酱香型酒糟生物炭对黄壤氮素运移及硝化过程的微生物学机制研究

The typical yellow soil in Guizhou is mainly distributed in mountainous hilly area, and it has the characteristics of acid and adhesion, and the loss is serious. Therefore, the utilization efficiency of nitrogen fertilizer is generally low. Biochar has the effect of promoting nitrogen fixation in soil and reducing nitrogen leaching, but the microbiological mechanism of biochar on nitrogen migration and nitrification of yellow soil is not clear. This project takes Maotai lees biochar as research materials, application of conventional analysis methods, isotope tracer technique, fluorescence quantitative PCR and Illumina Miseq sequencing technologies, the research focuses on: 1) the basic physicochemical properties of biochar and its characteristic structure will be analyzed qualitatively, and a hydrostatic adsorption test will be down to determine the adsorption capacity of NH4+-N and NO3--N, 2) the differences of nitrogen components and related enzymes in different soil layers will be analyzed to determine and the distribution and transformation characteristics of nitrogen in the yellow soil, 3) pot and field experiment are going to be conducted to analysis the microbial abundance and community structure of soil nitrification in response to Maotai lees biochar, which will be conducive to the clear the microbiological mechanism of the effect of Maotai lees biochar on nitrification in yellow soil. All these results will reveal the regulation mechanism of Maotai lees biochar on the nitrogen cycle of yellow soil in Guizhou with soil microecology, and provide a scientific basis for the efficient utilization of nitrogen fertilizer and the effect of reducing application in the typical yellow soil area of Guizhou province.

贵州典型黄壤主要分布在山地丘陵区，且具有酸、粘等特点，流失现象严重，因此氮肥利用效率普遍偏低。生物炭具有促进土壤氮素固持、减少氮素淋失等作用，但目前生物炭对贵州典型黄壤氮素运移及硝化过程的微生物学机制尚不明确，本项目以酱香型酒糟生物炭为研究材料，综合运用常规分析方法、同位素示踪技术、荧光定量PCR和Illumina Miseq测序技术，1）定性分析酒糟生物炭基本理化性质及表明特征结构，并通过静水吸附试验明确其对NH4+-N和NO3--N的吸附能力；2）利用土柱淋溶模拟试验，分析不同土层氮素组分及相关酶活性差异，明确酒糟生物炭对黄壤氮素迁移分布及转化特征规律；3）通过盆栽和田间试验，分析土壤硝化作用关键微生物（氨氧化细菌和氨氧化古菌）丰度及群落结构对酒糟生物炭的响应差异，探明酒糟生物炭对黄壤氮素硝化作用影响的微生物学机制。研究结果将从土壤微生态方面揭示酒糟生物炭对贵州黄壤氮素循环的调控机制，

生物炭具有促进土壤氮素固持、减少氮素淋失等作用，但是目前生物炭对贵州典型黄壤氮素运移及硝化过程的微生物学机制尚不明确。本项目以酱香型酒糟生物炭为供试材料，研究了酒糟生物炭的基本理化性质、表面结构特征和氮素吸附能力，同时定性研究了酒糟生物炭对贵州黄壤氮素迁移分布规律的影响，并从土壤微生物角度揭示了酒糟生物炭对黄壤氮素调控的作用机制。结果表明，酒糟生物炭主要由C和O组成，具有高度多孔的形貌特征，同时550℃炭化的酒糟生物炭具有较强的氮素吸附能力，均符合Freundlich和Langmuir等温吸附方程。施用生物炭显著提高了黄壤全氮（TN）和硝态氮（NN）含量，但却显著降低了微生物量氮（MBN）含量。与未施用生物炭处理相比，施用生物炭可以使肥料氮素固持率（NF）达到49.84%-95.23%。高生物炭施用量（2.0%和4.0%）拥有更高的肥料氮素固持率，而低生物炭施用量（0.5%和1.0%）仍存在氮素淋溶损失的风险。亚硝酸盐氧化菌（NOB）是影响黄壤氮素养分的主要影响因子，而并非氨氧化古菌（AOA）和氨氧化细菌（AOB）。酒糟生物炭通过降低亚硝酸氧化作用和改变氨氧化作用，进而影响黄壤氮素养分有效性。综上所述，4%的酒糟生物炭施用量可以更好的提高肥料氮素固持能力，并且有效降低黄壤氮素淋溶损失风险的发生。研究结果可为进一步丰富贵州喀斯特黄壤地区生物炭与氮素高效养分综合管理策略提供科学依据。