| In this paper,the shade cultivation and machine-plucking on tea trees were performed,and the fertility physiological characteristics of fresh tea shoots after shading were observed,in order to compare the yield and economic benefits in machine-plucking experimental garden and discuss the quality of tea made by fresh leaves after machineplucking.The experiment was conducted in adult tea garden,where the variety "Sanhua-1951" and Fuding Dabaicha were compared and analyzed,whose shade cultivation was made in late spring and early summer respectively.The writer picked fresh leaves timely,conducted tea-made test,and made sensory evaluation and quality determination on tea samples.This experiment was designed to study the efficient production mode of "saving energy and saving labor" for the shade cultivation and machine-plucking.And the experiment explored the problems of the low rate of fresh leaves during the late spring and summer period,caused by labor shortage and low harvesting efficiency in current tea production practice.The key technical bottleneck problems were ubiquitous in the current tea production practice,such as the low quality and value of bulk tea leaves,the waste of raw tea materials in summer and autumn,and the adaptability of machine-plucking fresh leaves.Supported by effectively experimental data,this paper provided feasible technical methods and solutions,which had significant reference value for solving the problems of tea production practice.The main research results were as follows:(1)The research demonstrated that the germination period of Sanhua 1951 was 3days earlier than that of the Fuding Dabaicha,and the bud-stopping period was 4 days earlier.The fresh tea shoot of Sanhua1951 was much more 6.9cm than that of Fuding Dabaicha,and the Chlorophyll was much more 1.98mg/g.The leaves were dark green,whose inclusions varied significantly at a bud with two leaves stage in spring.The water extracts,catechin,caffeine and amino acid were much more 1.30%,2.01%,0.82% and0.20% than Fuding Dabaicha respectively.The yield of early spring tea-bud was1.57kg/mu than Fuding Dabaicha and showed its salient superiority.(2)Spring shading prompted the telogen of the first round of fresh tea shoots to advance 3 to 7 days and the growth decreased by 5.08 to 9.91 cm,which contributed to making the second round of early germination,and increasing the picking rounds.This result indicated that the shading effect on the morphological traits of the new leaves at one bud with three leaves stage was more obvious than that at one bud with two leaves stage.(3)Studies on anatomical structure and photosynthesis parameters of the fresh tea shoots after shading indicated that shading helped become dark greener in leaves,increase chlorophyll,decrease chlorophyll a/b value and chloroplast number but increase its volume;after shading,the posterior leaves became thinner,the proportion of palisade tissue increased,and the tenderness keeping ability strengthened;the shortwave radiation absorbed by the blade increased,the temperature of the canopy layer decreased but the humidity rose.The instantaneous water use efficiency soared,which was beneficial to accumulate more organic Carbon by photosynthesis parameters.(4)The biochemical component of fresh leaves at one bud with two leaves stage after shading was measured.After shading,the water extracts and amino acids of Fuding Dabaicha increased by 1.64% and 1.25% respectively,while those of Sanhua 1951 rose by 1.57%、1.07%;after shading,the total tea polyphenols in Fuding Dabaicha and Sanhua 1951 samples decreased by 1.44% and 1.55% respectively,and the catechin in these two samples decreased by 0.47% and 0.62%,which was mainly represented in the fall of ester catechin.After shading,the Catechin astringent index decreased by 3.90 and 1.64 respectively.The increase of free amino acid was mainly caused by the increase of heanine.After shading,the theanine of Fuding Dabaicha and Sanhua 1951 samples increased 8.152mg/g,10.510mg/g,which indicated that the shading treatment can affect the content and proportion of the flavor component to enhance the flavor quality.(5)The single tea-picking machine was adopted to pick fresh leaves at one bud with five leaves stage.The total number of the complete fresh tea shoots accounted for 46.39%to 77.58%,and the mass ratio was 74.84% to 89.71%.The fresh leaves were mainly composed of one bud with three or four leaves,which accounted for 29.20% to 42.53%in quantity and 31.22% to 58.16% in quality.The economic benefits of tea gardens in different production modes were significantly different.Adopting the mode of “handpicking + machine-picking + shading + raising trees in summer and autumn or only in autumn”,per mu net income increased by 50% to 60%,and saved over 30% in the cost of tea pickers,which revealed that the machine-picking method can reduce labor input and significantly increase the income of tea farmers.(6)Raw materials after shading and machine-plucking were used for making tea,and the quality of the tea was analyzed and evaluated.The results showed that the spring one bud with two leaves were processed with roasted green tea,with tight leaves,deep green bloom and mellow and brisk flavor,which ranged from 94.0 to 95.8 scores;in the end of the spring,the scented green tea by machine-plucking was at one bud with five leaves stage,with fresh and mellow chestnut flavour of samples,which got over89 scores.In summer,the Tibetan tea by machine-plucking was also at one bud with four or five leaves stage,and the score is between 84.60 and 87.15 scores.In autumn,the black tea by top-plucking was at one bud with two leaves period,with red and brilliant liquor color,long-lasting heavy and mellow sweet aroma,and scored above 93 points.Top plucking white tea at one bud with one or two leaves stage,and it can be represented with more tippy leaves and floral and fresh flavor,getting a score between91.5 to 94,Among them,the quality of Tibetan tea in summer was excellent,and the shading weakened the degree of bitterness,coarseness and oldness.During the process of pile-up,the higher maturity of the fresh leaves by machine-plucking is changed from the disadvantage to the advantage.After 52 days of long-term pile-up,the Tibetan tea soup was orange-red,pure and normal,with mellow astringency.The machine-plucking fresh leaves after shading in summer boasted better tea suitability.(7)Studies on the main flavor components in the process of collecting tea from fresh leaves by machine-plucking in summer showed that shading increased the inclusive components of fresh leaves,which fluctuated with the processing procedure.However,when were processed to finished tea,the differences between treatments were reduced.Among them,the total amount of catechins decreased between 10.15 to 14.08%.The most significant decrease of each component from fresh leaves to dry stage was GC,followed by EGCG,EGC,ECG,EC,C,CG,and the least was GCG;The processing stages with the largest decrease in each component are different,in which ECG and EGCG are 10 days of pile-Fermentation;EC,EGC,CG are stir fixation and 30 days of pile-fermentation;GCG is after fixation;GC and C is a stack of 30 days.The Catechin quality index increased first and then decreased,and the catechin bitterness and astringency index demonstrated a downward trend.The decrease was the largest when the stir fixation was 10 days,which made the reduction of astringency contribute to the formation of Tibetan tea quality.The total amount of free amino acids decreased between 3.27 to 5.59%,and the largest degree of decline was the stir fixation to the pile-fermentation for 10 days.Each amino acid composition showed a downward trend with the processing procedure.From the fresh leaves to the dry stage,except for Cys,Gln and His decreased most dramatically,followed by The,and the smallest decrease was Met.The largest disparity was Asp,which made the reduction of Fuding Dabai Tea and Sanhua 1951 increase.The fall of the total amount of amino acids in the processing procedure was mainly represented in the decline of fresh and brisk amino acids,followed by the increase in the proportion of amino acids in the total amount of free amino acids,which were sweet and bitter.The bitter amino acids increased in the proportion of total free amino acids,which was the material basis on the flavor of Tibetan tea. |
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