中文关键词滴灌方式生物质炭设施农业矿质态氮细菌 英文关键词drip irrigationbiocharfacility agriculturemineral nitrogenbacteria

作者	单位	E-mail
蔡九茂	中国农业科学院农田灌溉研究所, 新乡 453002 农业农村部节水灌溉工程重点实验室, 新乡 453002	caijiumao@163.com
刘杰云	中国农业科学院农田灌溉研究所, 新乡 453002 农业农村部节水灌溉工程重点实验室, 新乡 453002
邱虎森	中国农业科学院农田灌溉研究所, 新乡 453002 中国农业科学院商丘农田生态系统国家野外科学观测研究站, 商丘 476000	qiuhusen2008@163.com
吕谋超	中国农业科学院农田灌溉研究所, 新乡 453002 农业农村部节水灌溉工程重点实验室, 新乡 453002
周新国	中国农业科学院农田灌溉研究所, 新乡 453002 中国农业科学院商丘农田生态系统国家野外科学观测研究站, 商丘 476000

中文摘要 滴灌和生物质炭添加均可影响土壤氮的形态及转化.深入了解滴灌方式和生物质炭对土壤矿质态氮和参与矿质态氮转化关键功能基因及微生物种群的综合影响，对改善设施农业生产管理方式，提高水分和氮源利用效率，降低硝酸盐积累及其淋失引起的地下水污染具有重要指导意义.在日光温室设置地表滴灌（D）、插入式滴灌（ID，插入深度15 cm）、地表滴灌+10 t·hm^-2生物质炭（DB）和插入式滴灌+10 t·hm^-2生物质炭（IDB，插深15 cm）这4个处理，以收获期辣椒根际和非根际土壤为研究对象.结果发现，非根际和根际土壤铵态氮含量不受滴灌方式和生物质炭的影响.与地表滴灌相比，插入式滴灌显著降低了非根际土壤硝态氮的含量（P<0.05），但生物质炭削弱了这种差异.同种滴灌方式下，生物质炭添加降低了根际土壤硝态氮的含量.生物质炭添加降低了地表滴灌辣椒非根际土壤AOA、AOB和nirK基因拷贝数以及根际土壤AOA基因拷贝数（P<0.05），提高了两种滴灌方式根际土壤AOB和nirK基因拷贝数（P<0.05）.结构方程模型分析结果显示，在非根际和根际土壤中，pH和电导率分别是对铵态氮和硝态氮含量影响最大的环境因子，AOB基因拷贝数是对硝态氮影响最大的生物因子.基于PICRUSt功能预测，γ-变形菌纲菌属对氨单加氧酶基因（K10945）表达的贡献高于其它菌属；α-变形菌纲，尤其是根瘤菌成员对参与含铜离子的亚硝酸还原酶基因（K00368）表达的贡献高于其他菌属.生物质炭对非根际土壤K10945和根际土壤K00368同源基因细菌群落结构的影响显著（P<0.05）.综上所述，相对于滴灌方式，生物质炭的添加对设施农业土壤硝态氮氮含量及其转化的关键微生物影响更大. 英文摘要 Drip irrigation and biochar amendment could affect the nitrogen form and transformation. Creating a deep understanding of the interacting effects of drip irrigation patterns and biochar on soil mineral nitrogen, as well as the key functional genes and microbial community involved in nitrogen transformation is helpful for improving facility agricultural management, increasing water and nitrogen use efficiency, and reducing the nitrate accumulation and groundwater pollution caused by nitrogen leaching. Four treatments [surface drip irrigation (D), insert drip irrigation (ID, insert depth 15 cm), surface drip irrigation +10 t·hm^-2 of biochar (DB), and insert drip irrigation +10 t·hm^-2 of biochar (IDB)] were conducted in a solar greenhouse, and non-rhizospheric and rhizospheric soils of pepper plants were studied. There was no effect of drip irrigation patterns and biochar on ammonium-nitrogen in the non-rhizospheric and rhizospheric soils. Compared with surface drip irrigation, insert drip irrigation decreased the nitrate-nitrogen concentration in the non-rhizosphere soil (P<0.05), but biochar addition weakened the difference. Biochar addition decreased the nitrate-nitrogen concentration in the rhizosphere soil under the same drip irrigation patterns. In the D treatment, biochar significantly decreased the number of copies of AOA, AOB, and nirK genes in the non-rhizospheric soil, and AOA gene copies in the rhizospheric soil (P<0.05); however, there was an increase in the number of copies of AOB and nirK genes in the rhizospheric soil of the D and ID treatments (P<0.05). Based on the structural equation model (SEM), in the non-rhizospheric and rhizospheric soils, pH and electrical conductivity were the environmental factors with the greatest influence on the ammonium-nitrogen and nitrate concentrations, respectively, and the gene copy number of AOB was the biotic factor with the greatest influence on the nitrate-nitrogen concentration. Based on PICRUSt, the γ-Proteobacteria contributed mostly to ammonia monooxygenase gene (K10945) expression, whereas the α-Proteobacteria, especially the rhizobia members, contributed mostly to nitrite reductase gene (K00368) expression. Biochar addition regulated the bacterial community structure that participated in K10945 gene expression in the non-rhizospheric soil and K00368 gene expression in the rhizospheric soil (P<0.05). Overall, biochar addition contributed more to nitrate-nitrogen and microbial mineral nitrogen-transformation processes in the agricultural soil than did the drip irrigation patterns.

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