聚丙烯酰胺和生物炭共施对土壤细菌群落、理化因子和玉米产量的影响

Effects of polyacrylamide and biochar co-application on soil bacterial community, physical and chemical factors, and maize yield

摘要:

【背景】细菌群落在土壤养分循环中扮演着重要角色，并且土壤理化性质及作物产量会对其产生一定的影响。【目的】明确河套灌区滴灌条件下聚丙烯酰胺和生物炭共施对土壤细菌群落多样性及结构组成、理化因子和玉米产量的影响。【方法】设置对照(CK)、聚丙烯酰胺22.5 kg/hm²+生物炭9 000 kg/hm² (PB1)、聚丙烯酰胺22.5 kg/hm²+生物炭13 500 kg/hm² (PB2)和聚丙烯酰胺 22.5 kg/hm²+生物炭18 000 kg/hm² (PB3)这4个不同处理，利用高通量测序技术研究土壤细菌群落与环境因子和玉米产量的相互关系。【结果】与CK相比，PB1和PB2处理均提高了土壤细菌群落的α多样性指数(chao1指数和shannon指数)。聚丙烯酰胺和生物炭共施可改变土壤细菌群落结构组成，不同处理的土壤细菌优势类群为变形菌门(Proteobacteria)和Subgroup_6。PB1处理的土壤水解氮和PB2处理的有效钾含量增加较为明显，且PB2处理的综合土壤肥力排名位于首位。冗余分析表明pH是影响细菌群落结构(门、属水平)的主要环境因子。PB2处理玉米的穗长、秃尖长、行粒数和百粒重均为最高。放线菌门(Actinobacteria)、Subgroup_6和RB41对玉米行粒数的增加起正向促进作用，Skermanella对玉米穗长的增加起正向促进作用。【结论】滴灌条件下聚丙烯酰胺和生物炭共施可通过改变土壤理化性质直接或间接增加细菌群落的多样性并改变细菌群落结构，从而提高玉米产量，且PB2处理效果最为明显。

Abstract:

[Background] Bacterial community plays an important role in soil nutrient cycling and meanwhile is affected by soil physical and chemical properties and crop yield. [Objective] To study the effects of co-application of polyacrylamide (PAM) and biochar on soil bacterial diversity and community structure, soil physical and chemical factors, and maize yield in Hetao irrigation area under drip irrigation. [Methods] We designed four treatments: control (CK, no polyacrylamide or biochar), 22.5 kg/hm² polyacrylamide+9 000 kg/hm² biochar (PB1), 22.5 kg/hm² polyacrylamide+ 13 500 kg/hm² biochar (PB2), and 22.5 kg/hm² polyacrylamide+18 000 kg/hm² biochar (PB3), to investigate the relationship among soil bacterial community, environmental factors, and maize yield by high-throughput sequencing technology. [Results] Compared with CK, PB1 and PB2 improved the alpha diversity indexes (Chao 1 and Shannon index) of soil bacteria. The co-application of polyacrylamide and biochar changed the structure of soil bacterial community, and the dominant groups of soil bacteria in different treatments were Proteobacteria and Subgroup_6. PB1 and PB2 significantly increased the content of available nitrogen and available potassium, respectively, and the comprehensive soil fertility was the highest in PB2 treatment. Redundancy analysis showed that pH was the main environmental factor affecting the bacterial community structure at the phylum and genus levels. The ear length, bald tip length, kernel number per row, and 100-kernel weight of maize in PB2 treatment were the highest. Actinobacteria, Subgroup_6, and RB41 played a positive role in increasing the kernel number per row, and Skermanella in increasing the ear length. [Conclusion] Under drip irrigation, co-application of polyacrylamide and biochar can directly or indirectly increase bacterial diversity and alter bacterial community structure by changing soil physical and chemical properties to improve maize yield, and PB2 treatment demonstrates the best performance.