which sheds light on soil sustainable management.
Key words: Fe leaching；Hydrus；ERT；Red soil
目录
摘要 1
关键词 . 1
Abstract .. 1
Key words . 1
引言 1
1 材料与方法 5
1．1 研究区概况 5
1．2 实验材料 .. 5
1．2．1 地面气象数据 . 5
1．2．2 经验参数和土壤基本性质数据 .. 5
1．2．3 土壤样品 .. 5
1．2．4 实验仪器 .. 5
1．3 方法 6
1．3．1 Hydrus-1D模型构建 .. 6
1．3．2 实测土壤Ks并优化模型模拟 . 7
1．3．3 铁离子运移影响因素分析 7
2 结果与分析 8
2．1 已有参数和实际气候数据结合的模拟结果 . 8
2．2 优化参数后的模拟结果 .. 9
2．3 降水和温度对铁离子淋溶过程的影响 . 10
2．3．1 降水对铁离子淋溶过程的影响 . 11
2．3．2 温度对铁离子淋溶过程的影响 . 12
3 讨论 .. 12
致谢 .. 14
参考文献： .. 15
附录 .. 16
引言 红壤集中分布在中国南方的热带和亚热带地区，范围涵盖了15个省市自治区，支撑着全国43 %的人口。同时，红壤中的耕地部分占全国总耕地面积的22.7 %左右[1]，对地区的发展至关重要。该土壤的成土过程包括一系列脱硅富铁铝化和生物富集过程，因此红壤呈酸性，缺乏碱金属元素，但富含铁、铝氧化物。 土壤中的水分和养分是影响土壤肥力的关键因素。红壤所在地区降水丰富，年均温较高，且常年受到酸雨的威胁，再加上红壤本身肥力低、质地黏[13]，这些内外部因素共同造成了红壤在农业生产能力上的不可持续性。当前我国南方红壤生态系统面临的首要威胁包括水土流失、土壤酸化、肥力退化和季节性干旱等[2]，这些问题严重抑制了对红壤潜在生产资源的开发。为了保护并改良土壤，进而尽可能减少其目前存在的对农业发展的不利影响，亟需加深对红壤中水分和溶质运移的了解，对反映土壤性质的指标进行量化。 以往对红壤田间水分动态及溶质运移的量化多以实地测量为主，这种方法在一定程度上保证了数据的真实性和差异性，但其花费高、耗时长、难开展和不具广适性的缺点也困扰着众多研究者[14]。