Effects of biogas slurry application on fine root biomass of poplar plantations

doi:10.12302/j.issn.1000-2006.202001015

JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2021, Vol. 45 ›› Issue (4): 123-129.doi: 10.12302/j.issn.1000-2006.202001015

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Effects of biogas slurry application on fine root biomass of poplar plantations

WANG Runsong¹(), SUN Yuan¹, XU Hanmei¹, CAO Guohua², SHEN Caiqin², RUAN Honghua¹^,^*()

1. College of Biology and the Environment, Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
2. Dongtai City Forest Farm of Jiangsu Province, Dongtai 224200, China

Received:2020-01-05 Accepted:2020-12-01 Online:2021-07-30 Published:2021-07-30
Contact: RUAN Honghua E-mail:runsong_wang@163.com;hhruan@njfu.edu.cn

Abstract

Abstract:

【Objective】The aim of this study was to explore the effects of different dosages of biogas slurry on the fine root biomass of a poplar plantation, to provide a theoretical basis for utilizing the biogas slurry scientifically, optimizing poplar fertilization technology and promoting the sustainable management of soil fertility in poplar plantations.【Method】Because ammonium nitrogen is the main nitrogen compound in biogas slurry, four application levels of biogas slurry were set according to its ammonium nitrogen content and the available nitrogen content in the soil of the sample plot. The ammonium nitrogen content in the biogas slurry was 0, 1, 2 and 3 times the content of soil available nitrogen with the corresponding biogas slurry amounts as 0, 125, 250 and 375 m³/hm², respectively. There were three replicates for each application level and 12 quadrats. In May, August and October of each year, biogas slurry was applied to the surface by uniform sprinkling irrigation using pumps. In October 2018, the continuous soil drill method was adopted to randomly select three sampling points in each quadrat to remove the litter layer. A root drill with an inner diameter of 5 cm was used to drill the soil core samples of three layers from top to bottom. The soil samples collected from the three sample points in the same quadrat were mixed evenly and placed in labeled plastic bags before it was brought back to the laboratory. After soaking, rinsing and sieving the soil cores, live fine roots of poplar trees were sorted and 1-5 roots were separated using forceps. The separated root samples were baked in an oven at 80 ℃ for 48 hours to a constant weight and then weighed with an electronic balance (± 0.000 1 g).【Result】①With the increase in biogas slurry application, the total fine root biomass in 0-60 cm showed a decreasing trend. Compared with the control, the total fine root biomass in 0-60 cm was decreased by 18.8%, 28.6% and 23.6% with low, medium and high amounts of biogas slurry treatments, respectively. The analysis of variance showed that the total fine root biomass in 0-60 cm was significantly decreased by the medium biogas slurry treatment (P<0.05). ②With an increase in the amount of biogas slurry, the fine root biomass in all soil layers showed a downward trend. Compared with the control, the fine root biomass in the 0-20 cm soil layer decreased by 21.5%, 34.8% and 28.3% with low, medium and high amounts of biogas slurry treatments, respectively; while the proportion of fine root biomass in the total soil layer decreased by 3.0%, 6.9% and 5.1% with low, medium and high amounts of biogas slurry treatments, respectively. The analysis of variance showed that the fine root biomass of the 0-20 cm soil layer was significantly decreased by low, medium and high amounts of biogas slurry treatments (P<0.05). ③With an increase in the amount of biogas slurry, the total fine root biomass of grade 1-5 showed a decreasing trend. Compared with the control, low, medium and high biogas slurry treatments reduced the fine root biomass of grades 1-5 by 17.7%-25.9%, 8.5%-14.5%, 17.6%-27.9%, 10.9%-27.3%, and 24.4%-31.3%, respectively. The analysis of variance showed that the biomass of fine roots of grade 1 was significantly decreased by the low biogas slurry treatment (P < 0.05). Meanwhile, the medium biogas slurry treatments significantly decreased the fine root biomass of grades 1-5 (P < 0.05) and the high amount of biogas slurry treatments significantly decreased the fine root biomass of grade 3 and grade 4 (P < 0.05). In addition, in the 0-60 cm soil layer, biogas slurry treatments increased the ratio of the fine root biomass of the lower roots (levels 1, 2 and 3) and decreased the fine root biomass of the higher roots (levels 4 and 5). With an increase in the amount of biogas slurry, the fine root biomass of each layer decreased, except for the 1^st and 2^nd level fine roots in the middle layer (≥20-40 cm) and the lower layer (≥40-60 cm). The analysis of variance (ANOVA) showed that low amounts of biogas slurry treatments significantly decreased the first-order root biomass in the 0-20 cm soil layer (P<0.05). Medium biogas slurry treatments significantly decreased the fine root biomass at all levels in the 0-20 cm soil layer (P<0.05), increased the fine root biomass at all levels in the 20-40 cm soil layer (P<0.05), and decreased the fine root biomass at all levels in the ≥40-60 cm soil layer (P<0.05). A high amount of biogas slurry treatments significantly decreased the fine root biomass of levels 1, 3 and 4 in the 0-20 cm soil layer (P<0.05), and increased the fine root biomass of levels 1 and 2 in the ≥20-40 cm soil layer (P<0.05).【Conclusion】The long-term application of biogas slurry can significantly inhibit the growth of fine roots in poplar plantations, and significantly affect the vertical distribution and diameter class distribution of fine roots, which is an adaptation strategy for plants used to mitigate against environmental changes. However, the mechanism by which the indirect effect of biogas slurry on fine roots affects other elements of the soil environment requires further study.

Key words: biogas slurry, poplar plantation, fine root biomass, vertical distribution, diameter grade distribution

CLC Number:

S718.51⁺6

WANG Runsong, SUN Yuan, XU Hanmei, CAO Guohua, SHEN Caiqin, RUAN Honghua. Effects of biogas slurry application on fine root biomass of poplar plantations[J]. JOURNAL OF NANJING FORESTRY UNIVERSITY, 2021, 45(4): 123-129.

Figures/Tables 3

References 36

[1]	张玲玲, 李兆华, 鲁敏, 等. 沼液利用途径分析[J]. 资源开发与市场, 2011, 27(3):260-262.
	ZHANG L L, LI Z H, LU M, et al. Analysis on utilization of biogas slurry[J]. Resour Dev Mark, 2011, 27(3):260-262. DOI: 10.3969/j.issn.1005-8141.2011.03.019. doi: 10.3969/j.issn.1005-8141.2011.03.019
[2]	林鸿雁, 叶美锋, 吴飞龙, 等. 沼液的综合利用现状综述[J]. 福建农业科技, 2012 (1):75-77.
	LIN H Y, YE M F, WU F L, et al. Current situation of comprehensive utilization to biogas slurry[J]. Fujian Agric Sci Technol, 2012(1):75-77. DOI: 10.13651/j.cnki.fjnykj.2012.01.003. doi: 10.13651/j.cnki.fjnykj.2012.01.003
[3]	曹汝坤, 陈灏, 赵玉柱. 沼液资源化利用现状与新技术展望[J]. 中国沼气, 2015, 33(2):42-50.
	CAO R K, CHEN H, ZHAO Y Z, et al. Resource utilization of biogas slurry: current status and future prospects[J]. China Biogas, 2015, 33(2):42-50. DOI: 10.3969/j.issn.1000-1166.2015.02.008. doi: 10.3969/j.issn.1000-1166.2015.02.008
[4]	叶小梅, 常志州, 钱玉婷, 等. 江苏省大中型沼气工程调查及沼液生物学特性研究[J]. 农业工程学报, 2012, 28(6):222-227.
	YE X M, CHANG Z Z, QIAN Y T, et al. Investigation on large and medium scale biogas plants and biological properties of digestate in Jiangsu Province[J]. Trans Chin Soc Agric Eng, 2012, 28(6):222-227. DOI: 10.3969/j.issn.1002-6819.2012.06.036. doi: 10.3969/j.issn.1002-6819.2012.06.036
[5]	李祎雯, 曲英华, 徐奕琳, 等. 不同发酵原料沼液的养分含量及变化[J]. 中国沼气, 2012, 30(3):17-20, 24.
	LI Y W, QU Y H, XU Y L, et al. Change of nutrition contents of biogas slurry with different fermentation raw materials[J]. China Biogas, 2012, 30(3):17-20, 24. DOI: 10.3969/j.issn.1000-1166.2012.03.004. doi: 10.3969/j.issn.1000-1166.2012.03.004
[6]	ZHENG X B, FAN J B, CUI J, et al. Effects of biogas slurry application on peanut yield, soil nutrients, carbon storage,and microbial activity in an Ultisol soil in southern China[J]. J Soils Sediments, 2016, 16(2):449-460.DOI: 10.1007/s11368-015-1254-8. doi: 10.1007/s11368-015-1254-8
[7]	PETERS K, JENSEN L S. Biochemical characteristics of solid fractions from animal slurry separation and their effects on C and N mineralisation in soil[J]. Biol Fertil Soils, 2011, 47(4):447-455. DOI: 10.1007/s00374-011-0550-8. doi: 10.1007/s00374-011-0550-8
[8]	孙芹菊, 凌玮, 韩建刚, 等. 沼液施肥对滨海盐碱地土壤性状的影响[J]. 南京林业大学学报(自然科学版), 2018, 42(5):91-98.
	SUN Q J, LING W, HAN J G, et al. Effects of biogas slurry application on the coastal saline-alkali soil properties[J]. J Nanjing For Univ (Nat Sci Ed), 2018, 42(5):91-98. DOI: 10.3969/j.issn.1000-2006.201706064. doi: 10.3969/j.issn.1000-2006.201706064
[9]	艾俊国, 顾万荣, 孔令中, 等. 沼肥与化学肥料配施对寒地春玉米幼苗根系形态生理特征的影响[J]. 作物杂志, 2013(3):56-62.
	AI J G, GU W R, KONG L Z, et al. The effects of biogas manure and chemical fertilizer on morphology and physiological characteristics of the cold spring maize seeding roots[J]. Crops, 2013(3):56-62. DOI: 10.16035/j.issn.1001-7283.2013.03.017. doi: 10.16035/j.issn.1001-7283.2013.03.017
[10]	党祝庆. 生化黄腐酸钾和有机肥对桃树根系生长和果实品质的影响[D]. 泰安: 山东农业大学, 2015.
	DANG Z Q. Effects of biochemical fulvic acid potassium and organic fertilizer on root growth and fruit quality of peach trees[D]. Tai’an: Shandong Agricultural University, 2015.
[11]	葛之葳, 张玲, 卜丹蓉, 等. 杨树人工林沼液和生物炭混施对表层土壤活性有机碳的影响[J]. 南京林业大学学报(自然科学版), 2016, 40(6):9-14.
	GE Z W, ZHANG L, BU D R, et al. Effects of biogas slurry and biochar application on active organic carbon in the topsoil of poplar plantation[J]. J Nanjing For Univ (Nat Sci Ed), 2016, 40(6):9-14.DOI: 10.3969/j.issn.1000-2006.2016.06.002. doi: 10.3969/j.issn.1000-2006.2016.06.002
[12]	龙秋宁, 王润松, 徐涵湄, 等. 沼液与生物炭联合施用对杨树人工林土壤甲螨(Oribatida)密度的影响[J]. 南京林业大学学报(自然科学版), 2020, 44(3):211-215.
	LONG Q N, WANG R S, XU H M, et al. Effects of biogas slurry and biochar on Oribatida density in a poplar plantation[J]. J of Nanjing For Univ (Nat Sci Ed), 2020, 44(3):211-215. DOI: 10.3969/j.issn.1000-2006.201904023. doi: 10.3969/j.issn.1000-2006.201904023
[13]	MOU P, JONES R H, TAN Z Q, et al. Morphological and physio-logical plasticity of plant roots when nutrients are both spatially and temporally heterogeneous[J]. Plant and Soil, 2013, 364(1/2):373-384. DOI: 10.1007/s11104-012-1336-y. doi: 10.1007/s11104-012-1336-y
[14]	EISSENSTAT D M, YANAI R D. The ecology of root lifespan[M]// Advances in Ecological Research Volume 27. Amsterdam: Elsevier, 1997: 1-60.DOI: 10.1016/s0065-2504(08)60005-7. doi: 10.1016/s0065-2504(08)60005-7
[15]	MAKITA N, HIRANO Y, MIZOGUCHI T, et al. Very fine roots respond to soil depth: biomass allocation, morphology, and physio-logy in a broad-leaved temperate forest[J]. Ecol Res, 2011, 26(1):95-104. DOI: 10.1007/s11284-010-0764-5. doi: 10.1007/s11284-010-0764-5
[16]	方升佐. 中国杨树人工林培育技术研究进展[J]. 应用生态学报, 2008, 19(10):2308-2316.
	FANG S Z. Silviculture of poplar plantation in China: a review[J]. Chin J Appl Ecol, 2008, 19(10):2308-2316.
[17]	胡觉, 彭长清, 甘世书, 等. 我国人工林变化动态及增长潜力分析[J]. 林业资源管理, 2014(21):6-8.
	HU J, PENG C Q, GAN S S, et al. Analysis on the dynamic changes and growth potential of China’s plantations[J]. Forest Resources Management, 2014(21):6-8.
[18]	田子凡. 苏北杨树产业碳库系统及碳价值评估[D]. 南京: 南京林业大学, 2017.
	TIAN Z F. Carbon pool of poplar industry in northern Jiangsu and the assessment of its carbon value[D]. Nanjing: Nanjing Forestry University, 2017.
[19]	LAIRD D, FLEMING P, WANG B Q, et al. Biochar impact on nutrient leaching from a midwestern agricultural soil[J]. Geoderma, 2010, 158(3/4):436-442. DOI: 10.1016/j.geoderma.2010.05.012. doi: 10.1016/j.geoderma.2010.05.012
[20]	PREGITZER K S, DEFOREST J L, BURTON A J, et al. Fine root architecture of nine north American trees[J]. Ecol Monogr, 2002, 72(2), 293-309. DOI: 10.1890/0012-9615(2002)072[0293:FRAONN]2.0.CO;2. doi: 10.1890/0012-9615(2002)072
[21]	闫美芳, 王璐, 郭楠, 等. 黄土高原杨树人工林的细根生物量与碳储量研究[J]. 中国农学通报, 2015, 31(35):146-151.
	YAN M F, WANG L, GUO N, et al. Study on fine root biomass and C stock in a poplar plantation in loess plateau[J]. Chinese Agricultural Science Bulletin, 2015, 31(35):146-151.
[22]	HENDRICKS J J, NADELHOFFER K J, ABER J D. Assessing the role of fine roots in carbon and nutrient cycling[J]. Trends Ecol Evol, 1993, 8(5):174-178. DOI: 10.1016/0169-5347(93)90143-D. doi: 10.1016/0169-5347(93)90143-D
[23]	于立忠, 丁国泉, 朱教君, 等. 施肥对日本落叶松人工林细根生物量的影响[J]. 应用生态学报, 2007, 18(4):713-720.
	YU L Z, DING G Q, ZHU J J, et al. Effects of fertilization on fine root biomass of Larix kaempferi plantation[J]. Chin J Appl Ecol, 2007, 18(4):713-720.
[24]	杨丽君. 杨树幼龄林细根构型对施肥的响应[D]. 雅安:四川农业大学, 2013.
	YANG L J. Effect of fertilization on fine root architecture of the plantation of Populus[D]. Ya’an: Sichuan Agricultural University, 2013.
[25]	BENDERS K E M, VAN WEEREN P R, BADYLAK S F. Extracellular matrix scaffolds for cartilage and bone regeneration[J]. Trends Biotechnol, 2013, 31(3):169-176. doi: 10.1016/j.tibtech.2012.12.004
[26]	MAGILL A H, ABER J D, BERNTSON G M, et al. Long-term nitrogen additions and nitrogen saturation in two temperate Forests[J]. Ecosystems, 2000, 3(3):228-253.
[27]	SON Y, HWANG J H. Fine root biomass, production and turnover in a fertilized Larix leptolepis plantation in central Korea[J]. Ecol Res, 2003, 18(3):339-346. DOI: 10.1046/j.1440-1703.2003.00559.x. doi: 10.1046/j.1440-1703.2003.00559.x
[28]	黎磊. 两种植物种群生物量与密度的异速比例关系研究[D]. 长春:东北师范大学, 2013.
	LI L. Qualifying the allometric relationships between biomass and density within plant populations of two species[D]. Changchun: Northeast Normal University, 2013.
[29]	HENDRICKS J J, HENDRICK R L, WILSON C A, et al. As-sessing the patterns and controls of fine root dynamics: an empirical test and methodological review[J]. J Ecol, 2006, 94(1):40-57. doi: 10.1111/jec.2006.94.issue-1
[30]	肖义发, 欧光龙, 胥辉. 林木细根生物量分布及其动态研究综述[J]. 林业调查规划, 2013, 38(1):34-38,57.
	XIAO Y F, OU G L, XU H. Tree fine root biomass distribution and its dynamic research[J]. For Invent Plan, 2013, 38(1):34-38, 57.
[31]	英慧, 殷有, 于立忠, 等. 土壤水分、养分对树木细根生长动态及周转影响研究进展[J]. 西北林学院学报, 2010, 25(3):36-42.
	YING H, YIN Y, YU L Z, et al. Effects of soil moisture and soil nutrient on the dynamic and turnover of the tree fine roots:a review[J]. J Northwest For Univ, 2010, 25(3):36-42.
[32]	赵倩. 施用沼液和生物炭对杨树人工林土壤碳、氮及重金属含量的的影响[D]. 南京: 南京林业大学, 2017.
	ZHAO Q. Effects of biogas slurry and biochar on soil carbon, nitrogen and heavy mental in a poplar plantation in a coastal area, China[D]. Nanjing: Nanjing Forestry University, 2017.
[33]	杜妍宁. 施用沼液和生物炭对杨树人工林土壤氮、磷的影响[D]. 南京: 南京林业大学, 2018.
	DU Y N. Effects of biogas slurry and biochar applications on soil nitrogenand phosphorus in the poplar plantation in a costal area, China[D]. Nanjing: Nanjing Forestry University, 2018.
[34]	杨潇. 污水灌溉土壤养分迁移转化规律的研究[D]. 乌鲁木齐:新疆大学, 2006.
	YANG X. Study on the nutrient transport and transformation in soil with sewage irrigation[D]. Urumqi: Xinjiang University, 2006.
[35]	邓飞. 模拟氮沉降对中亚热带常绿阔叶林细根生物量和生产量的影响研究[D]. 福州:福建师范大学, 2016.
	DENG F. Effects of simulated nitrogen deposition on fine root biomass and production in a mid-subtropical evergreen broadleaf forest[D]. Fuzhou: Fujian Normal University, 2016.
[36]	谷加存, 王东男, 夏秀雪, 等. 功能划分方法在树木细根生物量研究中的应用:进展与评述[J]. 植物生态学报, 2016, 40(12):1344-1351. doi: 10.17521/cjpe.2016.0167
	GU J C, WANG D N, XIA X X, et al. Applications of functional classification methods for tree fine root biomass estimation: advancements and synjournal[J]. Chin J Plant Ecol, 2016, 40(12):1344-1351.

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Effects of biogas slurry application on fine root biomass of poplar plantations

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