长期保护性耕作下土壤团聚体全氮与氮功能微生物关系研究  

Study on the Relationship Between Total Nitrogen and Nitrogen Functional Microorganisms in Soil Aggregates under Long-term Conservation Tillage

作　　者：王威雁 沈鹏飞 张侯平 莫非 温晓霞[1] 廖允成[1,2] WANG Weiyan;SHEN Pengfei;ZHANG Houping;Mo Fei;WEN Xiaoxia;LIAO Yuncheng(College of Agronomy,Northwest Agriculture and Forestry University,Yangling,Shaanxi 712100,China;Ministerial and Provincial Co-Innovation Centre for Endemic Crops Production with High-quality and Efficiency in Loess Plateau of Shanxi Agriculture University,Taigu,Shanxi 030801,China)

机构地区：[1]西北农林科技大学农学院,陕西杨凌712100 [2]山西农业大学黄土高原特色作物优质高效生产省部共建协同创新中心,山西太谷030801

出　　处：《土壤学报》2024年第6期1653-1667,共15页Acta Pedologica Sinica

基　　金：黄土高原特色作物优质高效生产省部共建协同创新中心基金项目(SBGJXTZXKF-08);陕西省重点研发计划-重点产业创新链(群)项目(2023-ZDLNY-03);中央高校基本科研业务费项目(2452021112)共同资助。

摘　　要：长期不同的耕作措施能够显著改变农田土壤团聚体分布、微生物丰度以及全氮储量,但其之间是否存在相关性尚不清楚。依托连续10年(2009—2020)旱作长期耕作试验平台,比较传统耕作(翻耕+秸秆还田,PT)和保护性耕作(深松耕+秸秆还田,CPT;免耕+秸秆还田,ZT)下土壤团聚体氮含量的变化及其与氮功能基因(amoA-AOA、amoA-AOB、nirS、nirK、nosZⅠ和nosZⅡ)丰度之间的关系。结果表明,长期保护性耕作(CPT和ZT)处理显著增加了机械稳定性和水稳定性宏团聚体(>2mm)和大团聚体(0.25~2mm)的质量百分比,降低了微团聚体(<0.25mm)质量百分比。与传统耕作相比,长期CPT和ZT处理0~20cm土层的全氮含量分别提高了53.4%和49.9%,宏团聚体全氮贡献率分别提高了16.2%和21.8%,但土壤氮矿化速率、硝化潜势和反硝化潜势显著降低。通过qPCR定量发现CPT和ZT显著提高了细菌、真菌以及氮功能基因(除氨氧化细菌(amoA-AOB外))丰度;在各粒级团聚体内部,大团聚体内部真菌、nirS、nosZⅠ的丰度显著高于微团聚体和宏团聚体,而nosZⅡ基因丰度则表现出相反趋势。Mantel分析结果表明,团聚体尺寸、土壤质地、矿质氮素含量、蔗糖酶活性、脲酶活性等因素是调控团聚体内部氮功能微生物丰度的关键因子。相关性分析表明,团聚体土壤全氮含量与微生物生物量氮、可溶性有机氮、细菌、真菌、amoA-AOB和nosZⅡ基因丰度呈现显著正相关关系,而与nirS和nirK型反硝化基因丰度呈现显著负相关关系。综上,长期保护性耕作不仅有利于改善旱作农田土壤团聚体组分,增加全氮在团聚体土壤中的储存,还调控了细菌、真菌和氮功能微生物在团聚体内部的丰度,从而改善了旱作农田土壤氮循环的趋势,有助于提升旱作农田土壤肥力。【Objective】Long-term tillage practices can significantly change the distribution of soil aggregates,microbial abundance and total nitrogen storage in farmland.However,whether there is a correlation between these properties remains unclear.This study aimed to reveal the relationship between total nitrogen content and nitrogen functional microorganisms within different particle sizes aggregates under long-term conservation tillage in dry farming areas of the Loess Plateau.【Method】Based on the 10-year(2009-2020)long-term tillage experiment(conventional tillage:plow tillage,PT;conservation tillage:chisel plow tillage,CPT and zero tillage,ZT),the effects of long-term conservation tillage on the distribution of total nitrogen and its relationship with the abundance of functional genes(amoA-AOA,amoA-AOB,nirS,nirK,nosZI and nosZII)within aggregates in dry farmland were studied.【Result】Long-term conservation tillage(CPT and ZT)significantly increased the mass percentage of mega-aggregates(>2 mm)and macro-aggregates(0.25-2 mm),while it decreased the mass percentage of micro-aggregates(<0.25 mm).Compared with PT,long-term CPT and ZT treatments significantly decreased the soil nitrogen mineralization rate,nitrification potential,and denitrification potential but increased the total nitrogen content in the 0-20 cm soil layer by 53.4%and 49.9%,respectively.The total nitrogen contribution rate of macro-aggregates of CPT and ZT treatments increased by 16.2% and 21.8%,respectively.Using qPCR technology,it was found that CPT and ZT significantly increased the abundance of bacteria,fungi and nitrogen functional genes(except amoA-AOB);and the abundance of fungi,nirS,and nosZI in macroaggregates was significantly higher than that in microaggregates and macroaggregates,while the abundance of nosZII gene showed the opposite trend.Mantel analysis showed that aggregate size,soil texture,mineral nitrogen content,sucrase activity,and urease activity were the key factors regulating the abundance of nitrogen-functional microorgan

关 键 词：保护性耕作 团聚体全氮 氮功能微生物 旱作农田 

分 类 号：S343.1[农业科学—作物栽培与耕作技术]