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

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單位：

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

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

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通訊作者地址：

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

Highlights

• （1）分析了種植多樣化對(duì)土壤氮循環(huán)的影響。

• （2）多樣化增加了固氮和反硝化基因豐度。
  

• （3）確定了控制氮循環(huán)基因豐度的因素。

• （4）土壤有機(jī)碳和氮與nifH、AOA、nirS和nirK密切相關(guān)。

Abstract

單種種植結(jié)構(gòu)對(duì)生態(tài)系統(tǒng)氮素的維持有顯著影響。雖然作物多樣性對(duì)土壤氮循環(huán)微生物的影響主要與環(huán)境因子的影響有關(guān)，但缺乏定量研究。本研究基于包含189對(duì)觀測(cè)數(shù)據(jù)的meta分析數(shù)據(jù)庫(kù)，定量分析不同種植方式對(duì)土壤氮循環(huán)中功能基因豐度的影響。結(jié)果表明:土壤氮酶編碼基因nifH、亞硝酸鹽還原酶編碼基因nirS、nirK和硝酸還原酶編碼基因narG的豐度受植物物種多樣性的正向影響，而氨單加氧酶編碼基因amoA和一氧化二氮還原酶編碼基因nosZ的響應(yīng)不顯著。多樣性持續(xù)時(shí)間和生態(tài)系統(tǒng)類型是調(diào)控土壤固氮和硝化基因豐度的重要因素。反硝化基因主要受種植方式、土層、施氮種類、施氮年限和土壤質(zhì)地等分類變量的影響。其中，長(zhǎng)期持續(xù)的多樣化主要表現(xiàn)為土壤nifH的減少和nirK豐度的增加。土壤有機(jī)碳和氮線性影響nifH、amoA、nirS和nirK的響應(yīng)。因此，為了保持土壤生態(tài)功能，需要通過(guò)調(diào)控氮循環(huán)基因的豐度來(lái)靈活應(yīng)用種植模式的多樣性。本研究結(jié)果可為陸地受控生態(tài)系統(tǒng)多樣化過(guò)程中氮的可持續(xù)性和管理措施的改進(jìn)提供理論參考。

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.)

本研究從功能基因豐度的角度揭示了作物多樣化對(duì)陸地管理生態(tài)系統(tǒng)土壤氮循環(huán)及其調(diào)控過(guò)程的影響。結(jié)果表明，植物種類的添加增加了土壤固氮和反硝化基因的表達(dá)。多樣性持續(xù)時(shí)間、生態(tài)系統(tǒng)類型、種植模式、施氮種類、土層和土壤質(zhì)地是調(diào)控氮循環(huán)基因豐度響應(yīng)的重要因子。同時(shí)，土壤有機(jī)碳和氮濃度與nifH、AOA、nirS和nirK拷貝數(shù)呈顯著線性相關(guān)。在長(zhǎng)期可持續(xù)多樣化下，nifH豐度的降低和nirK的增加使土壤氮轉(zhuǎn)化為損失。我們只分析了控制氮循環(huán)主要轉(zhuǎn)化過(guò)程的基因。它們對(duì)轉(zhuǎn)化強(qiáng)度和N2O排放的貢獻(xiàn)有待進(jìn)一步研究。綜合定量分析不同環(huán)境背景下管理生態(tài)系統(tǒng)土壤氮循環(huán)基因豐度，有利于改善物種多樣性，從而促進(jìn)氮的可持續(xù)利用。