Mechanism And Effect Of The Tea Yield And Quality Affected By The Inter-cropping Trees

Tea plant(Camellia sinensis)favour the special ecological habit of shade-liking,humidity and thermophilic.Few reports discovered the ecological and physiological mechanism of improving the tea yield and quality by intercropping aromatic trees.In order to select the ideal tea-trees intercropping pattern to produce high quality and yield teas and discover the ecological and physiological mechanism of improving the tea yield and quality by intercropping aromatic trees,three inter-cropping patterns(Osmanthus-Tea(OT),Michelia-Tea(MT),Osmanthus-Michelia-Tea(OMT))and a control(CK)was selected and designed at Chinese Academy of Science,comparisons of the ecological habits and their photosynthetic ecological functions,soil microbial bacteria community diversity,soil enzyme activity and soil nutrition,tea yield and quality of spring tea,summer tea and autumn tea has been conducted.1)During the spring tea,summer tea and autumn tea production seasons,the leaf temperature,the leaf relative humidity,photosynthesis active radiation flux varied with the turn of summer tea > autumn tea > spring tea significantly.Average of photosynthesis active radiation flux and leaf temperature of the tea varied by the turn of CK>MT>OT>OMT while the humidity varied with the turn of CK<MT<MT< OMT significantly.The daily variation of net photosynthetic rate and transpiration rate of spring tea leaves and autumn tea leaves in four modes were single-peak shape curve,but the daily variation of net photosynthetic rate and transpiration rate of summer tea leaves is asymmetrical bimodal curve;the curve of the stoma conductance daily variation of summer tea leaves was "M" shape for CK and MT patterns,while for the OT and OMT patterns was "inverted V" shape.The daily variation of carbon dioxide concentration between tea leaf cells of all the three seasons tea were "U" shape for OT and OMT patterns,while the CK and MT patterns in summer tea were "W" shape.The net photosynthetic rate,transpiration rate and stoma conductivity of tea leaves varied with the turn of summer tea >autumn tea> spring tea significantly(P<0.05).The daily mean values of carbon dioxide concentration in the tea leaf cells varied with the turn of autumn tea > spring tea>summer tea significantly,and the treatments varied with the turn of OMT>OT>MT>CK significantly(P<0.05)?2)OMT pattern improved the rhizosphere bacteria OTUs,Chao1,Ace and Shannon diversity index in the summer tea period significantly,Proteobacteria,Acidobacteria,Chloroflexi,Actinobacteria,Firmicutes were the dominant groups that can use plant root secretion better.OMT pattern improved the richness of the Rhizobiales and Rhodospirillales significantly,and they can fix the nitrogen and increase the soil nitrogen content.What's more,the richness of the beneficial bacteria such as Lactobacillus,Acinetobacter,Granulicella were improved significantly by the OMT pattern.While OMT pattern can reduce the richness of Xanthomonadales significantly,and the crop disease pathogens often caused by Xanthomonadales.So OMT pattern can reduce the harmful richness of soil bacterial community and improve the richness of the beneficial bacterial significantly.3)Different inter-cropping tree patterns improved the soil urease,invertase and acid phosphatase,dehydrogenase,polyphenol oxidase,cellulase activity with the turn of OMT > OT > MT > CK significantly.While the soil urease,invertase and acid phosphatase,dehydrogenase,polyphenol oxidase,cellulase activity decreased with the depth of soil layer.Soil enzyme activities also has seasonal variation,the activities of soil urease,invertase and acid phosphatase,polyphenol oxidase in spring tea production period were lower while the highest in summer.The activity of polyphenol oxidase reached the highest in spring tea production period,and the activity of cellulase reached the highest in autumn tea growing period.4)The organic matter content,total nitrogen,total phosphorus,total potassium,alkali solution nitrogen,phosphorus and available potassium content in soil can be increased by the three inter-cropping patterns with the turn of OMT>OT>MT>CK significantly while be decreased significantly with the depth of the soil.Soil nutrients also has the seasonal variation,total nitrogen,available phosphorus,available potassium content reached the highest in summer tea growing period while all the soil nutrients content of spring tea are annual minimum.Organic matter,alkali-hydro nitrogen,total phosphorus,total potassium content reached the highest in autumn tea growing period.Soil enzyme correlated positively with soil nutrients significantly.5)All the intercropping patterns can improve the yield and quality of tea leaves significantly,and the tea yield of OMT mode is significantly higher than that of CK control mode.The yield of the tea varied with the seasons by the turn of spring tea > summer tea >autumn tea.The leaf number,water content of new shoot varied with the seasons by the turn of spring tea > autumn tea > summer tea most significantly(P<0.01).The water content of new shoot of OMT pattern was higher than the others most significantly(P<0.01).Three kinds of intercropping tree patterns improved the amino acid content,caffeine,water extracted in spring tea and the amino acid content in summer tea and autumn tea significantly,while reduced the tea polyphenol content and the ratio of tea polyphenols/amino acid significantly.The ratio of polyphenols/amino acids in spring tea is 6%-8%,which is suitable for processing a good quality green tea.In tree intercropping treatment,the ratio of polyphenols/amino acids of the OT and OMT pattern in summer tea and autumn tea is 7.03%-10.88%,both of them can be made into high-grade green tea and good quality green tea.But the ratio of polyphenols/amino acids in CK is 15.4%,which can only be made into general green tea.So tea intercropping can obviously improve the tea quality.The net photosynthetic rate has the most influence on the tea quality and yield,followed by the inter-cellular carbon dioxide concentration and transpiration rate.The content of total phosphorus and available phosphorus correlated with chlorophyll and caffeine contents positively,while correlated with the content of tea polyphenols negatively.The content of total potassium,instant potassium correlated with caffeine,amino acid,water content of new shoot and tea polyphenols significantly.In a conclusion,inter-cropping especially OMT pattern can change the living conditions of the tea tree to improve the yield and quality of the tea by two ways.The first way is to change the direct light to scattered light to increase the time of photosynthesis,and long-time weak adaptation made the tea tree strengthen the ability to use the weak light,so the total ability of photosynthesis was improved and the yield was increased,and to decrease the direct light dense and the leaf temperature while increase the humility of the condition so as to avoid the “middy depression” to improve the yield and the quality of the tea tree.The second way is to increase the abundance and richness of the beneficial bacteria and to decrease the abundance and richness of the hazard bacteria so as to strengthen the ability of using the root exudates secretion components and increase the soil enzyme activity,as to increase the soil nutrition and improve the quality of the tea.