The effects of protists on an indigenous soil bacterial community, putative bacterial genes involved in N-cycling, and the rice plant growth were studied in poultry litter biochar (PL) and rice husk biochar (RH) amended (with two application doses: 2% and 4% w/w) paddy field soil. The bacterial community composition, which was evaluated using 16S rRNA gene amplicon sequencing, was significantly and differentially affected by the protists, the PL and the RH. The effects of protists on the bacterial community composition were decreased by the RH and the PL treatments. The number of protist-affected bioindicator bacterial taxa was decreased from 90 to 46, 29, 43, and 21 in the 2% RH-, 4% RH-, 2% PL-, and 4% PL-treated soils, respectively. The presence of the protist significantly increased the abundance of the putative bacterial genes involved in mineralisation, dissimilatory nitrate reduction to ammonium (DNRA), and NO 3 - assimilation, and the same occurred with PL treatments. The rice plant growth and N uptake were always higher in the presence of protists and PL amendments. Overall our results suggest a new insight into the effects of biochar on the bacterial community via altering the trophic interactions.

中文翻译：

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原生生物对生物炭改良土壤中根际细菌群落组成和水稻生长的影响

在家禽垫料生物炭 (PL) 和稻壳生物炭 (RH) 修正（两种施用剂量：2%）中研究原生生物对本地土壤细菌群落、涉及 N 循环的假定细菌基因和水稻植株生长的影响和 4% w/w) 稻田土壤。使用 16S rRNA 基因扩增子测序评估的细菌群落组成受到原生生物、PL 和 RH 的显着差异影响。RH和PL处理降低了原生生物对细菌群落组成的影响。在 2% RH-、4% RH-、2% PL-和 4% PL 处理的土壤中，受原生生物影响的生物指示剂细菌分类群的数量分别从 90 个减少到 46、29、43 和 21 个。原生生物的存在显着增加了与矿化、异化硝酸盐还原为铵 (DNRA) 和 NO 3 - 同化有关的假定细菌基因的丰度，PL 处理也发生了同样的情况。在原生生物和 PL 修正存在的情况下，水稻植株的生长和 N 吸收总是较高。总的来说，我们的结果表明，通过改变营养相互作用，我们对生物炭对细菌群落的影响有了新的认识。