【作者】 杨尽；

【导师】 孙传敏；

【作者基本信息】 成都理工大学 ， 矿物学、岩石学、矿床学， 2010， 博士

【摘要】 土地整理对土地资源的可持续利用乃至国民经济持续健康发展具有极为重要的现实意义。近年来,一方面我国通过大规模土地整理新增了相当数量的耕地,但这些新增耕地主要来源于未曾利用过的土地,其土壤结构较差,综合肥力水平较低,属贫瘠土壤。另一方面,因社会发展,不可避免地会产生固体废物,固体废物不但占用大量宝贵的土地资源,而且对自然环境造成严重污染,本文研究粉煤灰、磷石膏、污泥表明:这些固体废物不仅具有土壤所需养分,而且其特殊的理化性能,还具有改善土壤结构的显著作用。针对以上特点,本文采用多种现代分析测试技术,对研究区贫瘠土壤及富含矿物和矿物组合的粉煤灰、磷石膏、污泥的物质组分及微观结构特征进行了分析研究;从多学科的研究视角对土壤矿物改良剂的作用机理进行了有益的理论探索,并通过对土壤矿物改良剂优化配比方案选择及盆栽植物对比实验,为固体废物改良贫瘠土壤的运用提供了理论依据,从中获得新的认识。1)土地整理新增耕地土壤属贫瘠土壤:在综合分析成都地质构造、地层、第四系地质及农业地质特征的基础上,选择具有新增耕地来源、地质环境具有代表性的彭州、金堂、邛崃三地新增耕地土壤进行研究,并从土壤物性、化学成分、矿物组成及养分方面分析其物质组成特征。新增耕地土壤主要为砂土、壤质砂土及砂质壤土。化学成分SiO2含量较高,为64.18~76.42%,Al2O3含量次之,为10.31~14.73%,K2O含量相当较高,说明土壤中富K;硅铝风化系数最高达12.60,铝铁风化系数最高达7.11,氧化指数最高达0.92。矿物组成中原生矿物主要为石英、长石,次生矿物主要为粘土矿物,粘土矿物中以伊利石分布广,含量高,蒙脱石分布较广,含量较低,少数样品高岭石含量明显增加。土壤养分缺乏,基本为四级、五级土壤标准范围,属贫瘠土壤。2)富含矿物及矿物组合的粉煤灰、磷石膏、污泥具有改良土壤潜力:①微观结构方面,它们具有球粒结构、网状结构、针状结构,可以改善土壤结构,降低土壤容重,增加孔隙度。②化学成分方面,粉煤灰、污泥与土壤非常接近,但污泥中有机物含量高,烧失量近50%,磷石膏主要为CaO,烧失量较高,说明主要为SO2、H2O。③矿物组成方面,粉煤灰结晶质主要为石英和相变矿物莫来石,非晶质为玻璃质,其非晶质具有较高活性;磷石膏主要为石膏;污泥主要有石英、长石、伊利石、蒙脱石等,其矿物组成与土壤极为相似。④养分方面,粉煤灰有机质较高,达11.2%;磷石膏有效P很高,达1711mg/kg;污泥中各养分含量均较高,有效N、P、K及有机质分别为786 mg/kg、1200 mg/kg、685 mg/kg、39.7%。因此,由粉煤灰、磷石膏、污泥制备的土壤矿物改良剂能满足土壤所需的各养分要求。3)利用土壤矿物改良剂改良土壤,其比例控制在20%以内:依据pH值临界法,进行理论计算和实验对比,确定矿物土壤改良剂配比,粉煤灰:污泥:磷石膏=600:320:1;利用土壤矿物改良剂改良贫瘠土壤,其配比为,土壤矿物改良剂:土壤=2:8。对改良土壤检测结果显示,贫瘠土壤改良效果显著:所有改良土壤的养分全部超过二级土壤标准,部分达到一级土壤标准,其中有效N最高达629mg/kg,有效P最高达650 mg/kg,有效K最高达620 mg/kg,有机质最高达15.4%。对40K、238U、232Th比活度进行测试,虽比原土样高,但幅度较小,不影响作物生长。玉米盆栽对比实验显示,改良后土壤长势良好,出芽率高出14.87%,生长速度高出96.47%。对污染元素进行测定,Cd、Hg超过二级土壤标准,需通过降低土壤矿物改良剂比例(不超过20%)及适当提高pH值予以控制。4)土壤矿物改良剂能改善土壤结构,促进或参与有效N、P、K及有机质的增加转化,控制污染元素的生物活性:①土壤矿物改良剂具有容重轻、颗粒小、有网状、孔洞结构等有效物理特征,可以降低土壤容重,增加土壤孔隙度,提高土壤毛细管作用能力,提高土壤保水性能,使土壤团聚体增加,颗粒吸附能力增强;②土壤矿物改良剂中具有多种阴、阳离子,可以促进粘土矿物离子交换,维持土壤酸碱相对稳定;③土壤矿物改良剂具有较高的化学活性,2:1型粘土矿物含量高,有机物含量高,能提高土壤吸附能力,促进或参与土壤硝化反应、氨化作用、离子交换反应、有机物的腐殖化过程,促进氮、磷、钾向有效N、P、K转变,促进有机物向有机质转化;④土壤矿物改良剂具有大量阴离子及2:1型粘土矿物,能促进Cd、Hg、Pb等污染元素的固定,降低污染元素的生物活性。更多还原

【Abstract】 Land consolidation has very important practical significance on the sustainable use of land resources as well as the sustained and healthy development of national economy. On the one hand, a considerable amount of arable lands which are mainly from unused land are available through large-scale land consolidation in China in recent years. The soil structure of the lands is bad, and the integrated soil fertility level of the lands is low. The land is a type of barren soil. On the other hand, a lot of valuable land sources are occupied by solid waste produced by industrialization, and the natural environment are contaminated by the solid waste. In this thesis, fly ash, phosphogypsum and sludge with special physical and chemical properties are studied for improving soil structure and nutrients of the lands. The composition and microstructure of the soil and the fly ash, the phosphogypsum and the sludge are analyzed using a variety of modern analytical techniques. The mechanism of the improving soil quality through the materials mentioned is theoretical discussed. The study of optimization of the ratio of soil mineral conditioner selection and potted plant comparative experiments provide a theoretical basis in order to improve barren soil using the solid waste. The study results are followed:1) The added cultiviated land soil is barren soil.By analyzing of Chengdu area geological structure, stratigraphy, Quaternary geology and agriculture geological features, the soils from Pengzhou, Jintang and Qionglai are selected for the studies. The characteristics including soil properties, chemical composition, mineral composition and nutrient composition are analyzed. The new farmland soil of Qionglai and Pengzhou is mainly sand and loamy sand, and the soil of Jintang is mainly sandy loam. The content of SiO2 of the soils ranges from 64.18% to 76.42%, the content of Al2O3 changes from 10.31% to 14.73%, the soils rich in K element; weathering factor of aluminosilicate is up to 12.60, ferric weathering coefficient is up to 7.11; maximum of oxidation index is 0.92. The main minerals are quartz, feldspar, secondary minerals are clay minerals which are illite, montmorillonite and kaolinite. Illite is widely distributed and higher content, montmorillonite is widely spread and lower content.In a few samples,the content of kaolinite increase significantly. Soil nutrient analysis results show that the soil is in four or five soil standard class, and it is a barren soil.2) fly ash, phosphogypsum and sludge,which contain mineral and mineral assemblages, have potential of soil improvement.①In the microstructure,they exist spherical structure,network structure,andneedle-like structure.These structural features can improve soil structure, reduce soil bulk density, increase porosity.②In the chemical components, fly ash, sludge and soil is very close, but the sludge content high organic matter,and the ignition loss is 50%.Phosphogypsum is mainly CaO, the ignition loss is higher, which shows mainly SO2, H2O.③In the mineral composition, ash is mainly quartz and crystalline mineral mullite phase transition, glassy amorphous as its amorphous high activity; phosphorus is mainly gypsum plaster; sludge is mainly quartz, a long stone, illite, montmorillonite and so on, its mineral composition is very similar as soil.④In nutrient, organic matter of fly ash is up to 11.2%; phosphogypsum effective P isup to 1171 mg / kg, various nutrients of sludge are high, the effective N is up to 786mg/kg, the effective P is up to1200 mg / kg, the effective K is up to 685 mg / kg, organic matter is up to 39.7%. Thus soil mineral conditioner prepared by the fly ash, phosphogypsum and sludge can meet the nutrient requirements which soil required.3)The soil minerals conditioner must control in 20%,using them improve soil. According to the pH critical method, we repeated the experiment by changing soil mineral modifier ratio and computed by their theory value, the ratio of fly ash, sludge and phosphogypsum is 600:320:1. According to the ratio and the nutrient content, we calculate the theory value of the nutrient content of soil mineral modifier, and determine the ratio of soil minerals conditioner and soil is 2:8. The results of tests show that all improved soil nutrient is the more than two standard class soil to up to one standard class soil. In the soil effective N is up to 629mg/kg, the effective P is up to 650 mg / kg, the effective K is up to 620 mg / kg, organic matter is up to 15.4%. So the effect improving berren soil is remarkable. Although the specific activity of 40K, 238U, 232Th is higher than the original soil samples, it does not affect crop growth. Potted plants comparative experiments showed that improved soil is doing well,their budding percentage is higher than 14.78%, their growth speed is higher than 96.47%.. The pollution elements Cd and Hg is more than two standard soil, but we can control the conclusion by lowering the conditioner ratio (<20%)and appropriately increasing the pH.4) The minerals siol conditioner may improve soil structure, promote or participate the adding translation of the effective N, P, K and organic matter.①the soil mineral agents have effective physical characteristics such as a light bulk density, small particles, mesh pore structure and so on, which can reduce soil bulk density, increase soil porosity, soil capillary action to improve capacity, increase soil water retention properties and particle adsorption capacity.②Minerals soil conditioner has a variety of anions and cations which can promote the clay minerals ion exchange, maintain a relatively stable soil pH.③Soil mineral modifiers have high chemical activity. High content of 2:1 clay minerals and high organic matter content increase soil adsorption capacity, promote or participate in soil nitrification, ammonification, ion exchange reaction, organic matter humification process, promote nitrogen, phosphorus and potassium to turn to the effective N, P, K , promote organic to converse to organic matter.④Minerals soil conditioner which have a large number of anions, 2:1 clay minerals can promote the Cd , Hg, Pb and other pollution elements to fix, reduce their biological activity.更多还原