有机肥减量配施外源碳基肥对设施菜地氨挥发及黄瓜产量的影响

Reducing organic fertilizer with exogenous carbon-based fertilizers on impacts on ammonia volatilization and cucumber yield in greenhouse cropping

针对我国农业源氨排放过高的问题,本研究通过探究有机肥减量配施外源碳基肥(生物炭及腐植酸)对设施菜地土壤氨挥发及黄瓜产量的影响,并结合高通量qPCR基因芯片技术,研究影响氨挥发的微生物学机制,明晰设施菜地有效的氨减排措施。以天津市武清区设施菜地为研究对象,本研究共设置5个处理:不施氮CK、推荐施肥量N1(37500 kg·hm^(-2)有机肥)、推荐施肥量配施腐植酸N1F(37500kg·hm^(-2)有机肥+2250kg·hm^(-2)腐植酸)、推荐施肥量配施生物炭N1B(37500kg·hm^(-2)有机肥+40t·hm^(-2)生物炭)、农民常规用量N_(2)(60000 kg·hm^(-2)有机肥)。结果表明:不同处理氨挥发动态基本一致,N_(2)处理氨挥发速率处于较高水平。随着施肥量的增加,土壤氨挥发累积量逐渐增加,氨挥发累积量从高到低依次为N_(2)、N1、N1B、N1F、CK,N1F处理和N1B处理较N_(2)处理显著降低了24.5%和21.0%的氨挥发累积量(P<0.05)。N_(2)处理土壤在末果期铵态氮含量显著高于其他处理;N1、N1F、N1B处理在盛果期和末果期土壤硝态氮含量显著高于N_(2)处理。施肥以及配施生物炭和腐植酸均能显著增加AOA-amoA基因丰度,与CK相比,N1、N_(2)的AOA-amoA基因丰度显著提高(P<0.05);与N_(2)、N1相比,N1F和N1B处理AOA-amoA基因丰度显著提高(P<0.05)。推荐施肥量增加了土壤AOB-amoA的基因丰度,配施腐植酸和生物炭无显著影响。Mantel test+结果表明,NH4-N含量、AOA-amoA、AOB-amoA能够显著影响设施菜地土壤氨挥发。减量施肥配施生物炭和腐植酸能够在一定程度上降低设施菜地土壤的氨挥发量,且腐植酸配施效果更好,并能够有效固持土壤的无机氮。N1、N1F、N1B各处理保证了作物产量并较N_(2)处理显著提高了氮素利用率。综合考虑农学和环境效益,有机肥减量配施腐植酸N1F为适宜的施肥方式。

To address excessive ammonia emissions from agricultural sources in China,this study investigated the impact of reducing organic fertilizer application combined with exogenous carbon-based fertilizers(biochar and humic acid)on soil ammonia volatilization and cucumber yield in a greenhouse vegetable cropping system.High-throughout qPCR geochip technology was utilized to explore the microbial mechanisms influencing ammonia volatilization,aiming to identify effective measures for reducing ammonia emissions in greenhouse vegetable cropping systems.The experiment was conducted in a greenhouse vegetable cropping system in Wuqing District of Tianjin City.There were five experimental treatments:no N application(CK),recommended fertilizer application(N1,37500 kg·hm^(-2) organic fertilizer),recommended fertilizer application with humic acid(N1F,37500 kg·hm^(-2) organic fertilizer+2250 kg·hm^(-2) humic acid),recommended fertilizer application with biochar(N1B,37500 kg·hm^(-2) organic fertilizer+40 t·hm^(-2) biochar),and conventional fertilizer application(N_(2),60000 kg·hm^(-2) organic fertilizer).The results revealed consistent ammonia volatilization dynamics across various fertilizer treatments,with the N_(2) treatment exhibiting notably higher ammonia volatilization rates.As fertilizer application intensity increased,there was a gradual increase in cumulative soil NH_(3) volatilization,with the order being:N_(2)>N1>N1B>N1F>CK.By the final fruit stage,soil ammonium nitrogen content in the N_(2) treatment significantly surpassed that of the other treatments.Additionally,during the fruiting and late fruiting stages,soil nitrate nitrogen content in the N1,N1F,and N1B treatments was significantly higher than in the N_(2) treatment.Fertilizer application,particularly treatments with either biochar or humic acid,significantly increased the abundance of AOA-amoA genes.Compared to the CK treatment,both N1 and N_(2) exhibited a significant increase in AOA-amoA gene abundance(P<0.05),while compared to N_(2) and N1,the N1F and N1B treatments demonstrated a significant elevation in AOA-amoA gene abundance(P<0.05).Recommended fertilizer application led to an increase in the gene abundance of soil AOB-amoA,while the inclusion of humic acid or biochar had no significant effect.Mantel test results indicated that NH+4-N content,AOA-amoA,and AOB-amoA significantly affected soil ammonia volatilization in greenhouse vegetable cropping systems.Reduced fertilizer application with either biochar or humic acid could moderately reduce ammonia volatilization in greenhouse vegetable cropping systems,with humic acid demonstrating a more effective impact and effectively retaining soil mineral nitrogen.Reduced fertilizer application ensures crop yield and significantly improves nitrogen use efficiency.Considering both agronomic and environmental benefits,the recommended fertilizer application combined with humic acid(N1F)emerges as a suitable fertilization method.This study provides technical support for controlling nitrogen surface source pollution and achieving efficient nitrogen utilization in greenhouse vegetable cropping systems.