IMHE OpenIR  > 山地表生过程与生态调控重点实验室
典型紫色土剖面性质及其对磷素吸附-解吸的影响
Alternative TitlePhysicochemical Properties of Typical Purple Soils and Its Relations with Phosphorus Adsorption-desorption
Language中文
肖懿
Thesis Advisor唐家良
2014
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Name硕士
Degree Discipline土壤学
Abstract本论文研究以室内分析及控制实验为主,根据紫色土分布特点,选取了典型酸性,中性及石灰性紫色土采集土体剖面样品;在采集野外采集土壤样品时,记录剖面信息及土体环境信息,在实验室内分析剖面样品的pH,CaCO3,有机质,全氮,全磷,有效磷,土壤质地以及铁氧化物含量等指标;通过实验室磷吸附解吸实验对不同酸碱度紫色土磷吸附解吸特征进行研究分析,测定磷吸附解吸的变化规律,系统研究不同pH环境对磷吸附的影响;通过磷素培养实验,对不同磷浓度培养下的剖面样品进行磷分级,摸清各形态磷在不同磷浓度以及铁氧化物含量的情况下分布及转化特征。在此基础上,分析土壤理化性质及矿物学性质对磷吸附解吸影响的相关性,探讨铁氧化物及相关理化性质对土壤磷吸附解吸影响的机制,为完善紫色土矿物学性质研究和土壤磷素污染机制及控制管理提供决策依据和理论支持。主要研究结果如下: (1) 紫色土剖面理化性质 石灰性紫色土pH与碳酸钙含量呈显著正相关,中性及酸性紫色土pH与土层深度不存在显著相关性。三种土壤的林地表层有机质含量最高,农地土壤有机质随土层分布较为均匀。全氮含量随土层深度增加而减少,林地含量高于农地,石灰性>中性>酸性土壤。全磷含量剖面中间低,表层与底层较高,可能原因是紫色土作为岩性土,部分营养元素直接从母岩继承,而表层较高则是因为施肥以及动植物残体释放等后天原因。生物有效磷(Olsen-P),农田表层有效磷含量均高于林地,但在剖面上其分布并没有与深度呈现出明显相关性。紫色土总体砂粒含量较高,同时表现出较强淋溶特征,再次证实了紫色土易风化,成土时间短的特性。紫色土各形态铁氧化物含量与土壤质地因素相关性较高。相较于红壤,黄壤等地带性土壤,紫色土铁氧化物含量居中。 石灰性紫色土土体的粘土矿物组成为:伊利石含量占主体(40-50%),有少量(10-30%)的绿泥石,高岭石,石英及针铁矿,同时有痕量(<10%)的伊利石-绿泥石间层。所选土体的矿物学分析表明,在不同地点的石灰性紫色土间并无显著差异,粘土矿物在土壤剖面中分异较小也说明紫色土土壤处于风化过程中的早期阶段。在不同粒径X衍射分析中还发现赤铁矿同时分布在紫色土的粘、粉、砂粒中。 (2)紫色土对磷的吸附解吸特征 相较于中性紫色土及石灰性紫色土,酸性紫色土磷素最大吸附量(Qm)、吸附缓冲容量(MBC)最低,而磷素解吸能力(k)最高。紫色土母质类型(pH)、土壤质地及土壤总磷含量对磷素吸附解吸能力有直接影响。pH、粘粒含量越高,紫色土更易蓄持磷素;总磷、砂粒含量越高,土壤更易释放磷素;紫色土区域有机质含量普遍偏低,对磷素蓄持能力无显著影响。表层土研究中单个因素与磷素吸附解吸能力不存在显著线性相关。 (3)紫色土磷吸附的主要影响因素 酸性紫色土砂粒含量极高。磷吸附量仅在pH 4.5环境下与土壤质地条件无显著相关,磷吸附量显著低于中性及石灰性紫色土。 中性紫色土无定型铁氧化物含量较高。在酸性及中性环境下,铁氧化物含量与磷吸附有正相关,铁氧化物作用体系占主导作用;在碱性环境下,铁氧化物作用体系作用受抑制,磷吸附更多受控于土壤质地及土壤总磷含量。 石灰性紫色土碳酸钙及交换性钙离子含量显著高于其他两种紫色土。酸性条件下,铁氧化物作用主导磷吸附过程。中性条件下,铁氧化物作用主导地位削弱,土壤质地影响作用增强。碱性条件下,碳酸钙影响作用对磷吸附影响占主导作用。 林地土壤在低浓度磷及酸性环境下,磷吸附主要为非转型吸附,受到CEC、阳离子含量、铁氧化物影响。随pH升高,阳离子影响作用减弱,铁氧化物作用成为部分酸性及中性环境中磷吸附作用的主导体系。在碱性环境中,非石灰性土壤铁氧化物作用仍占主导地位,石灰性土壤中碳酸钙影响作用占主导。 受农业活动影响,农地土壤磷吸附在酸性及中性条件下规律性较差,无法全面及准确地找出影响磷吸附作用的相关指标,磷吸附的作用机理相较林地而言并不清晰。但在碱性环境下仍表现出与碳酸钙含量的极显著相关,土壤质地因素也有显著影响。 (4)紫色土磷形态分配特征与转化规律 自然状态下,无机磷含量(林地,农地)依次为:中性紫色土(0.57,0.45 mg/g)>酸性紫色土(0.25,0.24 mg/g)>石灰性紫色土(0.2,0.16 mg/g),林地含量均高于同类型农地。 酸性紫色土磷吸附受土壤质地及铁氧化物作用共同影响,主要影响因素为砂粒含量,自由态铁氧化物(Fed)及无定型铁氧化物(Feo),其次是CEC,总磷含量。低浓度磷环境中(自然状态及1.55 mg/g磷处理),无机磷主要为铁铝结合态磷,易溶磷集中在O至Bt1层,表明无机磷迁移集中在剖面表层。中浓度磷环境中(80 mg/g 磷),铁氧化物作用体系未达到饱和吸附,铁铝磷为主要无机磷形态;易溶磷比例随土层增加而递减。高浓度磷(155 mg/g 磷)处理后,铁氧化物作用体系达到饱和吸附,最大磷吸附量14 mg/g(Bt2层);大部分无机磷以易溶磷形态分布于整个紫色土剖面。 中性紫色土磷吸附受铁氧化物作用体系主导,主要影响因素为各形态铁氧化物含量,其次为CEC,交换性阳离子含量及土壤质地。低浓度磷处理后,铁铝磷比例已接近最大值,易溶磷比例较低,难以向下迁移。中浓度磷环境下,阳离子吸附作用增强,但铁氧化物作用体系依然占主导。高浓度磷环境下,铁氧化物作用体系达到饱和吸附状态,最大单层磷吸附量约为12 mg/g(C层),此时磷形态分配同酸性紫色土类似。 石灰性紫色土磷吸附作用受碳酸钙影响作用主导,主要影响因素为交换性钙离子,碳酸钙含量,其次为铁氧化物及土壤质地因素。低浓度磷处理后,钙磷含量比例显著高于其他土体,其次闭蓄态磷比例较高,易溶磷在剖面Bk2至C层分布;中浓度磷环境下,钙磷占比80%以上,碳酸钙影响作用吸附效力不减;易溶磷比例相对减少,分布于整个剖面。高浓度磷环境下,闭蓄态磷及易溶磷比例小幅增加,钙磷比例下降,但无法判定碳酸钙影响作用是否达到饱和吸附。 (5)不同类型紫色土磷素管理的措施建议 酸性紫色土区域,砂粒含量较高,土壤磷吸附过程主要受土壤质地及铁氧化物作用体系影响,吸附量最大值为Bt2层14 mg磷/g土壤,磷素最大单层吸附量(Qm)及最大缓冲容量(MBC)均低于其他两种土壤。上述结果表明该地区磷素易释放,难吸附,为典型砂壤土特征。磷素污染风险较高,应该采取适当的面源磷素流失控制措施及合理的农业施肥管理。 中性紫色土区域,土壤磷吸附过程受铁氧化物作用体系主导,其次为CEC及交换性阳离子。该区域无机磷主要以铁铝磷形态存在,可溶磷含量较低。表明磷素流失主要通过颗粒态,因此控制水土流失,保护地表植被对该区域防治磷素污染更为有效。 石灰性紫色土区域,土壤磷吸附过程受碳酸钙影响作用控制,主要影响因素为碳酸钙含量。大量无机磷以钙磷形态存在,因此该地区需要避免土壤酸化,防止钙磷转化为易溶磷。其次易溶态磷分布于整个土壤剖面,磷素可由土壤表层迁移至底层,造成壤中流磷含量增加,因此需要采取适当措施避免壤中流污染相关流域水体。
Other AbstractThis study is based on laboratory analysis and control experiments. According to the distribution characteristics of purple soil, typical acidic, neutral and calcareous purple soil profiles were chosen and collected as study samples. During the collecting of samples in the field, information on soil pedons and environment of cross-section were recorded. In the laboratory, indicators of soil pedons were analyzed, such as pH, CaCO3, organic matter, total nitrogen, total phosphorus, Olsen-P, iron oxides, soil texture. Though phosphorus adsorption and desorption experiments, characteristics of P adsorption and desorption of purple soil in different parent materials had been determined. After culture experiments with different phosphorus concentration, Phosphorus fractions of soil profile samples were analyzed using standard phosphorus fractionation method, by which to find out the distribution of various forms and transformation characteristics of phosphorus on purple soil profiles. On those bases, this study aimed to: Analyze the correlation of soil mineralogical and physicochemical properties and their effects on adsorption and desorption of phosphorus. Explore the mechanism of phosphorus adsorption and desorption of purple soil with iron oxides and associated physicochemical properties. Improve the research of soil mineralogy and control measurements of phosphorus pollution on purple soil. The main findings are as follows: (1)Physical and chemical properties of purple soil profiles Soil pH and calcium carbonate content were significantly positively correlated of calcareous purple, which had no significant correlation of neutral and acidic purple soil. Forest surface soils had the highest organic matter while farmland soils hadmore evenly distributed organic matter. Total nitrogen contents decreased with soil depth, higher in forestland than in farmland, and had a tendency of calcareous> neutral> acidic soils. Total phosphorus content was low in the middle of profile and higher in the surface and bottom. This was probably because some nutrients inherited directly from the rock for the purple soil as a rock soil. The reasons of higher phosphorus content in forestland surface were the release phosphorus of fertilizer and plant and animal residues. Overall, the purple soil had a high content of sand fraction, which confirmed the theory that purple soils are vulnerable to weathering and developed from parent materials in a short time. The mineralogy of the clay fractions in both pedons consisted predominantly of illite (40-50%) with smaller amounts (10-30%) of chlorite, kaolinite, quartz and goethite. Traces of illite-chlorite mixed layer were also found. Mineralogical study of the soil horizons showed little difference in the relative amount of clay minerals among the different sites of the calcareous purple soil, but the distribution of clay minerals indicated the characteristics of endodynamorphic soil and soil-forming process. Soils developed from purple rocks were mainly in their initial stage. Meanwhile, strenuous water loss and soil erosion caused by local terrain and climate suspend further development of purple soil, which was the external condition of clay mineral stabilization. (2) Purple Soil characteristics of phosphorus adsorption and desorption Compared to the neutral and calcareous soil, acidic soil had low maximum amount of phosphorus adsorption (Qm) and buffer capacity of adsorption, but high desorption capability of phosphorus. Purple soil parent material type (pH), soil texture and soil phosphorus content had a direct impact on phosphorus adsorption and desorption capabilities. With higher pH, clay content, purple soils held more phosphorus, and with higher total phosphorus and sand content, purple soil released more phosphorus. In the sampling area, purple soils generally had low organic matter content that had no significant effect on phosphorus adsorption and desorption capacity. (3) The main effective f
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/7996
Collection山地表生过程与生态调控重点实验室
Recommended Citation
GB/T 7714
肖懿. 典型紫色土剖面性质及其对磷素吸附-解吸的影响[D]. 北京. 中国科学院研究生院,2014.
Files in This Item:
File Name/Size DocType Version Access License
肖懿:典型紫色土剖面性质及其对磷素吸附-(2281KB)学位论文 开放获取CC BY-NC-SAView Application Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[肖懿]'s Articles
Baidu academic
Similar articles in Baidu academic
[肖懿]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[肖懿]'s Articles
Terms of Use
No data!
Social Bookmark/Share
File name: 肖懿:典型紫色土剖面性质及其对磷素吸附-解吸的影响.pdf
Format: Adobe PDF
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.