The Effect Of Different Plucking Standards And Nitrogen Application Levels On The Shoot Yield, Quality-related Chemical Compounds And N Utilization Efficiency Of Tea Plants

The experiment was carried out in the tea garden that planting varieties is Cuifeng. To explore theshoots production, quality and nitrogen absorption and utilization by tea plants under different modes ofproduction in the field, micro-plot15N labeling was carried out during2012-2013on a field experimentestablished in2008investigating interaction of plucking standards and N fertilization. Yield and qualityrelated chemical compounds of tea shoots and15N parameters (N uptake and N derived from fertilizer)in different seasons were measured under three plucking standards (A:one bud with one expandingleaf;B:one bud with three expanding leaves and C mixed plucking standard: spring shoot plucked A,and summer and fall shoots plucked B) and two N fertilization levels (200and450kg/ha). The purposeof study is to provide theoretical basis how to apply nitrogen in the reasonable way and achieve finequality and high yield of tea production This mainly results of the study were as follows:1The effect of different plucking standards and nitrogen application levels on the young shoot yieldThe results showed that nitrogen fertilization levels had no significant effects on tea yields andyoung shoots yields were mainly affected by plucking standards. The production of spring famous teaand common quality tea in summer and autumn were larger under mixed plucking standard. The totalyields were not significantly different between standard of a bud and three leaves and mixed pluckingstandard, being about3times larger than for that of a bud and one leaf.2The effect of different plucking standards and nitrogen application levels on the young shootquality-related chemical compoundsThe effects of plucking standards on the concentrations of quality related compounds were greaterthan those of N levels. High nitrogen level was able to improve tea quality that free amino acid and thetheanine content increased under those of N levels. The quality of spring tea was best in the threetea seasons, and it was greater for standard of a bud and one leaf than for that of a bud and threeleaves; The quality of autumn tea was middle and summer tea was worst, which were better forstandard of a bud and three leaves than for that of a bud and one leaf.The contents of theanine and total free amino acid in spring tea of one bud and one leaf wassignificantly higher than those of one bud and three leaves, and mixed plucking was between themiddle of them; The contents of caffeine and amino acid components in young shoots decreasedwith the increasing of nitrogen amount; Plucking standards and nitrogen levels had no significantimpact on the content of soluble sugar and catechins in young shoots; The contents of free aminoacids, theanine, glutamic acid, and soluble sugar in one bud and one leaf of plants supplied withN at450kg/ha were the highest among the six treatments, so tea quality was the greatest.For summer tea, the contents of free amino acid, theanine, caffeine, soluble sugar in one bud andleaf was higher than those in one bud and three leaves, but content of catechins was quite the contrary.The amino acids and caffeine content slightly increased with improving N application of young shoots;The total free amino acid and theanine content in summer shoots were about60%of spring tea.The effect of different plucking standards and nitrogen application levels on quality-related chemical compounds of autumn tea was similar to summer tea, but total free amino acid and theaninecontents of autumn tea was higher. The content of free amino acids in one bud and three leaves(including mixed plucking) of plants supplied with N at450kg/ha was the highest among the sixtreatments.3The effect of different plucking standards and nitrogen application levels on growth and N utilizationefficiency of tea plantsThe growth of tea plant under mixed plucking standard was higher with two nitrogen levels in theexperiment. But dry matter production of both aboveground and root portion with N at200kg/ha werehigher than N at450kg/ha, it might be450kg/ha N application levels was too much for test plant.Nitrogen concentrations in mature leaves decreased while Ndff increased through the period fromwinter dormancy (sampled on17December) to the end of spring tea season (on24April), Ndff in theyoung shoots was affected by N levels much greater than by plucking standards through the three teaseason. The recovery rates of15N in young shoots were below5.5%under six treatments in threeseasons. And throughout the year, nitrogen use efficiency for young shoots with mixed pluckingstandard was the highest. The nitrogen derived from fertilizer of young shoots was about7%~24%,most of the nitrogen came from soil and tea storage nitrogen recycling in the body.N utilization efficiency of tea plants was between16%~37%, the results showed that nitrogen useefficiency increased with reduction in N fertilizer and the increase of plucking standard. And the teaplants N utilization efficiency was highest in plants of one bud and one leaf supplied with N at200kg/ha. The recovery rate of N fertilizer in the soil and tea plant was between49%~87%. After the harvest,nitrogen residue was between13%~50%in tea garden, increased with the increase of N applicationrate.4The effect of different plucking standards and nitrogen application levels on N distribution ratio oftea plantsThe N distribution rate of plucking part was13%~13%.The distribution rate of the nitrogenfertilizer rate was above80%in the aboveground portion, which was much higher than root portion.And different plucking standards and nitrogen application levels had no significant effects on these.