Influence of straw mulching on the measurement result of farmland soil magnetic susceptibility
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摘要:目的
土壤磁化率是环境污染监测领域的常用参数，一般在裸土表面测量。农田土壤通常覆盖有作物秸秆，本文主要研究作物秸秆覆盖对农田土壤磁化率测量的影响。
方法在水稻田、甘蔗地1、甘蔗地2和玉米地4块试验田分别设置测量点并人为均匀叠加秸秆，测量不同秸秆材质和覆盖厚度下农田土壤磁化率，分析秸秆覆盖对农田土壤磁化率测量的影响。
结果随秸秆覆盖厚度的增加土壤磁化率不断减小，当厚度在0~5 cm时，磁化率测量值迅速衰减，但其值可在一定程度上反映裸土磁化率；当厚度超过6 cm时，磁化率测量值衰减趋缓；当超过10 cm时，磁化率测量值趋于0。试验中大部分测量点数据可用指数模型拟合，少数测量点用线性模型拟合。分别整合水稻田、甘蔗地1、甘蔗地2和玉米地所有测量点的数据，土壤磁化率与秸秆覆盖厚度之间分别表现为指数、指数、指数和线性负相关。不同秸秆覆盖厚度所对应的检测距离是造成土壤磁化率测量值衰减的主要因素，秸秆本身材质对测量值影响很小。
结论利用MS2D型磁化率仪测量农田土壤磁化率时，最好直接对裸土进行测量，如果有秸秆覆盖，覆盖厚度不宜超过5 cm。秸秆覆盖厚度对土壤磁化率测量值的影响可用指数或线性负相关函数模型表征。
Abstract:ObjectiveThe soil magnetic susceptibility is a common parameter for monitoring environmental pollution, and usually measured on the surface of bare soil. The farmland soil is often covered with crop straw, and this paper mainly studies the influence of straw mulching on farmland soil magnetic susceptibility measurement.
MethodThe measuring points were set in paddy field, sugarcane field 1, sugarcane field 2 and corn field respectively, and piled up with straws artificially and evenly. The soil magnetic susceptibility values were measured under different straw materials and straw mulching thicknesses to analyze the influence of straw mulching on farmland soil magnetic susceptibility measurement.
ResultThe soil magnetic susceptibilities decreased constantly with the increase of straw mulching thickness. When the thicknesses ranged from 0 to 5 cm, soil magnetic susceptibilities attenuated rapidly, but the values could reflect the magnetic susceptibility of bare soil to a certain extent. When the thicknesses exceeded 6 cm, soil magnetic susceptibilities attenuated slowly and when the thicknesses exceeded 10 cm, soil magnetic susceptibilities tended to zero. The test data of most measuring points were fitted with index model, while that of a few points were fitted with linear model. Data of all measuring points in paddy field, sugarcane field 1, sugarcane field 2 and corn field were respectively integrated, and the relationships between soil magnetic susceptibility and straw mulching thickness in above fields were characterized by index, index, index and linear negative correlations. The corresponding detection distances of different straw mulching thicknesses were the main factors causing the attenuation of soil magnetization susceptibilities, and the influences of straw materials on the measured value were very small.
ConclusionWhen measuring soil magnetic susceptibility with MS2D magnetic susceptibility meter, it is best to measure bare soil directly. If there is straw mulching, the mulching thickness should not exceed 5 cm. The influence of straw mulching thickness on soil magnetic susceptibility can be characterized by index function or linear negative correction model.
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Keywords:
- farmland /
- soil magnetic susceptibility /
- straw mulching thickness /
- fitting model
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图 1 试验田位置及测量点分布
Figure 1. Experimental field locations and the distributions of measuring points
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图 3 试验仪器装置实物图
1：MS2D探测手柄；2：MS2D探测线圈；3：MS3读数模块；4：PC机；5：TSC2控制手簿；6：Zephyr流动站天线；7：5700 GPS接收机；8：GPS通讯数据链模块；9：GPRS天线；10：12 V蓄电池
Figure 3. The picture of experimental apparatus
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图 4 不同试验田不同秸秆覆盖厚度下土壤磁化率平均值及标准偏差
Figure 4. The soil magnetic susceptibility mean values and their standard deviations of different experimental fields and straw mulching thicknesses
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图 5 各农田土壤磁化率–秸秆覆盖厚度关系图
“**”表示相关性极显著(P<0.01)；x：秸秆覆盖厚度，cm；y：土壤磁化率
Figure 5. The relationship between soil magnetic susceptibility and straw mulching thickness in each experimental field
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图 6 拟合模型的校正与检验
“**”表示相关性极显著(P<0.01)；rc、rv：分别为校正、检验模型的相关性系数；RMSEC：、RMSEV：分别为校正、检验模型的均方根误差
Figure 6. Calibration and validation of the fitting model
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[1] THOMPSON R, OLDFIELD F. Environmental magnetism[M]. London: Allen and Unwin, 1986: 1-227.
[2] OLDFIELD F. Environmental magnetism: A personal perspective[J]. Quat Sci Rev, 1991, 10(1): 73-85.
[3] LIU Q, ROBERTS A P, LARRASOANA J C, et al. Environmental magnetism: Principles and applications[J]. Rev Geophys, 2012, 50(4). doi: 10.1029/2012RG000393
[4] 刘青松, 邓成龙. 磁化率及其环境意义[J]. 地球物理学报, 2009, 52(4): 1041-1048. [5] 张春霞, 黄宝春. 环境磁学在城市环境污染监测中的应用和进展[J]. 地球物理学进展, 2005, 20(3): 705-711. [6] 段雪梅, 胡守云, 闫海涛, 等. 南京某钢铁公司周边耕作土壤的磁学性质与重金属污染的相关性研究[J]. 中国科学(D辑: 地球科学), 2009, 39(9): 1304-1312. [7] HANESCH M, SCHOLGER R. Mapping of heavy metal loadings in soils by means of magnetic susceptibility measurements[J]. Environ Geol, 2002, 42(8): 857-870.
[8] 陈轶楠, 张永清, 张希云, 等. 晋南某钢厂周边土壤重金属与磁化率分布规律及其相关性研究[J]. 干旱区资源与环境, 2014, 28(1): 85-91. [9] 旺罗, 刘东生, 吕厚远. 污染土壤的磁化率特征[J]. 科学通报, 2000, 45(10): 1091-1094. [10] HAY K L, DEARING J A, BABAN S M J, et al. A preliminary attempt to identify atmospherically-derived pollution particles in English topsoils from magnetic susceptibility measurements[J]. Phys Chem Earth, 1997, 22(1/2): 207-210.
[11] 卢瑛, 龚子同, 张甘霖. 城市土壤磁化率特征及其环境意义[J]. 华南农业大学学报, 2001, 22(4): 26-28. [12] 赵庆磊, 李凤全, 王天阳, 等. 金华城区表层土壤剖面磁化率变化规律[J]. 水土保持研究, 2015, 22(2): 340-344. [13] 闫倩, 戴霜, 刘海娇, 等. 兰州某钢厂附近土壤磁化率特征及其环境意义[J]. 中国环境科学, 2011, 31(10): 1732-1737. [14] STRZYSZCZ Z, MAGIERA T. Magnetic susceptibility and heavy metals contamination in soils of Southern Poland[J]. Phys Chem Earth, 1998, 23(9/10): 1127-1131.
[15] STRZYSZCZ Z, MAGIERA T. Record of industrial pollution in Polish ombrotrophic peat bogs[J]. Phys Chem Earth A, 2001, 26(11/12): 859-866.
[16] 周鸿斌, 角媛梅, 史正涛, 等. 云南沘江沿岸农田土壤磁测分析与重金属污染评价[J]. 农业环境科学学报, 2008, 27(4): 1586-1591. [17] 李晓庆, 胡雪峰, 孙为民, 等. 城市土壤污染的磁学监测研究[J]. 土壤, 2006, 38(1): 66-74. [18] 陈秀玲, 李志忠, 姜修洋, 等. 福州盆地不同土地利用方式下土壤磁化率特征[J]. 福建师范大学学报 (自然科学版), 2012, 28(3): 87-93. [19] 欧阳婷萍, 万洪富, 张金兰, 等. 珠江三角洲农业土壤磁化率空间分布特征及其影响因素分析[J]. 第四纪研究, 2012, 32(6): 1199-1206. [20] 吴丹, 欧阳婷萍, 匡耀求, 等. 佛山农业表层土壤磁化率特征及其与重金属含量的关系[J]. 生态环境学报, 2014, 23(11): 1826-1831. [21] BAGHDAD M E, JAKANI K, BARAKAT A, et al. Magnetic susceptibility and heavy metal contamination in agricultural soil of Tadla plain[J]. J Mater Environ Sci, 2011, 2(S1): 513-519.
[22] 黄倩. 秸秆覆盖对农田土壤磁化率影响的研究[D]. 广州: 华南农业大学, 2016. [23] BOYKO T, SCHOLGER R, STANJEK H. Topsoil magnetic susceptibility mapping as a tool for pollution monitoring: Repeatability of in situ measurements[J]. J Appl Geophy, 2004, 55(3/4): 249-259.
[24] 王颉. 试验设计与SPSS应用[M]. 北京: 化学工业出版社, 2006. [25] DEARING J A. Environmental magnetic susceptibility: Using the Bartington MS2 system[M]. Kenilworth: Chi Publishing, 1994.
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