STOEN | 土壤微生物氮循环基因丰度对作物多样化的响应：meta分析

作者：Jiaqi Hao a b, Yongzhong Feng a b*, Xing Wang a b, Qi Yu a b, Fu Zhang a b, Gaihe Yang a b, Guangxin Ren a b, Xinhui Han a b, Xiaojiao Wang a b, Chengjie Ren a b

单位：

aCollege of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China

bShaanxi Engineering Research Center of Circular Agriculture, Yangling 712100, Shaanxi, China

通讯作者地址：

College of Agronomy, Northwest A&F University, Yangling 712100, Shaanxi, China.

Highlights

• （1）分析了种植多样化对土壤氮循环的影响。

• （2）多样化增加了固氮和反硝化基因丰度。
  

• （3）确定了控制氮循环基因丰度的因素。

• （4）土壤有机碳和氮与nifH、AOA、nirS和nirK密切相关。

Abstract

单种种植结构对生态系统氮素的维持有显著影响。虽然作物多样性对土壤氮循环微生物的影响主要与环境因子的影响有关，但缺乏定量研究。本研究基于包含189对观测数据的meta分析数据库，定量分析不同种植方式对土壤氮循环中功能基因丰度的影响。结果表明:土壤氮酶编码基因nifH、亚硝酸盐还原酶编码基因nirS、nirK和硝酸还原酶编码基因narG的丰度受植物物种多样性的正向影响，而氨单加氧酶编码基因amoA和一氧化二氮还原酶编码基因nosZ的响应不显著。多样性持续时间和生态系统类型是调控土壤固氮和硝化基因丰度的重要因素。反硝化基因主要受种植方式、土层、施氮种类、施氮年限和土壤质地等分类变量的影响。其中，长期持续的多样化主要表现为土壤nifH的减少和nirK丰度的增加。土壤有机碳和氮线性影响nifH、amoA、nirS和nirK的响应。因此，为了保持土壤生态功能，需要通过调控氮循环基因的丰度来灵活应用种植模式的多样性。本研究结果可为陆地受控生态系统多样化过程中氮的可持续性和管理措施的改进提供理论参考。

Fig. 1.Response of the soil nifH abundance to crop diversification under the action of different categorical variables (left) and model-averaged importance of each group (right). The point in the forest plot represents the RR++. The error bar represents a 95 % confidence interval, and the effect of this category is considered to be significant if it does not overlap with 0. The sample size is indicated in brackets after each category. The parameters QB and P represent the heterogeneity and significance between groups (*P < 0.05; **P < 0.01; ***P < 0.001). The red dotted line is the critical value used to distinguish important (orange blocks) from unimportant (blue blocks) influencing factors. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 2.Response of the soil AOA (a) and AOB (b) abundance to crop diversification under the action of different categorical variables (left) and model-averaged importance of each group (right). The point in the forest plot represents the RR++. The error bar represents a 95 % confidence interval, and the effect of this category is considered to be significant if it does not overlap with 0. The sample size is indicated in brackets after each category. The parameters QB and P represent the heterogeneity and significance between groups (*P < 0.05; **P < 0.01; ***P < 0.001). The red dotted line is the critical value used to distinguish important (orange blocks) from unimportant (blue blocks) influencing factors. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 3.Response of the soil nirS (a), nirK (b), and nosZ (c) abundance to crop diversification under the action of categorical variables (left) and model-averaged importance of each group (right). The point in the forest plot represents the RR++. The error bar represents a 95 % confidence interval, and the effect of this category is considered to be significant if it does not overlap with 0. The arrow indicates that the interval is outside the abscissa range. The sample size is indicated in brackets after each category. The parameters QB and P represent the heterogeneity and significance between groups (*P < 0.05; **P < 0.01; ***P < 0.001). The red dotted line is the critical value used to distinguish important (orange blocks) from unimportant (blue blocks) influencing factors. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 7.Quantitative schematic diagram of the effect of crop diversification on the soil nitrogen-cycling gene abundances. The black number represents the overall response percentage of the corresponding index. The blue arrow represents the regulation processes of important environmental factors, the red number in parentheses represents inhibition, and the blue number represents promotion. The red arrow shows the negative linear effect of the duration (with individual studies as random effects) on the soil nifH copies. The black solid arrow indicates the positive correlations between the soil nutrients and gene abundance and the dotted line represents negative correlations. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

本研究从功能基因丰度的角度揭示了作物多样化对陆地管理生态系统土壤氮循环及其调控过程的影响。结果表明，植物种类的添加增加了土壤固氮和反硝化基因的表达。多样性持续时间、生态系统类型、种植模式、施氮种类、土层和土壤质地是调控氮循环基因丰度响应的重要因子。同时，土壤有机碳和氮浓度与nifH、AOA、nirS和nirK拷贝数呈显著线性相关。在长期可持续多样化下，nifH丰度的降低和nirK的增加使土壤氮转化为损失。我们只分析了控制氮循环主要转化过程的基因。它们对转化强度和N2O排放的贡献有待进一步研究。综合定量分析不同环境背景下管理生态系统土壤氮循环基因丰度，有利于改善物种多样性，从而促进氮的可持续利用。