DOI: 10.ki.cjea. 210380
孙雪, 张玉铭, 张丽娟, 胡春胜, 董文旭, 李晓欣, 王玉英, 刘秀萍, 邢力, 韩建. 长期添加外源有机物料对华北农田土壤团聚体有机碳组分的影响[J]. 中国生态农业学报(中英文), 2021, 29(8): 1384 1396 SUN X, ZHANG Y M, ZHANG L J, HU C S, DONG W X, LI X X, WANG Y Y, LIU X P, XING L, HAN J. Effects of long-term exogenous organic material addition on the organic carbon composition of soil aggregates in farmlands of North China[J]. Chinese Journal of Eco-Agriculture, 2021, 29(8): 1384 1396
长期添加外源有机物料对华北农田土壤团聚体有机碳组分的影响*
孙 雪1,2, 张玉铭1**, 张丽娟2, 胡春胜1, 董文旭1, 李晓欣1,
王玉英1, 刘秀萍1, 邢 力1,2, 韩 建1,2
(1. 中国科学院遗传与发育生物学研究所农业资源研究中心/河北省土壤生态学重点实验室/中
国科学院农业水资源重点 实验室 石家庄 050022; 2. 河北农业大学资源与环境科学学院 保定 071000)
摘 要: 土壤有机碳和团聚体对土壤肥力、作物产量、农业和环境发挥着重要作用, 是土壤肥力的核心和可持续农业的基础。本研究依托中国科学院栾城农业生态系统试验站18年野外长期有机质物料和矿质肥料配施试验, 开展不同施肥模式对土壤团聚体组成以及各组分有机碳在团聚体中分布影响的研究, 为阐明不同农业管理措施下土壤有机碳的物理保护机制提供依据。试验共设6个处理: 对照(CK)、单施秸秆(S)、单施有机粪肥(M)、单施化肥(NPK)、化肥配施秸秆(SNPK)和化肥配施有机粪肥(MNPK)。利用干筛法将全土筛分为大团聚体(>2 mm)、小团聚体(0.25~2 mm)和微团聚体(<0.25 mm) 3种粒径团聚体, 分别测定不同处理下全土及3种粒级团聚体中总有机碳(TOC)、可溶性有机碳(DOC)、酸解活性有机碳(AC)、惰性有机碳(ROC)和易氧化有机碳(LOC)含量。结果表明: 施肥对土壤团聚体分布及稳定性有显著影响, SNPK显著提高了粒径>0.25 mm团聚体含量和团聚体稳定性; DOC和ROC含量与粒径>2 mm团聚体含量显著正相关, 其对促进大团聚体形成至关重要。不同施肥处理下土壤团聚体各有机碳组分含量存在差异, 与传统的单独施用化肥处理(NPK)相比, SNPK和MNPK均显著提高了全土和团聚体各组分有机碳含量, SNPK对土壤有机碳的提升
效果优于MNPK。各有机碳组分在团聚体中的含量均为小团聚体>大团聚体>微团聚体, 其中, 70%以上的各组分有机碳来自于粒径>0.25 mm的团聚体。在施用化肥基础上增施有机肥(MNPK)和实施秸秆还田(SNPK)提高了LOC在TOC中的占比, 使LOC/TOC由CK的11.94%分别增加到14.95%和15.70%。MNPK利于LOC保存在大团聚体中, 提高了土壤供肥能力; 而SNPK促进了LOC向较小粒径团聚体迁移, 增强了其在团聚体中的稳定性, 提高了土壤的保肥能力。由此可见, 长期实施有机无机肥料配合可以提高土壤碳储量和稳定性, 这为全面实施秸秆还田的基础上推行有机粪肥部分替代化肥的养分管理策略提供了理论依据。
关键词: 长期施肥; 土壤团聚体; 有机碳组分; 化肥; 秸秆; 有机粪肥
中图分类号: S153; S154.36 :
Effects of long-term exogenous organic material addition on the organic carbon composition of soil aggregates in farmlands of North China*
SUN Xue1,2, ZHANG Yuming1**, ZHANG Lijuan2, HU Chunsheng1, DONG Wenxu1, LI
Xiaoxin1,
WANG Yuying1, LIU Xiuping1, XING Li1,2, HAN Jian1,2
(1. Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences / Hebei Key Laboratory of Soil Ecology / Key Laboratory of Agricultural Water Resources, Chinese Academy of Sciences, Shijiazhuang 050022, China; 2. College of Resources and Environmental Sciences, Agricultural University of Hebei, Baoding 071000, China)
Abstract: Soil organic carbon and aggregates play an important role in soil fertility, crop yield, and the farmland environment, all of which are key components for sustainable agriculture. A wild long-term organic material and mineral fertilizer field experiment was initiated in 2003 at the Luancheng Agroecosystem Experimental Station of the Chinese Academy of Sciences. The experiment sought to investigate how different fertilization patterns affect the soil aggregate composition and the levels of organic carbon in the aggregates to better understand how different agricultural management practices serve a
s physical protection mechanisms. There were six treatments: no fertilization (i.e., conventional, CK), straw application alone (S), organic manure application alone (M), mineral fertilizer application (NPK), NPK plus straw (SNPK), and NPK plus organic manure (MNPK). The contents of total organic carbon (TOC), soluble organic carbon (DOC), acidolytic active organic carbon (AC), resistant organic carbon (ROC), and labile organic carbon (LOC) were examined within the aggregate fractions, including the total soil, large aggregates (>2 mm), small aggregates (0.25–2 mm), and microaggregates (<0.25 mm). The results showed that fertilization had a significant effect on the distribution and stability of soil aggregates. SNPK significantly increased the amount of >0.25 mm aggregates. The contents of DOC and ROC were positively correlated with the amount of large aggregates and promoted the formation of large aggregates. Compared with NPK, SNPK and MNPK significantly increased the contents of SOC components in the aggregate fractions, and SNPK addition improved the SOC content compared to MNPK. In the aggregate fractions, the content of each organic carbon component was in the order of small aggregates > large aggregates > microaggregates, and more than 70%
of the organic carbon came from the >0.25 mm aggregates. The LOC/TOC ratio in the MNPK and SNPK treatments increased to 14.95% and 15.70%, respectively, which was 11.94% under CK treatment. MNPK was conducive to LOC storage in large aggregates, which improved the soil fertilizer supply capacity; while SNPK promoted LOC migration to the small-sized aggregates, enhanced its stability in the aggregates, and improved the soil fertilizer retention capacity. In conclusion, long-term organic and inorganic fertilizer combined application improved soil carbon storage and stability. The study provides a theoretical basis for a nutrient management strategy with partial substitution of chemical fertilizer by organic manure and straw.
Keywords: Long-term fertilization; Soil aggregates; Organic carbon fractions; Chemical fertilizers; Straw; Organic manure
土壤有机碳是土壤养分循环和营养供应的核心物质, 是土壤肥力的核心和可持续农业的基础[1], 也是全球碳循环的重要组成部分, 明确土壤有机碳库的组成特征是认知和理解碳循环过
程的重要基础[2]。土壤团聚体是土壤结构的基本单元, 是土壤中物质和能量转化与代谢的场所, 其数量和质量直接影响着土壤有机碳转化与固持以及土壤其他功能的发挥, 对协调土壤肥力状况、改善土壤耕性等有重要作用。通常, 土壤有机碳含量和团聚体组成被作为衡量土壤肥力水平的重要指标[3-4]。由于土壤有机碳和团聚体对土壤肥力、作物产量、农业和环境的重要作用, 探索土壤中有机碳组成及其在团聚体中的分布与迁移转化特征一直是科学研究的热点领域。
土壤有机碳是动植物和微生物残体在各个阶段降解物质的混合体, 对增强土壤颗粒团聚性、促进团粒结构的形成具有重要作用, 有机碳的组成直接影响土壤团聚体的数量和大小分布及其稳定性。添加到农田的外源有机物料在土壤生物, 特别是土壤微生物作用下产生的土壤腐殖质可以促进土壤团粒结构的形成[3-4]。20世纪末, 人们对土壤有机碳的研究主要集中在不同化学结构有机物质在土壤中的功能, 认为形成土壤团粒结构的基础物质为土壤有机物质分解和腐殖化后产生的化学结构复杂的长链物质; 而近年来中欧一些学者相关研究则表明有机物质经分解和腐殖化后生成的短链化合物才是形成土壤团粒结构的基础物质[1]。土壤有机碳作为土壤团聚体形成的重要胶结物质, 其对土壤团聚体的结构稳定有显著影响; 同时,
土壤团聚体也是土壤有机碳稳定性的主要影响因子, 团聚体的团聚作用被认为是土壤有机碳固定的核心机制。保存于不同粒级团聚体中的有机碳对土壤的供肥和保肥能力贡献不同, 存在于大团聚体中的有机碳易于被微生物分解转化, 在提高土壤供肥能力方面发挥重要作用; 封存于土壤微团聚体中的有机碳具有较高的稳定性, 很难被分解转化, 对提高土壤的保肥能力发挥着重要作用。因此, 研究土壤团聚体及有机碳分布和稳定性的变化特征, 对改善土壤结构及提高土壤肥力具有重要意义。
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