Effects of rotation tillage on available nutrients and structural characteristics of dissolved organic carbon of Fluvo-aquic soil in northern Henan Province
-
摘要: 本研究以豫北潮土为研究对象, 采用大田小区试验研究不同轮耕模式对不同深度土壤速效养分与可溶性有机碳结构特性的影响, 以筛选适合豫北潮土的轮耕模式。本研究于小麦季实施5种不同的耕作模式, 3年为一个周期: 1)连续旋耕(RT-RT-RT); 2)深耕-旋耕-旋耕(DT-RT-RT); 3)深耕-旋耕-条旋耕(DT-RT-SRT); 4)深耕-条旋耕-条旋耕(DT-SRT-SRT); 5)深耕-条旋耕-旋耕(DT-SRT-RT)。测定并分析土壤碱解氮、速效磷、速效钾、可溶性有机碳含量及其腐殖化程度、有机质分子量与聚合度、疏水组分比例、芳香化程度与分子量。结果显示, 各处理间的差异主要表现在0~40 cm土层。相较于RT-RT-RT, 轮耕处理对各项指标均有显著影响, 其中以DT-SRT-RT处理对各指标的影响最为突出, 具体表现为DT-SRT-RT处理显著增加了0~40 cm土层碱解氮、速效磷、速效钾含量(P<0.05), 最高增加17.8%、17.2%和19.6%。在0~40 cm土层中, DT-SRT-RT处理较RT-RT-RT最高增加了20.2%土壤可溶性有机碳含量(P<0.05)、53.1%腐殖化程度和27.4%疏水组分比例(P<0.05)。DT-RT-SRT处理较RT-RT-RT处理显著增加20~30 cm土层芳香化程度与分子量(P<0.05), 最高增加21.0%, 10~30 cm土层有机质分子量与聚合度显著降低36.7% (P<0.05)。土层深度与轮耕处理的单因素以及二者之间的交互效应均显著影响土壤速效养分和可溶性有机碳及其结构特性(P<0.05)。所有处理各指标间的相关性随土层深度的增加而减弱。综上所述, 相较于连续旋耕(RT-RT-RT), 深耕-条旋耕-旋耕模式(DT-SRT-RT)提高了土壤速效养分和可溶性有机碳含量, 增加可溶性有机碳的结构复杂性, 推荐为豫北潮土区适宜的轮耕模式。Abstract: Tillage is an important practice for improving soil quality. The effects of tillage on soil nutrient contents are well known. However, the understanding of the effects of tillage on soil dissolved organic carbon (DOC) and its structure is rare. This study aimed to select optimum tillage mode by exploring the effect of tillage mode on DOC and its structure in Fluvo-aquic soil in northern Henan Province. A field experiment was carried out using five treatments designed with different tillage rotation modes during the wheat season. The treatments were as follows: 1) continuous rotary tillage (RT-RT-RT); 2) deep tillage-rotary tillage-rotary tillage (DT-RT-RT); 3) deep tillage-rotary tillage-strip rotary tillage (DT-RT-SRT); 4) deep tillage-strip rotary tillage-strip rotary tillage (DT-SRT-SRT); 5) deep tillage-strip rotary tillage-rotary tillage (DT-SRT-RT). The contents of alkaline hydrolysis nitrogen (AN), available phosphorus (AP), available potassium (AK), DOC, degree of humification, molecular weight and polymerization degree of organic matter, proportion of hydrophobic components, degree of aromatization and molecular weight of soil were measured and analyzed. The results showed that the difference in all the indexes among treatments was mainly demonstrated in the 0–40 cm soil layer. Compared with those under RT-RT-RT in the 0–40 cm soil layer, the AN, AP, and AK increased by 17.8%, 17.2%, and 19.6% (P<0.05), respectively, under DT-SRT-RT, whereas the DOC content, degree of humification, and proportion of hydrophobic components increased by 20.2%, 53.1%, and 27.4% (P<0.05), respectively, under DT-SRT-RT. Compared with those under RT-RT-RT, the aromatization degree and molecular weight in the 20–30 cm soil layer increased by 21.0% (P<0.05), and the molecular weight and polymerization degree of organic matter in the 10–30 cm soil layer decreased by 36.7% (P<0.05) under DT-RT-SRT. Available soil nutrients and DOC and its structural characteristics were affected by soil depth, tillage mode, and the interaction between soil depths and tillage modes. The correlation among different indices decreased with increasing soil depth. In summary, compared with continuous rotary tillage, DT-SRT-RT improved soil available nutrients and DOC content and increased the complexity of the DOC structure. Therefore, the DT-SRT-RT mode was suggested as a suitable rotation tillage mode in the Fluvo-aquic soil areas of northern Henan.
-
图 1 不同处理下不同土层土壤碱解氮(A)、速效磷(B)和速效钾(C)含量
RT-RT-RT: 连续旋耕; DT-RT-RT: 深耕-旋耕-旋耕; DT-RT-SRT: 深耕-旋耕-条旋耕; DT-SRT-SRT: 深耕-条旋耕-条旋耕; DT-SRT-RT: 深耕-条旋耕-旋耕。不同小写字母表示同一取样深度不同处理间在P<0.05水平差异显著。RT-RT-RT: continuous rotary tillage; DT-RT-RT: deep tillage-rotary tillage-rotary tillage; DT-RT-SRT: deep tillage-rotary tillage-strip rotary tillage; DT-SRT-SRT: deep tillage-strip rotary tillage-strip rotary tillage; DT-SRT-RT: deep tillage-strip rotary tillage-rotary tillage. Different lowercase letters mean significant differences among treatments at P<0.05 level in the same sample depth.
Figure 1. Alkali hydrolyzable nitrogen (A), available phosphorus (B) and available potassium (C) contents in different soil layers under different treatments
图 2 不同处理不同土层土壤可溶性有机碳含量(A)、腐殖化程度(A250/A365, B)、有机质分子量与聚合度(A300/A400, C)、疏水组分比例(SUVA260, D)和芳香化程度与分子量大小(SUVA280, E)
RT-RT-RT: 连续旋耕; DT-RT-RT: 深耕-旋耕-旋耕; DT-RT-SRT: 深耕-旋耕-条旋耕; DT-SRT-SRT: 深耕-条旋耕-条旋耕; DT-SRT-RT: 深耕-条旋耕-旋耕。不同小写字母表示同一取样深度不同处理间在P<0.05水平差异显著。RT-RT-RT: continuous rotary tillage; DT-RT-RT: deep tillage-rotary tillage-rotary tillage; DT-RT-SRT: deep tillage-rotary tillage-strip rotary tillage; DT-SRT-SRT: deep tillage-strip rotary tillage-strip rotary tillage; DT-SRT-RT: deep tillage-strip rotary tillage-rotary tillage. Different lowercase letters mean significant differences among different treatments at P<0.05 level in the same sample depth.
Figure 2. Soil dissolved organic carbon content (A), degree of humification (A250/A365, B), molecular weight and polymerization degree of organic matter (A300/A400, C), proportions of hydrophobic components (SUVA260, D) and degree of aromatization and molecular weight (SUVA280, E) in different soil layers under different treatments
图 3 0~50 cm土层不同深度土壤养分指标与可溶性有机物紫外光谱参数的相关性分析
N、P、K 分别代表碱解氮、速效磷、速效钾; DOC、A250/A365、A300/A400、SUVA260、SUVA280分别代表可溶性有机碳、腐殖化程度、有机质分子量与聚合度、疏水组分比例、芳香化程度与分子量大小。 N, P, K represent alkaline hydrolyzable nitrogen, available phosphorus and available potassium; DOC, A250/A365, A300/A400, SUVA260 and SUVA280 represent dissolved organic carbon, degree of humification, molecular weight and polymerization degree of organic matter, hydrophobic components, degree of aromatization and molecular weight.
Figure 3. Correlation analysis of soil nutrient indices and UV spectral parameters of dissolved organic matter in different depthes of 0−50 cm soil layer
表 1 可溶性有机物(DOM)的紫外–可见光谱特征参数描述及表征意义
Table 1. Description and significance of characteristic parameters of ultraviolet-visible spectroscopy of dissolved organic matter (DOM)
吸光度
Wavelength (nm)定义
Definition意义
SignificanceA250/A365 DOM滤出液在250 nm和365 nm处吸光度的比值
The ratio of absorbance of DOM filtrate at 250 nm and 365 nm表征DOM腐殖化程度[20]
Indicates the degree of DOM humificationA300/A400 DOM滤出液在300 nm和400 nm处吸光度的比值
The ratio of absorbance of DOM filtrate at 300 nm and 400 nm表征DOM分子量与聚合度[21]
Indicates the molecular weight and degree of polymerization of DOMSUVA260 单位DOM浓度在波长260 nm处的吸收系数
Absorption coefficient of unit DOM concentration at wavelength 260 nm表征DOM疏水性组分比例[16-17]
Indicates the proportion of DOM hydrophobic componentsSUVA280 单位DOM浓度在波长280 nm处的吸收系数
Absorption coefficient of unit DOM concentration at wavelength 280 nm表征DOM芳香化程度和分子量大小[18-19]
Indicates the degree of aromatization and molecular weight of DOM表 2 轮耕模式对不同土层土壤速效养分含量的主体间效应检验
Table 2. Tests on the intersubjective effects of rotation tillage patterns on soil available nutrients contents in different soil layers
源
Source土壤养分
Soil nutrientⅢ 型平方和
Sum of squared deviations from meandf 均方
Mean squareF P 土层
Soil layer碱解氮 Alkaline hydrolysis nitrogen 30 433.346 4 7608.34 8956.67 0 有效磷 Available phosphorus 3279.283 4 819.82 3538.85 0 速效钾 Available potassium 59 707.959 4 14 926.99 2893.77 0 轮耕
rotation tillage碱解氮 Alkaline hydrolysis nitrogen 92.541 4 23.14 27.24 0 有效磷 Available phosphorus 21.505 4 5.38 23.21 0 速效钾 Available potassium 523.974 4 130.99 25.40 0 土层×轮耕
Soil layer ×
rotation tillage碱解氮 Alkaline hydrolysis nitrogen 39.188 16 2.45 2.88 0.002 有效磷 Available phosphorus 9.668 16 0.60 2.61 0.005 速效钾 Available potassium 320.027 16 20.002 3.88 0 表 3 轮耕模式对不同土层土壤可溶性有机碳及其结构特性主体间效应的检验
Table 3. Tests on the intersubjective effects of rotation tillage patterns on soil dissolved organic carbon and its structural characteristics in different soil layers
源
Source因变量
Dependent variableⅢ 型平方和
Sum of squared deviations from meandf 均方
Mean squareF P 土层
Soil layer可溶性有机碳含量 Dissolved organic carbon content 21 246.08 4 5311.52 4180.36 0 腐殖化程度 Degree of humification 1839.13 4 459.78 1363.44 0 有机质分子量与聚合度
Molecular weight and polymerization degreee of organic matter2199.53 4 549.88 1036.17 0 疏水组分比例 Hydrophobic components 0.59 4 0.15 942.02 0 芳香化程度与分子量大小
Degree of aromatization and molecular weight0.47 4 0.12 1305.51 0 轮耕
Rotation tillage可溶性有机碳含量 Dissolved organic carbon content 192.42 4 48.10 37.86 0 腐殖化程度 Degree of humification 27.15 4 6.79 20.13 0 有机质分子量与聚合度
Molecular weight and polymerization degree of organic matter45.66 4 11.41 21.51 0 疏水组分比例 Hydrophobic components 0.012 4 0.003 20.04 0 芳香化程度与分子量大小
Degree of aromatization and molecular weight0.007 4 0.002 20.86 0 土层×轮耕
Soil layer × rotation tillage可溶性有机碳含量 Dissolved organic carbon content 114.126 16 7.13 5.61 0 腐殖化程度 Degree of humification 16.671 16 1.04 3.09 0.001 有机质分子量与聚合度
Molecular weight and polymerization degree of organic matter30.861 16 1.93 3.64 0 疏水组分比例 Hydrophobic components 0.02 16 0.001 8.15 0 芳香化程度与分子量大小
Degree of aromatization and molecular weight0.009 16 0.001 6.32 0 -
[1] 曹志磊, 俞花美, 葛成军, 等. 可溶性有机物对土霉素在土壤中吸附-解吸的影响[J]. 热带作物学报, 2018, 39(4): 825−831 doi: 10.3969/j.issn.1000-2561.2018.04.034CAO Z L, YU H M, GE C J, et al. Effects of dissolved organic matter on adsorption-desorption behavior of oxytetracycline in soil system[J]. Chinese Journal of Tropical Crops, 2018, 39(4): 825−831 doi: 10.3969/j.issn.1000-2561.2018.04.034 [2] 张浩, 吕茂奎, 谢锦升. 红壤侵蚀区芒萁对土壤可溶性有机质光谱特征的影响[J]. 植物生态学报, 2017, 41(8): 862−871 doi: 10.17521/cjpe.2016.0363ZHANG H, LYU M K, XIE J S. Effect of Dicranopteris dichotoma on spectroscopic characteristic of dissolved organic matter in red soil erosion area[J]. Chinese Journal of Plant Ecology, 2017, 41(8): 862−871 doi: 10.17521/cjpe.2016.0363 [3] 周国模, 姜培坤. 不同植被恢复对侵蚀型红壤活性碳库的影响[J]. 水土保持学报, 2004, 18(6): 68−70, 83 doi: 10.3321/j.issn:1009-2242.2004.06.016ZHOU G M, JIANG P K. Changes in active organic carbon of erosion red soil by vegetation recovery[J]. Journal of Soil Water Conservation, 2004, 18(6): 68−70, 83 doi: 10.3321/j.issn:1009-2242.2004.06.016 [4] 刘翥, 杨玉盛, 司友涛, 等. 植被恢复对侵蚀红壤可溶性有机质含量及光谱学特征的影响[J]. 植物生态学报, 2014, 38(11): 1174−1183 doi: 10.3724/SP.J.1258.2014.00113LIU Z, YANG Y S, SI Y T, et al. Effects of vegetation restoration on content and spectroscopic characteristics of dissolved organic matter in eroded red soil[J]. Chinese Journal of Plant Ecology, 2014, 38(11): 1174−1183 doi: 10.3724/SP.J.1258.2014.00113 [5] 陈兰, 唐晓红, 魏朝富. 土壤腐殖质结构的光谱学研究进展[J]. 中国农学通报, 2007, 23(8): 233−239 doi: 10.3969/j.issn.1000-6850.2007.08.051CHEN L, TANG X H, WEI C F. Spectroscopies of soil humic substances: a review[J]. Chinese Agricultural Science Bulletin, 2007, 23(8): 233−239 doi: 10.3969/j.issn.1000-6850.2007.08.051 [6] 侯贤清, 李荣, 韩清芳, 等. 轮耕对宁南旱区土壤理化性状和旱地小麦产量的影响[J]. 土壤学报, 2012, 49(3): 592−600 doi: 10.11766/trxb201107290282HOU X Q, LI R, HAN Q F, et al. Effects of alternate tillage on soil physicochemical properties and yield of dryland wheat in arid areas of south Ningxia[J]. Acta Pedologica Sinica, 2012, 49(3): 592−600 doi: 10.11766/trxb201107290282 [7] 王丽, 李军, 李娟, 等. 轮耕与施肥对渭北旱作玉米田土壤团聚体和有机碳含量的影响[J]. 应用生态学报, 2014, 25(3): 759−768WANG L, LI J, LI J, et al. Effects of tillage rotation and fertilization on soil aggregates and organic carbon content in corn field in Weibei Highland[J]. Chinese Journal of Applied Ecology, 2014, 25(3): 759−768 [8] 王健波. 耕作方式对旱地冬小麦土壤有机碳转化及水分利用影响[D]. 北京: 中国农业科学院, 2014WANG J B. Effect of different tillage practices on soil organic carbon transformation and water use in dryland winter wheat[D]. Beijing: Chinese Academy of Agricultural Sciences, 2014 [9] 丁晋利, 武继承, 杨永辉, 等. 免耕对农田土壤有