适宜氮肥施用量显著提升夏季绿茶品质  

Suitable nitrogen fertilization rate effectively improve the quality of summer green tea

作　　者：刘美雅 汤丹丹 矫子昕 石元值[1] 马立锋[1] 张群峰[1] 阮建云[1] LIU Mei-ya;TANG Dan-dan;Jiao Zi-xin;SHI Yuan-zhi;MA Li-feng;ZHANG Qun-feng;RUAN Jian-yun(Tea Research Institute,Chinese Academy of Agricultural Sciences/Key Laboratory of Tea Plant Biology and Resources Utilization,Ministry of Agriculture and Rural Affairs,Hangzhou,Zhejiang 310008,China;Graduate School,Chinese Academy of Agricultural Sciences,Beijing 100081,China)

机构地区：[1]中国农业科学院茶叶研究所/农业农村部茶树生物学与资源利用重点实验室,浙江杭州310008 [2]中国农业科学院研究生院,北京100081

出　　处：《植物营养与肥料学报》2021年第8期1407-1419,共13页Journal of Plant Nutrition and Fertilizers

基　　金：国家重点研发计划项目(2016YFD0200901);国家自然科学基金(32072627,31700614);中国农业科学院科技创新工程(CAAS-ASTIP-2020-TRICAAS);国家茶叶现代产业技术体系建设资金(CARS 19);中国农业科学院茶叶研究所基本科研业务费专项(1610212019003)。

摘　　要：【目的】我国30%的茶园氮肥施用过量。氮肥过量施用不仅造成能源浪费和茶园土壤质量恶化(如酸化、板结等),还使茶叶特别是绿茶增产提质边际效应逐渐下降。夏季绿茶品质(尤其是香气)往往低于春茶,但其产量却远大于春茶,因此,研究施氮对夏季绿茶的品质影响,为夏季绿茶提质增效提供理论依据。【方法】茶园氮肥长期定位试验位于浙江杭州,始于2005年。氮肥施用水平分别为0、119、285、474、569和712 kg/hm^(2)。采集连续施用12年氮肥的茶树夏季新梢一芽二叶制成绿茶样。采用GB/T 23776—2018茶叶感官审评方法、茚三酮/福林酚-比色法、CN分析仪、氨基酸自动分析仪、顶空固相微萃取法结合气相色谱–质谱联用技术,分别对绿茶感官品质、氨基酸和茶多酚总量、氮含量、氨基酸组分以及香气组分进行检测分析。【结果】不同氮肥施用水平对绿茶香气影响较大。在施N 0~474 kg/hm^(2)范围内,绿茶氨基酸总量随着施氮量增加而升高,在施N 474 kg/hm^(2)时达到最高。施氮量提高到569和712 kg/hm^(2)后,绿茶氨基酸总量降低,茶多酚总量升高,对应的酚氨比升高,而绿茶样品氮含量反而低于N 474 kg/hm^(2)处理。在鉴定到的16种氨基酸组分中,大部分氨基酸含量在施氮量285和474 kg/hm^(2)时达到最高,包括决定成品茶鲜爽味的茶氨酸、谷氨酸和天冬氨酸含量,而当施氮量超过474 kg/hm^(2)时,这些氨基酸的含量开始下降。醇类、酮类、烯类、醛类、酯类以及其他香气化合物受氮素供应水平影响存在差异,主导绿茶呈香的醇类物质相对含量在施N 0~285 kg/hm^(2)范围内,随着施氮量的升高而增加,其中以占醇类物质总量比重最高的β-芳樟醇和橙花叔醇变化最为明显。酮类香气化合物在不同氮素供应水平下变化趋势与醇类一致,但受氮素供应水平影响小于醇类。烯类香气物质对氮素供应水平的响�【Objectives】Excessive application of N fertilizer occurs in 30%of the tea plantation area in China,decreasing tea production efficiency and quality.Therefore,we studied the effect of different N application rates on the sensory quality of green tea.【Methods】The long-term N fertilization experiment of green tea in Hangzhou,Zhejiang Province,started in 2005.The N application treatments included 0,119,285,474,569,and 712 kg/hm^(2).Samples of young tea shoots were collected in summer for sensory quality assessment according to the standardized procedure GB/T 23776-2018.Also,the total contents of amino acids,polyphenols,N,and aroma compounds were measured.【Results】N application rate affected aroma but not the appearance,taste,colour,and infusion of leaves(P<0.05).The total amino acids increased with the increase in N application rate,reaching the peak at N 474 kg/hm^(2) and decreased at N 569 kg/hm^(2) and N 712 kg/hm^(2).The total polyphenol content increased with the increasing of N application rate and reached the highest polyphenols vs.amino acids ratio at N 712 kg/hm^(2).However,the total N content in the green tea at N 569 kg/hm^(2) and N 712 kg/hm^(2) was lower than that at N 474 kg/hm^(2).Amino acids content was the highest at N 285 kg/hm^(2) and N 474 kg/hm^(2),including theanine,glutamine,and aspartic acid,which were all closely related to the umami taste.From N 0-285 kg/hm^(2),the R-OH compounds such asβ-linalool,nerolidol,and ketones increased while alkene contents decreased.There were no obvious regular changes in the aroma related aldehydes,ester compounds,and other compounds.【Conclusions】Nitrogen fertilization at 285-474 kg/hm^(2) is beneficial for forming good tea quality due to the high contents of umami related amino acids and dominant aroma compounds.

关 键 词：绿茶 长期氮肥定位施肥 氮肥施用水平 氨基酸组分 香气化合物 

分 类 号：S571.1[农业科学—茶叶生产加工]