Availability of Phosphorus Associated with Soil Humic Substance
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摘要: 以棕色针叶林土、暗棕壤和黄棕壤为供试土壤,采用常规的碱(0.1 mol L−1 NaOH + 0.1 mol L−1 Na4P2O7)提取液酸化法分离出胡敏酸(HA),碱不溶性的粗胡敏素(CHU)再经10%HF-HCl处理得到去除矿质灰分后纯化的胡敏素(PHU);利用酶水解和紫外照射方法,分析了上述各腐殖物质组分结合态磷素的有效性。结果表明:供试腐殖物质组分中磷含量以HA最高,其次为PHU,而CHU最低;HA、CHU和PHU中分别有32.1% ~ 51.7%、17.2% ~ 28.5%和22.3% ~ 35.7%的磷是以活性无机磷的形式存在,而29.5% ~ 37.6%、20.6% ~ 31.1%和26.2% ~ 41.5%的磷是以活性有机磷的形式存在;活性有机磷中,类植酸态磷的比例(9.51% ~ 27.6%)最高,其次为简单单酯磷(5.89% ~ 13.7%),而多核苷酸磷的比例(1.03% ~ 9.28%)最低;与未经紫外照射的样品相比,紫外照射合并酶水解使HA、CHU和PHU中活性磷的比例分别增加了0.90% ~ 3.77%、0.73% ~ 7.57%和0.69% ~ 3.91%;几种腐殖物质组分中,总活性磷的顺序为HA > PHU > CHU,而惰性磷的顺序则与之相反;总活性磷与Al含量呈显著负相关,而惰性磷则与Al含量呈显著正相关。上述结果说明,不同腐殖物质组分结合态磷素的有效性不同,其中HA结合态磷素的有效性最高,其次为PHU,而CHU结合态磷素的有效性最低,Al的存在能够抑制腐殖物质组分结合态磷素的有效性。Abstract: In this study, humic substance fractions were extracted from Brown coniferous forest soil, Dark Brown soil, and Yellow Brown soil. Humic acid (HA) was separated by acidification using a conventional method of alkali (0.1 mol L−1 NaOH + 0.1 mol L−1 Na4P2O7) extraction procedure. Alkali-insoluble crude humin (CHU) was treated with 10% HF-HCl to obtain pure humin (PHU) through removal of mineral ash. The availability of humic substance fractions-bound phosphorus (P) was analyzed using the methods of enzymatic hydrolysis and ultraviolet irradiation. The results showed that the content of P in the tested humic substance components was the highest in HA, followed by PHU, and the lowest in CHU. About 32.1%-51.7%, 17.2%-28.5% and 22.3%-35.7% of HA, CHU and PHU -bound P were in the form of labile inorganic P, while 29.5%-37.6%, 20.6%-31.1% and 26.2 %-41.5% of them was in the form of labile organic P. In the labile organic P, phytate-like P displayed the highest proportion (9.51%-27.6%), followed by simple monoester P (5.89%-13.7%), and the proportion of polynucleotide P (1.03%-9.28%) was the lowest. Compared with samples without UV irradiation, UV irradiation combined with enzymatic hydrolysis increased the proportion of labile P in the HA, CHU, and PHU fractions by 0.90%-3.77%, 0.73%-7.57%, and 0.69%-3.91%, respectively. The content of total labile P in the humic substance components decreased in the order of HA > PHU > CHU, while the opposite order was found in the content of recalcitrant P. Total labile P was significantly negatively correlated with Al content, while recalcitrant P was significantly positively correlated with Al content. The availability of HA-bound P was the highest, followed by that of PHU-bound P, and that of CHU-bound P was the lowest. The existence of Al can inhibit the availability of humic substance -bound P.
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Key words:
- Humic acid /
- Humin /
- Phosphorus availability /
- Enzymatic hydrolysis /
- Ultraviolet irradiation
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图 1 酶水解对土壤腐殖物质组分正磷酸盐释放量的影响
HA:胡敏酸;CHU:未经纯化的粗胡敏素;PHU:经纯化的胡敏素;P-e表示未添加酶,P + e表示添加酸性磷酸酶,P + 2e表示添加酸性磷酸酶和植酸酶,P + 3e表示添加酸性磷酸酶、植酸酶和核酸酶P1;不同的大写字母表示相同腐殖物质组分不同酶处理之间差异显著(P < 0.05),小写字母表示相同酶处理不同腐殖物质组分之间差异显著(P < 0.05);a:棕色针叶林土;b:暗棕壤;c:黄棕壤
Figure 1. Effect of enzyme hydrolysis on orthophosphate released from soil humic substance fractions
图 2 紫外照射合并酶水解对土壤腐殖物质组分正磷酸盐释放量的影响
HA:胡敏酸;CHU:未经纯化的粗胡敏素;PHU:经纯化的胡敏素;P-e表示未添加酶,P + e表示添加酸性磷酸酶,P + 2e表示添加酸性磷酸酶和植酸酶,P + 3e表示添加酸性磷酸酶、植酸酶和核酸酶P1;不同的大写字母表示相同腐殖物质组分不同酶处理之间差异显著(P < 0.05),小写字母表示相同酶处理不同腐殖物质组分之间差异显著(P < 0.05);a:棕色针叶林土;b:暗棕壤;c:黄棕壤。
Figure 2. Effect of ultraviolet irradiation combined with enzyme hydrolysis on orthophosphate released from soil humic substance fractions
表 1 供试土壤的基本理化性质
Table 1. Basic physical and chemical properties of the studied soils
土壤
SoilpH 有机碳
Organic carbon
(g kg−1)全氮
Total nitrogen
(g kg−1)全磷
Total phosphorus
(g kg−1)机械组成(%)
Mechanical composition2 ~ 0.2 mm 0.2 ~ 0.02 mm 0.02 ~ 0.002 mm < 0.002 mm 棕色针叶林土 5.11 ± 0.05 c 18.7 ± 1.36 b 1.17 ± 0.02 b 0.66 ± 0.05 b 17.4 ± 0.15 a 46.7 ± 2.25 a 23.5 ± 2.52 c 12.2 ± 0.15 c 暗棕壤 5.84 ± 0.24 b 52.8 ± 6.64 a 4.01 ± 0.91 a 1.07 ± 0.13 a 5.14 ± 1.92 b 33.3 ± 1.29 b 34.7 ± 0.46 b 24.6 ± 1.69 b 黄棕壤 6.58 ± 0.03 a 14.3 ± 0.11 b 1.41 ± 0.01 b 0.47 ± 0.03 c 1.65 ± 0.43 c 30.0 ± 0.14 c 38.2 ± 0.39 a 29.9 ± 0.22 a 表 2 土壤腐殖物质组分的元素含量(g kg–1)
Table 2. Contents of elements in soil humus
样品
SampleP Ca Al Fe Mg Zn Mn 棕色针 HA 1.00 ± 0.03 a 1.27 ± 0.03 c 0.19 ± 0.04 e 0.28 ± 0.02 e 0.13 ± 0.01 d 0.04 ± 0.00 b 0.01 ± 0.00 b 叶林土 CHU 0.09 ± 0.04 d 0.37 ± 0.01 f 1.21 ± 0.03 c 0.65 ± 0.11 c 0.09 ± 0.00 e 0.03 ± 0.00 c < 0.01 d PHU 0.16 ± 0.03 d 0.87 ± 0.00 d 0.18 ± 0.01 e 0.09 ± 0.01 f 0.06 ± 0.00 f 0.01 ± 0.00 f < 0.01 e 暗棕壤 HA 0.94 ± 0.04 a 0.68 ± 0.02 e 0.08 ± 0.00 f 0.47 ± 0.01 d 0.07 ± 0.00 f 0.04 ± 0.00 b 0.01 ± 0.00 c CHU 0.11 ± 0.06 d 0.23 ± 0.01 h 1.90 ± 0.00 b 1.06 ± 0.01 a 0.20 ± 0.00 a 0.02 ± 0.00 d 0.01 ± 0.00 b PHU 0.13 ± 0.04 d 0.35 ± 0.01 fg 0.05 ± 0.01 f 0.06 ± 0.00 f 0.03 ± 0.00 g 0.01 ± 0.00 g < 0.01 f 黄棕壤 HA 0.81 ± 0.04 b 1.95 ± 0.05 a 0.26 ± 0.01 d 0.54 ± 0.01 cd 0.17 ± 0.00 b 0.05 ± 0.00 a 0.01 ± 0.00 a CHU 0.11 ± 0.02 d 0.31 ± 0.01 g 1.99 ± 0.05 a 0.95 ± 0.02 b 0.14 ± 0.00 c 0.01 ± 0.00 e 0.01 ± 0.00 c PHU 0.22 ± 0.03 c 1.65 ± 0.07 b 0.19 ± 0.01 e 0.22 ± 0.14 e 0.09 ± 0.01 e 0.01 ± 0.00 fe 0.01 ± 0.00 c 注:HA:胡敏酸;CHU:未经纯化的粗胡敏素;PHU:经纯化的胡敏素;同一列内不同小写字母表示腐殖物质组分之间差异显著(P < 0.05)。 表 3 土壤腐殖物质组分中不同形态磷素的相对比例(%)
Table 3. Relative proportions(%)of different forms of phosphorus in soil humic substance fractions
磷形态
Phosphorus form棕色针叶林土
Brown coniferous forest soil暗棕壤
Dark brown soil黄棕壤
Yellow brown soilHA CHU PHU HA CHU PHU HA CHU PHU 活性无机磷 51.7 a 21.1 e 22.8 e 51.2 a 17.2 f 22.3 e 32.1 c 28.5 d 35.7 b 酶解活性有机磷 31.6 bc 31.1 bc 41.5 a 37.6 ab 22.2 cd 31.2 bc 29.5 bcd 20.6 d 26.2 cd 简单单酯磷 10.9 11.4 13.7 5.89 7.25 10.3 8.96 7.72 9.26 类植酸态磷 15.5 12.4 21.5 27.6 9.51 11.7 13.2 11.8 14.4 多核苷酸磷 5.18 7.25 6.35 4.08 5.44 9.28 7.38 1.03 2.57 紫外活性磷⑥ 0.90 a 0.73 a 3.91 a 0.94 a 7.57 a 1.46 a 3.77 a 1.88 a 0.69 a 紫外活性无机磷 3.17 1.04 0.97 1.02 3.17 2.44 2.17 1.89 1.35 紫外活性有机磷 −2.27 −0.31 2.93 −0.08 4.40 −0.98 1.60 −0.01 −0.67 总活性磷 84.2 a 52.9 cd 68.2 b 89.8 a 47.0 e 55.0 bcd 65.4 bc 49.4 de 62.7 bcd 惰性磷 15.8 d 47.1 ab 31.8 c 10.2 d 53.0 a 45.0 b 34.6 c 49.0 ab 37.3 c 注:HA:胡敏酸;CHU:未经纯化的粗胡敏素;PHU:经纯化的胡敏素;同一行内不同小写字母表示腐殖物质组分之间差异显著(P < 0.05)。 表 4 土壤腐殖物质组分中不同形态磷素相对比例与其元素含量之间的相关系数
Table 4. Pearson correlation coefficients between relative proportions of different forms of phosphorus and elemental contents in humic substance fractions
磷形态
Phosphorus formP Ca Mg Al Fe Mn Zn 活性无机磷 0.872** 0.450 −0.081 −0.496 −0.264 0.550 0.545 酶解活性有机磷 0.336 0.144 −0.667* −0.722* −0.684* −0.496 0.209 简单单酯磷 −0.257 0.128 −0.414 −0.319 −0.589 −0.728* −0.233 类植酸态磷 0.506 0.130 −0.477 −0.548 −0.390 0.012 0.242 多核苷酸磷 −0.015 −0.027 −0.300 −0.379 −0.380 −0.655 −0.218 紫外活性磷 −0.242 −0.157 0.606 0.436 0.480 0.129 −0.066 紫外活性无机磷 0.170 −0.023 0.561 0.223 0.251 0.364 0.144 紫外活性有机磷 −0.338 −0.163 0.430 0.386 0.423 −0.012 −0.133 总活性磷 0.863** 0.434 −0.283 −0.700* −0.474 0.257 0.558 惰性磷 −0.864** −0.428 0.277 0.686* 0.462 −0.269 −0.552 注:n = 9,*P < 0.05,**P < 0.01。 -
[1] 陈成荣, 唐才贤, 胡红青. 土壤磷有效性//“10000个科学难题”农业科学编委会. 10000个科学难题-农业科学卷[M]. 北京: 科学出版社, 2001, 321–324. [2] Weihrauch C, Opp C. Ecologically relevant phosphorus pools in soils and their dynamics: the story so far[J]. Geoderma, 2018, 325: 183 − 194. doi: 10.1016/j.geoderma.2018.02.047 [3] Zhang W, Tang X, Feng X, et al. Management strategies to optimize soil phosphorus utilization and alleviate environmental risk in China[J]. Journal of Environmental Quality, 2019, 48: 1167 − 1175. doi: 10.2134/jeq2019.02.0054 [4] Dodd R J, Sharpley A N. Recognizing the role of soil organic phosphorus in soil fertility and water quality[J]. Resources, Conservation and Recycling, 2015, 105: 282 − 293. doi: 10.1016/j.resconrec.2015.10.001 [5] Cade-menun B J. Characterizing phosphorus forms in cropland soils with solution 31P-NMR: past studies and future research needs[J]. Chemical and Biological Technologies in Agriculture, 2017, 4: 19. doi: 10.1186/s40538-017-0098-4 [6] 徐明岗, 张文菊, 黄绍敏, 等. 中国土壤肥力演变(第二版)[M]. 北京: 中国农业科学技术出版社, 2015. [7] Haygarth P M, Hinsinger P, Blackburn D. Organic phosphorus: potential solutions for phosphorus security[J]. Plant and Soil, 2018, 427: 1 − 3. doi: 10.1007/s11104-018-3675-9 [8] Huang L, Jia X, Zhang G, et al. Soil organic phosphorus transformation during ecosystem development: a review[J]. Plant and Soil, 2017, 417: 17 − 42. doi: 10.1007/s11104-017-3240-y [9] Stevenson F J. Humus chemistry: genesis, composition, and reactions[M]. New York: Wiley, 1994. [10] Gerke J. Humic (organic matter)-Al(Fe)-phosphate complexes: an underestimated phosphate form in soils and source of plant-available phosphate[J]. Soil Science, 2010, 175: 417 − 425. doi: 10.1097/SS.0b013e3181f1b4dd [11] He Z, Olk D C, Cade-menun B J. Forms and lability of phosphorus in humic acid fractions of Hord silt loam soil[J]. Soil Science Society of America Journal, 2011, 75: 1712 − 1722. doi: 10.2136/sssaj2010.0355 [12] He Z, Tazisong I A, Senwo Z N. Forms and lability of phosphorus in humic and fulvic acids//He Z, Wu F. Labile organic matter-chemical compositions, function, and significance in soil and the environment[M]. Madison, USA: SSSA Special Publication, 2015. [13] 孙元宏, 李翠兰, 张晋京. 不同来源胡敏酸化学组成及其结合态磷素的生物有效性[J]. 环境科学学报, 2019, 39(7): 2269 − 2278. [14] Olk D C, Bloom P R, Perdue E M, et al. Environmental and agricultural relevance of humic fractions extracted by alkali from soils and natural waters[J]. Journal of Environmental Quality, 2019, 48: 217 − 232. doi: 10.2134/jeq2019.02.0041 [15] Hayes M H B, Mylotte R, Swift R S. Humin: its composition and importance in soil organic matter[J]. Advances in Agronomy, 2017, 143: 47 − 138. [16] Joshi D C. Distribution of total and humus phosphorus in relation to some soil characteristics[J]. Annals Arid Zone, 1981, 20: 137 − 144. [17] He Z, Griffin T S, Honeycutt C W. Enzymatic hydrolysis of organic phosphorus in swine manure and soil[J]. Journal of. Environmental Quality, 2004, 33: 367 − 372. doi: 10.2134/jeq2004.0367 [18] Zhang J, Wei Y, Liu J, et al. Effects of maize straw and its biochar application on organic and humic carbon in water-stable aggregates of a Mollisol in Northeast China: a five-year field experiment[J]. Soil and Tillage Research, 2019, 190: 1 − 9. doi: 10.1016/j.still.2019.02.014 [19] He Z, Olk D C, Honeycutt C W, et al. Enzymatically and ultraviolet-labile phosphorus in humic acid fractions from rice soils[J]. Soil Science, 2009, 174: 81 − 87. doi: 10.1097/SS.0b013e3181981dc5 [20] Tazisong I A, Senwo Z N, He Z. Phosphatase Hydrolysis of Organic Phosphorus Compounds[J]. Advances in Enzyme Research, 2015, 3: 39 − 51. doi: 10.4236/aer.2015.32005 [21] Menezes-blackburn D, Jorquera M A, Greiner R, et al. Phytases and phytase-labile organic phosphorus in manures and soils[J]. Critical Reviews in Environmental Science and Technology, 2013, 43(9): 916 − 954. doi: 10.1080/10643389.2011.627019 [22] He Z, Ohno T, Cade-menun B J, et al. Spectral and chemical characterization of phosphates associated with humic substances[J]. Soil Science Society of America Journal, 2006, 70: 741 − 751. [23] He Z, Honeycutt C W. A modified molybdenum blue method for orthophosphate determination suitable for investigating enzymatic hydrolysis of organic phosphates[J]. Communications in Soil Science and Plant Analysis, 2005, 36: 1373 − 1383. doi: 10.1081/CSS-200056954 [24] Makarov M I, Guggenberger G, Zech W, et al. Organic phosphorus species in humic acids of mountain soils along a toposequence in the Northern Caucasus[J]. Zeitschrift für Pflanzenernährung und Bodenkunde, 1996, 159: 467 − 470. [25] Mahieu N, Olk D C, Randall E W. Analysis of phosphorus in two humic acid fractions of intensively cropped lowland rice soils by 31P-NMR[J]. European Journal of Soil Science, 2000, 51: 391 − 402. [26] Jacundino J S, Santos O S, Santos J C C, et al. Interactions between humin and potentially toxic metals: prospects for its utilization as an environmental repair agent[J]. Journal of Environmental Chemical Engineering, 2015, 3: 708 − 715. doi: 10.1016/j.jece.2015.03.032 [27] Liu G, Zhu J, Jin R, et al. Accelerating effects of humin on sulfide-mediated azo dye reduction[J]. Ecotoxicology and Environmental Safety, 2019, 175: 102 − 109. doi: 10.1016/j.ecoenv.2019.03.047 [28] Hamdan R, El-rifai H M, Cheesman A W, et al. Linking phosphorus sequestration to carbon humification in wetland soils by P-31 and C-13 NMR spectroscopy[J]. Environmental Science and Technology, 2012, 46: 4775 − 4782. doi: 10.1021/es204072k [29] Urrutia O, Guardado I, Erro J, et al. Theoretical chemical characterization of phosphate-metal-humic complexes and relationships with their effects on both phosphorus soil fixation and phosphorus availability for plants[J]. Journal of the Science of Food and Agriculture, 2013, 93: 293 − 303. doi: 10.1002/jsfa.5756 [30] 严玉鹏, 万 彪, 刘 凡, 等. 环境中植酸的分布、形态及界面反应行为[J]. 应用与环境生物学报, 2012, 18(3): 494 − 501. [31] Feng W, Zhu Y, Wu F, et al. Forms and lability of phosphorus in algae and aquatic macrophytes characterized by solution 31P NMR coupled with enzymatic hydrolysis[J]. Scientific Report, 2016, 6: 37164. doi: 10.1038/srep37164 [32] Lobartini J C, Tan K H, Pape C. Dissolution of aluminum and iron phosphate by humic acids[J]. Communication in Soil Science and Plant Analysis, 1998, 29: 535 − 544. doi: 10.1080/00103629809369965 [33] Pant h K, Warman P R. Phosphorus release from soils upon exposure to ultra-violet light[J]. Communications in Soil Science and Plant Analysis, 2000, 31: 321 − 329. doi: 10.1080/00103620009370439 [34] 闫金龙, 江 韬, 魏世强, 等. 河流汇合处水体磷素形态特征及紫外光照的影响: 以渠江-嘉陵江、涪江-嘉陵江交汇为例[J]. 环境科学, 2014, 35(12): 4522 − 4529. [35] Allard B, Borén H, Pettersson C, et al. Degradation of humic substances by UV irradiation[J]. Environmental International, 1994, 20: 97 − 101. doi: 10.1016/0160-4120(94)90072-8 [36] Hur J, Jung K, Jung Y M. Characterization of spectral responses of humic substances upon UV irradiation using two-dimensional correlation spectroscopy[J]. Water research, 2011, 45: 2965 − 2974. doi: 10.1016/j.watres.2011.03.013 [37] 吴文丽, 闫金龙, 江 韬, 等. 天然有机质-金属离子/氧化物–磷复合物的研究进展[J]. 生态与农村环境学报, 2019, 35(9): 1089 − 1096. [38] Jarosch K A, Doolette A L, Smernik R J, et al. Characterisation of soil organic phosphorus in NaOH-EDTA extracts: a comparison of 31P NMR spectroscopy and enzyme addition assays[J]. Soil Biology and Biochemistry, 2015, 91: 298 − 309. doi: 10.1016/j.soilbio.2015.09.010 [39] Johnson N R, Hill J E. Phosphorus species composition of poultry manure-amended soil using high-throughput enzymatic hydrolysis[J]. Soil Science Society of America Journal, 2010, 74: 1786 − 1791. doi: 10.2136/sssaj2009.0431 [40] Mahieu N, Olk D C, Randall E W. Multinuclear magnetic resonance analysis of two humic acid fractions from lowland rice soils[J]. Journal of Environmental Quality, 2002, 31: 421 − 430. doi: 10.2134/jeq2002.0421