琼中黎母山-湾岭地区土壤硒、碘分布特征及其影响因素探讨

龚晶晶; 高健翁; 杨剑洲; 吴慧; 唐世新; 马生明

doi:10.19509/j.cnki.dzkq.2021.0625

琼中黎母山-湾岭地区土壤硒、碘分布特征及其影响因素探讨

doi: 10.19509/j.cnki.dzkq.2021.0625

龚晶晶^{1, 2,},
高健翁^{1, 2},
杨剑洲^{1, 2},
吴慧^{1, 2, ,},
唐世新^{1, 2},
马生明^{1, 2}

基金项目:

中国地质调查局地质调查项目 DD20190305

详细信息

作者简介:
龚晶晶(1989-), 男, 工程师, 主要从事生态地质研究工作。E-mail: gjingjing@cgs.gov.cn

通讯作者:
吴慧(1988-), 女, 工程师, 主要从事矿床地球化学研究工作。E-mail: wuhui@cgs.gov.cn

中图分类号: X53
计量
- 文章访问数: 684
- PDF下载量: 202
- 被引次数: 0
出版历程
- 收稿日期: 2021-01-05

Distribution and influencing factors of soil selenium and iodine in Limushan-Wanling, Qiongzhong area

Gong Jingjing^{1, 2
,},
Gao Jianweng^{1, 2},
Yang Jianzhou^{1, 2},
Wu Hui^{1, 2
, ,},
Tang Shixin^{1, 2},
Ma Shengming^{1, 2}

摘要

摘要: 琼中黎母山-湾岭地区位于海南岛中部，调查发现该地区土壤同时具有富硒、富碘的特征。以研究区表层（0~20 cm）、中层（80~100 cm）、深层（180~200 cm）土壤样品分析结果为基础，探讨了土壤硒、碘的分布特征及其影响因素。结果显示，表层土壤中Se、I质量分数具有高正相关性，并与高程为正相关关系，结合已有研究成果，推断在研究区范围内降雨作用是研究区表层土壤Se、I质量分数空间分布格局的关键影响因素。通过分析表层、中层、深层土壤Se、I质量分数与土壤pH值、总有机碳（TOC）、Al₂O₃、Fe₂O₃质量分数的相关关系和变化规律，总结了研究区Se、I在土壤垂向剖面上的赋存、迁移规律。这些结果可为当地优质土地资源的高效利用提供科学依据，也可为土壤Se来源、迁移研究提供新的证据。
- 琼中 /
- 土壤 /
- 硒 /
- 碘 /
- 降雨
Abstract: Qiongzhong Limushan-Wanling area is located in the middle of Hainan Island, where has an abundance of selenium-rich and iodine-rich soil resources.The distribution characteristics of Se and I contents were analyzed based on the analysis results of soil samples in the topsoil (0-20 cm), middle-layer-soil(80-100 cm), and deep-soil (180-200 cm) of the study area.The correlation characteristics of Se and I in soil and their relationship with elevation potentially indicate that the input of rainfall to soil Se and I is a key factor leading to the enrichment of Se and I.By analyzing the correlation and change law between the contents of Se, I and the contents of pH, soil organic matter, Al₂O₃ and Fe₂O₃ in top, middle and deep layer soil, the enrichment and migration of Se and I in the vertical section of soil in the study area was summarized.These results can provide scientific basis for the efficient use of local high-quality land resources and provide new evidence for the study of soil Se source and migration.
- Qiongzhong area /
- soil /
- Se /
- I /
- precipitation

HTML全文

图 1 研究区地质简图和采样点位置示意图

Figure 1. Geological skematic maps and sampling location

下载: 全尺寸图片幻灯片

图 2 琼中县平均降雨量图(a)和土壤发生类型图(b)

注: 海拔数据来源于国家科技基础条件平台—国家地球系统科学数据中心，土壤发生类型数据来源于《中华人民共和国多目标区域地球化学图集(海南岛)》

Figure 2. Maps of annual rainfall (a) and soil type (b) of Qiongzhong County

下载: 全尺寸图片幻灯片

图 3 研究区表层(a, b)-中层(c, d)-深层(e, f)土壤Se、I质量分数分布图

γπK.中白垩世花岗斑岩；ηγJ₃.晚侏罗世二长花岗岩；γδP₁.早二叠世花岗闪长岩；δK₁.早白垩世闪长岩；γδK₁.早白垩世黑云花岗闪长岩；ηγK₁.早白垩世二长花岗岩；ξγJ₃.晚侏罗世正长花岗岩；ηγT₂.中三叠世二长花岗岩；ξγT₂.中三叠世正长花岗岩；ηγP₂.中二叠世二长花岗岩；ξγP₂.中二叠世正长花岗岩；Pt₂g.戈枕村组黑云斜长片麻岩；Pt₂^1-2e.峨文岭组石英云母片岩；l.细晶岩脉

Figure 3. Se and I content distribution in the top (a, b), middle (c, d) and deep (e, f) soil of the study area

下载: 全尺寸图片幻灯片

图 4 不同成壤母岩形成的土壤Se、I平均质量分数柱状图(地质体代号同图 3)

Figure 4. Bar graph of soil selenium and iodine contents by different soil parent rocks

下载: 全尺寸图片幻灯片

图 5 不同深度土壤Se、I质量分数与高程散点图

r为皮尔逊相关系数；n为样品数量；p为皮尔逊相关显著性检验值

Figure 5. Scatter plots of soil selenium, iodine contents at different depths and elevation

下载: 全尺寸图片幻灯片

图 6 不同土壤类型不同深度土壤I-Se质量分数散点图

Figure 6. Scatter plots of soil Se and I contents at different depths in various soil types

下载: 全尺寸图片幻灯片

图 7 不同土壤类型不同深度土壤Se、I与pH值质量分数散点图

Figure 7. Scatter plots of soil Se, I contents and pH at different depths in various soil types

下载: 全尺寸图片幻灯片

图 8 不同土壤类型不同深度土壤Se、I质量分数与TOC质量分数散点图

Figure 8. Scatter plots of soil Se, I and TOC contents at different depths in various soil types

下载: 全尺寸图片幻灯片

图 9 不同土壤类型不同深度土壤Se、I质量分数与Fe₂O₃质量分数散点图

Figure 9. Scatter plots of soil Se, I and Fe₂O₃ contents at different depths in various soil types

下载: 全尺寸图片幻灯片

图 10 不同土壤类型不同深度土壤Se、I质量分数与土壤Al₂O₃质量分数散点图

Figure 10. Scatter plots of soil Se, I and Al₂O₃ contents at different depths in various soil types

下载: 全尺寸图片幻灯片

表 1 各指标分析方法及检出限

Table 1. Analytical methods and detection limits of various indicators

指标	分析方法	检出限	单位
Se	AFS	0.010 0	mg/kg
I	COL	0.350 0	mg/kg
pH	ISE	0.100 0	无量纲
TOC	VOL	0.030 0	%
Hg	AFS	0.000 5	mg/kg
Al₂O₃	XRF	0.050 0	%
Fe₂O₃	ICP-AES	0.050 0	%

下载: 导出CSV

表 2 研究区土壤Se、I丰缺划分界线及特征

Table 2. Abundance and deficiency demarcation value of soil selenium and iodine

全量w(Se)/ (mg·kg^-1)	硒效应	样品数(占比/%)			全量w(I)/ (mg·kg^-1)	碘效应	样品数(占比/%)
全量w(Se)/ (mg·kg^-1)	硒效应	表层	中层	深层	全量w(I)/ (mg·kg^-1)	碘效应	表层	中层	深层
< 0.125	硒不足	20(6.6)	57(18.8)	113(37.2)	< 1	碘不足	40(13.2)	67(22.0)	100(32.9)
[0.125, 0.175)	硒潜在不足	11(3.6)	37(12.2)	37(12.2)	[1, 1.5)	碘潜在不足	27(8.9)	23(7.6)	34(11.2)
[0.175, 0.4)	足硒	140(46.1)	127(41.8)	114(37.5)	[1.5, 5)	足碘	80(26.3)	106(34.9)	120(39.5)
[0.4, 3)	富硒	133(43.8)	83(27.3)	40(13.2)	[5, 100)	富碘	157(51.6)	108(35.5)	50(16.4)
≥3	硒中毒	0	0	0	≥100	碘中毒	0	0	0

下载: 导出CSV

表 3 不同成壤母岩形成的土壤Se、I平均质量分数

Table 3. Comparison of soil selenium and iodine contents by different soil parent rocks

地质体	数量/ 个	w(Se)/(mg·kg^-1)				w(I)/(mg·kg^-1)
地质体	数量/ 个	表层	中层	深层	表层/深层	表层	中层	深层	表层/深层
ξγT₂	18	0.39	0.27	0.18	2.17	5.61	4.04	2.67	2.10
ξγJ₃	22	0.37	0.30	0.21	1.78	5.65	4.93	3.34	1.69
ηγT₂	129	0.44	0.34	0.24	1.86	6.51	5.24	3.14	2.07
ηγP₂	30	0.40	0.30	0.21	1.89	5.92	4.15	2.67	2.21
ηγJ₃	23	0.35	0.23	0.18	1.89	5.28	3.57	3.26	1.62
γπK₂	10	0.50	0.27	0.22	2.23	6.05	2.68	2.06	2.93
δK₁	8	0.39	0.28	0.19	2.05	6.65	5.12	3.56	1.87
γδK₁	45	0.37	0.31	0.22	1.69	4.46	3.61	2.24	2.00
Pt₂g	9	0.41	0.43	0.26	1.58	6.03	6.52	3.58	1.60
注：地质体代号同图 1

下载: 导出CSV

表 4 不同土壤发生类型中Se、I质量分数与其他指标相关性

Table 4. Correlation between soil selenium, iodine contents and other indicators in various soil types

其他指标	砖红壤(n=274)						水稻土(n=30)
	表层		中层		深层		表层		中层		深层
	Se	I	Se	I	Se	I	Se	I	Se	I	Se	I
Se		0.855^**		0.781^**		0.720^**		0.647^**		-0.042		-0.052
I	0.855^**		0.781^**		0.720^**		0.647^**		-0.042		-0.052
pH	-0.556^**	-0.476^**	-0.448^**	-0.353^**	-0.404^**	-0.327^**	-0.362^*	-0.163	-0.281^*	0.235	-0.389^*	0.242
TOC	0.350^**	0.177^**	0.323^**	0.194^**	0.307^**	0.145^**	0.513^**	0.333^*	0.643^**	0.027	0.737^**	0.005
Fe₂O₃	0.281^**	0.330^**	0.176^**	0.369^**	0.172^**	0.420^**	0.491^**	0.411^*	0.327	0.244	0.074	0.247
Al₂O₃	0.470^**	0.480^**	0.329^**	0.432^**	0.302^**	0.436^**	0.410^*	0.346	0.017	0.203	-0.161	0.265
Hg	0.499^**	0.312^**	0.488^**	0.407^**	0.753^**	0.595^**	0.600^**	0.311	0.682^**	0.046	0.721^**	0.078
注：n为样品数量；*表示在0.01级别相关性显著；表示在0.05级别相关性显著；统计过程中，删除了表层砖红壤TOC离群数据点1个，删除了表层、中层砖红壤Hg离群数据点各4个

下载: 导出CSV

表 5 高程与土壤中Se、I、TOC质量分数以及pH值的相关性

Table 5. Correlation between elevation and soil selenium, iodine contents, TOC, pH

	高程-Se质量分数		高程-I质量分数		高程-TOC质量分数		高程-pH值
	相关系数	P	相关系数	P	相关系数	P	相关系数	P
表层	0.302	< 0.01	0.309	< 0.01	0.086	0.135	-0.146	0.011 < 0.05
中层	0.105	0.069	0.087	0.129	0.058	0.312	-0.116	0.043 < 0.05
深层	0.040	0.492	0.065	0.257	0.005	0.925	-0.134	0.020 < 0.05

下载: 导出CSV

表 6 不同类型岩石中Se的质量分数

Table 6. Selenium contents in various rock types

岩石	w(Se)/(mg·kg^-1)	数据来源
中国酸性岩	0.033	文献[23]
中国中性岩	0.058	文献[23]
中国东部片岩	0.100	文献[24]
中国东部斜长片麻岩	0.070	文献[24]
琼中县中酸性岩	0.060	(N=77，中位数，尚未发表数据)
琼中县变质岩	0.180	(N=5，中位数，尚未发表数据)

下载: 导出CSV

表 7 不同高程范围内样品土壤发生类型分布

Table 7. Distribution of soil types in various elevation ranges

高程/m		[50, 100]	(100, 150]	(150, 200]	(200, 250]	(250, 300]	(300, 350]	(350, 400]	(400, 450]
水稻土	数量/个	1	3	11	3	7	4	1	0
水稻土	占比/%	50.0	15.8	15.9	3.2	8.3	16.0	11.1	0.0
砖红壤	数量/个	1	16	58	91	77	21	8	2
砖红壤	占比/%	50.0	84.2	84.1	96.8	91.7	84.0	88.9	100.0

下载: 导出CSV

参考文献(51)

[1]	Fordyce F M, Guangdi Z, Green K, et al. Soil, grain and water chemistry in relation to human selenium-responsive diseases in Enshi District, China[J]. Applied Geochemistry, 2000, 15(1): 117-132. doi: 10.1016/S0883-2927(99)00035-9
[2]	Johnson C C, Fordyce F M, Rayman M P. Symposium on "geographical and geological influences on nutrition" factors controlling the distribution of selenium in the environment and their impact on health and nutrition[J]. Proc. Nutr. Soc., 2010, 69(1): 119-132. doi: 10.1017/S0029665109991807
[3]	Huang Y, Wang Q X, Gao J, et al. Daily dietary selenium intake in a high selenium area of Enshi, China[J]. Nutrients, 2013, 5(3): 700-710. doi: 10.3390/nu5030700
[4]	Dinh Q T, Cui Z W, Huang J, et al. Selenium distribution in the Chinese environment and its relationship with human health: A review[J]. Environment International, 2018, 112: 294-309. doi: 10.1016/j.envint.2017.12.035
[5]	Jones G D, Droz B, Greve P, et al. Selenium deficiency risk predicted to increase under future climate change[J]. Proceedings of the National Academy of Sciences, 2017, 114(11): 2848-2853. doi: 10.1073/pnas.1611576114
[6]	Liu H L, Wang X Q, Zhang B M, et al. Concentration and distribution of selenium in soils of mainland China, and implications for human health[J]. Journal of Geochemical Exploration, 2021, 220: 106654. doi: 10.1016/j.gexplo.2020.106654
[7]	周国华. 富硒土地资源研究进展与评价方法[J]. 岩矿测试, 2020, 39(3): 319-336. https://www.cnki.com.cn/Article/CJFDTOTAL-YKCS202003002.htm Zhou G H. Research progress of selenium-enriched land resources and evaluation methods[J]. Rock and Mineral Analysis, 2020, 39(3): 319-336(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-YKCS202003002.htm
[8]	Matos R P, Lima V M P, Windmöller C C, et al. Correlation between the natural levels of selenium and soil physicochemical characteristics from the Jequitinhonha Valley (MG), Brazil[J]. Journal of Geochemical Exploration, 2017, 172: 195-202. doi: 10.1016/j.gexplo.2016.11.001
[9]	Ni R X, Luo K L, Tian X L, et al. Distribution and geological sources of selenium in environmental materials in Taoyuan County, Hunan Province, China[J]. Environmental Geochemistry and Health, 2016, 38(3): 927-938. doi: 10.1007/s10653-015-9772-2
[10]	程湘, 李福林, 王成刚, 等. 鄂西地层硒的分布、富硒岩石成因及硒的来源[J]. 地质科技情报, 2019, 38(2): 45-52. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201902006.htm Cheng X, Li F L, Wang C G, et al. Distribution and source of selenium in western Hubei and the genesis of the rocks rich in selenium[J]. Geological Science and Technology Information, 2019, 38(2): 45-52(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201902006.htm
[11]	Lei W S, Cicchella D, Liu T, et al. Origin, distribution and enrichment of selenium in oasis farmland of Aksu, Xinjiang, China[J]. Journal of Geochemical Exploration, 2021: 106723.
[12]	Li M L, Yang B Y, Xu K Y, et al. Distribution of Se in the rocks, soil, water and crops in Enshi County, China[J]. Applied Geochemistry, 2020, 122: 104707. doi: 10.1016/j.apgeochem.2020.104707
[13]	陈锦平, 刘永贤, 曾成城, 等. 降雨对土壤硒迁移转化的影响研究进展[J]. 生态学杂志. 2019, 38(6): 1909-1915. https://www.cnki.com.cn/Article/CJFDTOTAL-STXZ201906035.htm Chen J P, Liu Y X, Zeng C C, et al. Research advances in the effects of rainfall on soil selenium migration and transformation[J]. Chinese Journal of Ecology, 2019, 38(6): 1909-1915(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-STXZ201906035.htm
[14]	Sun G X, Meharg A A, Li G, et al. Distribution of soil selenium in China is potentially controlled by deposition and volatilization?[J]. Scientific Reports, 2016, 6(1): 20953. doi: 10.1038/srep20953
[15]	田欢. 典型富硒区岩石-土壤-植物中硒的赋存状态及环境行为研究[D]. 武汉: 中国地质大学(武汉), 2017. Tian H. The occurrence state and speciation of selenium and its environmental behaviors in rock-soil-plant from typical high-Se areas[D]. Wuhan: China University of Geosciences(Wuhan), 2017(in Chinese with English abstract).
[16]	Yu T, Yang Z, Lü Y, et al. The origin and geochemical cycle of soil selenium in a Se-rich area of China[J]. Journal of Geochemical Exploration, 2014, 139: 97-108. doi: 10.1016/j.gexplo.2013.09.006
[17]	Blazina T, Sun Y, Voegelin A, et al. Terrestrial selenium distribution in China is potentially linked to monsoonal climate[J]. Nature Communications, 2014, 5(1): 4717. doi: 10.1038/ncomms5717
[18]	杨忠芳, 余涛, 侯青叶, 等. 海南岛农田土壤Se的地球化学特征[J]. 现代地质, 2012, 26(5): 837-849. doi: 10.3969/j.issn.1000-8527.2012.05.001 Yang Z F, Yu T, Hou Q Y, et al. Geochemical characteristics of soil selenium in farmland of Hainan Island[J]. Geoscience, 2012, 26(5): 837-849(in Chinese with English abstract). doi: 10.3969/j.issn.1000-8527.2012.05.001
[19]	傅杨荣. 海南岛土壤地球化学与优质农业研究[D]. 武汉: 中国地质大学(武汉), 2014. Fu Y R. Studies on soil geochemistry and high-quality agriculture in Hainan Island[D]. Wuhan: China University of Geosciences(Wuhan), 2014(in Chinese with English abstract).
[20]	张黎明, 魏志远, 漆智平. 近30年海南不同地区降雨量和蒸发量分布特征研究[J]. 中国农学通报, 2006, 22(4): 403-407. doi: 10.3969/j.issn.1000-6850.2006.04.108 Zhang L M, Wei Z Y, Qi Z P. Characteristics of rainfall and evaporation of different region in recent 30 years in Hainan Province[J]. Chinese Agricultural Science Bulletin, 2006, 22(4): 403-407(in Chinese with English abstract). doi: 10.3969/j.issn.1000-6850.2006.04.108
[21]	谭见安. 中华人民共和国地方病与环境图集[M]. 北京: 科学出版社, 1989. Tan J A. The atlas of endemic diseases and their environment in the People's Republic of China[M]. Beijing: Science Press, 1989(in Chinese).
[22]	中国环境监测总站. 中国土壤元素背景值[M]. 北京: 中国环境科学出版社, 1990. China National Environmental Monitoring Centre. Background values of soil elements in China[M]. Beijing: China Environmental Press, 1990(in Chinese).
[23]	迟清华, 鄢明才. 应用地球化学元素丰度数据手册[M]. 北京: 地质出版社, 2007. Chi Q H, Yan M C. Handbook of elemental abundance for applied geochemistry[M]. Beijing: Geological Publishing House, 2007(in Chinese).
[24]	鄢明才, 迟清华. 中国东部地壳与岩石的化学组成[M]. 北京: 科学出版社, 1997. Yan M C, Chi Q H. The chemical compositions of crust and rocks in the eastern part of China[M]. Beijing: Science Press, 1997(in Chinese).
[25]	郭跃品, 杨奕, 张固城, 等. 海南省土地质量地球化学评估[R]. 海口: 海南省地质调查院, 2011. Guo Y P, Yang Y, Zhang G C, et al. Geochemical assessment of land quality in Hainan Province[R]. Haikou: Hainan Geological Survey, 2011(in Chinese).
[26]	Whitehead D C. The distribution and transformations of iodine in the environment[J]. Environment International, 1984, 10(4): 321-339. doi: 10.1016/0160-4120(84)90139-9
[27]	Johanson K J. Iodine in soil[J]. Technical Report, 2000, 1(21): 42-48.
[28]	朱发庆, 谭见安. 我国降水、降尘中硒、碘、氟的研究[J]. 环境科学学报, 1988, 8(4): 428-437. https://www.cnki.com.cn/Article/CJFDTOTAL-HJXX198804005.htm Zhu F Q, Tan J A. Selenium, iodine and fluorine in rainwater and dustfall in China[J]. Acta Scientiae Circumstantiae, 1988, 8(4): 428-437(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-HJXX198804005.htm
[29]	Wen H J, Carignan J. Reviews on atmospheric selenium: Emissions, speciation and fate[J]. Atmospheric Environment, 2007, 41(34): 7151-7165. doi: 10.1016/j.atmosenv.2007.07.035
[30]	Blazina T, Läderach A, Jones G D, et al. Marine primary productivity as a potential indirect source of selenium and other trace elements in atmospheric deposition[J]. Environmental Science & Technology, 2016, 51(1): 108-118. http://www.ncbi.nlm.nih.gov/pubmed/27959548
[31]	Suess E, Aemisegger F, Sonke J E, et al. Marine versus continental sources of iodine and selenium in rainfall at two european high-altitude locations[J]. Environmental Science & Technology, 2019, 53(4): 1905-1917. http://www.onacademic.com/detail/journal_1000041599120999_b7c1.html
[32]	温新平, 陈永祥, 王三祥, 等. 山西省水土含硒量及大骨节病区的海拔分布[J]. 广东微量元素科学, 1996, 3(2): 61-64. https://www.cnki.com.cn/Article/CJFDTOTAL-GWYS602.017.htm Wen X P, Chen Y X, Wang S X, et al. Selenium content in water, soil of Shanxi Province and effects of sea-level elevation on Kaschin-Beck disease endemic areas[J]. Guangdong Trace Elements Science, 1996, 3(2): 61-64(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-GWYS602.017.htm
[33]	张晓平, 张玉霞. 西藏土壤中硒的含量及分布[J]. 土壤学报, 2000, 37(4): 558-562. doi: 10.3321/j.issn:0564-3929.2000.04.018 Zhang X P, Zhang Y X. Content and distribution of selenium in soils of Tibet[J]. Acta Pedologica Sinica, 2000, 37(4): 558-562(in Chinese with English abstract). doi: 10.3321/j.issn:0564-3929.2000.04.018
[34]	章海波, 骆永明, 吴龙华, 等. 香港土壤研究: Ⅱ. 土壤硒的含量、分布及其影响因素[J]. 土壤学报, 2005, 42(3): 404-410. doi: 10.3321/j.issn:0564-3929.2005.03.009 Zhang H B, Luo Y M, Wu L H, et al. Hong Kong soil researches: Ⅱ. Distribution and content of selenium in soils[J]. Acta Pedologica Sinica, 2005, 42(3): 404-410(in Chinese with English abstract). doi: 10.3321/j.issn:0564-3929.2005.03.009
[35]	王晓杰, 孟凡乔, 吴文良. 内蒙古武川县土壤硒分布特性研究[J]. 土壤通报, 2016, 47(3): 624-629. https://www.cnki.com.cn/Article/CJFDTOTAL-TRTB201603018.htm Wang X J, Meng F Q, Wu W L. Distribution patterns of soil Se in Wuchuan County, Inner Mongolia, China[J]. Chinese Journal of Soil Science, 2016, 47(3): 624-629(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-TRTB201603018.htm
[36]	Xu Y F, Li Y H, Li H R, et al. Effects of topography and soil properties on soil selenium distribution and bioavailability (phosphate extraction): A case study in Yongjia County, China[J]. Science of the Total Environment, 2018, 633: 240-248. doi: 10.1016/j.scitotenv.2018.03.190
[37]	邵亚. 桂林富硒长寿区小流域地理环境中硒分布特征、控制因素及其生态效应[D]. 武汉: 华中农业大学, 2019. Shao Y. Distribution characteristics, controlling factors and ecological effects of Se in the geographical environment of small watershed in Guilin Se-enriched longevity area[D]. Wuhan: Huazhong Agricultural University, 2019(in Chinese with English abstract).
[38]	廖金凤. 海南岛生态环境中的硒[J]. 中山大学学报: 自然科学版, 1992, 31(3): 110-116. doi: 10.3321/j.issn:0529-6579.1992.03.001 Liao J F. Selenium in the ecological environment of Hainan Island[J]. Acta Scientiarum Naturalium Universitatis Sunyatseni, 1992, 31(3): 110-116(in Chinese with English abstract). doi: 10.3321/j.issn:0529-6579.1992.03.001
[39]	傅抱璞. 地形和海拔高度对降水的影响[J]. 地理学报, 1992, 47(4): 302-314. doi: 10.3321/j.issn:0375-5444.1992.04.003 Fu B P. The effects of topography and elevation on precipitation[J]. Acta Geographica Sinica, 1992, 47(4): 302-314(in Chinese with English abstract). doi: 10.3321/j.issn:0375-5444.1992.04.003
[40]	Germann U, Joss J. Spatial continuity of alpine precipitation[J]. Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere, 2000, 25(10): 903-908. http://www.sciencedirect.com/science?_ob=ShoppingCartURL&_method=add&_eid=1-s2.0-S1464190900001234&originContentFamily=serial&_origin=article&_ts=1414134409&md5=e4a928332576c1ebe0b82c5aeb6fa2f3
[41]	Sevruk B, Nevenic M. The geography and topography effects on the areal pattern of precipitation in a small prealpine basin[J]. Water Science and Technology, 1998, 37(11): 163-170. http://www.sciencedirect.com/science/article/pii/S0273122398003291
[42]	丁昌璞, 保学明, 潘淑贞, 等. 土壤氧化还原状况的空间分异和特征[J]. 土壤学报, 1993, 30(3): 289-296. https://www.cnki.com.cn/Article/CJFDTOTAL-TRXB199303007.htm Ding C P, Bao X M, Pan S Z, et al. Spatial variation and characteristics of oxidation-reduction regime in soils[J]. Acta Pedologica Sinica, 1993, 30(3): 289-296(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-TRXB199303007.htm
[43]	丁昌璞. 中国自然土壤、旱作土壤、水稻土的氧化还原状况和特点[J]. 土壤学报, 2008, 45(1): 66-75. doi: 10.3321/j.issn:0564-3929.2008.01.009 Ding C P. Oxidation-reduction regimes and characteristics of natural soil, upland soil and paddy soil in China[J]. Acta Pedologica Sinica, 2008, 45(1): 66-75(in Chinese with English abstract). doi: 10.3321/j.issn:0564-3929.2008.01.009
[44]	Fordyce F M. Selenium deficiency and toxicity in the environment[M]. Dordrecht: Springer Netherlands, 2012.
[45]	Yuita K. Dynamics of iodine, bromine, and chlorine in soil: Ⅱ. Chemical forms of iodine in soil solutions[J]. Soil Science and Plant Nutrition, 1992, 38(2): 281-287. doi: 10.1080/00380768.1992.10416491
[46]	武少兴, 龚子同, 黄标. 土壤中的碘与人类健康[J]. 土壤通报, 1998, 29(3): 44-47. https://www.cnki.com.cn/Article/CJFDTOTAL-TRTB803.015.htm Wu S X, Gong Z T, Huang B. Iodine in the soil and human health[J]. Chinese Journal of Soil Science, 1998, 29(3): 44-47(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-TRTB803.015.htm
[47]	Whitehead D C. The sorption of iodide by soil components[J]. Journal of the Science of Food and Agriculture, 1974, 25(1): 73-79. doi: 10.1002/jsfa.2740250109
[48]	Dai J L, Zhang M, Zhu Y G. Adsorption and desorption of iodine by various Chinese soils[J]. Environment International, 2004, 30(4): 525-530. doi: 10.1016/j.envint.2003.10.007
[49]	付中彪, 何宁洁, 鲍征宇, 等. 赣南地区水稻-根系土系统中硒含量影响因素分析[J]. 地质科技情报, 2019, 38(5): 220-229. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201905024.htm Fu Z B, He N J, Bao Z Y, et al. Analysis of influencing factors of selenium content in rice-root soil system in southern Jiangxi[J]. Geological Science and Technology Information, 2019, 38(5): 220-229(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201905024.htm
[50]	Liu Y L, Tian X L, Liu R, et al. Key driving factors of selenium-enriched soil in the low-Se geological belt: A case study in Red Beds of Sichuan Basin, China[J]. Catena, 2021, 196: 104926. doi: 10.1016/j.catena.2020.104926
[51]	Fordyce F. Selenium geochemistry and health[J]. Ambio., 2007, 36(1): 94-97. doi: 10.1579/0044-7447(2007)36[94:SGAH]2.0.CO;2